Reflexes

Front 1

Reflex

Back 1

 A quick movement that occurs in response to stimuli
 An automatic or unconscious response of an effector organ ( muscle or gland ) to an appropriate stimulus

Front 2

Reflex Arc

Back 2

- Components involved for a reflex to occur is known as

reflex arc consist of :
 a receptor
 an afferent neuron
 Interneuron
 an efferent neuron
 an effector organ

Front 3

Stretch Reflex

Back 3

 This is a basic reflex present in the spinal cord.

 Stretch reflex also known asmyotaticreflex .
 Describes the contraction of a muscle in response to stretch.
Mechanism?
 Stimulus: muscle stretch
 Receptors: stretch receptors located in the musclespindle
 Response: contraction of the muscle

Front 4

Stretch Reflex process

Back 4

 Stretch of muscle stimulates the muscle spindle .

 The impulse travels to the spinal cord by way of an afferent neuron .
 Transmission of the impulse to an efferent neuron may be direct or by way of an interneuron .
 Stimulation of an efferent neuron to striated muscle counteracts stretch by causing contraction .
 Muscle contracts .
 It is a very quick impulse , since the impulse only has to go to the spinal cord and back , not all the way to the brain
 It generally occurs in 1 – 2 milliseconds

Front 5

Stretch Reflex process

Back 5

Front 6

Importance of stretch reflex

Back 6

 Detects muscle length and changes in muscle length.
 To avoid injury to the muscles by limiting the
amount of lengthening.
 Also helps regulate and maintain muscles tone