Question -
Answer -
The differences are asfollows:
(a) Afferent neuronsand efferent neurons
| Afferent neurons | Efferent neurons |
| Afferent neurons are sensory neurons | Efferent neurons are motor neurons |
| Conduction of sensory impulses from the receptors towards the central nervous system | Conduction of motor impulses from the central nervous system to the responsive or effector organs |
| Located in sense organs | Found in the brain and the spinal cord |
(b) Impulse conductionin a myelinated nerve fibre and unmyelinated nerve fibre
| Impulse conduction in a myelinated nerve fibre | Impulse conduction in an unmyelinated nerve fibre |
| Impulse is transmitted from node to node | Impulse travels across the length of the nerve fiber |
| Speed of impulse-conduction is 50 times faster than non-myelinated axon | Comparatively lower |
| Less amount of energy is expended during the transmission of an impulse | Excess energy is expended during the transmission of an impulse |
(c) Aqueous humor andvitreous humor
| Aqueous humor | Vitreous humor |
| Found in the aqueous chamber between the cornea and lens | Found in the vitreous chamber between the retina and lens |
| Produced by ciliary processes | Produced by the retina of the eye |
| Has a jelly-like consistency | Has a watery consistency |
| Provides support to the lens | Renders support to the lens and retina |
(d) Blind spot andyellow spot
| Blind spot | Yellow spot |
| It is a point on the retina where the optic nerve exits the eye while the retinal blood vessels enter the eye | It is a point on the retina which is found exactly opposite to the center of the cornea |
| It does not contain photoreceptor cells | It contains two kinds of photoreceptor cells – rods and cones |
| They are not sensitive to light | They are light-sensitive |
| It is not functional in vision | The yellow spot is the region that has the most distinct vision |
(e) Cranial nerves andspinal nerves
| Cranial nerves | Spinal nerves |
| Human body has 12 pairs of cranial nerves | We have 31 pairs of spinal nerves |
| Cranial nerves emerge from the brain and extend to other parts of the body | They originate from the spinal cord, extending to other parts of the body |
| Cranial nerves can be mixed, motor or sensory | Spinal nerves are mixed nerves |