Question:

Distinguish between thalamus and hypothalamus.

Answer:

Step 1: Research the definition of the thalamus and the hypothalamus.

Step 2: Compare the functions of the thalamus and the hypothalamus.

Step 3: Identify the differences between the thalamus and the hypothalamus.

Question:

Write short note on organ of corti.

Answer:

1. The organ of Corti is a structure located in the inner ear of mammals. It is responsible for the sense of hearing and is composed of several types of cells, including hair cells, supporting cells, and nerve cells.

2. The organ of Corti contains the auditory receptors, which are specialized cells that detect sound waves and convert them into electrical signals that are sent to the brain. The organ is also responsible for the perception of pitch, loudness, and timbre.

3. The organ of Corti is located in the cochlea, a spiral-shaped organ that is filled with fluid. It is connected to the vestibulocochlear nerve, which carries the electrical signals from the organ to the brain.

4. The organ of Corti is composed of three main parts: the basilar membrane, the tectorial membrane, and the organ of Corti itself. The basilar membrane is a sheet of tissue that vibrates when sound waves enter the cochlea. The tectorial membrane is a thin sheet of tissue that overlies the organ of Corti.

5. The organ of Corti contains hair cells, which are specialized cells that contain tiny hairs that bend when sound waves enter the cochlea. This bending triggers a nerve impulse that is sent to the brain, allowing us to hear.

6. The organ of Corti is essential for hearing and is a vital part of the auditory system. Damage to the organ of Corti can lead to hearing loss.

Question:

Distinguish between cranial nerves and spinal nerves.

Answer:

Step 1: Understand the definition of cranial nerves and spinal nerves.

Step 2: Compare and contrast the two types of nerves. Cranial nerves are found in the head and neck region and are responsible for controlling functions such as vision, hearing, smell, taste, and facial expressions. Spinal nerves are found along the spinal cord and control the movement and sensation of the body.

Step 3: Identify the differences between cranial nerves and spinal nerves. Cranial nerves are connected directly to the brain, while spinal nerves are connected to the spinal cord. Cranial nerves control functions such as vision, hearing, smell, taste, and facial expressions, while spinal nerves control movement and sensation throughout the body.

Question:

How does the eye regulate the amount of light that falls on the retina?

Answer:

1. The eye regulates the amount of light that falls on the retina through a combination of pupil dilation and constriction, and the adjustment of the lens.

2. The pupil is the dark opening in the center of the eye that allows light to enter. When the pupil is dilated, it opens up, allowing more light to enter the eye and reach the retina.

3. The lens is a transparent structure located behind the pupil. It helps to focus the light that enters the eye, and can be adjusted to change the amount of light that reaches the retina.

4. When the amount of light entering the eye is too bright, the pupil constricts, reducing the amount of light that reaches the retina. Conversely, when the amount of light entering the eye is too dim, the pupil dilates, allowing more light to reach the retina.

Question:

Write short note on cochlea.

Answer:

A. Cochlea is a small, spiral-shaped organ located in the inner ear. It is responsible for hearing and balance in humans. The cochlea is filled with fluid and lined with tiny hair cells, which convert sound vibrations into electrical signals that are transmitted to the brain. The cochlea also contains two chambers, the scala vestibuli and the scala tympani, which are separated by a membrane called the basilar membrane. The basilar membrane vibrates when sound waves enter the cochlea, causing the hair cells to move and generate electrical signals. These signals are then sent to the brain, where they are interpreted as sound. The cochlea is an essential part of the auditory system and is essential for hearing and balance.

Question:

Write short note on ear ossicles.

Answer:

A. Ear ossicles are three small bones in the middle ear that help to transmit sound from the outer ear to the inner ear. They are the malleus, incus, and stapes. The malleus is attached to the eardrum and transmits sound vibrations to the incus, which then passes them to the stapes. The stapes then transmits the vibrations to the inner ear, where they are converted into nerve impulses that are sent to the brain. The ear ossicles are important for hearing and are responsible for amplifying sound vibrations.

Question:

Compare the following. (a) Central neural system (CNS) and Peripheral neural system (PNS) (b) Resting potential and action potential (c) Choroid and retina

Answer:

(a) Central neural system (CNS) and Peripheral neural system (PNS): The CNS is composed of the brain and spinal cord, and is responsible for the coordination and control of bodily activities. The PNS is composed of all the nerves and ganglia outside of the brain and spinal cord, and is responsible for transmitting signals from the CNS to the rest of the body.

(b) Resting potential and action potential: Resting potential is the electrical charge of a cell when it is not actively conducting an impulse. Action potential is the electrical charge of a cell when it is actively conducting an impulse.

(c) Choroid and retina: The choroid is the layer of tissue in the eye that supplies blood to the retina. The retina is the layer of tissue in the eye that contains photoreceptors, which convert light into electrical signals that are sent to the brain.

Question:

Explain the following processes: (a) Polarisation of the membrane of a nerve fibre (b) Depolarisation of the membrane of a nerve fibre (c) Conduction of a nerve impulse along a nerve fibre (d) Transmission of a nerve impulse across a chemical synapse

Answer:

(a) Polarisation of the membrane of a nerve fibre: This is the process by which the membrane of a nerve fibre becomes electrically charged, with the inside having a negative charge relative to the outside. This occurs when positively charged ions, such as sodium and potassium, move into the cell, while negatively charged ions, such as chloride, move out of the cell. This creates a difference in electrical potential across the membrane, known as the resting potential.

(b) Depolarisation of the membrane of a nerve fibre: This is the process by which the membrane of a nerve fibre becomes less electrically charged, with the inside having a less negative charge relative to the outside. This occurs when positively charged ions, such as sodium and calcium, move out of the cell, while negatively charged ions, such as potassium, move into the cell. This reduces the difference in electrical potential across the membrane, known as the resting potential.

(c) Conduction of a nerve impulse along a nerve fibre: This is the process by which an electrical signal is transmitted along a nerve fibre. This occurs when the depolarisation of the membrane at one point causes the adjacent membrane to become depolarised. This causes a wave of depolarisation to travel along the nerve fibre, known as an action potential.

(d) Transmission of a nerve impulse across a chemical synapse: This is the process by which an electrical signal is transmitted across a chemical synapse. This occurs when the action potential travelling along the nerve fibre causes the release of neurotransmitters from the presynaptic neuron. These neurotransmitters then bind to receptors on the postsynaptic neuron, causing a change in the electrical potential of the membrane and the transmission of the signal across the synapse.

Question:

Give a brief account on: (a) Mechanism of synaptic transmission (b) Mechanism of vision (c) Mechanism of hearing

Answer:

(a) Mechanism of Synaptic Transmission: Step 1: Neurons communicate through electrical and chemical signals. Step 2: When an electrical signal reaches the end of an axon, it triggers the release of neurotransmitters from the synaptic vesicles in the axon terminal. Step 3: These neurotransmitters then travel across the synaptic cleft and bind to receptors on the postsynaptic neuron. Step 4: This binding triggers a change in the membrane potential of the postsynaptic neuron, either excitatory or inhibitory. Step 5: This change in membrane potential can then trigger an electrical signal to be sent down the postsynaptic neuron’s axon.

(b) Mechanism of Vision: Step 1: Light enters the eye and passes through the lens, which focuses the light onto the retina. Step 2: The retina contains photoreceptor cells called rods and cones, which convert the light into electrical signals. Step 3: These electrical signals are transmitted to the brain via the optic nerve. Step 4: The brain then processes these signals to create a visual image.

(c) Mechanism of Hearing: Step 1: Sound waves enter the ear and cause the eardrum to vibrate. Step 2: This vibration is transmitted to the small bones of the middle ear, which amplify the sound waves. Step 3: These amplified sound waves then travel to the cochlea, where they cause the fluid inside to vibrate. Step 4: The vibration of the fluid causes tiny hair cells to bend, which triggers the release of neurotransmitters. Step 5: These neurotransmitters then travel to the auditory nerve, which transmits the signals to the brain. Step 6: The brain then processes these signals to create the sensation of sound.

Question:

Differentiate between: (a) Myelinated and non-myelinated axons (b) Dendrites and axons (c) Rods and cones (d) Thalamus and hypothalamus (e) Cerebrum and cerebellum

Answer:

(a) Myelinated axons have a fatty substance called myelin sheath surrounding them which helps to speed up the transmission of signals. Non-myelinated axons do not have this sheath, so their signals travel more slowly.

(b) Dendrites are short, branching extensions of nerve cells that receive signals from other neurons. Axons are long, thin fibers that transmit signals away from the neuron to other neurons.

(c) Rods and cones are photoreceptors in the retina of the eye. Rods are sensitive to low levels of light and are responsible for vision in dim light. Cones are sensitive to bright light and are responsible for color vision.

(d) The thalamus is a structure in the brain that acts as a relay station for sensory information. It receives and sends signals to various parts of the brain. The hypothalamus is a region of the brain responsible for regulating hormones and controlling certain behaviors such as eating and drinking.

(e) The cerebrum is the largest part of the brain and is responsible for higher cognitive functions such as language, memory, and decision-making. The cerebellum is located at the back of the brain and is responsible for coordinating movements and maintaining balance.

Question:

Write short note on hindbrain.

Answer:

Answer:

A. Introduction: The hindbrain is a region of the brain located at the base of the skull. It is composed of the medulla, pons, and cerebellum, and is responsible for controlling basic functions such as breathing, heart rate, and movement. It also plays a role in learning and memory.

B. Medulla: The medulla is the most primitive part of the hindbrain and is responsible for controlling vital functions such as breathing, heart rate, and blood pressure. It also plays a role in controlling the body’s reflexes.

C. Pons: The pons is located above the medulla and is responsible for controlling the body’s sleep-wake cycles, regulating movement, and controlling facial expressions.

D. Cerebellum: The cerebellum is located above the pons and is responsible for controlling balance, coordination, and muscle movement. It also plays a role in learning and memory.

E. Conclusion: The hindbrain is an important part of the brain that is responsible for controlling basic functions such as breathing, heart rate, and movement. It also plays a role in learning and memory. It is composed of the medulla, pons, and cerebellum.

Question:

Write short note on forebrain.

Answer:

A. Forebrain:

The forebrain is the largest and most complex part of the brain. It is responsible for higher-level functions such as thought, memory, language, problem solving, and emotion. It consists of several structures, including the thalamus, hypothalamus, and the cerebral cortex. The thalamus acts as a relay station for sensory information from the body to the cortex. The hypothalamus is responsible for regulating hormones and other bodily functions, such as temperature, hunger, and thirst. The cerebral cortex is the outermost layer of the brain and is responsible for higher-level cognitive functions such as reasoning, decision-making, language, and emotion. The forebrain is essential for many of the functions that make us human.

Question:

Differentiate between rods and cones.

Answer:

Step 1: Understand the meaning of ‘differentiate’.

Step 2: Research the characteristics of rods and cones.

Step 3: Compare and contrast the characteristics of rods and cones.

Step 4: Summarize the differences between rods and cones.

Question:

What effect did the linnet’s song have over Hail and the North Wind?

Answer:

1. The linnet is a small European bird known for its beautiful song.

2. Hail and the North Wind are characters in a poem by William Wordsworth.

3. In the poem, the linnet’s song has a calming effect on Hail and the North Wind, making them pause in their destructive path.

Question:

Draw a well-labelled diagram of an ear.

Answer:

1. Start by drawing a basic outline of the ear.

2. Label the different parts of the ear, such as the outer ear (pinna), ear canal, eardrum (tympanic membrane), middle ear (ossicles), inner ear (cochlea), and auditory nerve.

3. Add details to the diagram, such as the folds of the pinna, the shape of the ear canal, the size of the eardrum, and the location of the ossicles.

4. Color in the diagram to make it look more realistic.

5. Add labels to the diagram to show the names of the different parts of the ear.

Question:

(a) How do you perceive the colour of an object? (b) Which part of our body helps us in maintaining the body balance? (c) How does the eye regulate the amount of light that falls on the retina?

Answer:

(a) We perceive the colour of an object by the light that reflects off of the object’s surface and is detected by our eyes.

(b) Our inner ear helps us maintain body balance by detecting the position of our head and body in space.

(c) The eye regulates the amount of light that falls on the retina by controlling the size of the pupil. The pupil gets larger in dim light and smaller in bright light to regulate the amount of light that enters the eye.

Question:

Write a short note on midbrain.

Answer:

1. The midbrain, also known as the mesencephalon, is a part of the brain located between the hindbrain and the forebrain.

2. It is responsible for a variety of functions, including vision, hearing, and motor control. It also plays a role in the regulation of sleep and wakefulness.

3. The midbrain is made up of several structures, including the tectum, tegmentum, and cerebral peduncle. The tectum is responsible for controlling visual and auditory reflexes, while the tegmentum is involved in motor coordination and the regulation of sleep and wakefulness. The cerebral peduncle is responsible for connecting the midbrain to other parts of the brain.

4. The midbrain is an important part of the brain and is responsible for many vital functions. Damage to the midbrain can lead to serious health problems, including paralysis, impaired vision, and difficulty controlling movement.

Question:

Write short note on retina.

Answer:

A. Retina is a thin layer of tissue that lines the back of the eye and is responsible for sensing light and transmitting signals to the brain. It contains millions of tiny light-sensitive cells called photoreceptors that detect light and convert it into electrical signals. These signals are then sent to the brain where they are interpreted as images. The retina is also responsible for maintaining the eye’s focus and controlling the size of the pupil. Damage to the retina can cause vision problems, such as blurred vision, blind spots, and color blindness.

Question:

Give a brief account on mechanism of vision.

Answer:

1. Vision is the ability to detect and interpret light, allowing us to see and interpret the world around us.

2. The mechanism of vision begins when light enters the eye and is focused onto the retina, a thin layer of light sensitive cells at the back of the eye.

3. The retina contains two types of cells: rods and cones. Rods are sensitive to light and help us to see in dim light, while cones are sensitive to color and provide us with sharp, detailed vision.

4. When light hits the retina, it is converted into electrical signals which are sent to the brain via the optic nerve.

5. The brain then processes these signals, allowing us to perceive and interpret the world around us.

6. In addition to the rods and cones, the retina also contains other specialized cells that help us to detect movement and perceive depth.

7. The mechanism of vision is a complex process that allows us to see and interpret the world around us.

Question:

Which part of our body helps us in maintaining the body balance?

Answer:

Answer:

1. The part of our body that helps us in maintaining body balance is the vestibular system.

2. The vestibular system is located in the inner ear and is composed of the semicircular canals, the utricle, and the saccule.

3. The semicircular canals are filled with fluid and contain tiny hairs that detect the movement of the head.

4. The utricle and saccule are filled with tiny crystals that detect the position of the head.

5. Together, the vestibular system helps us maintain our balance and orientation in space.

Question:

Give the difference between impulse conduction in a myelinated nerve fibre and unmyelinated nerve fibre.

Answer:

1. Impulse conduction in a myelinated nerve fibre occurs when the action potential is conducted along the axon by saltatory conduction. This means that the electrical signal jumps from one node of Ranvier to the next, allowing for faster conduction.

2. In contrast, impulse conduction in an unmyelinated nerve fibre occurs when the action potential is conducted along the axon by a continuous wave of depolarization. This means that the electrical signal spreads continuously along the axon, resulting in slower conduction.

Question:

Explain the mechanism of generation of light-induced impulse in the retina.

Answer:

1. Light enters the eye and passes through the cornea, lens, and aqueous humor before reaching the photoreceptor cells in the retina.

2. When light hits the photoreceptor cells, it triggers a chemical reaction in the cell membrane that causes the photoreceptor cells to become depolarized.

3. This depolarization causes the photoreceptor cells to release a neurotransmitter called glutamate, which binds to the glutamate receptors on the bipolar cells.

4. The binding of glutamate to the receptors causes the bipolar cells to become depolarized, which triggers the release of another neurotransmitter called gamma-aminobutyric acid (GABA) from the bipolar cells.

5. GABA binds to the GABA receptors on the ganglion cells, causing the ganglion cells to become depolarized.

6. This depolarization of the ganglion cells triggers an action potential, which is an electrical impulse that travels down the axon of the ganglion cell and is sent to the brain. This electrical impulse is the light-induced impulse generated in the retina.

Question:

Give the difference between aqueous humor and vitreous humor.

Answer:

1. Aqueous humor is a clear, watery fluid that is located in the front of the eye between the cornea and the lens.

2. Vitreous humor is a clear, jelly-like substance that fills the large central cavity of the eye behind the lens.

3. The main difference between aqueous humor and vitreous humor is that aqueous humor is a watery fluid, while vitreous humor is a jelly-like substance. Aqueous humor is constantly produced and drained, while vitreous humor is a stagnant fluid. Aqueous humor helps to maintain the shape of the eye and regulate intraocular pressure, while vitreous humor helps to maintain the shape of the eye and provide a clear path for light to enter the eye.

Question:

Draw labelled diagrams of the following: (a) Neuron (b) Brain (c) Eye (d) Ear

Answer:

(a) Neuron

Diagram:

(b) Brain

Diagram:

(c) Eye

Diagram:

(d) Ear

Diagram:

Question:

Write short notes on the following: (a) Neural coordination (b) Forebrain (c) Midbrain (d) Hindbrain (e) Retina (f) Ear ossicles (g) Cochlea (h) Organ of Corti
(i) Synapse

Answer:

a) Neural coordination: Neural coordination is the process by which the nervous system coordinates the activities of the body to produce a desired outcome. It involves the transmission of signals from the brain to the muscles and other organs, which then respond to the signals and perform the desired action.

b) Forebrain: The forebrain is the part of the brain that is responsible for higher-level functions such as thought, memory, language, and emotions. It is composed of several structures, including the thalamus, hypothalamus, and the cerebral cortex.

c) Midbrain: The midbrain is a part of the brain that is located between the forebrain and the hindbrain. It is responsible for vision, hearing, and motor control.

d) Hindbrain: The hindbrain is the part of the brain that is responsible for basic functions such as breathing, heart rate, and reflexes. It is composed of several structures, including the medulla, pons, and cerebellum.

e) Retina: The retina is the innermost layer of the eye. It contains light-sensitive cells that convert light into electrical signals. These signals are then sent to the brain, which interprets them as images.

f) Ear ossicles: The ear ossicles are three small bones in the middle ear that help to transmit sound waves from the outer ear to the inner ear. They are the malleus, incus, and stapes.

g) Cochlea: The cochlea is a spiral-shaped organ in the inner ear that contains hair cells that convert sound waves into electrical signals. These signals are then sent to the brain, which interprets them as sound.

h) Organ of Corti: The organ of Corti is a structure in the inner ear that contains hair cells that convert sound waves into electrical signals. These signals are then sent to the brain, which interprets them as sound.

i) Synapse: A synapse is a junction between two neurons that allows them to communicate with each other. It is composed of an axon terminal of one neuron, which releases neurotransmitters that bind to receptors on the other neuron.

Question:

Draw a well labelled diagram of eye.

Answer:

Step 1: Draw a circle to represent the eye.

Step 2: Draw a smaller circle inside the first circle to represent the pupil.

Step 3: Draw a curved line above the eye to represent the eyebrow.

Step 4: Draw a curved line below the eye to represent the eyelid.

Step 5: Draw a curved line below the pupil to represent the iris.

Step 6: Draw a curved line below the iris to represent the sclera.

Step 7: Draw a curved line between the pupil and the sclera to represent the limbus.

Step 8: Draw a curved line above the pupil to represent the cornea.

Step 9: Draw a small curved line above the pupil to represent the aqueous humor.

Step 10: Label the diagram with the parts of the eye.

Question:

Give account on mechanism of hearing.

Answer:

1. The mechanism of hearing involves the conversion of sound waves into electrical signals that travel to the brain.

2. The process starts with sound waves entering the external auditory canal and reaching the eardrum.

3. The eardrum vibrates in response to the sound waves and these vibrations are transmitted to the middle ear by three small bones called the ossicles.

4. The ossicles amplify the sound vibrations and transmit them to the inner ear.

5. In the inner ear, the vibrations are converted into electrical signals by the cochlea.

6. The cochlea contains thousands of tiny hair cells that are sensitive to the vibrations.

7. The electrical signals are then sent to the auditory nerve, which carries the signals to the brain.

8. The brain interprets the signals as sound and we are able to hear.

Question:

Write short note on synapse.

Answer:

Synapse:

1. A synapse is a junction between two neurons, or between a neuron and a target cell, that allows electrical or chemical signals to be transmitted from one cell to the other.

2. Synapses can be either chemical or electrical, depending on the type of signal being transmitted. Chemical synapses involve the release of neurotransmitters, while electrical synapses involve the passage of electrical current between two neurons.

3. Synapses are responsible for the communication between neurons and other cells in the body, allowing for the coordination of complex behaviors such as movement, learning, and memory.

4. Synapses are dynamic structures, meaning that they can be strengthened or weakened depending on the activity of the neurons involved. This plasticity is an important factor in learning and memory.

5. Synapses are essential for the functioning of the nervous system, and any disruption in the synapse can lead to a variety of neurological disorders.

Question:

Which part of our central neural system acts as a master clock?

Answer:

1. The Central Nervous System (CNS) is the body’s main control and coordination center.

2. Within the CNS, the hypothalamus is responsible for regulating many of the body’s functions, including the circadian rhythm, or the body’s “master clock.”

3. Therefore, the hypothalamus is the part of the central nervous system that acts as a master clock.

Question:

Give difference between blind spot and yellow spot.

Answer:

Step 1: Understand what a blind spot and a yellow spot are. A blind spot is an area of the eye where the optic nerve passes through the retina, blocking light from reaching the photoreceptor cells. A yellow spot is a small area in the center of the retina that is packed with light-sensitive cells, called cones, which are responsible for color vision.

Step 2: Compare and contrast the two. The main difference between a blind spot and a yellow spot is that a blind spot does not contain any photoreceptor cells, while a yellow spot is packed with light-sensitive cones which are responsible for color vision. Additionally, a blind spot produces no vision, while a yellow spot produces a sharp image.

Question:

The region of the vertebrate eye, where the optic nerve passes out of the retina, is called as (a) Fovea (b) Iris (c) Blind spot (d) Optic chaisma

Answer:

Answer: (c) Blind spot

Question:

Distinguish between: (a) Afferent neurons and efferent neurons (b) Impulse conduction in a myelinated nerve fibre and unmyelinated nerve fibre (c) Aqueous humor and vitreous humor (d) Blind spot and yellow spot (e) Cranial nerves and spinal nerves

Answer:

(a) Afferent neurons are sensory neurons that carry information from the body to the central nervous system. Efferent neurons are motor neurons that carry information from the central nervous system to the body.

(b) Impulse conduction in a myelinated nerve fibre is faster than in an unmyelinated nerve fibre due to the presence of the myelin sheath, which acts as an insulator and increases the speed of conduction.

(c) Aqueous humor is a clear, watery fluid that fills the space between the cornea and the lens of the eye. Vitreous humor is a thick, gel-like substance that fills the space between the lens and the retina of the eye.

(d) The blind spot is an area on the retina where there are no photoreceptors and no vision. The yellow spot is an area on the retina where there are a high concentration of cones, which are responsible for color vision.

(e) Cranial nerves are nerves that originate in the brain and supply the head and neck. Spinal nerves are nerves that originate in the spinal cord and supply the body.

Question:

Explain the mechanism through which a sound produces a nerve impulse in the inner ear.

Answer:

1. Sound waves enter the ear and travel through the outer ear, also known as the pinna, to the ear canal.

2. The sound waves then travel to the eardrum, a thin membrane that vibrates when it is struck by sound waves.

3. The vibrations of the eardrum cause the three tiny bones of the middle ear (the malleus, incus, and stapes) to move.

4. The movement of the bones causes the fluid inside the cochlea, a snail-shaped organ in the inner ear, to ripple.

5. The rippling of the fluid causes the tiny hairs in the cochlea to move.

6. The movement of the hairs creates electrical signals that travel along the auditory nerve to the brain, where they are interpreted as sound.

Question:

Differentiate between dendrites and axon.

Answer:

Step 1: Understand what dendrites and axons are.

Step 2: Dendrites are short, thin nerve fibers that extend from the cell body of a neuron and receive signals from other neurons.

Step 3: Axons are long, thin nerve fibers that carry signals away from the cell body of a neuron to other neurons.

Step 4: Compare the two: Dendrites receive signals from other neurons, while axons carry signals away from the cell body of a neuron.

Question:

Distinguish between cerebrum and cerebellum.

Answer:

Step 1: Understand the definition of cerebrum and cerebellum.

Step 2: Compare and contrast the two structures.

Step 3: Identify the differences between the two structures.

Step 4: Explain how the two structures differ in terms of their functions and roles in the body.

Question:

Briefly describe the structure of brain.

Answer:

1. The brain is made up of three main parts: the forebrain, midbrain, and hindbrain.

2. The forebrain is the largest part of the brain and is responsible for higher-level functions such as thinking, planning, and decision-making. It is composed of the cerebral cortex, thalamus, hypothalamus, and limbic system.

3. The midbrain is located between the forebrain and hindbrain and is responsible for controlling motor functions, such as eye movement, and processing auditory and visual information.

4. The hindbrain is located at the base of the skull and is composed of the cerebellum, pons, and medulla oblongata. It is responsible for maintaining basic body functions, such as breathing and heart rate.

Question:

Explain the following. (a) Role of Na+ in the generation of action potential. (b) Mechanism of generation of light-induced impulse in the retina. (c) The mechanism through which a sound produces a nerve impulse in the inner ear.

Answer:

(a) The role of Na+ in the generation of action potential is to allow the cell membrane to become more permeable to sodium ions. This causes a rapid influx of sodium ions into the cell, which causes the membrane potential to become more positive. This depolarization of the membrane potential is what triggers the action potential.

(b) The mechanism of generation of light-induced impulse in the retina involves the photoreceptors in the retina. When light enters the eye and hits the photoreceptors, it causes a change in the membrane potential of the photoreceptors. This change in membrane potential triggers the release of neurotransmitters, which then travel to other neurons in the retina. These neurons then send out an action potential, which is the light-induced impulse.

(c) The mechanism through which a sound produces a nerve impulse in the inner ear involves the hair cells of the cochlea. When sound waves enter the ear, they cause the hair cells to vibrate. This vibration causes the hair cells to open ion channels, which allows for the influx of ions into the cell. This causes the membrane potential to become more positive, which triggers the release of neurotransmitters. These neurotransmitters then travel to other neurons in the inner ear, which then send out an action potential, which is the sound-induced nerve impulse.

Question:

Answer the following: (a) Which part of the ear determines the pitch of a sound? (b) Which part of the human brain is the most developed? (c) Which part of our central neural system acts as a master clock?

Answer:

(a) The inner ear, specifically the cochlea, determines the pitch of a sound.

(b) The prefrontal cortex is the most developed part of the human brain.

(c) The suprachiasmatic nucleus (SCN) is a part of the hypothalamus that acts as a master clock for our central nervous system.