Explain The Types of Reflex Actions

Types of Reflex Actions

Depending upon the part of central nervous system used in re-routing reflex arc, reflex actions are of two types, spinal and cerebral. In spinal reflex, spinal cord is the relay centre, e.g., withdrawal of hand coming in contact with hot surface. In cerebral reflex part of the brain is

used as relay centre without involving the thinking part, e.g., closing of eyes when bright light is focused on them.

On the basis of origin, reflex action can be unconditioned or conditioned.

Unconditioned or Natural Reflex Action.

It is reflex action which is inborn or present right from birth. The response is the same in all the individuals. Some common examples are

(i) Closing of eyes when strong light is flashed on them or some moving object approaches them.

(ii) Wide opening of pupil in dim light and narrowing of pupil in strong light.

(iii) Withdrawal of hand or foot when pricked.

(iv) Jerking of knee when it is hit below the knee

Conditioned or Acquired Reflex Action.

It is reflex action that develops after birth due to learning, habit or regular association of indifferent stimulus with a natural stimulus. Conditioned reflexes can change or disappear with change in habit or environment. Some common examples are

(i) Tying of shoe laces without looking             (ii) Knitting without looking

(iii) Pedalling            (iv) Reading (v) Writing.