Muscular System Flashcards

1
Q

all or nothing principle

A

when a muscle contractions it must contract with all possible force or none at all.

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

isometric contraction

A

muscle length remains the same but tension increases; they work but do not produce movement.

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

isotonic contraction

A

the tone or tension within the muscle remains the same; occurs usually when there is little or no resistance

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

motor unit

A

functional unit of skeletal muscle; composed of motor neuron and the attached muscle fibers

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

myofibril

A

fine fibers closely packed together

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

myofilament

A

proteins in the myofibers that are arranged into groups that cause striations to appear (bands)

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

neuromuscular junction

A

motor neurons attaching to a motor endplate,

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

sarcolemma

A

surrounds each muscle fiber; located in the plasma membrane.

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

sacromere

A

segment between 2 successive Z lines or discs.
ex. between thick and thin myofilaments

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

sarcoplasm

A

the cytoplasm of striated muscle cells

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

sarcoplasmic reticulum

A

a modified ER system for pumping Ca++ ions

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

t tubules

A

allow electrical signals to travel deeper into the cell
* a sandwiched t tubules is a triad.

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

tetanus

A

muscle that does not have enough time between contractions to completely relax; displayed by skeletal muscle

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

threshold stimulus

A

minimal level of stimulation needed to cause contraction

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

excitability

A

the ability to respond to a stimulus, which may be delivered from a motor neuron or a hormone.

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

contractility

A

the ability of muscle cells to forcefully shorten.

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

extensibility

A

the ability of a muscle to be stretched or extended.

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

motor neuron

A

neuronal cells located in the central nervous system (CNS) controlling a variety of downstream targets.

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

cross bridges

A

the “heads” of myosin

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

acetylcholine

A

neurotransmitter diffuses into the synapse in order to initiate an impulse. (contraction)

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

relaxation

A

occurs after Ca++ is released the SR begins to pump it back into sacs. when Ca++ is removed, it frees up the troponin molecules and shuts down the contraction.

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

grades strength principle

A

muscles get stronger when they are constantlly challanged.

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

visceral

A

(single-unit) form continuous sheets, is found in digestive, urinary and reproductive tracts, and exhibits peristalsis, autorhythmicity

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

peristalsis

A

a series of wave-like muscle contractions that move food through the digestive tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
antagonist
muscles that directly oppose a movement
26
fixator
joint stabilizers that help maintain posture
27
synergist
muscles that assist prime movers
28
insertion
distal; the site where bone and muscle are attached and move during contraction.
29
lever
force weight, level balance. includes 4 parts... 1) rigid rod or bar (bone) lever 2) fixed pivot (joint) fulcrum 3)weight or resistance that is moved load 4) force or pull (the contraction) effort
30
prime mover
muscle/group that performs specific movement.
31
endomysium
connective tissue membrane that covers individual muscle fibers. (inner)
32
perimycium
a tougher connective tissue membrane that holds fascicles together (middle)
33
tendon
strong tough cord that attaches muscle to bone
34
tendon sheath
tube shaped fibrous connective tissue
35
aponeurosis
broad flat sheet of connective tissue
36
fascicle
sheet/broad band of connective tissue.
37
origin
the site where bone and muscle are attached, but do not move during contraction
38
treppe
also known as the staircase phenomenon. shows that muscles contract more forcefully after they have been contracted a few times.
39
what are the basic functions of muscle?
1) contraction 2) heat production from movement 3) maintaining posture (standing, sitting, etc) 4) storing and moving substances throughout the body.
40
what are the 3 types of muscle?
cardiac, smooth, and skeletal
41
how does each type of muscle differ structurally?
cardiac - involuntary, branched, stiriated. smooth - involuntary skeletal - voluntary, striated.
42
what are the three stages of a muscle contraction?
1) latent period 2) contraction phase 3) relaxation phase
43
what are the 3 types of levers?
1st class lever, 2nd class lever, 3rd class lever
44
how does the first class lever work?
joint is in the middle of the force and pull. like seesaw ex. atlas of spine and skull
45
how does the second class lever work?
weight lies between fulcrum and joint. like wheelbarrow. ex. standing on tippy toes.
46
how does the third class lever work?
pull exerted between fulcrum and weight. like lifting a shovel ex. flexing biceps.
47
how are muscles named? provide an example
1) location- arm, brachialis 2) function- move towards, adductor 3) shape- triangle, deltoid 4) direction of fibers- straight, rectus 5) # of heads or divisions- two, biceps 6) points of attachment- sternocleidomastoid
48
what are the two types of tetanus?
fused and unfused
49
what is the difference between the two different types of tetanus?
fused - smooth, stiriated muscle contractions unfused - sustained but wavering contraction
50
what is the graded strength principle influenced by?
1) metabolic condition of muscle fibers 2) # of muscle fibers contracting 3) # of motor units recruited 4) intensity and frequency of stimulation
51
what are the four types of proteins that make up myofilaments
myosin, acting, tropomyosin, troponin.
52
myosin
make up most of thick filament
53
actin
globular proteins; make bulk of thin filaments.
54
tropomyosin
blocks active sites of actin
55
troponin
holds tropomyosin in place at finding site
56
titin
accounts for most of the myofilaments elasticity and extensibility bc it can stretch to four times its initial length and return unharmed.
57
dysrophin
cytoskeletal protein that links thin filaments to the sarcolemma; help transmit tension.
58
tonic contraction
continued partial contractions
59
flaccid
muscles with less than normal tone are considered
60
spastic
muscles with more than normal tone are considered
61
concentric / eccentric
reduces the angle of the joint / increasing the angle and lengthening the muscle
62
stretch reflex
The amount of a load on muscles can also influence contraction.
63
what is a length-tension relationship
the max strength a muscle can supply is directly related to the initial length of its fibers.
64
intercalated discs
strong electrically coupled junctions