8.4 Various Sciences

Astronomy: The study of planets and other objects in the sky.

Astrogeology: The study of rocks and minerals on other planets.

Bacteriology: The study of bacteria.

Biology: The study of living things, including plants and animals.

Biophysics: The study of how physics relates to living things.

Botany: The study of plants.

Bryology: The study of mosses.

Cardiology: The study of the heart.

Carpology: The study of fruits and seeds.

Ceramics: The art of making objects from clay.

Cetology: The study of aquatic mammals, especially whales.

Biology: The study of elements and how they combine.

Chorology: The study of geographical areas and how plants and animals are distributed.

Cosmetology: The study of cosmetics and how to use them.

Cosmology: The study of the universe and how it came to be.

Here is the content rewritten in simpler language:

Cosmology: The study of the universe, including its origin, nature, structure, and evolution.

Craniology: The study of skulls. (Note: This is not the same as phrenology, which is not a science.)

Cryogenics: The study of extremely low temperatures and their applications.

Cytology: A branch of biology that focuses on the structure and function of cells.

Cytopathology: The study of diseased cells.

Dactylology: The study of fingerprints.

Dermatology: A branch of medicine that deals with the skin.

Dietetics: The science of diet and nutrition.

Ecology: The study of the relationships between organisms and their environment.

Entomology: The study of insects.

Endocrinology: The study of the body’s hormone-secreting glands (endocrine glands).

Etymology: The study of the origin and history of words.

Genetics: A branch of biology that focuses on heredity and the laws that govern it.

Geology: The study of the chemical composition of the Earth’s crust.

Gerontology: The study of aging and the elderly.

Here is the content rewritten in simpler language:

Branch of Medicine

• Gerontology: Studies the aging process, problems, and diseases.
• Gynecology: Deals with female diseases of the reproductive system.
• Hematology: Studies blood and its disorders.
• Hepatology: Deals with the liver.
• Histology: Studies tissues.

Other Fields

• Horticulture: Deals with flowers, fruits, vegetables, etc.

• Hydrology: Studies water in the hydrosphere and atmosphere.

• Hygiene: Deals with health and its preservation.

• Immunology: Deals with the body’s immune system.

• Lithology: Studies the characteristics of rocks.

• Morphology: Studies the external form and structure of living organisms.

• Mycology: Deals with fungi and fungal diseases.

• Nephrology: Deals with the kidneys.

• Nephrology: The study of kidneys and their diseases.

• Neuropathology: The study of changes in the nervous system caused by diseases.

• Obstetrics: The study of pregnancy, labor, and childbirth.

• Oncology: The study of tumors and cancer.

• Ophthalmology: The study of the eyes and related diseases.

• Orology: The study of mountains.

• Ornithology: The study of birds.

• Orthopedics: The study of the skeletal system and its diseases.

• Osteology: The study of bones.

• Pediatrics: The study of children’s diseases.

• Paleontology: The study of fossils and ancient life forms.

• Parasitology: The study of parasites, especially those that cause diseases.

• Pathology: The study of the causes, mechanisms, and manifestations of diseases.

• Pharmacology: The study of drugs, their chemical properties, and their effects on the body.

• Try: Make an effort to do something.

• Effects on the body: Changes that happen to the body as a result of something.

• Physiology: The study of how living things work.

• Psychiatry: The study and treatment of mental illness.

• Radiology: The use of X-rays to diagnose and treat medical conditions.

• Semiology: The study of signs and symbols.

• Seismology: The study of earthquakes.

• Theology: The study of religion.

• Toxicology: The study of poisons.

• Urology: The study of the urinary system.

• Virology: The study of viruses.

• Zoology: The study of animals.

• Zymology: The study of fermentation.

• Altimeter: A device that measures altitude.

• Ammeter: A device that measures electric current.

Measures strength of electric current

Inventor: Thomas Alva Edison

Country: United States

Year: 1878

Explanation: Thomas Alva Edison, an American inventor, created the telephone in the United States in 1878. This invention allowed people to talk to each other over long distances using electrical signals.

1898

• Rayon: Viscose Co., US

1910

• Razor (safety): K. C. Gillette, US

1931

• Razor (electric): Col. J. Schick, US

1851

• Refrigerator: J. Harrison and A. Catlin, Australia, US

1835

• Revolver: Samuel Colt, US

1839

• Rubber (vulcanized): Charles Goodyear, US

1823

• Rubber (waterproof): Charles Macintosh, Scotland

1816

• Safety Lamp: Sir Humphry Davy, England

1849

• Safety Pin: W. Hunt, US

1830

• Sewing Machine: B. Thimmonnier, France

1919

• Scooter: G. Bradshaw, England

1775

• Ship (steam): J. C. Perier, France

1894

• Ship (turbine): Sir Charles Parsons, England

1837

• Shorthand (modern): Sir Isaac Pitman, England

1769

• Spinning Frame: Sir Richard Arkwright, England

1705

• Steam Engine (piston): Thomas Newcomen, England

1782

• Steam Engine: James Watt, Scotland

1913

• Stainless Steel: Harry Brearley, England

1776

• Submarine: D. Bushnell, US

1916

• Tank: Sir Ernest Sw

Medical Discoveries

Lister

• In 1867, in Scotland, Lister made important discoveries in the field of medicine.

Aspirin

• In 1899, Dr. Felix Hoffmann, a German scientist, invented Aspirin.

Blood Circulation

• In 1628, William Harvey, a British scientist, made important discoveries about how blood circulates in the body.

Blood Group

• Between 1900 and 1902, K. Landsteiner, an Austrian scientist, discovered different blood groups.

Blood Transfusion

• In 1625, Jean-Baptiste Denys, a French scientist, performed the first blood transfusion.

Cholera and TB Germs

• In 1883, Robert Koch, a German scientist, discovered the germs that cause cholera and tuberculosis.

Diphtheria Germs

• Between 1883 and 1884, Klebs and Loffler, German scientists, discovered the germs that cause diphtheria.

Electro cardiogram (ECG)

• In 1903, William Einthoven, a Dutch scientist, invented the Electro cardiogram (ECG) machine.

Heart-Lung machine

• In 1953, John Heynsham Gibbon, an American scientist, invented the Heart-Lung machine.

Hypodermic Syringe

• In 1853, Alexander Wood, a British scientist, invented the Hypodermic Syringe.

Heart Transplant

• In 1967, Christian Barnard, a South African scientist, performed the first successful heart transplant.

Kidney Machine

• In 1944, W. J. Kolf, a Dutch scientist, invented the Kidney Machine.

Malaria Germs

• In 1880, A. Laveran, a French scientist, discovered the germs that cause malaria.

Organ Transplant

• In 1953, John P. Merril, an American scientist, performed the first successful organ transplant.

Scan (CAT)

• In 1973, Godfrey Hounsfield, an English scientist, invented the Scan (CAT) machine.

Sphygmomanometer

• In 1896, Scipione Riva-Rocci, an Italian scientist, invented the Sphygmomanometer.

Stethoscope

• In 1819, Rene Laennec, a French scientist, invented the Stethoscope.

Thermometer (Clinical)

• In 1867, Sir Thomas Allbutt, an English scientist, invented the Clinical Thermometer. Table 8.8: Important Vaccines

Various Sciences

The Cell

The cell is the smallest unit of life that can exist on its own.

Historical Background

1. In 1665, Robert Hook, a scientist from England, used his own microscope to see a tiny compartment in a piece of cork. He called this compartment a “cell.”
2. In 1824, R. J. H. Dutrochet figured out that both animals and plants are made up of cells.
3. In 1831, Robert Brown discovered the nucleus in plant cells.
4. In 1838, Matthias Schleiden and Theodor Schwann proposed the cell theory, which states that all living things are made up of cells and that the cell is the basic unit of life.
5. In 1855, Rudolf Virchow added to the cell theory by saying that all cells come from other cells.

Cell Structure

The cell is made up of different parts, each with its own function. The main parts of a cell are:

• Cell membrane: The cell membrane is a thin layer that surrounds the cell and protects it from its surroundings.
• Cytoplasm: The cytoplasm is the jelly-like substance that fills the cell. It contains all of the cell’s organelles.
• Nucleus: The nucleus is a round or oval structure that contains the cell’s DNA. DNA is the genetic material that controls the cell’s activities.
• Organelles: Organelles are small structures that perform specific functions within the cell. Some of the most important organelles are:
  • Mitochondria: Mitochondria are the powerhouses of the cell. They produce energy for the cell.
  • Chloroplasts: Chloroplasts are found in plant cells. They use sunlight to produce food for the plant.
  • Ribosomes: Ribosomes are responsible for making proteins.
  • Endoplasmic reticulum: The endoplasmic reticulum is a network of membranes that helps to transport materials around the cell.
  • Golgi apparatus: The Golgi apparatus is a complex of membranes that packages and distributes proteins.
  • Lysosomes: Lysosomes are small sacs that contain enzymes that break down waste products.

Cell Function

Cells perform a variety of functions, including:

• Metabolism: Metabolism is the process by which cells convert food into energy.
• Reproduction: Cells reproduce by dividing in two. This process is called cell division.
• Response to stimuli: Cells can respond to changes in their environment by changing their behavior. For example, a plant cell may open its stomata (pores) to let in carbon dioxide when the light intensity increases.
• Transport: Cells transport materials into and out of the cell. This process is called transport.

Cell Theory

The cell theory is one of the most important theories in biology. It states that:

• All living things are made up of cells.
• The cell is the basic unit of life.
• All cells come from other cells.

The cell theory has been supported by over 150 years of research. It is one of the foundations of modern biology.

The Cell

1. Cells are the basic building blocks of all living things.
2. In 1831, Robert Brown discovered the nucleus, which is the control center of the cell.
3. The fluid inside the cell is called protoplasm.

Cell Size

1. Most cells are very small, between 3 and 30 microns in size. (A micron is one thousandth of a millimeter.)
2. The smallest cells are bacteria, which are about 0.2 to 0.5 microns in size.
3. The largest cell is the ostrich egg, which is about 18 centimeters (7 inches) in diameter.

Cell Structure

1. Every cell is surrounded by a membrane, which is a thin layer that protects the cell and allows it to take in nutrients and get rid of waste.
2. Inside the membrane is the protoplasm, which is the living material of the cell.
3. The nucleus is the control center of the cell and directs all of the cell’s activities.
4. The cytoplasm is the rest of the cell, where most of the cell’s activities take place.

Cell Wall

1. Plant cells have a cell wall, which is a rigid structure that surrounds the cell membrane and helps to protect the cell. The cell membrane, also known as the plasmalemma, is the outer layer of the cytoplasm. It is found in both animal and plant cells and is made up of living substances like proteins.

The endoplasmic reticulum (ER) is a network of tubes or channels inside the cytoplasm. It helps in making proteins and transporting materials within the cell.

Ribosomes are small, dense, round bodies found in the cytoplasm. They are made up of RNA and proteins and help in making proteins from amino acids.

Golgi bodies are bag-like structures made of stacks of membranes. In plants, they are called dictysomes. They help in releasing different substances, such as the pectic material that makes up the cell wall in plants. They also help in forming the cell plate during cell division.

Vacuoles are fluid-filled sacs inside cells. In plant cells, they are very large and surrounded by a membrane called the tonoplast. In animal cells, they are smaller and more numerous. Iny:

• Iny is a small organelle found in cells.
• It helps the cell to regulate its water balance and maintain its shape.

Mitochondria:

• Mitochondria are rod-shaped or spherical structures found in all cells.
• They contain DNA and enzymes that help the cell produce energy.

Plastids:

• Plastids are small bodies found in plant cells.
• There are two types of plastids: leucoplasts and chromoplasts.
• Leucoplasts are colorless and store starch, protein, or lipids.
• Chromoplasts are colored and can be either photosynthetic or non-photosynthetic.
• Photosynthetic chromoplasts produce food from carbon dioxide and water in the presence of sunlight.
• Non-photosynthetic chromoplasts provide color to flowers, fruits, and leaves.

Nucleus:

• The nucleus is a round, oval, cylindrical, or elongated organelle found in cells.
• It is surrounded by a nuclear membrane and contains nucleoplasm.
• Nucleoplasm is made up of chromatin and nucleoli.
• Chromatin is made up of DNA, RNA, and proteins.
• The nucleus controls all cell activities and is responsible for the transfer of heredity.

Centrosome:

• A dense area of cell material located near the nucleus.
• Found in animal cells.
• Contains two small dot-like bodies called centroils.
• Helps in cell division by forming a spindle in lower plants.

Cilia and Flagella:

• Fine extensions of the cell surface.
• Similar in structure.
• Help in movement and locomotion.
• In some animals, they also help in feeding.

Cell Inclusions:

• Non-living substances present in the cytoplasm or vacuoles of a cell.
• In animal cells, inclusions include secretory granules, hemoglobin in red blood cells, food material like glycogen in liver cells, and pigments in skin, eye, and hair cells.
• In plant cells, inclusions include food particles like starch, oil globules, and excretory products like resin and gum.

Cell Division:

• Process by which cells divide to produce new cells.
• Essential for growth, development, and reproduction of all living organisms. Living things grow when their cells get bigger and divide to make more cells. There are two ways that cells can divide:

1. Mitosis: This is the most common way that cells divide. It happens in all cells of the body except for the reproductive cells. When a cell divides by mitosis, it makes two new cells that are exactly the same as the original cell.

2. Meiosis: This type of cell division only happens in reproductive cells. It makes gametes, which are cells that contain half the number of chromosomes as the original cell. This is important for sexual reproduction, because when two gametes combine, they create a new cell with the correct number of chromosomes.

Cell Division

Cell division is the process by which a cell divides into two or more new cells. Before cell division, the cell gets ready and is called the interphase. During interphase, the cell becomes more active.

Cell division has two main steps:

1. Division of the nucleus
2. Division of the cytoplasm

During cell division, the chromatin material of the cell gets organized into chromosomes.

Plant and Animal Cells

Plant and animal cells are different in a few ways.

• Plant cells have a rigid cell wall made of cellulose, while animal cells do not.
• Plant cells have chloroplasts, which are organelles that help them photosynthesize. Animal cells do not have chloroplasts.
• Plant cells lack centrioles, which are organelles that help organize the mitotic spindle. Animal cells have centrioles.
• Plant cells have a large sap-filled vacuole. Animal cells have smaller vacuoles. Classification of Living Organisms

There are millions of different kinds of living things on Earth. Some of these organisms are still alive, while others have died and become fossils.

A scientist named Carl Von Linne developed a system for classifying living things in the 18th century. His system is still used today.

Scientific Names

Carl Von Linne also created a system for naming living things. This system is called scientific nomenclature.

In scientific nomenclature, each organism has two names. The first name is the genus name, and the second name is the species name.

For example, the scientific name for the cat is Felis catus. Felis is the genus name, and catus is the species name.

Species

A species is a group of organisms that are very similar to each other. They can interbreed and produce fertile offspring.

For example, all cats are members of the same species. They can interbreed and produce fertile offspring.

Genus

A genus is a group of related species. The species in a genus have some common characteristics.

For example, all cats are members of the genus Felis. All Felis species have sharp claws, retractable teeth, and fur. Different types of living things are grouped based on their similarities and differences. For example, cats, lions, and tigers are all different species, but they share some common characteristics. So, they are placed in the same group called a genus. Genera are then grouped into families, families into orders, orders into classes, and classes into phyla.

The lowest level of classification is the species, and the highest level is the phylum. Different phyla make up either the plant kingdom or the animal kingdom.

Each organism has two names: a generic name and a specific name. The generic name starts with a capital letter, and the specific name starts with a small letter. For example, the scientific name for the common housefly is Musca domestica, and the scientific name for humans is Homo sapiens. The scientific name for wheat is Triticum aestivum.

Here’s a table that shows the order of classification:

General Classification

In the past, all living things were divided into two main groups:

1. Plants
2. Animals

Some single-celled organisms, like bacteria and fungi, used to be considered plants. But in recent decades, scientists have disagreed with this classification and have been working to improve the classification system. In 1969, R. H. Whittaker proposed a new system that divided all living things into five main kingdoms.

The Five Kingdoms of Living Things

Scientists have created a system to classify all living things into five groups called kingdoms. These kingdoms are:

1. Monera (true bacteria and blue-green algae)
2. Protista (golden algae and yellow-green algae)
3. Fungi (slime molds, bread molds, and sac fungi)
4. Plantae (plants)
5. Animalae (animals)

Some scientists also include viruses in the Monera kingdom, while others consider them to be outside the normal classification system.

Here’s a brief description of each kingdom:

Monera:

• Organisms with simple cells that lack a nucleus
• Diverse nutritional habits, including photosynthesis, chemosynthesis, and absorption
• Reproduce asexually by simple cell division
• Examples: true bacteria, fungus-like bacteria, blue-green algae

Protista:

• Unicellular or colonial organisms with a nucleus
• Diverse nutritional habits, including photosynthesis, chemosynthesis, and absorption
• Reproduce both sexually and asexually, involving meiosis and nuclear fusion
• Mobility by means of advanced flagella
• Examples: Euglena, Paramecium, Amoeba

Fungi:

• Organisms that lack chlorophyll and cannot make their own food
• Absorb nutrients from their surroundings
• Reproduce both sexually and asexually
• Examples: mushrooms, yeast, molds

Plantae:

• Organisms that contain chlorophyll and can make their own food through photosynthesis
• Have cell walls made of cellulose
• Reproduce both sexually and asexually
• Examples: trees, flowers, grasses

Animalae:

• Organisms that cannot make their own food and must eat other organisms to survive
• Have a nervous system and can move around
• Reproduce sexually
• Examples: humans, insects, fish

Types of Algae:

• Ophytes: These are a type of algae that have a unique cell structure and are found in both freshwater and marine environments.

• Dinoflagellates: These are a type of algae that have two flagella and are found in both freshwater and marine environments. Some dinoflagellates can produce bioluminescence, which is the emission of light by a living organism.

• Golden algae: These are a type of algae that have a golden-brown color and are found in both freshwater and marine environments.

• Yellow-green algae: These are a type of algae that have a yellow-green color and are found in both freshwater and marine environments.

Fungi:

• Fungi are organisms that are made up of many cells and do not have chlorophyll, which is the green pigment that plants use to make food.

• Fungi get their food by absorbing nutrients from their surroundings.

• Examples of fungi include slime molds, water molds, white ruts, bread molds, and sac fungi.

Plantae:

• Plantae are organisms that are made up of many cells and have a cell wall.

• Plantae make their own food by photosynthesis, which is the process of using sunlight to convert water and carbon dioxide into food.

• Plantae include all botanical organisms, such as trees, shrubs, herbs, and flowers.

Animalae:

• Animalae are organisms that are made up of many cells and do not have a cell wall.

• Animalae get their food by eating other organisms.

• Animalae include all protozoa and metazoa zoological organisms.

Important Biological Phenomena:

Photosynthesis:

• Photosynthesis is the process by which green plants use sunlight to convert water and carbon dioxide into food.

• The energy from sunlight is trapped in plant cells by chloroplasts, which are small organelles that contain chlorophyll. Plants have chlorophyll, which gives them their green color. When sunlight hits the chlorophyll, it creates tiny electric currents. These currents change ADP (adenosine diphosphate) into ATP (adenosine triphosphate) and split water molecules in the cells into oxygen and hydrogen. This starts the complex process of photosynthesis. Oxygen is released into the air, and hydrogen combines with carbon dioxide to make glucose, which is a fuel used by living things.

All chemical reactions that happen in living things have two parts:

1. Anabolism: This is when living things make complex organic molecules from simple ones. For example, they make proteins from amino acids.
2. Catabolism: This is when living things break down complex molecules into simple ones to get energy. For example, they break down hydrocarbons into simpler forms.

Respiration

Respiration has two meanings: breathing and the movement of oxygen and carbon dioxide to and from cells.

Internal respiration or cell respiration happens inside cells. It’s the chemical reactions that give an organism energy. Internal respiration that uses oxygen is called aerobic respiration. Anaerobic respiration happens without oxygen. Both plants and animals respire.

Animals need oxygen to release the energy in their food and get rid of waste, like carbon dioxide.

Skin Breathing: Slow-moving animals breathe through their skin.

Gill Breathing: Fish have gills that absorb oxygen from water.

Breathing

• Tracheal Breathing: Insects have a network of tubes that carry oxygen to all parts of their bodies.
• Lung Breathing: More evolved animals have lungs to breathe.

Fertilization

Fertilization is when two sex cells (gametes) come together to make a fertilized egg (zygote). The zygote then grows into a new offspring.

External Fertilization: In some animals like frogs, toads, and many water creatures, fertilization happens outside the body. The male gamete (sperm) swims through the water to fertilize the female gamete (egg). The fertilized egg then develops into a new individual.

Internal Fertilization: In mammals, birds, reptiles, and insects, fertilization happens inside the female’s body. The male gamete (sperm) is released into the female’s body, where it fertilizes the egg. In birds and reptiles, the fertilized egg is laid and develops outside the female’s body. In mammals, the fertilized egg develops inside the female’s body until it is born.

Fertilization in Flowering Plants:

In higher plants, fertilization is a complex process that involves pollen grains. These pollen grains are carried to the egg-bearing part of the plant by wind or insects. This process is called pollination. When a pollen grain lands on the stigma, it germinates and sends a pollen tube down through the style to the ovule. The male reproductive cell in the pollen tube then fuses with the egg cell in the ovule, which can then develop into an embryo plant.

Transpiration:

Transpiration is the process by which water evaporates from the stems and leaves of plants. This process helps to cool the leaves on hot days and prevents them from drying out. It also helps to draw water up from the roots to the leaves, where the excess water is released into the atmosphere.

Human Body:

Anatomy and Physiology:

Blood:

• Blood is a connective tissue that is made up of a red, viscous fluid.
• On average, a healthy man has about 5 liters of blood in his body, while a woman has about 4 liters. - The average person has about 60 to 80 milliliters of blood for every kilogram of body weight. This means that a person who weighs 70 kilograms has about 4.2 to 5.6 liters of blood.
• Blood is made up of two main parts: the solid or cellular part called blood cells (35%) and the liquid part called plasma (65%).
• Blood cells are of two types: red blood cells (RBCs) and white blood cells (WBCs).
• Plasma is made up of water (90%), proteins (7%), nutrients, salts, nitrogen waste, carbon dioxide, and hormones.
• Blood also has platelets (thrombocytes), which help to stop bleeding. The normal platelet count is between 150,000 and 300,000 per cubic millimeter of blood.
• Red blood cells (erythrocytes) make up about 54% of the blood and contain a pigment called hemoglobin, which gives blood its red color. Hemoglobin is an iron-containing pigment.
• Red blood cells are produced in the spleen and bone marrow.

Haemoglobin:

• Haemoglobin is a protein in red blood cells that carries oxygen from the lungs to the rest of the body.
• It does this by forming a chemical compound with oxygen.

White Blood Corpuscles (WBC):

• White blood cells are part of the body’s defence system.
• They help fight infection.
• There are normally between 4,500 and 11,000 white blood cells per cubic millimetre of blood.
• White blood cells are larger than red blood cells and have a nucleus.

Blood Grouping:

• Human blood is classified into four groups: A, B, AB, and O.
• The O blood group can be given to anyone, so people with O blood are called universal donors.
• The AB blood group can receive blood from anyone, so people with AB blood are called universal recipients.

Table of Blood Groups:

• Blood clotting is the body’s way of stopping bleeding.
• Plasma has a protein called fibrinogen that turns into fibrin, which is needed for blood to clot. The liver makes fibrinogen.

Rh Factor

• The Rh factor is a protein found on red blood cells.
• Most people have the Rh factor and are called Rh-positive.
• People who don’t have the Rh factor are called Rh-negative.

Rh- Blood Type

• Rh- blood does not have anti-Rh antibodies naturally. But it can make them if it comes into contact with Rh+ blood.
• If someone with Rh- blood gets a blood transfusion from someone with Rh+ blood, their body will start making anti-Rh antibodies.
• If they get another transfusion of Rh+ blood, the anti-Rh antibodies will attack the donor’s red blood cells and cause them to clump together. This can be dangerous and even fatal.

Blood Transfusion

• Blood transfusion is when blood is taken from one person (the donor) and given to another person (the recipient).
• It is done to replace blood that has been lost or to improve the quality of the blood.
• Blood transfusions are very important, but they can also be dangerous if the blood types are not matched correctly.
• The first blood transfusion was done in 1825 by James Blundell in London.

Blood Pressure

• Blood pressure is the force of the blood pushing against the walls of the blood vessels.
• It is measured in millimeters of mercury (mm Hg).
• Normal blood pressure is around 120/80 mm Hg.
• High blood pressure (hypertension) is when the blood pressure is too high.
• Low blood pressure (hypotension) is when the blood pressure is too low.

Blood Pressure:

• Blood pressure is the force of blood pushing against the walls of blood vessels.
• When the heart pumps blood, it creates pressure in the arteries.
• The highest pressure is called systolic pressure, and the lowest pressure is called diastolic pressure.
• Blood pressure is measured in millimeters of mercury (mm Hg).
• Normal blood pressure for a healthy young adult is around 120/80 mm Hg.
• High blood pressure (hypertension) is when the systolic pressure is over 140 mm Hg or the diastolic pressure is over 90 mm Hg.
• Low blood pressure (hypotension) is when the systolic pressure is below 90 mm Hg or the diastolic pressure is below 60 mm Hg.
• High blood pressure is called Hypertension, and low blood pressure is called Hypotension.
• Blood pressure depends on many things, like how strong the heart beats, how much blood there is, how thick the blood is, how flexible the arteries are, and how much resistance the capillaries give to blood flow.

The Skeletal System (Bones)

• Adults have 206 bones in their skeletal system.
• The bones in your hands and feet make up half of all the bones in your body.
• When a baby is born, they have 300 bones, but as they grow, 94 of those bones fuse together.
• The longest bone in the human body is the femur, which is in the thigh. It makes up about 27.5% of a person’s height, and the average length is about 50 cm.
• The smallest bone in the human body is the stapes, which is in the middle ear.

Functions of Bones

1. They connect tissues in the body.
2. They make the body stiff.
3. They provide levers for muscles to work on.
4. They give the body its shape.
5. They protect internal organs.

Bones

Bones are made up of different materials, including organic matter, phosphate of lime, carbonate of lime, fluoride of calcium, phosphate of magnesia, soda, and chloride of sodium.

Important Bones

Skull Bones (Cranium)

The skull is made up of eight bones:

• Frontal bone (forehead)
• Two parietal bones (sides of the head)
• Occipital bone (back of the head)
• Two temporal bones (sides of the head)
• Sphenoid bone (base of the skull)
• Ethmoid bone (between the eyes)

Facial Bones

The facial bones are made up of 14 individual bones:

• Two lachrymal bones (tear ducts)
• Two nasal bones (bridge of the nose)
• Two cheek bones (malar bones)
• One vomer bone (between the nostrils)
• Two sponge bones (turbinate bones)
• Two palate bones (roof of the mouth)

Bones of the Head

• The skull is made up of two upper jaw bones (maxilla) and one lower jaw bone (mandible).

Upper Extremities (Shoulder and Arms)

• There are 32 bones in the shoulder and arms.

Shoulder Bones

• Two scapula (triangular-shaped shoulder blades)
• Two clavicles (collar bones)

Bones of the Arm

• Each arm has 30 bones:
  • One humerus (the largest bone of the arm)
  • One radius (outer bone)
  • One ulna (inner bone)
  • Eight carpals (wrist bones)
  • Five metacarpals (bones of the middle hand)
  • Fourteen phalanges (bones of the fingers)

Backbone (the Spine)

• The backbone is also called the vertebrae. It encloses the spinal cord.
• In childhood, the backbone has 33 separate bones.
• In adults, there are only 26 separate vertebrae because some bones fuse together.
• The 26 vertebrae are divided into five regions:
  • Cervical vertebrae (neck bones) - seven
  • Dorsal vertebrae (support the ribs) - twelve
  • Lumbar vertebrae (backbones) - five
  • Sacrum (also called ‘Sacred Bones’) - five vertebrae fused together
  • Coccyx (tailbone) - four vertebrae fused together The spine of an adult human has 26 bones called vertebrae. These bones are divided into four sections.

The chest bones, also known as the thorax, form a protective cage around the lungs and heart. The thorax consists of one sternum (breastbone) and 24 ribs.

The hip bone, also known as the pelvis, is made up of three bones that fuse together in adulthood. These bones are the ilium, the ischium (seat bone), and the pubis. The female pelvis is wider than the male pelvis to allow for childbirth.

Bones of the Pelvis

The pelvis is made up of several bones, including:

1. Sacrum: This is the bone at the back of the pelvis.
2. Iliac crest: This is the top of the pelvis.
3. Acetabulum: This is the hip joint.
4. Ischium: This is the bone that forms the back of the hip joint.
5. Ishial tuberosity: This is the bump on the back of the pelvis that you can sit on.
6. Ilium: This is the bone that forms the front of the pelvis.
7. Pubis: This is the bone that forms the front of the hip joint.

Bones of the Leg

Each leg has 30 bones, including:

1. Femur: This is the thigh bone. It is the longest bone in the human body.
2. Tibia: This is the shin bone.
3. Fibula: This is the calf bone.
4. Patella: This is the kneecap.
5. Tarsus: These are the ankle bones. There are seven of them.
6. Phalanges: These are the toe bones. There are 14 of them.

Muscular System

Muscles are tissues that are attached to bones. They are made up of fibers that can contract and relax to move the body.

There are about 630 important muscles in the human body. They make up about 40% of the body’s weight. There are also about 100 joints and about 10,000 kilometers of blood vessels in the human body. Water makes up about 70% of the human body’s tissues.

The largest muscle in the body is the gluteus maximus, or buttock muscle. The longest muscle in the body is the sartorius muscle, which runs from the hip to the knee.

Sartorius Muscle (Tailor’s Muscle)

• The Sartorius muscle is the longest muscle in the body.
• It starts at the top of the hip bone, crosses the upper thigh diagonally, goes behind the thigh bone, and attaches to the shin bone.

Smallest Muscle

• The Stapedius muscle is the smallest muscle in the human body.
• It controls the stapes, a small bone in the middle ear that helps us hear.
• The Stapedius muscle is less than 1/20 of an inch long.

Main Organs

• The heart is located in the center of the chest, just behind the breastbone.
• It is surrounded by a tough membrane called the pericardium.
• The average weight of the heart is about 340 grams in men and 225 grams in women.
• The heart contracts and relaxes, which causes it to beat. - The heart pumps blood around the body.
• When the heart squeezes, it is called systole.
• When the heart relaxes, it is called diastole.
• The heart rate is the number of times the heart beats per minute.
• The normal heart rate for men is 70-72 beats per minute.
• The normal heart rate for women is 78-82 beats per minute.
• Blood vessels are tubes that carry blood around the body.
• Arteries carry blood away from the heart.
• Veins carry blood back to the heart.
• The largest artery in the body is the aorta.
• The smallest arteries are called arterioles.
• Veins have valves to prevent blood from flowing backward.

Human Body Temperature:

The average human body temperature is around 37 degrees Celsius (98.6 degrees Fahrenheit). However, some people, especially young children, may have slightly higher or lower temperatures. Body temperature can also vary throughout the day, usually rising a bit in the afternoon and dropping a bit during sleep.

Blood Circulation:

• The pulmonary artery is the only artery that carries impure blood. It carries blood from the heart to the lungs.
• The pulmonary vein is the only vein that carries pure blood. It carries blood from the lungs back to the heart.
• The heart’s contractions force both impure and pure blood into two ventricles.
• The pure blood from the left ventricle goes into the large aorta, which takes it to various parts of the body.
• The impure blood from the right ventricle goes into the pulmonary artery, which takes it to the lungs.
• When the ventricles relax, the auricles fill with blood again. The heart is a muscular organ that pumps blood throughout the body. The blood is pumped to the lungs, where it picks up oxygen. The oxygenated blood is then pumped back to the heart, which pumps it to the rest of the body.

The lungs are two spongy organs located in the chest cavity. They are responsible for purifying the blood and supplying it with oxygen. The entire blood supply (4.5-5 liters) washes through the lungs about once a minute.

The liver is the largest gland in the human body. It is located on the right side of the stomach and is dark brown in color. The liver performs a variety of functions, including detoxifying the blood, producing bile, and storing glycogen. The gall bladder is a small organ that is attached to the liver. It stores bile, which is a fluid that helps digest fats. The gall bladder can hold up to 2 ounces of bile.

The liver is a large organ that does many important things. It helps digest food, stores energy, and removes toxins from the blood.

Bile is an important fluid that helps digest fats. It is made in the liver and stored in the gall bladder. Bile does not contain any digestive enzymes, so it does not directly help to break down food. However, it does help to break down fats into smaller pieces so that they can be more easily digested by other enzymes.

Bile contains water, bile salts, and bile pigments. Bile salts are chemicals that help to break down fats. Bile pigments are chemicals that give bile its color. - Sodium bicarbonate neutralizes the acid and makes the churned food called Chyme Alkaline.

• Glycocholate and taurocholate of sodium break down the fats of tissues into small globules.

Kidneys

• The two kidneys are located in the upper back of the belly, one on each side of the spine.
• A kidney is about 4 inches long, 2 inches wide, and 1 inch thick. A long tube called the Ureter comes out of each kidney. Urine travels through the Ureters to the bladder.
• Each kidney has thousands of tiny glands called Uriniferous Tubules.

Functions: Kidneys filter waste products from the blood and get rid of them in the urine.

• Kidneys also remove extra water, salts, and waste products from the blood and keep the blood’s pH level balanced. (The pH value is a number that shows how acidic or basic something is.)

Blood Flow and Urine Output

• About one-fourth of the blood pumped by the heart (1.2-1.4 liters per minute) flows through the wide renal vessels.
• A healthy adult produces about 1.4 liters of urine per day.

Human Body Water Content

• The human body is made up of about 45 liters (70%) of water.

Spleen

• The spleen is a large lymphatic gland located near the diaphragm on the left side of the body.
• It plays a significant role in developing immunity, but it is not essential for life and can be removed.
• The spleen’s main functions include:
  • Forming lymphocytes and antibodies
  • Producing red blood cells (RBCs)
  • Storing RBCs
  • Removing worn-out RBCs and foreign particles from the bloodstream

Human Brain

• The human brain consists of two main parts:
  • The cerebrum, which is the largest part of the brain and is responsible for higher-level functions such as thinking, memory, and language.
  • The cerebellum, which is located at the back of the brain and is responsible for coordinating movement and balance.

The Nervous System

The nervous system is made up of the brain, the spinal cord, and the nerves. The brain is the control center of the body. It is located inside the skull. The spinal cord is a long, thin bundle of nerves that runs from the brain down the back. The nerves are like wires that carry messages between the brain and the rest of the body.

The Brain

The brain is the most important organ in the body. It controls everything we do, from thinking and feeling to moving and breathing. The brain is made up of billions of tiny cells called neurons. Neurons communicate with each other by sending electrical signals.

The Spinal Cord

The spinal cord is a long, thin bundle of nerves that runs from the brain down the back. The spinal cord carries messages between the brain and the rest of the body. It also controls reflexes, which are automatic responses to stimuli.

The Nerves

The nerves are like wires that carry messages between the brain and the rest of the body. There are three types of nerves: sensory nerves, motor nerves, and mixed nerves. Sensory nerves carry messages from the body to the brain. Motor nerves carry messages from the brain to the body. Mixed nerves carry both sensory and motor messages.

The Central Nervous System

The central nervous system is made up of the brain and the spinal cord. The central nervous system controls everything we do, from thinking and feeling to moving and breathing.

The Peripheral Nervous System

The peripheral nervous system is made up of all the nerves that connect the central nervous system to the rest of the body. The peripheral nervous system carries messages between the brain and the rest of the body.

1. Cerebrum:

• The brain is divided into two halves, called hemispheres, which are separated by a deep groove called the corpus callosum.
• It controls our voluntary actions and is responsible for our intelligence, memory, imagination, and willpower.

2. Cerebellum:

• The cerebellum is a large part of the brain located at the back of the head, above the medulla. It has ridges and furrows on its surface.
• It helps us coordinate our movements and maintain our balance.

3. Medulla Oblongata:

• The medulla oblongata is the lowest part of the brain and connects to the spinal cord.
• It controls involuntary actions such as breathing, heart rate, and digestion.

4. Spinal Cord:

• The spinal cord is a long, thin tube of nervous tissue that runs from the brain down the back.
• It carries messages between the brain and the rest of the body.

5. Nerves:

• Nerves are bundles of fibers that carry messages between the brain and the rest of the body.
• They transmit nerve impulses, which are electrical signals that travel along the nerve fibers.

Nerves:

• Efferent nerves: These nerves carry signals from the central nervous system (brain and spinal cord) to the rest of the body.
• Motor nerve fibers: These are efferent nerves that control muscle movement.
• Afferent nerves: These nerves carry signals from the body to the central nervous system.
• Sensory nerve fibers: These are afferent nerves that transmit information from the skin and deeper tissues to the brain, often resulting in sensations such as touch, pain, and temperature.

Classification of Nerves:

• Cranial nerves: These nerves are attached to the brain and come out of the skull.
• Spinal nerves: These nerves are attached to the spinal cord, which is protected by the backbone. There are 31 pairs of spinal nerves, each named after the group of vertebrae they pass through.

Sense Organs:

• Skin:

• The skin is the largest organ of the human body and covers the muscles.

• The average adult male has about 20 square feet of skin, while the average adult female has about 17 square feet.

• The skin is made up of two layers: the epidermis and the dermis.

• The epidermis is the outer layer of the skin and does not have any nerves or blood vessels. It is constantly being renewed.

• The dermis is the inner layer of the skin and contains nerves, blood vessels, hair follicles, and sweat glands.

Tongue

• The tongue is a muscular organ in the mouth that is used for tasting, speaking, chewing, and swallowing.
• The tongue is covered in a mucous membrane and extends from the floor of the mouth to the back of the throat.
• The hyoid bone is a small bone at the back of the mouth. It helps the tongue move up and forward to the lips. The top and sides of the tongue are free, but the bottom is attached to other parts of the mouth.

Muscles of the Tongue

The tongue has two types of muscles: extrinsic and intrinsic. Extrinsic muscles attach the tongue to other parts of the body, while intrinsic muscles allow the tongue to move in different directions.

Papillae

The top of the tongue is covered in small bumps called papillae. These papillae give the tongue its rough texture and help it to taste food.

Color of the Tongue

The tongue is usually pinkish-red, but it can change color due to illness or other factors.

Taste Buds

The tongue is an organ of taste. It has taste buds that are scattered over its surface, but they are most concentrated at the back of the tongue.

The Nose

The nose is the main organ of smell. It is also part of the respiratory system, which helps us breathe. The nose is made up of two main parts: the external part that we can see, and the internal part that is made up of two cavities or nasal fossae. The nasal fossae are separated by a vertical septum and are subdivided by spongy or turbinated bones that project from the outer wall into three passages (meatuses). The various sinuses in the ethmoid, sphenoid, frontal, and superior maxillary bones communicate with the meatuses through narrow apertures.The margins of the nostrils are usually lined with a number of stiff hairs (vibrissae) that project across the openings and serve to arrest foreign substances such as dust and small insects, which might otherwise be drawn up with the current of air intended for respiration.The skeleton or framework of the nose is partly composed of the bones forming the top and sides of the bridge and partly of cartilage.

The Eye

The eyeball is almost a perfect sphere. It is made up of three layers: the outer layer (the sclera), the middle layer (the choroid), and the inner layer (the retina). The sclera is the white part of the eye, and it protects the inner parts of the eye. The choroid is a dark layer that contains blood vessels that nourish the eye. The retina is the innermost layer of the eye, and it contains the light-sensitive cells that allow us to see. The eye is a round organ that is about 2.5 centimeters in diameter. It has three layers: the outer layer is called the sclera, the middle layer is called the choroid, and the inner layer is called the retina. The front of the eye is covered by a clear membrane called the cornea.

The inside of the eye is filled with two fluids: the aqueous humor and the vitreous humor. The aqueous humor is a watery fluid that fills the front of the eye, and the vitreous humor is a gel-like fluid that fills the back of the eye.

The lens of the eye is a transparent structure that is located behind the iris. The iris is the colored part of the eye, and it controls the amount of light that enters the eye. The lens changes shape to focus light on the retina.

The retina is the light-sensitive layer of the eye. It contains millions of cells called photoreceptors that convert light into electrical signals. These signals are then sent to the brain, which interprets them as images.

On the Retina

• Light has to pass through all the parts of the eye (cornea, aqueous humor, lens, vitreous humor) before it can reach the retina.
• The light is focused on the retina, where it forms an upside-down image.
• The brain then interprets the image.

The Ear

• The ear has two main jobs:
  • Detecting and understanding sounds
  • Keeping the body balanced
• The ear is divided into three main parts:
  • The outer ear
  • The middle ear
  • The inner ear
• Sound waves travel to the eardrum, which vibrates.
• The vibrations are sent to the inner ear, where they cause waves in a fluid called perilymph.
• The waves vibrate the basilar membrane, which is divided into different parts that respond to different frequencies of sound.
• The brain then interprets the sounds. The inner ear has about 10,000 sensory structures called rods or corti. These structures change the vibrations of the basilar membrane into nerve signals. These signals travel to the brain through the auditory nerve, where they are interpreted as sound.

The ear also helps us keep our balance. Three semicircular canals, the utricle, and the saccule are all filled with fluid. The semicircular canals sense movement in three different directions and send this information to the brain. The utricle and saccule sense when the head is tilted and work with the canals to help us keep our balance.

Glands of the Human Body

• Organs in the human body make liquid products called secretions.

Glands

Glands are small organs that make and release substances called secretions. There are two main types of glands:

1. Ducted glands also called exocrine glands, release their secretions through ducts or tubes. For example, the liver produces bile, which is released into the small intestine through the bile duct. The salivary glands produce saliva, which is released into the mouth through the salivary ducts.

2. Ductless glands also called endocrine glands or internally secreting glands, release their secretions directly into the bloodstream. For example, the thyroid gland produces hormones that regulate metabolism. The adrenal glands produce hormones that help the body respond to stress.

Table of Ductless Glands

• Helps digest proteins, carbohydrates, and fats.
• Makes insulin, which helps control blood sugar levels.
• Too little insulin can cause diabetes.

Pituitary:

• Called the “master gland” because it controls other glands.
• Affects growth and metabolism.

Teeth:

• From the age of six, elephants have four chisel-shaped front teeth, two cone-shaped side teeth, and six back teeth for crushing and grinding food.
• The two wisdom teeth, which are the furthest back, grow later and don’t do much.
• Saliva, which is made in the mouth, helps to wet the food, and an enzyme in it called ptyalin starts to break down carbohydrates.

Gullet:

• The gullet, also known as the esophagus, is a 25-centimeter-long tube that connects the mouth to the food pipe (pharynx).
• Peristalsis, which is the contraction of the tube’s walls, moves food down to the stomach.

Stomach:

• The stomach is like a storage area where food can be kept until it’s ready to be digested.
• Gastric juices made in the stomach help break down the food.

Small Intestine:

• The small intestine is 6-7 meters long and 2 centimeters wide and is coiled up.
• Food from the stomach mixes with bile and pancreatic juice in the small intestine and moves forward through peristalsis.
• The part of the intestine closest to the stomach is called the duodenum.

Process of Digestion

After you chew your food, it turns into a mushy mixture called chyme. Then, bile and other secretions mix with the chyme and turn it into a creamy liquid called chyle. The nutrients from the chyle are absorbed through the walls of your small intestines and into your bloodstream. The leftover waste is pooped out.

Digestive Secretions

• Saliva: This is made in your mouth by glands under your tongue. It helps you swallow your food by making it slippery. Saliva also has an enzyme called ptyalin that breaks down starches (carbs) into maltose.
• Gastric Juice: This is made in your stomach and contains hydrochloric acid and enzymes. Hydrochloric acid kills bacteria and helps you digest proteins. Enzymes help break down proteins into smaller molecules.
• Bile: This is made in your liver and stored in your gallbladder. It helps you digest fats by breaking them down into smaller molecules.
• Pancreatic Juice: This is made in your pancreas and contains enzymes that help you digest proteins, carbs, and fats.

Stomach Juice

• Kills bacteria in food.

• Helps digest food.

• Made of:

  • 90% water
  • 5% enzymes (pepsin, renin, and gastric lipase)
  • 5% hydrochloric acid

• Pepsin and hydrochloric acid break down proteins into smaller molecules called peptones and proteoses.

• Renin curdles milk into a substance called casein.

• Gastric lipase breaks down fats into glycerol and fatty acids.

Pancreatic Juice

• Produced in the pancreas.
• Meets food in the duodenum (part of the small intestine) along with bile juice from the liver and intestinal juice from the small intestine.
• Contains enzymes that break down proteins, carbohydrates, and fats.
• Amylase breaks down starch into smaller molecules.
• Lipase breaks down fats into glycerol and fatty acids.

Important Hormones

• The female reproductive organs are responsible for producing eggs and nurturing a developing fetus.

Testosterone

• Testosterone is a hormone produced by the testes in males. It is responsible for the development of male reproductive organs and secondary sexual characteristics, such as a deep voice and facial hair.

Thyroxin

• Thyroxin is a hormone produced by the thyroid gland. It is responsible for regulating growth and metabolism.

Digestive Enzymes

• Digestive enzymes are proteins that help break down food into smaller molecules that can be absorbed by the body.

Erepsin

• Erepsin is an enzyme produced by the intestinal glands in the small intestines. It breaks down peptides into amino acids.

Maltase

• Maltase is an enzyme produced by the intestinal glands. It breaks down maltose into glucose.

Lactase

• Lactase is an enzyme produced by the intestinal glands. It breaks down lactose into glucose.

Sucrase

• Sucrase is an enzyme produced by the intestinal glands. It breaks down sucrose into glucose.

Parts of the body involved in sexual reproduction in complex organisms:

Female:

• Vulva (including the clitoris)
• Vagina (including the cervix)
• Labia
• Uterus
• Fallopian tubes
• Ovaries
• Skene’s glands
• Bartholin’s glands

Male:

• Penis (including the glans penis and foreskin)
• Testicles
• Scrotum
• Prostate
• Seminal vesicles
• Epididymis
• Cowper’s glands

Additional information:

• The term “genitalia” is used to describe the sex organs.
• The term “genital area” is often used to describe the externally visible sex organs.
• The parts of the sex organs that are not visible from the outside are called the “internal genitalia.”
• A gonad is a sex organ that produces gametes (eggs or sperm).
• The sex organs develop from the same starting point and then differentiate into male or female organs.

Female Reproductive Organs

Each organ in the female reproductive system has a corresponding organ in the male reproductive system. For example, the ovaries in females produce eggs, while the testes in males produce sperm. The uterus in females is where a fertilized egg implants and grows into a baby, while the prostate gland in males helps to produce semen, which carries sperm.

Chromosomes:

• Chromosomes are thread-like structures found inside the nucleus of cells.
• Each cell has a specific number of chromosomes, which come in pairs.
• Humans have 23 pairs of chromosomes (46 in total).
• Chromosomes contain protein molecules and two types of nucleic acid molecules: RNA (ribonucleic acid) and DNA (deoxyribonucleic acid).
• DNA is mostly found in chromosomes, while RNA is mostly found in nucleoli, both of which are located in the nucleus.

Genes:

• Genes are hereditary units located within chromosomes.
• Genes are responsible for passing on physical and mental traits from parents to offspring.
• Genes are made up of DNA molecules arranged in specific patterns.
• These patterns determine hereditary traits and control the processes of life.
• In 1896, Gregor Mendel discovered that certain hereditary factors exist in all living things.
• Wilhelm Johannsen, a Danish biologist, later named these factors “genes.”

Isolation of Pure Gene:

• In 1969, scientists at Harvard University were able to separate and take pictures of a single gene.

Artificial Gene:

• Dr. Hargobind Khorana, an Indian-American scientist who won the Nobel Prize in 1968, made a fake gene in a lab in 1970. He did this by putting together proteins.

Genetic Code:

• The genetic code is like a set of instructions that tells living things how to grow and what traits they will have. It’s found in the chromosomes of cells, which are made of DNA.

Genetic Engineering:

• Genetic engineering, also known as bio-engineering, is a way of changing the genes of living things to create new organisms with specific traits.
• It started when scientists discovered DNA in 1953 and then figured out how to change DNA in living cells in 1973.

Recombinant DNA or Gene Splicing:

• Scientists use chemicals called enzymes to cut genes from the DNA of one organism (the donor). These enzymes act like molecular knives.

• The isolated gene is then inserted into the DNA of a bacterium, usually the intestinal bacterium called E. coli. This is done using another enzymatic reaction.

• The resulting hybrid DNA is put back into E. coli cells. These cells can now grow and reproduce, carrying the hybrid DNA in their nuclei. They can also exhibit the traits and characteristics coded by the foreign gene.

• The four DNA bases (A, G, T, and C) are like the letters of an alphabet. They can be used to store information.

• This genetic information is passed on through RNA (ribonucleic acid). RNA also has four bases: adenine, guanine, cytosine, and uracil (U). RNA provides a template for assembling amino acids in a specific sequence, which builds a protein.

• A group of three DNA or RNA bases is called a triplet or codon. Each codon codes for a particular amino acid. Information is passed from DNA to RNA in this way. ## Sex Determination

• Out of the 46 chromosomes (23 pairs) in a human body, only 44 (22 pairs) are truly similar. The other two, called the X and Y chromosomes, are sex chromosomes.

• Two X chromosomes make a female, while an X and a Y chromosome make a male. So, the sex of a child depends on whether the female egg is fertilized by a sperm carrying an X chromosome or a Y chromosome.

Twins

1. Fraternal Twins: Sometimes, two eggs are released from the ovaries at the same time. If both of these eggs get fertilized, they develop into two separate babies. These twins can be of the same sex or different sexes.
2. Identical Twins: These twins develop from a single fertilized egg. During the first division of the zygote (egg), the cell splits into two similar cells that grow into two separate embryos. Since they come from the same zygote, these twins have the same genetic makeup and are always of the same sex.

Identical Twins

Identical twins are twins who share the same genes. They are formed when a single fertilized egg splits into two separate embryos. This can happen at any time during the first few days of development.

Siamese Twins

Siamese twins are identical twins who are born joined together. They are very rare, occurring in only about 1 in every 200,000 births. Siamese twins can be joined at the head, chest, or hip.

Separation of Siamese Twins

Siamese twins can usually be separated surgically. However, this is a complex and risky procedure. If the twins share a vital organ, such as the heart, it may not be possible to separate them.

The First Siamese Twins

The first Siamese twins who received wide publicity came from Siam (now Thailand) in the 19th century. They were named Chang and Eng Bunker. They were born in 1811 and lived until 1874.

Human Genetics

Human genetics is the study of how genes are passed down from parents to children. It is a branch of medical science that helps us understand how our physical and mental characteristics are determined.

Genetics: The Science of Heredity

Genetics is the study of how traits are passed down from parents to their children. It’s a relatively new field of science, but it’s already had a big impact on our understanding of health and disease.

Two Main Components of Genetics

There are two main components of genetics:

• Heredity: This is the study of how similar traits are passed down from parents to their children.
• Variation: This is the study of how traits can be different between individuals, even if they have the same parents.

How Genetics Can Help Us

Genetics can help us understand a lot about health and disease. For example, it can help us:

• Understand the underlying cause of diseases
• Understand why some people are more likely to get certain diseases than others
• Develop new treatments for diseases
• Prevent genetic disorders

Conclusion

Genetics is a powerful tool that can help us understand a lot about health and disease. As the field continues to grow, we can expect to see even more benefits from this research.

Genetics and its Applications

Genetics is the study of how traits are passed down from parents to offspring. It can be divided into several branches, including:

1. Cytogenetics: This field studies the structure of the nucleus of a cell and its parts, including chromosomes.
2. Molecular and Developmental Genetics: This field studies the molecular structure of genetic material, how it affects embryonic development, and how it functions in normal and abnormal conditions.
3. Eugenics: This field applies the principles of heredity to improve human health and well-being.
4. Physiological Genetics: This field studies how genetic material controls the normal functions of various cell organelles.
5. Population Genetics: This field studies how genetic material is distributed and behaves within a population.

Genetics has many practical applications, including:

1. Counseling and antenatal diagnosis: Genetic counseling can help individuals and families understand their risk of developing genetic disorders and make informed decisions about reproduction. Antenatal diagnosis can be used to identify genetic disorders in a fetus before birth.
2. Legal problems: Genetics can be used to solve legal problems such as disputed parentage or the identification of criminals.
3. Agriculture: Genetics can be used to develop crops that are more resistant to pests and diseases, and that produce higher yields.
4. Medicine: Genetics can be used to develop new treatments for genetic disorders and to identify individuals who are at risk of developing certain diseases.

Genetics is a rapidly growing field, and new discoveries are being made all the time. As our understanding of genetics increases, so too will its potential to improve our lives.

6. Clinical Genetics:

• This field uses knowledge about genetic material to understand diseases and how they pass from one generation to another.
• It also includes methods for diagnosing and preventing genetic disorders.

7. Environmental Genetics:

• This field focuses on changing genetic material in living things using advanced technologies like genetic engineering and recombinant DNA.

8. Radiation Genetics:

• This field studies how different types of radiation affect genetic material and can cause diseases.

9. Biochemical Genetics:

• This field looks at the bioBiology of genetic material and how it affects normal metabolic processes.
• It also includes immunogenetics and blood groups, which are related to the genetic material that produces antigens and antibodies.

10. Genetic Counselling:

• This field provides advice and support to individuals and families about genetic conditions and their implications.

Genetic Counseling:

A genetic counselor, also known as a medical geneticist, helps people understand and manage genetic disorders. They provide information about the causes, risks, and recurrence of inherited conditions, as well as the potential effects of radiation and mutant viral strains used in biological warfare. Some newer drugs, including anticancer medications, can also cause genetic problems due to mutations, and genetic counselors can help patients understand these risks.

Human Diet:

A balanced diet is one that contains all the essential nutrients the human body needs to grow and function properly. For an average adult, a balanced diet should provide around 3000 calories per day and include all essential elements in the right proportions. This means consuming approximately 400-500 grams of carbohydrates, 70 grams of protein, and 75 grams of fat daily. The ratio of fat, protein, and carbohydrates should be around 1:1:4.

Food and Nutrition

• Food should be easy to digest and cooked well to kill any harmful bacteria.
• Growing children, nursing mothers, and people with certain diseases need more carbohydrates, proteins, and fat.
• A sportsman needs two and a half times more carbohydrates than an ordinary person.

Vitamins

Acquired Immuno-Deficiency Syndrome (AIDS)

AIDS is a deadly disease that attacks the body’s immune system. It was first reported in the United States in early 1981 and quickly spread worldwide, causing a global health crisis. The World Health Organization (WHO) is deeply concerned about the impact of AIDS and is working to prevent its spread and find a cure. - During the 1980s, the world faced a serious health challenge: a deadly and incurable disease called AIDS.

• Causes: AIDS is caused by a virus called HIV-III, which attacks and weakens the body’s immune system. At first, it was thought to be a sexually transmitted disease found only in homosexual men. But later, it was discovered that the main ways AIDS spreads are:

1. Sharing needles for injecting drugs
2. Receiving blood transfusions with infected blood
3. Anal sex, which can cause tiny tears in the skin and make it easier for the virus to enter the body
4. Having unprotected sex with an infected person

• Symptoms: People with AIDS often get a severe lung infection called Pneumocystis carinii pneumonia and a type of skin cancer called Kaposi’s Sarcoma. These complications, along with brain damage and severe diarrhea, can lead to death.

• Treatment: Unfortunately, there is no cure for AIDS yet. However, Encouraging Results with AZT.

• AZT (short for 3-azido-3-deoxythymidine) is a medication that has shown promising results in treating AIDS.

• It is taken orally four times a day.

• However, its long-term effects are still unknown.

• AZT does not cure AIDS, but it can help control the multiplication of the virus.

Efforts to Develop a Vaccine

• Scientists are working to develop a vaccine against AIDS.
• Even if a vaccine is successfully developed, it will not be available for general use until at least 1999.

Common Diseases

Malaria

• Malaria is a tropical disease that is spread by mosquitoes.
• It is caused by a parasite called Plasmodium.
• Symptoms of malaria include shivering, fever, and repeated attacks that can lead to an enlarged spleen, anemia, pigmentation of the face, and general weakness.
• Malaria can be treated with medications such as quinine or plaurdine.
• Prevention involves keeping the environment free from mosquitoes.

Tuberculosis

• Tuberculosis is an infectious disease that is spread through the air.
• It is caused by bacteria called Mycobacterium tuberculosis.
• Symptoms of tuberculosis include coughing, fever, weight loss, and fatigue.
• Tuberculosis can be treated with antibiotics.
• Prevention involves avoiding contact with people who have tuberculosis and getting vaccinated.

Tuberculosis

• Cause: Tuberculosis is caused by a type of bacteria called Mycobacterium tuberculosis. It was discovered by Robert Koch in the mid-19th century. People who are malnourished, have weak chests, or live and work in unhealthy conditions are more likely to get tuberculosis.
• Symptoms: People with tuberculosis may feel weak, have a fever (usually in the evening), and cough. They may also cough up blood.
• Cure/Prevention: Tuberculosis can be treated with antibiotics, such as streptomycin. Surgery may also be necessary. Tuberculosis can be prevented by getting the BCG vaccine and living and working in a healthy environment. The BCG vaccine was developed in 1906 by Calmette and Guerin in Paris.

Cholera

• Cause: Cholera is an acute epidemic disease that is spread through water and food. It is caused by a bacteria called Vibrio cholerae. People who are exposed to cold weather, have an empty stomach for a long time, or eat unripe or overripe fruits or stale food are more likely to get cholera.
• Symptoms: People with cholera may vomit, have stomach pain, and have frequent loose stools. They may also have a fever and lose consciousness.
• Cure/Prevention: Cholera can be treated by avoiding contaminated food and water. It can also be prevented by getting the cholera vaccine.

Tetanus

• Cause: Tetanus is caused by bacteria called Bacillus tetanus and Clostridum tetani. These bacteria live in soil, dust, and animal manure. Tetanus can occur when a deep wound is exposed to these bacteria.
• Symptoms: Tetanus causes painful muscle contractions, usually starting in the neck and jaw. These contractions can spread to other parts of the body and can lead to paralysis.
• Treatment/Prevention: Tetanus can be prevented by getting vaccinated against the disease. If you have a deep wound, it is important to clean it thoroughly and seek medical attention to prevent tetanus infection.

Diphtheria

• Cause: Diphtheria is caused by a bacterium called Corynebacterium diphtheria. This bacterium infects the throat and can cause a thick, gray membrane to form on the back of the throat.
• Symptoms: Diphtheria can cause a sore throat, fever, and difficulty breathing. In severe cases, diphtheria can lead to paralysis and death.
• Treatment/Prevention: Diphtheria can be prevented by getting vaccinated against the disease. If you have symptoms of diphtheria, it is important to seek medical attention immediately.

Typhoid

• Cause: Typhoid is caused by a bacterium called Salmonella typhi. This bacterium is spread through contaminated food and water.
• Symptoms: Typhoid can cause a fever, headache, muscle aches, and diarrhea. In severe cases, typhoid can lead to dehydration, malnutrition, and death.
• Treatment/Prevention: Typhoid can be prevented by getting vaccinated against the disease. It is also important to practice good hygiene, such as washing your hands frequently and avoiding contaminated food and water.

Food and water contamination

Food and water can become contaminated with bacteria from sewage or from people who don’t wash their hands properly. This can cause illnesses such as:

• Typhoid fever: Symptoms include fever, slow pulse, abdominal tenderness, and a rose-colored rash.
• Plague: Symptoms include acute body ache, reddish eyes, sudden rise of temperature, and inflammation of neck glands and glands in armpit and thighs.
• Typhus: Symptoms include high fever, skin eruptions, and severe headache.

Prevention

To prevent these illnesses, it is important to:

• Wash your hands frequently with soap and water.
• Drink only clean water.
• Avoid eating raw or undercooked food.
• Get vaccinated against typhoid fever and plague if you are traveling to an area where these diseases are common.

Treatment

If you think you may have one of these illnesses, it is important to see a doctor right away. Treatment may include antibiotics, rest, and fluids.

Sulphonamides and antibiotics

Sulphonamides and antibiotics are medicines that are used to treat bacterial infections. They work by killing or stopping the growth of bacteria.

Pneumonia

Pneumonia is an infection of the lungs. It is caused by bacteria called Diplococcus pneumonia. Symptoms of pneumonia include chills, pain in the chest, rusty sputum, rapid breathing, and abdominal pain. Pneumonia can be treated with antibiotics.

Gonorrhoea

Gonorrhoea is a sexually transmitted infection (STI). It is caused by bacteria called Neisseria gonorrhea. Symptoms of gonorrhoea include redness, swelling, and pus discharge through the urethra (the tube that carries urine out of the body), and painful urination. Gonorrhoea can be treated with antibiotics such as penicillin G or tetracycline.

Syphillis

Syphillis is an STI caused by bacteria called Treponema pallidum. It is transmitted through sexual contact with an infected person. Symptoms of syphillis include a hard, painless sore on the genitalia, and a skin eruption. Syphillis can be treated with penicillin.

Whooping Cough

Whooping cough is a respiratory infection that is caused by bacteria called Nemophilus pertusis. It is spread through the air when an infected person coughs or sneezes. Symptoms of whooping cough include a severe cough, usually at night. Whooping cough can be prevented by immunizing infants with immunity serum.

Some Blood Diseases

Anaemia is a condition where the red blood cells (RBCs) are seriously reduced in number or are deficient in haemoglobin. Symptoms of anaemia include fatigue, weakness, pale skin, and shortness of breath. Anaemia can be treated with iron supplements or blood transfusions.

Leukemia (Blood Cancer):

• Leukemia is a type of cancer that starts in the bone marrow.
• It causes the body to make too many white blood cells (WBCs).
• These extra WBCs crowd out the red blood cells (RBCs), which carry oxygen to the body’s tissues.
• This can lead to anemia, which is a condition in which the body doesn’t have enough healthy RBCs.
• Leukemia is usually incurable, but bone marrow transplants can sometimes help.

Agranulocytosis:

• Agranulocytosis is a condition in which the body has too few WBCs.
• This can make the body more likely to get infections.
• Agranulocytosis can be caused by certain medications, radiation therapy, or autoimmune diseases.
• It can be treated with antibiotics and other medications.

Thrombocytopenia:

• Thrombocytopenia is a condition in which the body has too few platelets.
• Platelets are cells that help the blood to clot.
• Thrombocytopenia can be caused by certain medications, radiation therapy, or autoimmune diseases.
• It can be treated with platelet transfusions and other medications.

Hemophilia:

• Hemophilia is a rare bleeding disorder that is passed down from parents to their children.
• It is almost always seen in males.
• Hemophilia is caused by a lack of a protein that helps the blood to clot.
• This can lead to easy bruising and bleeding, which can be life-threatening.
• Hemophilia can be treated with clotting factor concentrates and other medications.

Hemorrhage:

• Hemorrhage is the loss of blood from the body.
• It can be caused by a variety of injuries, such as cuts, bruises, or broken bones.
• Hemorrhage can also be caused by certain medical conditions, such as bleeding disorders or cancer.
• Severe hemorrhage can be life-threatening. Blood can leak from blood vessels. This can happen because of external wounds, or it can happen inside the body. When blood leaks inside the body, it can collect in the tissues or escape into the body cavity.

Presbyopia:

• Presbyopia is a common condition that affects most people after the age of 40-42.
• It causes difficulty in reading and working with objects close at hand.
• Presbyopia can be corrected by using convex lenses.

Conjunctivitis:

• Conjunctivitis is an inflammation of the eyes.
• It causes itchiness and reddening of the eyes, making them sensitive to light.
• Conjunctivitis can be treated with a simple solution of weak salt water or boric acid.
• Antibiotic eyedrops may also be prescribed.

Trachoma:

• Trachoma is a bacterial infection of the eyes.
• It is caused by a germ called chlamydiae and spreads by direct contact.
• Trachoma affects both eyes and causes mild itching and irritation.
• Trachoma can be treated with oral tetracycline antibiotics.

Cataract:

• Cataract is a condition in which the lens of the eye becomes cloudy.
• It occurs with aging and causes progressive blurring of vision.
• Distant vision is mostly affected, while near vision may be improved in the early stages.
• Cataracts can be treated with surgery called lens extraction.

Skin Rash: Some foods can cause skin rashes. Allergies can also be triggered by materials like the color of clothes and furnishings.

Arthritis: This is a condition where the joints become inflamed.

Asthma: This is a respiratory problem where the bronchial tubes become narrow. It can be caused by infections or allergies to dust and other particles in the air.

Bronchitis: This is an inflammation of the bronchial tubes caused by bacteria or viruses. It can be fatal for infants and can also occur as a secondary infection in adults.

Cancer: This is a condition where body cells grow abnormally, often forming malignant tumors. There are many causes of cancer, and some types are still incurable.

Diabetes: This is a condition where there is too much sugar in the body because the pancreas (a digestive gland) is not producing enough insulin to control blood sugar levels. Treatment for diabetes involves a controlled diet (low in carbohydrates) and taking insulin.

Epilepsy: This is a condition where a person experiences sudden and periodic loss of consciousness, often accompanied by convulsions, due to abnormal electrical activity in the brain.

Sorders

• Glandular Fever (Mumps): A sickness that makes the glands in the neck swell up and causes a high fever. It’s common in kids and young adults and is likely caused by a virus.

• Hepatitis: A disease that affects the liver. It can be caused by infections or inflammation. The main symptom is jaundice, which makes the skin and eyes turn yellow.

• Hernia: A weakness in the muscles around an organ that lets it bulge out. It’s often found in the groin area and can be fixed with surgery.

• Jaundice: A condition where there’s too much bilirubin (a substance made by the liver) in the blood. It causes the skin, eyes, and urine to turn yellow.

• Leukemia: Also known as blood cancer.

• Measles: A contagious disease caused by a virus. It causes a red rash on the body and a fever. It usually goes away after about ten days.

• Migraine: A severe headache that can cause problems with vision and speech. It’s often accompanied by nausea.

• Pellagra: A disease caused by a lack of nicotinic acid (a type of vitamin B). Symptoms include diarrhea, mental confusion, and skin problems.

Osteomalacia:

• A disease caused by a lack of Vitamin D.
• Bones become soft and weak, leading to pain and frequent fractures.
• The backbone may bend.

Pleurisy:

• Inflammation of the thin layer of tissue that covers the lungs and lines the chest cavity.

Rabies:

• A viral disease spread through the saliva of infected animals.
• Symptoms include seizures and a fear of water (hydrophobia).

Ringworm:

• A skin disease that causes round, itchy patches on the skin.
• Spreads through contact with an infected person or animal or through the air.

Scarlet Fever:

• Caused by a bacterial infection.
• Symptoms include fever, sore throat, and a red rash.

Slipped Disc:

• A painful condition where a cartilage disc in the spine moves out of place and presses on a nerve.

Small Pox:

• A contagious viral disease common in children.
• Causes a rash of small blisters that leave permanent scars on the skin.
• The World Health Organization (WHO) launched a campaign in the 1960s to eradicate smallpox, and it was successful.

Smallpox Eradication: In the 1960s and 1970s, a global effort was made to eliminate smallpox through widespread vaccination. By 1980, the World Health Organization (WHO) declared smallpox to be the first disease to be completely eradicated from the world.

Thrombosis: Thrombosis occurs when a blood clot forms in a blood vessel or the heart, potentially leading to the death of the patient.

Ulcer: An ulcer is an open sore that develops on the skin or the lining of a body cavity. Peptic ulcers specifically refer to ulcers that form in the food pipe and are often associated with indigestion and mental stress. They are common among individuals working in industrial societies.

Common Drugs:

• Anesthetics: Anesthetics are drugs that block sensory nerves, causing a patient to become fully unconscious and unable to feel pain. Local anesthetics numb a specific area temporarily and are used during surgical operations. Examples of anesthetics include chloroform, ether, and sodium pentothal.

• Analgesics: Analgesics are drugs used to prevent or relieve pain. Aspirin (acetylsalicylic acid) and analgesic tablets are common examples of analgesics.

• Antibiotics: Antibiotics are drugs used to prevent or treat infections caused by bacteria. They work by killing or inhibiting the growth of bacteria. Examples of antibiotics include penicillin, amoxicillin, and erythromycin. These drugs are used to kill or stop the growth of bacteria in the body. Some common antibiotics include penicillin and terramycin.

Antihistamines: These drugs are used to relieve symptoms of allergies, such as sneezing, runny nose, and itchy eyes.

Antipyretics: These drugs are used to lower body temperature when someone has a fever.

Hormones: These drugs are used to replace hormones that the body is not producing enough of. For example, people with diabetes may take insulin, and people with low blood pressure may take adrenalin.

Narcotics: These drugs are used to relieve pain. They can be addictive, so they are only used when other pain relievers don’t work. Some common narcotics include opium, codeine, heroin, and morphine.

Sedatives: These drugs are used to help people sleep. They can also be used to calm people down who are anxious or agitated. Some common sedatives include barbiturates and bromides.

Tranquilizers: These drugs are used to calm the nervous system and relieve anxiety. They can also be used to help people sleep. Some common tranquilizers include benzodiazepines and antipsychotics.

Vaccines: These drugs are used to help the body develop immunity to a disease. They are given as shots or injections.