Question

Compare the following :

(a) Central neural system (CNS) and Peripheral neural system (PNS)

(b) Resting potential and action potential

(c) Choroid and retina

Answer 1

(a) Central neural system (CNS) and Peripheral neural system (PNS)
$\begin{array}{cc}\text{Central neural system (CNS)}& \text{Peripheral neural system (PNS)}\\ \text{It is the main coordinating centre of the body.}& \text{It is not the main coordinating centre of the body.}\\ & \text{body.}\\ \text{It lies inside the skull.}& \text{It is present outside the skull in the peripheral areas of the body.}\\ \text{This includes brain and spinal cord}.& \text{This includes all the nerves of the body}\\ & \text{associated with the CNS (brain and spinal}\\ & \text{cord).}\end{array}$

(b) Resting potential and action potential
$\begin{array}{cc}\text{Resting potential}& \text{Action potential}\\ \text{It is the potential difference across the nerve}& \text{It is the potential difference across nerve fibre}\\ \text{fibre when there is no conducting of nerve}& \text{when there is conduction of nerve impulse.}\\ \text{impulse.}& \\ \text{The interior of the neuron is electronegative}& \text{The interior of the neuron is electropositive}\\ \text{and the exterior is electropositive}.& \text{and the exterior is electronegative.}\\ \text{An active sodium pump operates.}& \text{No sodium pump operates.}\end{array}$

(c) Choroid and retina
$\begin{array}{cc}\text{Choroid}& \text{Retina}\\ \text{Choroid is the middle vascular layer of eye.}& \text{Retina is the innermost nervous coat of eye.}\\ \text{It is rich in blood cells}& \text{It is rich in neurons}\\ \text{Its function is to supply nutrients and oxygen}& \text{Its function is to form an image of an object}\\ \text{to other parts of eye like retina}& \text{over it.}\end{array}$