Summary Reflex Actions.

Reflex Actions:
 Reflexes are rapid, involuntary responses to stimuli.
 They do not involve conscious parts of the brain.
 They minimise damage to the body.




Reflex Process
 If your cornea is touched your eyelids will briefly close to protect it from
Blinking damage.
Reflex  This also occurs in bright light or with very loud sounds.
(Corneal  Sensory neurone from the cornea sends an impulse to the brainstem.
Reflex).  Theis synapses with an intermediate neurone.
 A motor neurone then causes the eyelid muscles to contract.
Knee  Its function is to quickly straighten the leg if the quadriceps are
Jerk suddenly stretched & this helps maintain posture & balance.
Reflex  The patella tendon is stretched.
 Stretch receptors called muscle spindles detect the increase in length of
the muscle.
 The sensory neurone directly stimulates a motor neurone which causes
the extensor muscle at the front of the quadriceps to contract,
straightening the leg.
 At the same time the sensory neurone sends an impulse to the relay
neurone that inhibits the motor neurone of the flexor muscle, causing it
to relax