REFLEX PT 1 Flashcards
(33 cards)
what are inborn reflexes
intrinsic, predictable motor response to a stimulus; can be mofidiied
what are learned/acquired reflexes
results from practice or repetition
whats the stimulus receptors
site of stimulus action
what does the sensory neuron do
transmits afferent signals
whats the integration center
synapse between neurons
what are motor neurons
conducts efferent impulses to the integration center to effector organs
whats the effector
muscle fiber or gland cell that responds to efferent signals
what are somatic reflexes
activate skeletal muscles
what are autonomic visceral reflexes
activate visceral effectors (smooth or cardiac muscle glands)
why do we need to test somatic reflexes
assess condition of nervous system
what do exaggerated, distorted or absent reflexes indicate
degeneration and pathology of specific nervous system regions
what are the most common assessed reflexes
stretch, flexor, and superficial
what are somatic reflexes mediated by
spinal cord
what does the nervous system need to know for stretch and tendon reflexes
length of muscles and amount of tension in muscles and tendons
describe flexor and crossed-extensor reflexes
automatic withdrawal of threatened body part from stimulus
describe superficial reflexes
depend both on functional upper motor pathways and on cord-level reflex arcs
describe reflexes and muscle length
brain sets a muscle’s allowed length and reflexes keep muscle at that length, with compensation for overstretching
what does the CNS need to know about muscle in order to coordinate its activity or reflexes
muscle length (muscle spindles) and muscle tension (Golgi tendon organs); specialized proprioceptors play a role
what do muscle spindles consist of
3-10 intramural muscle fibers (within connective tissue)
what is the central region of muscle spindle
receptive surface, that lacks myofilaments and is non contractile
what are muscle spindles wrapped by
two types of afferent endings, anulospinal endings (1o sensor) and flower spray endings (2o sensor)
describe the end region of muscle spindles
the contractile region which is innervated by efferent fibers from small motor neurons in spinal cord which maintains spindle sensitivity
describe muscle spindle excitation: external stretch
external force (load) that lengthens entire muscle (like carry heavy weights) or contraction of antoginitic muscles
describe muscle spindle excitation: internal stretch
activation of g motor neuron that stimulates distal end of the intrafusal fibers to contract, which results in stretch center of spindle
