Brainscape's Knowledge GenomeTM

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


See full index

Anatomy > EXAM 3 > Flashcards

EXAM 3 Flashcards

1
Q

Define Rigor Mortis

A

postmortem contraction of the skeletal muscles due to lack of new ATP synthesis

ATP is no longer being produced

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

Name the proteins in the thin filaments of smooth muscle and their functions

A
  • Actin - contains binding sites for myosin heads
  • Tropomyosin - supports the structure of actin. Does not block the myosin binding sites on actin in a relaxed smooth muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the function of tropomyosin in a relaxed skeletal muscle

A

wraps around the actin filament and covers myosin binding sites, so contraction cannot occur

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

Name the structures PRESENT in SKELETAL muscle fibers that are ABSENT from SMOOTH muscle cells (4)

A
  • sarcomeres - cellular units of skeletal (and cardiac) muscle
  • troponin -“regulates actin-myosin interactions in skeletal and cardiac muscle contraction”
  • z-lines - protein that encloses the thin filament
  • t-tubules - involutions of sarcomere that action potentials flow through
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Compare and Contrast… single-unit smooth muscle and multiunit smooth muscle

A

Similarities

  • innervated with autonomic nerve fibers
  • stimulated to contract by chemicals

Differences

  • single unit:
    • ​circular and longitudinal muscle sheets
    • electrically coupled by gap junctions
    • functional syncytium
    • pacemaker activity
  • multiunit:
    • ​individual smooth muscle fibers
    • no gap junctions
    • no pacemaker activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define the neuromuscular junction

A

junction between the axon terminal of a motor neuron and a skeletal muscle fiber that is separated by a small space called the neuromuscular (synaptic) cleft

each muscle fiber has only ONE neuromuscular junction

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

How will an increase in extracellular calcium affect the strength of a cardiac muscle

A

strength will increase; relies on extracellular calcium to release calcium from the SR

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

in smooth muscle cells, the thin filaments are anchored by…

A

dense bodies

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

Compare and Contrast… skeletal muscle and cardiac muscle

A

Similarities

  • Striations present
  • sarcomeres present
  • T-tubules present
  • Ca2+ binds to TnC
  • Grows through hypertrophy

Differences

  • Skeletal muscle: ​voluntary movement, no syncytium, no gap junctions
  • cardiac muscle: involuntary movement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define a Triad

A

the structure formed by a transverse (T) tubule in between two terminal cisternae

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

define indirect attachment of the skeletal muscle

A

tendon extends from the muscle to attach to the bone

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

Autonomic Nervous System divisions

A

Sympathetic Nervous System

Parasympathetic Nervous System

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

Give the role of ATP in muscle contraction (3)

A
  1. ATP is hydrolyzed by ATPase to produce ADP and Pi to activate the myosin heads
  2. ATP is required for crossbridge detachment
  3. ATP is required for the sequestration of calcium ions back into the SR for storage (active transport)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Place the three skeletal muscle fibers in order of GLYCOCEN CONTENT (high to low)

A

FG > FO >SO

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

What is the power stroke in excitation-contraction coupling in skeletal muscle?

A

ADP + Pi dissociate from myosin

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

List the sources of ATP to support skeletal muscle contraction (4)

A
  1. stored ATP - used first
  2. Direct phosphorylation of ADP by creatine phosphate
    • CP + ADP –> ATP + creatine
  3. Aerobic catabolism of glucose - produces the most ATP, slowest
  4. Anaerobic catabolism of glucose - fastest
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which type of skeletal muscle fiber is fatigable and why?

A

Fast Glycolitic Fibers because they produce ATP from anaerobic respiration, which produces powerful, high-tension contractions, but fatigues quickly

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

Define the motor end plate and its function

A
  • definition: Highly folded region of the sarcolemma
  • function: expresses acetylcholine receptors on surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How will the contraction of smooth muscle be affected if the autonomic innervation is severed?

A

Contraction of smooth muscle will occur due to pacemaker activity

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

Place the three skeletal muscle fibers in order of MYOGLOBIN CONTENT (high to low)

A

SO > FO > FG

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

Define the sliding filament mechanism

A

when contraction (shortening) occurs when thin filaments “slide” into the H zone (towards the M line) pulling the Z discs inward

length of sarcomere shortens, shortening the entire muscle

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

How will an increase in extracellular calcium affect the strength of a smooth muscle?

A

strength will increase; relies on extracellular calcium to release calcium from the SR

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

Define isometric contraction

A

force (tension) generated by the muscle is increasing at a constant muscle length; muscle does not shorten

FORCE < WEIGHT

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

In SMOOTH muscle cells, myosin heads are activated when…

A

MLCK hydrolyzes Pi from ATP to activate myosin

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

Discuss the role of calcium in skeletal muscle contraction

A

Ca2+ binds to TnC

Troponin undergoes a conformational change that moves TnT and Tropomyosin from blocking the myosin binding sites on actin

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

what is the function of triads?

A

Triad releases Ca2+ ions into the sarcoplasm when the sarcolemma depolarizes

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

Characteristics of Fast Glycolitic (FG) Fibers

A

Fast ATPase; produces ATP quickly through anaerobic respiration

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

Which skeletal muscle fiber is also known as “red fibers” and why?

A

Slow Oxidation Fibers because they have the highest myoglobin content, which gives them a red pigment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

In SKELETAL muscle fibers myosin heads are activated when…

A

ATP hydrolyzes to ADP + Pi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Describe the structural organization of a sarcomere (6)

A
  • A band: thick filament
  • M line: bisects and anchors A bands
  • Thin filaments: give the striated appearance of skeletal/cardiac muscle
  • Z lines (Z discs): anchor thin filaments
  • H zone: middle region of A band
  • I bands: regions of thin filaments not overlapping with A band
31
Q

What can inhibit the contraction of cardiac muscle?

A

Calcium Channel Blockers

32
Q

Characteristics of Fast Oxidative (FO) Fibers

A

Fast ATPase; produces ATP quickly through aerobic respiration

33
Q

What can inhibit a the contraction of a skeletal muscle?

A

chemicals that block acetylcholine receptors

34
Q

Describe the divisions of the motor (efferent) nerves of the PNS

A

Somatic Nervous System

Autonomic Nervous Sustem

35
Q

Activation of the sympathetic nervous system causes…

A

bronchodilation and vasoconstriction

36
Q

Function of dense bodies

A

anchor thin filaments

37
Q

Place the three skeletal muscle fibers in order of recruitment (first to last)

A

SO > FO > FG

38
Q

Discuss the role of calcium in smooth muscle contraction

A

Calcium binds to calmodulin –> forms calcium-calmodulin complex –> activated Myosin Light-Chain Kinase (MLCK)

39
Q

What can inhibit the contraction of skeletal muscles?

A

Chemicals that block acetylcholine receptors

40
Q

what is the consequence (result) of the power stroke?

A

Sliding of the thin filaments toward the H Zone and M line

41
Q

Name the proteins in the thin filament of a cardiac muscle and their functions

A
  • Actin - contains binding sites for myosin heads
  • Tropomyosin - regulatory protein that “wraps around the actin filament and covers myosin binding sites to prevent contraction in a relaxed skeletal muscle”
  • Troponin - three polypeptide complex (TnC, TnT, TnI) that regulates actin-myosin interactions in skeletal and cardiac muscle contraction
42
Q

How will an increase in extracellular calcium affect the strength of the skeletal muscle?

A

strength is unaffected because skeletal muscle doesn’t use extracellular calcium

43
Q

Characteristics of Slow Oxidative (SO) Fibers

A

Slow ATPase; produces ATP slowly through aerobic respiration

44
Q

Autonomic Nervous System function

A

takes information to the smooth muscles and cardiac muscles (soft organs)

45
Q

Types of skeletal muscle fibers (3)

A

Slow Oxidative (SO) Fibers

Fast Oxidative (FO) Fibers

Fast Glycolytic (FG) Fibers

46
Q

Define Muscle Fatigue

A

physiological inability of a stimulated skeletal muscle to contract due to an ATP deficit

ATP is still being produced but not at the rate of demand

47
Q

function of calmodulin

A

regulatory protein that calcium binds to

48
Q

List the subunits of troponin (3) and their functions

A

TnC - binds calcium ions

TnT - binds to tropomyosin

TnI - inhibitory subunit that binds to actin

49
Q

Describe the function of the motor (efferent) nerves of the PNS

A

To take information from CNS to the effector structures

50
Q

Define direct attachment of the skeletal muscles

A

when the epimysium fuses directly to the periosteum of the bone

51
Q

Name the structures PRESENT in SMOOTH musle cells that are ABSENT from SKELETAL muscle fibers (4)

A
  • dense bodies
  • intermediate filaments
  • caveolae
  • calmodulin
52
Q

Define a motor unit

A

motor neuron and all of the skeletal muscle fibers it innervates

53
Q

function of intermediate filaments

A

resist tension

54
Q

Somatic Nervous System function

A

Takes information to the skeletal muscles (hard organs)

55
Q

cross bridge detachment occurs when…

A

phosphate is removed from the myosin heads by phosphorylase enzymes and intracellular Ca2+ levels fall

56
Q

Define functional syncytium

A

The contraction of the muscle as a single unit

57
Q

Place the three skeletal muscle fibers in order of FIBER DIAMETER (large to small)

A

FG > FO > SO

58
Q

what are activated globular heads?

A

When ATPase hydrolyzes ATP into [ADP and Pi] and attach to the myosin globular heads… they become ACTIVATED

(Activated Myosin globular heads attach to actin which is called CROSS BRIDGES)

59
Q

Compare and Contrast… smooth muscle and cardiac muscle

A

Similarities:

  • gap junctions present
  • functional syncytium
  • involuntary muscle control

Differences:

  • Smooth muscle grows through hyperplasia AND hypertrophy
  • Cardiac muscle grows through hypertrophy
60
Q

caveolae

A

shallow cavities in the sarcolemma that contain extracellular fluid that is saturated with calcium

61
Q

What can inhibit the contraction of smooth muscle?

A

Calcium Channel Blockers

62
Q

Describe the structural organization of a skeletal muscle

A
  • epimysium: outer protective layer
  • perimysium: surrounds fasicles
  • fasicle: group of muscle fibers
  • endomysium: surrounds single muscle fiber (cell)
63
Q

How will the contraction of cardiac muscle be affected if the parasympathetic innervation is severed?

A

Contraction of cardiac muscle will occur because there is no parasympathetic inhibition of the cardiac muscle

64
Q

Structures of the sarcomere that shorten when a skeletal muscle contracts

A

H zone and I bands

65
Q

Factors that affect the strength of skeletal contraction

A
  1. Size of the motor unit activated
  2. Number of motor units activated
  3. Frequency of activation of the skeletal muscle fibers by the motor neuron
  4. Length of the sarcomere prior to contraction
66
Q

structures of the sarcomere that remain the same when a skeletal muscle contracts

A

A bands and Thin filaments

67
Q

the diffuse junctions form directly between…

A

varicosity of an autonomic fiber and a smooth muscle cell

68
Q

Explain recruitment as it pertains to the strength generated by skeletal muscle contraction

A

smallest motor units are used first and larger units recruited after

69
Q

Define isotonic contraction

A

[sliding filament mechanism] generates force by changing the length of the muscle

FORCE > WEIGHT

(me lifting a 5 lb weight)

70
Q
A
71
Q
A
72
Q
A
73
Q
A

Anatomy (5 decks)

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