(a) Central neural system (CNS) and Peripheral neural system (PNS)
(b) Resting potential and action potential
(c) Choroid and retina
(a) Central neural system (CNS) and Peripheral neural system (PNS)
| Central neural system (CNS) | Peripheral neural system (PNS) |
| Contains – Spinal cord, Brain | Contains – Spinal nerves, Cranial nerves |
| Brain and Spinal column are protected by the vertebral column and the skull. | There is no protective system. |
| There is no subdivisions in CNS | Division – Autonomic nervous system, Somatic nervous system |
| Function: Processing of information and regulation of the responses to the nerve impulses. | Function: Nerves of PNS passes impulses to the CNS and responses from the CNS to various structures of the body |
| Nuclei – Group of neurons | Ganglia – Group of neurons |
(b) Resting potential and action potential
| Resting potential | Action potential |
| Potential difference – When the neuron is at resting phase | Potential difference – When the neuron is triggered |
| Exterior side – Positively charged; Interior side – Negatively charged | Exterior side – Negatively charged; Interior side -Positively charged |
| The Permeability of K+ ions is more | The Permeability of Na+ ions is more |
(c) Choroid and retina
| Choroid | Retina |
| Formation of the mid coat and vascular layer of the eyeball is done by Choroid. | Formation of the inner coat and neurosensory layer of the eye ball is done by Retina. |
| No photoreceptor cells present | Rods and cones are present |
| Function: Prevents reflection of light in the eye, nourishes the retina | Function: Imparts vision |