Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NEURO 3000 > ch. 13 - spinal control of movement > Flashcards

ch. 13 - spinal control of movement Flashcards

1
Q

motor system

A

all muscles and the neurons that control them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

behavior requires the coordination of how many muscles?

A

almost 700

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

smooth muscle

A

lines the GI tract, arteries, and related structures; innervated by autonomic nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the role of smooth muscles?

A

peristalsis and blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

cardiac muscle

A

heart muscle that functions without innervation but can be modified by ANS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

skeletal muscle

A

the bulk of muscles mass; muscle within a sheath and composed of hundreds of fibers. innervated by CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

functions of skeletal muscle

A
  • move bones around joints
  • move eyes within the head
  • control respiration
  • control facial expression
  • produce speech
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

muscles that work in opposite directions

A

synergists and antagonists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

T or F: muscles ONLY pull (shorten), not push

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

axial muscles

A

move trunk, posture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

proximal muscles

A

move shoulder, elbow, knee, and pelvis - locomotion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

distal muscles

A

move fingers, feet, and hands - manipulation of objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

which neurons command muscle contraction?

A

ONLY lower motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

lower motor neurons (LMN)

A

distributed in proportion to skeletal muscle density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

LMN controlling flexors are located…

A

dorsal to extensors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

LMN controlling axial muscles are located…

A

medial to those controlling distal muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

which type of LMN triggers muscles?

A

alpha motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

which typer of LMN innervates intrafusal fibers?

A

gamma motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

motor unit

A

one alpha motor neuron and all muscle fibers it innervates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

motor neuron pool

A

all alpha motor neurons which innervate a single muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is NT used by alpha motor neurons?

A

acetylcholine (ACh)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how does the CNS grade muscle contraction?

A

by controlling firing rate of motor units and by recruiting more motor units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

size principle

A

small motor units have small motor neurons, large have large

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

are small or large neurons more easily excited?

A

small

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

twitch

A

rapid sequence of contraction and relaxation

26
Q

“dark meat”

A
  • red muscle fibers
  • slow to contract
  • slow to fatigue
  • present in antigravity muscles
  • many mitochondria
  • use oxidative metabolism
27
Q

“white meat”

A
  • fewer mitochondria
  • anaerobic metabolism
  • rapid
  • powerful
  • fatigue rapidly
  • present in “escape muscle”
28
Q

fast motor units contain

A

white fibers

- 30-60 AP/sec bursts

29
Q

slow motor units contain

A

red fibers

- 10-20 AP/sec steady

30
Q

crossed-innervation experiment

A

muscle switched phenotype to match motor neuron type

31
Q

sarcomere

A

a segment compromised of two Z lines and the myofibril in between

32
Q

myosin

A

major thick filament protein

33
Q

actin

A

major thin filament protein

34
Q

why is Ca2+ required for muscle contraction?

A
  • it initiates contraction by binding to troponin

- contraction continues as long as Ca2+ and ATP are available

35
Q

steps of excitation

A
  1. AP occurs in alpha motor neuron
  2. ACh is released by axon terminal at NMJ
  3. nicotinic receptor channels in sarcolemma open, posysynaptic sarcolemma depolarize (EPSP)
  4. voltage-gated Na+ channels open, AP is generated in muscle fiber, which sweeps down the sarcolemma and into T tubules
  5. depolarization of T tubes causes Ca2+ release from sarcoplasmic reticulum
36
Q

steps of contraction

A
  1. Ca2+ binds to troponin
  2. myosin binding sites on actin are exposed
  3. myosin heads bind actin
  4. myosin heads pivot
  5. myosin heads disengage at the expense of ATP
  6. cycle continues as long asCa2+ and ATP are present
37
Q

steps of relaxation

A
  1. as EPSPs end, the sarcolemma and T tubules return to their rest potentials
  2. Ca2+ is sequestered by sarcoplasmic reticulum by an ATP-driven pump
  3. myosin binding sites on actin are covered by troponin
38
Q

excitation-contraction coupling

A

this AP, excitation, triggers release of Ca2+ from organelle inside muscle fiber, which leads to the contraction of the fiber

39
Q

sliding filament theory

A

process of sacromere shortening when thin filaments slide toward one another on the thick filament

40
Q

muscle spindles

A
  • stretch receptor

- specialized muscle fibers in a fibrous capsule

41
Q

Ia sensory axons

A
  • largest and fastest
  • innervate spindle
  • enter spine at dorsal roots
  • synapse on interneurons and alpha motor neurons
42
Q

proprioception

A

body sense

43
Q

myotatic reflex

A
  • aka stretch reflex

- involves sensory feedback from muscle, shown by cutting the dorsal roots

44
Q

what is an example of myotatic reflex?

A

knee jerk

45
Q

intrafusal fibers

A

modified skeletal fibers within the muscle spindle

46
Q

gamma motor neurons

A
  • innervate intrafusal fibers

- activation keeps the muscle “on air” by contracting the poles of the spindle

47
Q

alpha activation alone..

A

decreases Ia activity

48
Q

gamma activation alone…

A

increases Ia activity

49
Q

circuit of myotatic feedback loop

A

gamma motor neuron to intrafusal muscle fiber to Ia afferent axon to alpha motor neuron to extrafusal fiber

50
Q

golgi tendon organ

A
  • monitors muscle tension or force of contraction

- located in series

51
Q

what innervates golgi tendon organ?

A

Ib sensory neurons

52
Q

reverse myotatic reflex

A
  • keeps muscle from being overloaded
  • muscle tension in optimal range
  • important for manipulation of fragile objects
53
Q

joint receptors

A
  • combined with muscle spindle, golgi tendon organ, and skin receptors
  • rapidly adapting
54
Q

synaptic input from spinal interneurons

A
  • primary sensory axons
  • descending axons from brain
  • collateral of LMN axons
  • other interneurons
55
Q

reciprocal inhibition

A

the contraction of one set of muscles accompanied by the relaxation of the antagonists muscle

56
Q

flexor reflex

A

complex reflex arc used to withdraw limb from adverse stimulus

57
Q

crossed-extensor reflex

A

the activation of extensor muscles and the inhibition of flexor muscles on the OPPOSITE side

58
Q

central patter generators

A

produce rhythmic motor activity

59
Q

rhythms are produced by…

A

pacemaker cells and synaptic connections

60
Q

rhythmic activity steps

A
  1. membrane depolarizes
  2. Na+ and Ca2+ flow into cell through NMDA receptors
  3. Ca2+ activates potassium channels
  4. K+ flows out of cell
  5. membrane hyperpolarizes
  6. Ca2+ stops flowing into cell
  7. potassium channels close
  8. membrane depolarizes, cycle repeats

NEURO 3000 (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions