Brainscape's Knowledge GenomeTM

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


See full index

PHYSIOLOGY > Muscle Physiology Part 2 > Flashcards

Muscle Physiology Part 2 Flashcards

1
Q

When 💡action potential is transmitted along the sarcolemma and then down the tubules, __ is released from the terminal cisternae SR into the myoplasm.

A

Calcium

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

Release of Ca raises intracellular Ca which promotes __; that is 💡Twitch.

A

Actin-myosin interaction and contraction

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

Skeletal Muscle (Electromechanical coupling)

A

i. Depolarization of sarcolemma is caused by Na
ii. Tropomyosin is covered
iii. Triad – association with two terminal opposing cisternae and T tubule
iv. Source from SR

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

Cardiac Muscle (Electrochemical coupling)

A
  • *SA node = generates AP
  • *Ach = regulation (binds with GPR for inhibition)
  • *Catecholamine = calcium released = Inc. cardiac activity)

i. Depolarization sarcolemma is caused by Na
ii. Tropomyosin is covered
iii. Diad: 1 T tubule and 1 terminal
iv. Source from SR and ECF

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

Smooth Muscle (Pharmacochemical coupling)

A

**Does not need AP but rather an agonist (IP3)

i. Depolarization sarcolemma is caused by Ca
ii. Tropomyosin is not covered; inactive
iii. No troponin instead it has calmodulin
iv. Myosin is inactive and needs to be activated by Ca-calmodulin complex
v. Membrane is leaky to Ca > Ca gets into the cell > bind to calmodulin > trigger release of Ca in SR > Ca-Calmodulin complex > activate myosin light chain kinase: activates tropomyosin/myosin
vi. Source from ECF and SR

**Thick filament regulated

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

💡Feet:bridging proteins between t tubule and cisternae

A

i. Ca release channels in the membrane of cisternae
ii. Responsible for elevation in intracellular Ca in response to action potential
iii. Binds to ryanodine that is why called as ryanodine receptor

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

At the 💡T tubule membrane 💡RYR interacts with __ receptor which is 💡critical for the ability of the action potential in the T tubule to 💡induce release of Ca from SR.

A

Dihydropyridine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Skeletal muscle is able to contract in the absence of (1)__ or with mutated (2)__.

A

(1) extracellular Ca

(2) DHPR

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

Release of Ca from (1)__ -> conformational changes in (2)__-> opens (3)__- > release calcium in (4)__.

A

(1) terminal cisternae
(2) DHPR
(3) RYR
(4) myoplasm

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

o Located in 💡lumen of cisternae

o Allows Ca to be stored at 💡high concentration.

A

Calsequestrin

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

o Bind both 💡RYR and 💡calsequestrin

o Increases 💡buffering capacity at the site of Ca release.

o 💡Histidine rich calcium binding Protein:
Binds to triadin

A

Triadin and Junctin

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

o 💡Increases Ca uptake by SERCA (Sarcoplasmic endoplasmic Reticulum Calcium ATPase)

o Most 💡abundant protein in SR of skeletal muscle

o Transports 💡2 molecules of Ca for each ATP hydrolyzed.

A

Sarcalumenin

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

Skeletal muscle contraction is possible because it is innervated by __

A

Nerve

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

If denervated, the muscle will be __.

A

Paralyzed

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

MUSCLE CONTRACTION MECHANISM

A
  1. Activation of the nerve
  2. Produce action potential
  3. Travel along axon
  4. Reach terminal button action potential
  5. Depolarization
  6. Ca++ voltage gated channel opens
  7. Ca++ gets in
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

MUSCLE CONTRACTION MECHANISM (detailed version)

A
  1. Binding of 💡Ach to its nicotinic 💡Ach receptor
  2. Opening of 💡cation channel (Na, K)
  3. Sarcolemma 💡depolarization due to Na influx
  4. Generation of 💡local potential (end plate potential) = open voltage gated = reach threshold
  5. Generation of 💡action potential
  6. Transmission of action potential along sarcolemma going to 💡T Tubule structure (used to transmit AP along sarcolemma to inner portion of the muscle fiber)
  7. Activation of 💡DHP (voltage sensor) > undergo mechanical conformational
  8. Activate 💡RYR
  9. 💡Release of Ca from terminal cistern (💡simple diffusion)
  10. Ready to bind to 💡Trop C (translocation of tropomyosin laterally > exposed binding site > interaction between actin and myosin > initiate muscle contraction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

MUSLE RELAXATION MECHANISM

A
  1. 💡Remove Ca
  2. 💡Release of Ca from the Trop C
  3. Sequestration of Ca to SR
  4. 💡Muscle relaxation
  5. 💡Actin-Myosin Interaction: Cross Bridge Formation
  6. Ca released by SR binds to 💡troponin C
  7. Troponin C facilitates movement of associated 💡tropomyosin molecules towards the cleft of actin filaments
  8. 💡Exposes myosin binding site and allows 💡cross bridge to form
  9. Generation of 💡tension
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  • Has 💡four binding sites

- Involved in 💡controlling and 💡enhancing interaction between trop I and trop C

A

Troponin C

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

Troponin C binding site is for what ions?

A

Calcium and Magnesium

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

SLIDING FILAMENT THEORY / CROSS BRIDGE CYCLING SARCOMERE SHORTENING

A

The 💡myosin cross-bridge is 💡pulling the actin thin filament 💡toward the center of the sarcomere, thereby resulting in an apparent 💡“sliding” of the thin filament past the thick filament; there is 💡sliding of myofilaments but 💡no shortening, there is 💡narrowing of or decreasing H zone

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

The myosin cross-bridge is pulling the (1)__ toward the center of the (2)__, thereby resulting in an apparent (3)__ of the thin filament past the thick filament; there is sliding of myofilaments but (4)__, there is narrowing of or decreasing H zone

A

(1) actin thin filament
(2) sarcomere
(3) “sliding”
(4) no shortening

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

1 attachment

A

power stroke

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

↑ power stroke generated

A

↑ force of contraction

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

When calcium binded with Troponin C, what will happen?

A

a. ATP is Hydrolyzed into ADP (Affinity is High)
b. Myosin crossbridge binds with Troponin
c. After Contraction, ADP will be Phosphorylated to ATP (Affinity is Low)
d. Remove Binding and back to Relaxed State

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

It is an 💡excitation signal, needed to free myosin

A

Calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Absence of calcium

A

No binding, muscle is relaxed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

It is needed for power stroke

A

ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The mechanism by which myosin produces force and shortens the sarcomere is thought to involve four basic steps:

A
  1. ATTACHED STATE
  2. RELEASED STATE
  3. COCKED STATE
  4. POWER STROKE STATE
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q
  1. ATTACHED STATE
A
  • Hydrolyzed ATP > ADP > affinity of myosin to actin is high

- Myosin binds with actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q
  1. RELEASED STATE
A
  • The head will pull it to the center and detach through ATP
  • ATP binds with myosin head
  • Dissociation of myosin to actin (detachment)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q
  1. COCKED STATE
A
  • ATP will be hydrolyzed again causing the head to move to another binding site
  • Binding of myosin head to another binding site of actin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q
  1. POWER STROKE STATE
A
  • Phosphate is released

- Detachment through ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Binding of ATP to myosin decreases the __, thereby resulting in the release of myosin from the actin filament

A

Affinity of myosin for actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

If myoplasmic [Ca++] is still elevated, the cycle __.

A

Repeats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

If myoplasmic [Ca++] is low = __ results. The cycle continues until the SERCA pumps Ca++ back into the SR

A

Relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

If the supply of ATP is exhausted, as occurs with death, the cycle stops in cocked state with the formation of (1) __ causing (2) __.

A

(1) Permanent actin-myosin complexes

(2) Rigor mortis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

💡Mechanical response of muscle brought about by a single 💡action potential which is composed of a 💡brief period of contraction and 💡brief period of relaxation

A

MUSCLE TWITCH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

TWO ACTIVITIES OF MUSCLE TWITCH

A
  • Electrical - Action potential

* Mechanical - Contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

3 PHASES IN MUSCLE TWITCH

**Take note that all phases require ATP

A
  1. Latent period
  2. Period of Contraction
  3. Period of Relaxation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

💡Between the start of depolarization and start of contraction
-Includes the events happening 💡before contraction.

**From binding Acetylcholine to the nicotinic receptors up to the binding of Ca2+ with Troponin C that causes Tropomyosin translocation

A

Latent period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

From the 💡start of contraction to 💡peak of tension curve

💡All phase in sliding filament theory

A

Period of Contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q
  • From 💡peak of tension curve up to the 💡end of muscular response
  • Includes events from 💡release if Ca2+ from Trop C, and 💡sequestration back to SR
  • Involves 💡SERCA
A

Period of Relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

SKELETAL MUSCLE TYPES

Two main groups according to the speed of contraction:

A
  1. Fast-twitch Muscle Fibers

2. Slow-twitch Muscle Fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q
  • Contracts 💡very quickly in response to action potential, then 💡relaxes very quickly, which results in 💡short duration of contraction.
  • Can deliver 💡extreme amounts of power for few seconds to minute/s
  • Contain myosin isoforms that 💡HYDROLYZES ATP QUICKLY
  • Could contain 💡type IIa, 💡type IIx, or 💡type IIb myosin heavy chains
  • 💡Oxidative capacity ranges from relatively high (type IIa myosin heavy chain) to low (type IIb myosin heavy chains).
  • The 💡low oxidative capacity of fast type IIb muscle fibers, coupled with the 💡high myosin ATPase activity, increases the 💡susceptibility of these muscle fibers to fatigue.
A

Fast-twitch Muscle Fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q 
Type 2 fiber
Glycolytic White Muscle
SERCA 2
Large Diameter
Shorter duration of twitch
A

Fast Twitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q
  • 💡Slower to reach peak tension in response to an action potential, and then it 💡relaxes slowly
  • Provide 💡endurance, delivering 💡prolonged strength of contraction over many minutes to hours
  • Contain myosin isoforms that 💡HYDROLYZE ATP SLOWLY
  • Express 💡type I myosin heavy chain
  • 💡High oxidative capacity which in combination with the 💡low myosin ATPase activity contribute to the fatigue resistance of slow-twitch muscle fibers.
A

Slow-twitch Muscle Fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q 
Type 1 fiber
Oxidative Red Muscle
SERCA 1
Small Diameter
Longer duration of twitch
A

Slow Twitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

See anki

A

Se anki

49
Q

TYPES OF MUSCLE CONTRACTION

A

A. Isometric Contraction
B. Isotonic Contraction
C. Isokinetic Contraction (in sports)

50
Q
  • One in which 💡muscle length is held constant, and the 💡force generated during the contraction is then measured
  • 💡“same length”
  • Muscle stays at a 💡fixed length
  • (-) shortening and lengthening (distance)
  • (-) change in length, (+) generation of force therefore,(-) work
  • Work = Force x Distance
  • Energy is converted to heat
A

Isometric Contraction

51
Q
  • One in which the 💡force (or tone) is held constant, and the 💡change in length of the muscle is then measured
  • (+) Length changes, whether lengthening or shortening
  • 💡Same tension but muscle length changes
  • (+) work because muscle length changes
  • Work = Force x Distance
A

Isotonic Contraction

52
Q

(+) muscle shortening (+) work
o Ex. your weight > weight of the load

(force exerted > what is being lifted)

A

Concentric contraction

53
Q

(+) muscle lengthening (-) work

Ex. your weight < weight of the load (force exerted < what is being lifted) exerting force (-)

o How to improve?
Increase the force by increasing the mass of muscle (hypertrophy – exercise with load)

A

Eccentric contraction

54
Q

** (+) in concentric contraction because some energy is (1)__; (-) in eccentric contraction because exerting more energy but (2)__; (0) in isometric because all energy is (3)__.

A

(1) converted to work
(2) not converted to work
(3) converted to heat but no work

55
Q

Same 💡velocity of muscle shortening

A

Isokinetic Contraction

56
Q

LENGTH-TENSION RELATIONSHIP

A

Resting length = physiologic length

Beyond the resting length = overstretching

57
Q

It is a tension generated when a 💡muscle at rest is 💡stretched.
Muscles are made up of connective
tissue or titin, when you stretch muscle: connective
tissue resists the stretching → creates tension

A

Passive Tension

58
Q

Passive Tension

↑ Stretch = ?

A

↑ Passive tension = ↑ muscle fiber length

59
Q

Passive Tension is __ to muscle length.

A

Directly proportional

60
Q

It is a 💡tension generated when the 💡muscle is stretched and stimulated

💡Maximal at resting or optimal length

A

Active Tension

61
Q

Active tension is not created by the
connective tissue but of the number of
__.

A

Power stroke

62
Q

Active Tension

↑ Stretch = ?

A

= expose more actin = ↑ power stroke =

↑ Active tension

63
Q

It is the 💡sum of passive and active tension

A

Total Tension

64
Q

💡Before the resting length:

↑ active tension, ↑ passive tension = ?

A

↑ Total tension

**directly proportional

65
Q

💡Beyond the resting length:

↑ Passive tension

A

↓ Active tension (decrease in
active is greater than passive) = ↓ total tension

**inversely proportional

66
Q

💡Stretch it further:

↓ Active tension

A

↑ passive tension (increase in

passive is greater than active) = ↑ total tension

67
Q

It is an 💡opposing/ reverse force to velocity

A

Load

68
Q

LOAD VS VELOCITY OF SHORTENING

↑ Load = ?

**inversely proportional

A

↓ Velocity of shortening

69
Q

LOAD VS WORK PERFORMED

↑ Load = ?

**directly proportional

A

↑ mass = ↑ force = ↑ work (acceleration

and distance are not yet affected)

70
Q

If the too much load is added:

↑ Load = ?

A

↓ acceleration = ↓ shortening = ↓ work

**inversely proportional

71
Q

LOAD VS POWER

↑ Load = ?

A

↑ mass = ↑ force = ↑ work = ↑ power

initially directly proportional

72
Q

But as you keep on contracting, there is also ↑

time = ?

A

↓ power (inversely proportional)

73
Q

In muscle contraction:

Highest power of muscle =

A

within 10 seconds

But, ↑ contraction = ↓ Power

74
Q

ENERGY SOURCES DURING CONTRACTION

A

PHOSPHAGEN SYSTEM

GLYCOGEN - LACTIC SYSTEM

AEROBIC SYSTEM

75
Q

PHOSPHAGEN SYSTEM

A

ADENOSINE TRIPHOSPHATE

CREATINE PHOSPHATE

76
Q

💡Immediate source for muscle contraction

💡ATP is the energy source used for this conversion.

A

PHOSPHAGEN SYSTEM

77
Q

💡Stored ATP can sustain muscle contraction for?

A

3 sec

78
Q

It is used to convert ADP to ATP and thus replenish the ATP store during muscle contraction.

A

CREATINE PHOSPHATE (phosphocreatine)

79
Q

Stored ATP can sustain muscle contraction for?

A

5-8 sec

80
Q

Short term source for muscle contraction

A

GLYCOGEN - LACTIC SYSTEM

81
Q

Long term source for muscle contraction

A

AEROBIC SYSTEM

82
Q

Oxygen debt ≅ Energy consumed during exercise minus that supplied by oxidative metabolism.

A

True

83
Q
  • It is a condition characterized by 💡sustained contraction

* Transport Ca to the SR is 💡inhibited therefore 💡relaxation does not occur even though there are no more AP

A

CONTRACTURE

84
Q

It is a 💡state of rigidity of the muscle that occurs after death

A

RIGOR MORTIS

85
Q

In rigor mortis. there is complete depletion of __ that almost all of the myosin heads are attached to actin but in an abnormal, fixed, and resistant way

A

ATP

86
Q

EFFECTS OF DENERVATION LOWER MOTOR NEURON

A

MUSCLE ATROPHY
FASCICULATION
MYASTHENIA GRAVIS

87
Q

💡Denervation hypersensitive (fibrillation) not usually visible contraction

A

MUSCLE ATROPHY

88
Q

• It is 💡jerky visible contractions or small, irregular contractions of groups of muscle fibers caused by 💡release of acetylcholine from the terminals of the degenerating distal portion of the axon.

  • Example: upper eyelid
  • Fatigue
A

FASCICULATION

88
Q

It is characterized by 💡spontaneous, repetitive contractions. At this time, the 💡cholinergic receptors have spread out over the entire cell membrane, in effect reverting to their preinnervation embryonic arrangement.

It reflect supersensitivity to acetylcholine.

A

Fibrillation

89
Q

TYPES OF HEAT PRODUCTION IN MUSCLE

A

Resting Heat
Initial Heat
Recovery Heat
Relaxation Heat

90
Q

It is the heat given off at 💡rest basal metabolic process. (Na-K pump)

A

Resting Heat

91
Q

It is the heat produced in 💡excess of resting heat during contraction

A

Initial Heat

92
Q

It is the heat produced 💡during contraction

A

Activation Heat

93
Q

It is a 💡distance the muscle shortens

A

Shortening Heat

94
Q

It is the heat liberated by the 💡metabolic processes that 💡restore the muscle to its💡 precontraction state; equal to initial heat

A

Recovery Heat

95
Q

It is the 💡extra heat in addition to the recovery heat

A

Relaxation Heat

96
Q

It is the 💡functional contractile unit of 💡muscle.

It consists of the 💡motor nerve and 💡all the muscle fibers innervated by the nerve.

A

MOTOR UNIT

98
Q

It is the 💡functional contractile unit of 💡“muscle fibers”

A

Sarcomere

98
Q

Activation of motor units with a small number of fibers facilitates __.

A

Fine motor control

99
Q

Innervation Ratio

A

motor neuron:muscle fiber

99
Q

It is a 💡neuromuscular junction formed by the α motor neuron.

A

Motor end plate

100
Q

<500 muscle fibers/motor unit =

A

for fine, graded, and precise movement

101
Q

> 500 muscle fibers/motor unit =

A

for postural, and gross movement Motor Unit

102
Q

Excitability relies on?

A

Size

**Inversely proportional

103
Q

Smaller size = ?

A

More excitable

104
Q

Larger size= ?

A

Less excitable

105
Q

see anki

A

see anki

106
Q

What is the other term of 💡Spatial Summation?

A

Multiple fiber summation / Recruitment
of motor units

**Quantal / Graded Response- old name

106
Q

A simple means of increasing the force of contraction of a muscle is to recruit more muscle fibers.

A

Recruitment

108
Q

Because all the muscle fibers within a motor unit are activated (1)__, a muscle recruits more (2)__by recruiting more (3)__.

A

(1) simultaneously
(2) muscle fibers
(3) motor units

109
Q

The process of increasing the force of contraction by 💡recruiting additional motor units

Apply 💡several stimuli in 💡increasing intensity

Increase of motor units activity = increase in
force contraction

A

Spatial Summation

109
Q

Because all fibers in a motor unit are innervated by a single (1)__, all fibers within a motor unit are of the __.

A

(1) α motor neuron

(2) same type

111
Q

Once reached, contraction force 💡won’t increase even with the recruitment of more motor units

A

Maximal Force of Contraction

113
Q

What is the other term of Temporal Summation?

A

Frequency/ tetanization

114
Q
  • Several stimuli of 💡increasing frequency

* Increase in frequency= increase force of contraction

A

Temporal Summation

116
Q

If the muscle is stimulated a second time before it is fully relaxed, the force of contraction increases. Thus twitch forces are amplified as stimulus frequency increases. At a high level of stimulation, intracellular [Ca++] increases and is maintained throughout the period of stimulation, and the amount of force developed greatly exceeds that observed during a twitch.

A

Complete Tetany

117
Q

At intermediate stimulus frequency, intracellular [Ca++] returns to baseline just before the next stimulus. However, there is a gradual rise in force.

A

Incomplete tetany

118
Q

Similar to tetany but 💡allows full relaxation between each stimulus

A

Treppe / Staircase Phenomenon

119
Q

● 💡Decreased ability of the muscle to generate force
due to prolonged and strong contractions
● 💡Directly proportional to the rate of depletion of glycogen and creatine phosphate, but 💡not of ATP
● Lactic acid and inorganic phosphate accumulation.

💡Protective mechanism to minimize the risk of
muscle cell injury death

A

FATIGUE

PHYSIOLOGY (13 decks)

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