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241 A&P > Exam 4, Chapter 13b - Somatic Motor (Part 2) > Flashcards

Exam 4, Chapter 13b - Somatic Motor (Part 2) Flashcards

1
Q
  1. Receptor
  2. Sensory neuron
  3. Integration center
  4. Motor neuron
  5. Effector
A

Reflex Arcs

Five Components of

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2
Q

site of stimulus

A

Reflex Arcs

Receptor

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3
Q

transmits the afferent impulse to the CNS

A

Reflex Arcs

Sensory neuron

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4
Q

either monosynaptic or polysynaptic region within the CNS

A

Reflex Arcs

Integration center

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5
Q

conducts efferent impulses from the integration center to an effector

A

Reflex Arcs

Motor Neuron

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6
Q

muscle fiber or gland that responds to the efferent impulse

A

Reflex Arcs

Effector

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7
Q

For skeletal muscles to perform in a normal coordinated fashion, the nervous system needs
___ types of information:

A

Reflex Component Anatomy

2

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8
Q

Length of the muscle: provided by the

A

Reflex Component Anatomy

muscle spindles

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9
Q

Amount of tension in the muscles: provided by the

A

Reflex Component Anatomy

Golgi tendon organs (proprioceptors)

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10
Q

Composed of modified muscle fibers called intrafusal muscle fibers that are wrapped in a
connective tissue capsule (the spindle = fusal) and serve as receptive surfaces.

A

Muscle Spindles

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11
Q

Only the ends of the ___ are contractile & are innervated by gamma (gamma) efferent fibers

A

Muscle Spindles

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12
Q

Contractile skeletal muscle fibers are extrafusal fibers & are innervated by alpha (α) efferent fibers

A

Muscle Spindles

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13
Q

signals from the brain cause the muscle spindles to be more taut (greater force of extrafusal contraction can be anticipated; e.g. high vertical jump) or to be
less taut, as the situation demands

A

Operation of the Muscle Spindles

Gamma / efferent

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14
Q

Stretching the muscles also activates the ____, which then sends afferent impulses to the spinal cord

A

Muscle spindles

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15
Q

The greater the rate and degree of stretch, the ___ the impulse frequency

A

Muscle spindles

higher

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16
Q

Stretch Reflex
Patellar Reflex Example
Tapping the patellar tendon quickly - stretches the quadriceps and starts the reflex action

A

yes

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17
Q

Stretch Reflex
Patellar Reflex Example
The ___ is activated and sends afferent impulses to the spinal cord (dorsal horn)
-Two components!

A

muscle spindle

18
Q

synapses with an alpha (alpha) motor neuron in the ipsilateral
ventral horn causing immediate contraction of the quadriceps, with resultant knee extension

A

Monosynaptic component

19
Q

the muscle spindle afferent simultaneously synapses with an inhibitory interneuron which subsequently synapses with the ventral horn α-motor neuron for the antagonist muscle (in this case, the hamstrings)

A

Polysynaptic component

20
Q

While the quadriceps muscles are contracting, the hamstrings are inhibited and unable to resist the contraction.

A

Net result: Reciprocal Inhibition:

21
Q

Stretch Reflex and Muscle Tone
The brain sends commands to _____ neurons, effectively setting a muscle’s length (or
tone).

A

gamma motor neurons

22
Q

The stretch reflex assists in maintaining this “set point” for muscle tone, especially in
the postural muscles of the trunk

A

ex:
knees don’t buckle during squat (stretched quadriceps muscle triggers a stretch reflex, which causes the quadriceps to contract, preventing a fall)

23
Q

activate skeletal muscles

A

Somatic (voluntary) reflexes: activate skeletal muscles

24
Q

activate visceral effectors

A

Autonomic Reflexes

25
Q

smooth muscle, cardiac muscle, glands

A

Autonomic Reflexes

Effectors

26
Q

these are used as neurotransmitters

A

Autonomic Reflexes
Acetylcholine
Norepinephrine

27
Q

Autonomic motor endings and visceral effectors are ___ than somatic junctions

A

Autonomic Reflexes

simpler

28
Q

Visceral responses are faster?/slower? than somatic responses

A

Autonomic Reflexes

slower

29
Q

Produces the opposite effect of the stretch reflex

A

Golgi Tendon Reflex and Flexor Withdrawal

30
Q

are located in the muscle tendons and are activated during a significant increase in muscle tension (e.g.: carrying a dangerously heavy load)

A

Golgi Tendon Reflex and Flexor Withdrawal

Golgi Tendon Organs (GTO)

31
Q

Helps prevent muscles and tendons from tearing when they are subjected to a damaging
stretching force

A

Golgi Tendon Reflex and Flexor Withdrawal

32
Q

-The GTO afferent travels to the dorsal horn and synapses with an inhibitory
interneuron.
-This interneuron synapses with the ventral horn α-motor neuron for the
contracting muscle.
-The GTO afferent also synapses with an excitatory interneuron.
-This interneuron synapses with the ventral horn α-motor neuron for the antagonist muscle.

A

Golgi Tendon Reflex and Flexor Withdrawal

33
Q

(contracting muscle relaxes & antagonist activates)

A

Golgi Tendon Reflex and Flexor Withdrawal

Net Result: Reciprocal Activation

34
Q

-reflex is initiated by a painful stimulus (actual or perceived) that causes automatic withdrawal of the threatened body part

A

Flexor Withdrawal Reflexes

35
Q

-Polysynaptic and ipsilateral

A

Flexor Withdrawal Reflexes

36
Q

-overrides other spinal pathways and other reflexes

A

Flexor Withdrawal Reflexes

Protective

37
Q

Can be overridden by descending signals from the brain (not pulling away from a needle
during a blood draw)

A

Flexor Withdrawal Reflexes

Protective

38
Q

includes the flexor withdrawal component plus The contralateral side is extended
(opposite arm swing when you pull one back)
THINK DISCUS

A

Crossed Extensor Reflex

39
Q

initiated by firmly/sharply stimulating the lateral aspect of the sole of the foot, moving medially at the metatarsal heads

A

Plantar reflex

40
Q

normal response is downward flexion of all toes (including the hallux)

A

Plantar Reflex

41
Q

abnormal plantar reflex where the hallux extends and pedal digits 2-5 fan laterally

A

Babinski’s sign

42
Q

Indirectly tests for corticospinal tract functioning (Indicates an UMN lesion)

A

Babinski’s sign

241 A&P (19 decks)

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