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Reflex Arc   (Short Answer)

Dr.A.P.Ganesan
Komarapalayam


Explain the reflex arc with the help of a diagram

Definition
Reflex action is a sudden  involuntary response to a sensory stimulus without mediation of higher centres.
It is mediated by the centres in the spinal cord

Reflex Arc
In the reflex action, many structures involve in the accomblishment of a reflex.
These  structure are together called reflex arc.
It consists of a receptior , the afferent limb , the reflex centre , the connector fibres , the efferent limb and the effector organ.

1. Afferent limb 
It consists of
A.Receptor :  When it is stimulated ,impulses are formed .
B.Afferent nerve fiber :  It tranmists the impulses to the reflex centre .

2.Reflex centre 
It consists of
nerve cells where sensory impulses are converted into motor impulses .

3.Efferent limb :
It is made of
A. Motor or efferent  nerve fibre : it transmits motor impulses to the organ
B.Effector organ : this may be muscle or gland which show the response

Applied Physiology
Knee jerk : Patellar tendon reflex.


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