REFLEX PT 1

Question 1

what are inborn reflexes

Answer 1

intrinsic, predictable motor response to a stimulus; can be mofidiied

Question 2

what are learned/acquired reflexes

Answer 2

results from practice or repetition

Question 3

whats the stimulus receptors

Answer 3

site of stimulus action

Question 4

what does the sensory neuron do

Answer 4

transmits afferent signals

Question 5

whats the integration center

Answer 5

synapse between neurons

Question 6

what are motor neurons

Answer 6

conducts efferent impulses to the integration center to effector organs

Question 7

whats the effector

Answer 7

muscle fiber or gland cell that responds to efferent signals

Question 8

what are somatic reflexes

Answer 8

activate skeletal muscles

Question 9

what are autonomic visceral reflexes

Answer 9

activate visceral effectors (smooth or cardiac muscle glands)

Question 10

why do we need to test somatic reflexes

Answer 10

assess condition of nervous system

Question 11

what do exaggerated, distorted or absent reflexes indicate

Answer 11

degeneration and pathology of specific nervous system regions

Question 12

what are the most common assessed reflexes

Answer 12

stretch, flexor, and superficial

Question 13

what are somatic reflexes mediated by

Answer 13

spinal cord

Question 14

what does the nervous system need to know for stretch and tendon reflexes

Answer 14

length of muscles and amount of tension in muscles and tendons

Question 15

describe flexor and crossed-extensor reflexes

Answer 15

automatic withdrawal of threatened body part from stimulus

Question 16

describe superficial reflexes

Answer 16

depend both on functional upper motor pathways and on cord-level reflex arcs

Question 17

describe reflexes and muscle length

Answer 17

brain sets a muscle’s allowed length and reflexes keep muscle at that length, with compensation for overstretching

Question 18

what does the CNS need to know about muscle in order to coordinate its activity or reflexes

Answer 18

muscle length (muscle spindles) and muscle tension (Golgi tendon organs); specialized proprioceptors play a role

Question 19

what do muscle spindles consist of

Answer 19

3-10 intramural muscle fibers (within connective tissue)

Question 20

what is the central region of muscle spindle

Answer 20

receptive surface, that lacks myofilaments and is non contractile

Question 21

what are muscle spindles wrapped by

Answer 21

two types of afferent endings, anulospinal endings (1o sensor) and flower spray endings (2o sensor)

Question 22

describe the end region of muscle spindles

Answer 22

the contractile region which is innervated by efferent fibers from small motor neurons in spinal cord which maintains spindle sensitivity

Question 23

describe muscle spindle excitation: external stretch

Answer 23

external force (load) that lengthens entire muscle (like carry heavy weights) or contraction of antoginitic muscles

Question 24

describe muscle spindle excitation: internal stretch

Answer 24

activation of g motor neuron that stimulates distal end of the intrafusal fibers to contract, which results in stretch center of spindle

Question 25

what are muscle spindles activated by

Answer 25

stretch

Question 26

what do sensory neurons synapse with

Answer 26

efferent fibers in spinal cord

Question 27

what are efferent impulses sent from

Answer 27

spinal cord to resist further stretch of extrafusal fibers (muscle contracts)

Question 28

whats reciprocal inhibition

Answer 28

antagonist muscles are inhibited from resisting the contraction (relax)

Question 29

describe the first step of stretch reflex events

Answer 29

TELLS intramural fibers stretched

Question 30

describe the second step of stretch reflex events

Answer 30

RESPONSE is to send output to extrafusal fibers; activates stretch pathway 1 2

Question 31

describe the third step of stretch reflex events

Answer 31

stimulates contraction of end portions of spindle fibers

Question 32

describe the fourth step of stretch reflex events

Answer 32

alpha-gamma coactivation, which helps maintain spindle sensitivity

Question 33

describe alpha-gamma coactivation

Answer 33

impulses simultaneously sent to muscle extrafusal fibers and to muscle spindle