Golgi Tendon Reflux

1
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

2
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 .

3
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.

4
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.