Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Reproduction > muscle contraction and function > Flashcards

muscle contraction and function Flashcards

1
Q

3 types of muscle tissue in the body

A

skeletal, smooth and cardiac muscle

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

each muscle is an organ composed of what ?

A

skeletal muscle tissue, blood and other connective tissues

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

what is fascia and its role

A

layers of dense connective tissue which surround and separate each muscle

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

fascia extends and give rise to ?

A

tendons which are fused to the periosteum of bones

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

what is aponeuroses

A

when muscles are connected to each other by broad sheets of connective tissues

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

what is the layer of connective tissue around each skeletal muscle

A

facia blending with epimysium

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

does perimysium extend inward

A

yes it extends inwards from the epimysium

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

what does perimysium do

A

surrounds bundles of skeletal muscle fibres called fascicles within each muscle

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

what is endomysium

A

each muscle cell fibre covered by a connective tissue layer

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

Describing muscle fibre

A

is a single, long, cylindrical muscle cell which responds to stimulation by contracting

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

the name of the cell membrane of a muscle fibre is ?

A

sarcolemma

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

the cytoplasm of a muscle cell is? and what does it contain?

A

sarcoplasm and it contains many mitochondria and nuclei

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

sarcoplasm contains what apart from mitochondria and nuclei?

A

parallel myofibrils, which are active in muscle contraction

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

what protein thick filaments in myofibrils contain

A

protein myosin

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

what protein is contained in think filaments in myofibrils

A

protein actin, troponin and tropomyosin

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

what is the name given to organisation of the filaments producing bands

A

striations

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

why darker image appears in skeletal muscles striations

A

it appears darker because actin and myosin overlap A band
I band is lighter

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

what are myofibrils made up of?

A

small units Called sarcomere that are joined end to end

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

sarcomere extends from where?

A

Z line to the next

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

what are I bands made up of

A

I bands are light
made up of actin filaments which are anchored to the Z lines

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

what are A bands are made up of

A

A bands appear dark, and there is a overlapping of thick and thin filaments

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

what zone is in the centre of A band

A

the centre of A band is H zone and it consists of myosin filaments only

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

where is the M line

A

M line is in the centre of the H zone

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

M line consists of what?

A

M line consists of proteins that hold the myosin filaments in place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
where is sarcoplasmic reticulum
beneath the sarcolemma of a muscle fibre lies a network of membraneous channels
25
SR Is a what of muscle
endoplasmic reticulum
26
describe T tubules
lies between 2 cisternae of the SR and are open to the outside of the muscle fibre
27
how SR and T tubules work together
- by activating muscle contraction when fibre is stimulated
28
when skeletal muscle fibres contract
only when stimulated by a motor neuron
29
how synapses are created
each skeletal muscle fibre cell is functionally connected to the axon of a motor neuron
30
how neurons and muscle fibres communicate
by neurotransmitters which are released at synapse
31
how neurons communicate with the muscle fibre
neurotransmitters which released at synapses
32
what do you call a synapse between motor neuron and a muscle fibre which regulates.
neuromuscular junction
33
The cytoplasm of the distal end of the motor neuron contains what?
it contains numerous mitochondria and synaptic vesicles storing neurotransmitters
34
motor end plate
it is specialised area in the muscle fibre membrane
35
where sarcolemma tightly folded ?
in the motor end plate
36
what motor end plate contains
it contains specific receptors for the neurotransmitter
37
what happens when an electrical impulse reaches the end of the motor neuron axon?
synaptic vesicles release neurotransmitter into the synaptic cleft
38
what is synaptic cleft
the gap between the membranes of the neuron and muscle fibre
39
how muscle fibre contract
the neurotransmitter diffuses across the cleft and bind to the motor end plate and cause stimulation and muscle fibre contract
40
what are the events involved in muscle contraction?
shortening of sarcomeres and pulling of the muscle against it attachments
41
where is the pulling force exerted from?
by binding of myosin and actin molecules
42
shortening of a muscle fibre results from where?
from actin and myosin filaments overlapping as they slide pass each other
43
shortening of muscle fibres results in what?
it results in shortening of the entire muscle, which pulls on the skeleton to cause movement
44
describe myosin
consist of two twisted strands, with globular heads projected outward along the strands
45
how a thick filament is formed
by a group of myosin molecules
46
what is actin
a globular protein arranged in twisted filaments ( a double helix) , containing myosin binding sites
47
what are 2 proteins that are associated with the surface of actin molecules?
troponin and tropomyosin and all 3 proteins will form the thin filaments
48
how cross-bridge is made according to the sliding filament model of muscle contraction?
during a muscle contraction, myosin head attaches to a binding site on the actin filament which forms a cross-bridge
49
what does the binding between myosin to actin cause
it causes the head to bend, pulling an actin filament and moving it toward the centre of the sarcomere
50
what happens when filaments increase their overlap?
the sarcomere shortens from both ends
51
what happens when many sarcomeres shorten
at the same time muscle fibre shortens
52
what happens when ATP is broken down
it causes the heads to return to the cocked position ready to bind to another actin binding site
53
what is acetylcholine
is a neurotransmitter for skeletal muscle fibre contraction at the neuromuscular junction
54
where is acetylcholine produced and stored
it is produced in motor neuron and stored in synaptic vesicles at the distal end of the neuron
55
what does acetylcholine stimulate
muscle fibre
56
where is acetylcholine released into
acetylcholine is released into synaptic cleft in the response to an impulse in the motor neuron
57
what happens after muscle fibre impulse
the sarcoplasmic reticulum releases its stored calcium to the cytosol of the muscle fibre
58
where the stored calcium released into
released into cytosol of the muscle fibre
59
the high levels of calcium in the sarcoplasmic reticulum interacts with what?
with the troponin and tropomyosin molecules which move aside exposing the myosin binding sites on the actin filaments
60
explain the events after nerve impulse stops and lead to relaxation of the muscle
first the enzyme acetylcholinesterase on the motor end plate rapidly decomposes the acetylcholine secondly, calcium is returned to the sarcoplasmic reticulum, using ATP as an energy source 3rd ATP now binds to the myosin heads breaking the linkages between myosin and actin finally the actin returns to its original position and the muscle relaxes
61
what is a myogram
is the recording of an electrically stimulated muscle contraction
62
definition of latent period
brief delay of between the stimulation and beginning of the contraction
63
latent period is followed by?
by a period of contraction and a period of relaxation
64
what is all or none response
when a muscle fibre contracts it contracts to its full extent
65
muscle consist of a combination of both types:
- fatigue resistant slow twitch fibres -fatigable fast twitch fibres
66
describe partial tetany
when exposed to higher frequency of stimulation, relaxation time becomes very short
67
describe complete tetanic contraction
if the frequency of stimulation is very high and the sustained contraction lacks any relaxation
68
partial tetany occurs in the body what about complete tetany
no it can only be accomplished in a lab
69
what is recruitment
an increase in the number of activated motor units within a muscle at higher intensities of stimulation
70
summation and recruitment together can produce what
sustained contraction of increasing strength
71
muscle tone is achieved by what?
a continues state of sustained contraction of a few motor units at a time within a muscle
72
muscle tone is important for?
maintenance of posture
73
types of smooth muscle cell
- multiunit smooth muscle -visceral smooth muscle
74
describe multi smooth muscle
in blood vessels and iris of the eye, fibres occur separately rather than sheets; stimulated by neurons and some hormones
75
describe visceral smooth muscle
occurs in sheets and is found in the walls of hollow organs; these fibres can stimulate one another and display rhythmicity; these features accomplish peristalsis in tubular organs
76
name similarities between smooth and skeletal muscle contraction
- both involve reaction between actin and myosin - both are stimulated by membrane impulses, require an increase in calcium ions in the cells, and use ATP energy
77
describe differences smooth and skeletal muscle contraction
- both Ach and norepinephrine stimulate and inhibit Smooth muscle contraction while only Ach stimulates skeletal muscle -hormones can stimulate or inhibit contraction of smooth muscle but not skeletal muscle - smooth muscle is slower to contract or relax -
78

Reproduction (8 decks)

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