(a) Differences between central neural system and peripheral neural system
| Central Neural system | Peripheral Neural System |
| It is a hollow, dorsally placed structure lying along the mid- dorsal axis of the body. | It comprises of the nerves arising from the central nervous system. |
| It comprises of the brain and the spinal cord. | It is made up of nerves originating from the brain called cranial nerves and those originating from the spinal cord called spinal nerves. |
| CNS controls all the activities of the body. | The function of PNS is to transmit impulses from the sense organs to CNS and from the CNS to the sense organs. |
(b) Differences between resting potential and action potential
| Resting potential | Action potential |
| The potential differences existing between the two sides of neurilemma in a resting nerve fibre is called resting potential. | The potential difference existing between the two sides of neurilemma at a state of depolarisation is called action potential. |
| Its value ranges from –40 to –90 mV and on an average is –70 mV. | Its value changes from –70 mV through 0 mv to +30 mV. |
(c) Differences between choroid and retina.
| Choroid | Retina |
| It is a component layer of the middle vascular coat of the human eye. | It is a component layer of the inner nervous coat of the human eye. |
| It is rich in blood vessels. | It is rich in neurons. |
| Its functions is to supply nutrients and oxygen to other parts of eye like retina. | Its function is to form an image of the object over it. |