(motor system examination part II (reflexes

Reflexes are involuntary movement in
response to a stimulus.
Reflex arc:
is a neural pathway that controls an
action reflex.
?A basic reflex arc consists of:
?The receptor.
?Sensory neuron(afferent).
?Integration center in CNS.
?Motor neuron(efferent).
? The effector (muscle or gland) .
How the Message Travels From the
Receptor to the Effector.
?A sensory neuron carries
the message from the
Receptor to the
central nervous system
(the spinal cord and brain).
?A motor neuron carries the
message from the central
nervous system to
the effector.
Monosynaptic vs. polysynaptic
? Monosynaptic reflex: When a reflex arc consists of only two neurons one sensory neuron, and one motor neuron and presence of a single chemical synapse. As knee reflex.
? Polysynaptic reflex: when one or more interneurons connect afferent (sensory) and efferent (motor) signals.
Human reflexes
1. Deep tendon reflexes called Stretch reflex : is a muscle contraction in response to stretching within the muscle.
? It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length, as knee jerk, ankle jerk, Triceps and biceps jerk .