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physiology > PNS and reflex activity (ch 13) > Flashcards

PNS and reflex activity (ch 13) Flashcards

1
Q

the CNS sends info

A

out

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2
Q

effectors are activated when

A

a NT is secreted onto an effector organ

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3
Q

where does innervation of skeletal muscle take place

A

at the level of the neuromusculojunction (NMJ)

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4
Q

what is the neurotransmitter involved in skeletal muscle innervation

A

Acetylcholine (ACh)

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5
Q

steps of skeletal muscle innervation

A

nerve impulse reaches axon terminal to release ACh, which binds to receptors and results in excitation (movement of Na+/K+ across the membrane, depolarization of muscle cell), end plate potential triggers an AP in the cell, resulting in contraction

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6
Q

autonomic motor endings and visceral effectors are _____ than somatic junctions

A

simpler

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7
Q

steps of visceral muscle and gland innervation

A

branches form synapses en passant via varicosities, two different NTs (ACh and NE(norepinephrine)) act indirectly via second messenger systems

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8
Q

compared to somatic, visceral motor responses are

A

slower

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9
Q

in skeletal muscle, the cerebellum and basal nuclei are

A

the main coordinators of muscle control

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10
Q

_____ motor behavior depends on _____ patterns of control

A

complex, complex

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11
Q

what are the three levels of motor control in skeletal muscle

A

segmental, projection, pre-command

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12
Q

the segmental level of motor control is

A

the lowest level of motor hierarchy

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13
Q

the segmental level involves

A

reflexes, spinal cord circuits, and central pattern generators (CPGs)

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14
Q

T/F: the segmental level is not conscious

A

true

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15
Q

CPGs are

A

segmental circuits that activate networks of ventral horn neurons to stimulate specific groups of muscles

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16
Q

the projection level of motor control consists of

A

the precentral gyrus (cortex, brain stem motor areas)

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17
Q

the cortex contains _____ that initiate the _____

A

upper motor neurons, direct (pyramidal) system

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18
Q

the brain stem motor areas oversee the _____

A

indirect (extrapyramidal) system

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19
Q

the direct pyramidal system involves

A

voluntary movement

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20
Q

the indirect (extrapyramidal) system involves

A

reflexes and CPGs

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21
Q

projection level motor pathways send information to _____ and let _____ know what is happening

A

lower motor neurons, higher command levels

22
Q

the precommand level is

A

the highest level of motor control

23
Q

what occurs in the precommand level

A

neurons in the cerebellum and basal nuclei control outputs of the cortex and brainstem

24
Q

functions of the cerebellum

A
  • act on motor pathways through projection areas located in the brainstem
  • act on motor cortex via the thalamus (sensory relay station)
25
Q

functions of the basal nuclei

A
  • at rest, acts to inhibit motor centers
  • when you need to move of change movement, it stops motor inhibition
26
Q

parkinson’s results in

A

a resting tremor and stiffness/lack of movement

27
Q

a reflex is

A

a rapid, predictable, involuntary motor response to a given stimulus

28
Q

two categories of reflexes

A

autonomic and somatic

29
Q

there are more of this type of reflex

A

autonomic

30
Q

autonomic reflexes involve

A

smooth muscle, cardiac muscle, and glands

31
Q

examples of autonomic reflexes

A

sweating when hot, increasing heart rate when exercising, salivating when eating

32
Q

somatic reflexes involve

A

skeletal muscle

33
Q

examples of somatic reflexes

A

knee jerk, shivering, cough, sneeze

34
Q

steps of the reflex arc

A

receptor picks up a stimulus, sensory neurons carry the info (APs) to the CNS, integration of synapses occurs in the CNS, motor neurons carry APs away from the CNS, effector gives a response

35
Q

speed of skeletal muscle

A

quick

36
Q

parts of the muscle stretch reflex

A

muscle spindle (receptor), alpha motor neurons (outside)

37
Q

parts of the muscle spindle

A
  • intrafusal muscle fibers (made of skeletal muscle cells)
  • sensory neurons
  • motor neurons
38
Q

types of sensory neurons and their functions

A
  • type I responds to stretch speed
  • type II responds to stretch degree/amount
39
Q

function of gamma motor neurons

A

adjust spindle/intrafusal therefore adjusting the spindle response

40
Q

function of alpha motor neurons

A

acts on extrafusal fibers

41
Q

alpha and gamma motor neurons are stimulated _____ so _____

A

together, the spindle can still respond at various muscle lengths

42
Q

events of the muscle stretch reflex

A

stretched muscle increases APs to CNS via a sensory neuron, sensory neuron synapses with alpha motor neuron of the stretched muscle and inhibitory interneuron to inhibit the alpha motor neuron of the antagonist muscle, stretched muscle contracts and the antagonist relaxes

43
Q

example of muscle stretch reflex

A

knee jerk reflex (knee/quads contract, hamstrings relax)

44
Q

examples of somatic reflexes

A
  • withdrawal reflex
  • crossed extensor reflex
  • golgi tendon organ reflex
  • superficial spinal reflexes (babinski)
45
Q

the withdrawal reflex is

A

pulling away from painful stimuli

46
Q

the crossed extensor reflex is

A

where one side flexes and the other side extends

47
Q

the crossed extensor reflex is

A

where one side flexes and the other side extends

48
Q

the golgi tendon reflex

A

acts to inhibit the muscle from pulling too hard on a tendon

49
Q

the babinski reflex is

A

when the toes flex in response to a stimulus on the bottom of the foot

50
Q

the babinski reflex develops around age

A

1-2

51
Q

examples of autonomic reflexes

A

digestive - stomach stretch moves colon
cardiovascular - heart rate, BP, vessel flow
integument/skin - sweat, goosebumps
senses (eyes) - pupil, focus
urinary - bladder contracts
reproductive - childbirth, orgasm

52
Q

what information is gained by testing the reflexes

A
  • function of nerves
  • spinal cord/brain function at various levels
  • degree of stimulation or inhibition of motor areas from brain

physiology (11 decks)

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