Transcript Golgi Tendon Reflux

Golgi Tendon Reflux
The Golgi tendon reflex is a normal component of the reflex arc of the
peripheral nervous system. In a Golgi tendon reflex, skeletal muscle
contraction causes the antagonist muscle to simultaneously lengthen and
relax. This reflex is also called the inverse myotatic reflex, because it is the
inverse of the stretch reflex. Though muscle tension is increasing during the
contraction, alpha motor neurons in the spinal cord supplying the muscle are
inhibited. However, antagonistic muscles are activated
Function of Golgi tendon reflux
The Golgi tendon reflex protects the skeletal muscle from excessively 
heavy loads by causing the muscle to relax and drop the load.[citation
needed] First, as a load is placed on the muscle, the afferent neuron
from the Golgi tendon organ fires into the central nervous system.
Second, the motor neuron from the spinal cord is inhibited via an IPSP
and muscle relaxes. Recently, however, this information has proven to
be inaccurate since the GTO cannot create sufficient inhibition .
Contrast to stretch reflex
The stretch reflex operates as a feedback mechanism to control muscle 
length by causing muscle contraction. In contrast, the tendon reflex
operates as a feedback mechanism to control muscle tension by causing
muscle relaxation before muscle force becomes so great that tendons
might be torn. Although the tendon reflex is less sensitive than the stretch
reflex, it can override the stretch reflex when tension is great, making you
drop a very heavy weight, for example. Like the stretch reflex, the tendon
reflex is ipsilateral. The sensory receptors for this reflex are called tendon
Golgi receptors, which lie within a tendon near its junction with a muscle.
In contrast to muscle spindles, which are sensitive to changes in muscle
length, tendon organs detect and respond to changes in muscle tension
that are caused by passive stretch or muscular contraction.
Steps
A tendon reflex operates as follows:
1- nerve impulses (action potentials) arise and propagate into the spinal cord
along a sensory neuron.
2- within the spinal cord (integrating center) the sensory neuron activates an
inhibitory interneuron that makes a synapse with a motor neuron.
3- the inhibitory neurotransmitter inhibits (hyperpolarizes) the motor
neuron which then generates nerve impulses.
4- the muscle relaxes and excess tension.