Brainscape's Knowledge GenomeTM

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


See full index

Physiology > Chapter 12-muscles > Flashcards

Chapter 12-muscles Flashcards

1
Q

Extensor action

A

Increases the angle at a joint

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

Flexor action

A

Decreases the angle at a joint

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

Abductor action

A

Moves limb away from midline of body

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

Adductor action

A

Moves limb toward midline of body

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

Levator action

A

Moves insertion downward

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

Rotator action

A

Rotates a bone along its axis

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

Sphincter action

A

Constricts an opening

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

The prime mover of any skeletal movement is the

A

Agonist muscle. In flexing for example, the flexor is the agonist muscle

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

Flexors and extenders that act on the same joint to produce opposite actions are

A

Anatagonistic muscles

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

Epimysium is the

A

Fibrous connective tissue proteins within the tendons extend around the muscle in an irregular arrangement forming a sheath (epimysium)

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

Fascicles are

A

Inside the muscle epimysium divides muscle into columns called fasicles

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

Connective tissue around fascia is

A

perimysium

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

Plasma membrane of muscle is

A

sarcolemma

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

What are antagonist muscles?

A

muscles (flexors and extensors) that act on the same joint to produce opposite actions

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

What is a motor end plate?

A

Region on sarcolemma where the neuromuscular junction is the motor end plate

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

Which are considered the dark bands and light bands?

A

A bands are dark, I bands are light.

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

The motor neuron stimulates the muscle fiber to contract by _____________ at the neuromuscular junction

A

liberating acetylcholine

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

Where is the cell body of a somatic neuron located?

A

the ventral horn of the gray matter of spinal cord.

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

What is a motor unit?

A

Each somatic motor neuron together with all of the muscle fibers that it innervates.

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

What are graded concentrations?

A

Where contraction strength is varied.

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

What happens when a somatic motor neuron is activated?

A

All of the muscle fibers it innervates are stimulated to contract.

22
Q

When contractions of greater strength are required, larger and larger motor units are activated in a process known as

A

recruitment of motor units

23
Q

The light I band contains _____ filaments

A

thin

24
Q

The dark A band contains ______ filaments

A

thick

25
Q

Thick filaments are composed of the protein ______

A

myosin

26
Q

The thin filaments are composed of the protein ______

A

actin

27
Q

What is the central region of sarcomere?

A

H zone. Only contains thick filaments

28
Q

What is titin?

A

A type of elastic protein that runs through the thick filaments from the M lines to the Z disc

29
Q

Titin purpose

A

Contribute to elastic recoil of muscles that helps them to return to their resting length during muscle relaxation

30
Q

As sarcomeres shorten in length… the _ bands do not ______, but move ______ together

A

A, shorten, closer

31
Q

The I bands which represent the distance between A bands of successive sarcomeres _______ in length

A

decrease

32
Q

The thin filaments composing the I band _______

A

do not shorten

33
Q

During contraction, thick and thin filaments _______

A

remain the same length

34
Q

Shortening of the sarcomeres is produced not by shortening of the filaments but rather by _______ of thin filaments over and between the thick filaments

A

sliding

35
Q

The I bands (contain only thin filaments) and H bands (containing only thick filaments) get _______ during contraction

A

shorter

36
Q

Describe steps of sliding filament theory of contraction

A
  1. A myofiber, along with all its myofibrils shorten by movement of the insertion toward the origin of the muscle.
  2. Shortening of the myofibrils is caused by shortening of the sarcomeres- the distance between Z lines is reduced.
  3. Shortening of the sarcomeres is done by sliding of the myofilaments-the length of each filament remains the same during contraction.
  4. Sliding of the filaments id produced by asychronous power strokes of myosin cross bridges, which pull the thin filaments (Actin) over the thick filaments (myosin)
  5. The A bands remain the same length during contraction, but are pulled toward the origin of the muscle.
  6. Adjacent A bands are pulled closer together as I bands between them shorten.
  7. The H bands shorten during contraction as the thin filaments on the sides of the sarcomeres are pulled toward the middle.
37
Q

Muscle contracts because _____ get shorter

A

myofibrils

38
Q

_____ filaments slide over and between _____ filaments towards the center

A

thin, thick

39
Q

Sliding of filaments is produced by the action of numerous

A

cross bridges that extend out from myosin toward the actin.

40
Q

Cross bridges are part of the _____ protein that extend from the axis of thick filaments to form “arms” that terminate in globular “heads”

A

myosin

41
Q

Each myosin head contains an _____ binding site which functions as ______

A

ATP binding site and ATPase

42
Q

Cross bridge power stroke steps

A
  1. Resting fiber, cross bridge is not attached to acin. ADP. Inorganic phosphate are attached,
  2. Cross bridge binds to actin
  3. Pi is released from myosin head, causing conformational change in myosin.
  4. Power stroke causes filaments to slide. ADP is released
  5. A new ATP bings to myosin head, allowing it to release from actin.
  6. ATP is hydrolyzed and phosphate binds to myosin, causing cross bridge to return to its orginal orientation.
43
Q

Twitch is a ____ ________

A

single contraction

44
Q

A single rapid contraction and relaxation of muscle fibers is a

A

twitch

45
Q

Skeletal muscles can produce

A

graded contractions, the strength of which depends on the number of fibers stimulated rather than on the strength of the contractions of individual muscle fibers.

46
Q

Imcomplete tetanus refers to

A

If muscle is stimulated by an increasing frequency of electrical shocks, its tension will increase to a maximum

47
Q

Complete tetanus refers to

A

Contraction that is smooth and sustained as it is during normal muscle contracction within body.

48
Q

Treppe (stair case effect) refers to

A

If cold muscle is repeatedly stimulated with maximum voltage to produce individual twitches, successive twitches get larger

49
Q

Treppe is caused by

A

accumulation of intracellular Ca++

50
Q

During isotonic contraction…

A

force remains constant throughout shortening process, length changes. (Lifting something off table)

51
Q

During isometric contraction…

A

exerted force does not cause load to move and length of fibers remains constant (Lifting table, holding the weight)

Physiology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions