Explain the process of the transport and release of crneurotransmitter with the help of a labelled diagram showing a complete neuron, axon terminal and synapse.
Chemicals called neurotransmitters are involved in the transmission of impulses at chemical synapses. The axon terminals contain vesicles filled with these chemicals. When an impulse arrives at the axon terminal, it stimulates the movement of the synaptic vesicles towards the membrane where they fuse with the plasma membrane and release their neurotransmitters in the synaptic cleft. The released neurotransmitters bind to their specific receptors, present on the post-synaptic membrane. This binding opens ion channels allowing the entry of ions which can generate a new potential in the post-synaptic neuron.
Fig.: Diagram showing neuron, axon terminal and synapse
If someone receives a blow on the back of neck, what would be the effect on the person’s CNS?
Label the following parts in the given diagram using arrow.
(a) Aqueous chamber
(b) Cornea
(c) Lens
(d) Retina
(e) Vitreous chamber
(f) Blind spot
Answer the following.
(a) Which part of the ear determines the pitch ofa 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?
Neural system and computers share certain common features. Comment in five lines. (Hint: CPU, input-output devices).
Rearrange the following in the correct order of involvement in electrical impulse movement- Synaptic knob. Dendrites, Cell body. Axon terminal. Axon.
The major parts of the human neural system is depicted below. Fill in the empty boxes with appropriate words.
6. Give a brief account of
(a) Mechanism of synaptic transmission.
(b) Mechanism of vision.
(c) Mechanism of hearing.
While travelling at a higher altitude, a person complains of dizziness and vomiting sensation. Which part of the inner ear is disturbed during the journey?
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) Mechanism through which a sound produces a nerve impulse in the inner ear.
Arrange the following in the order of reception and transmission of sound wave from the ear drum:
Cochlear nerve.External auditoru canal, Ear drum, Stapes, Incus, Malleus, Cochlea.
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) Mechanism through which a sound produces a nerve impulse in the inner ear.
The region of the vertebrate eye, where the optic nerve passes out of the retina, is called the
(a) fovea (b) iris
(c) blind spot (d) optic chiasma
Which sensory organ is involved in vertigo (sensation of oneself or objects spinning around)?
Our reactions like aggressive behaviour, use of abusive words, restlessness etc. are regulated by brain, name the parts involved.
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
Compare the following:
(a) Central neural system (CNS) and Peripheral neural system (PNS).
(b) Resting potential and action potential.
(c) Choroid and retina.
Answer briefly.
(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?
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.
Explain the process of the transport and release of crneurotransmitter with the help of a labelled diagram showing a complete neuron, axon terminal and synapse.
During resting potential, the axonal membrane is polarised, indicate the movefnent of +ve and -ve ions leading to polarisation diagrammatically.
Distinguish between
(a) Afferent neurons and efferent neurons
(b) Impulse conduction in myelinated nerve fibre and unmyelinated nerve fibre
(c) Aqueous humour and vitreous humour
(d) Blind spot and yellow spot
(e) Cranial nerves and spinal nerves
Differentiate between
(a) Myelinated and non-myelinated axons
(b) Dendrites and axons
(c) Rods and cones
(d) Thalamus and Hypothalamus
(e) Cerebrum and Cerebellum
