(a) Central neural system (CNS) and Peripheral neural system (PNS)
|
Central neural system |
|
Peripheral neural system |
1. |
It is the main coordinating centre of the body. |
1. |
It is not the main coordinating centre of the body. |
2. |
It includes brain and spinal cord. |
2. |
It includes cranial and spinal nerves that connect central nervous system to different parts of the body. |
(b) Resting potential and action potential
|
Resting potential |
|
Action potential |
1. |
It is the potential difference across the nerve fibre when there is no conduction of nerve impulse. |
1. |
It is the potential difference across nerve fibre when there is conduction of nerve impulse. |
2. |
The membrane is more permeable to K+ ions than to Na+ ions. |
2. |
The membrane is more permeable to Na+ ions than to K+ ions. |
(c) Choroid and retina
|
Choroid |
|
Retina |
1. |
Choroid is the middle vascular layer of eye. |
1. |
Retina is the innermost nervous coat of eye. |
2. |
It contains numerous blood vessels that provide nutrients and oxygen to retina and other tissues. |
2. |
It contains photoreceptor cells, rods and cones that are associated with twilight and colour vision respectively. |
Briefly describe the structure of the following:
(a) Brain
(b) Eye
(c) Ear
Which of the following is not correct?
(a) Robert Brown discovered the cell.
(b) Schleiden and Schwann formulated the cell theory.
(c) Virchow explained that cells are formed from pre-existing cells.
(d) A unicellular organism carries out its life activities within a single cell.
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