STRUCTURE + MUSCLE CONTRACTION Flashcards

1
Q

What are the three different types of sheath of connective tissue?

A
  1. Epimysium
  2. Perimysium
  3. Endomysium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is found in the muscle (organ)?

A

Epimysium

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

What is found in the muscle fascicle?

A

Perimysium

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

What is found in the muscle fiber?

A

Endomysium

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

What is the myofibril made up of?

A

Many sacromeres

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

What is the sacroplasmic reticulum?

A

Stores Ca2+ for muscle contraction

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

What is a sacromere?

A

The basic contractile unit of muscle

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

What are the boundaries of sacromeres called?

A

A pair of Z-lines

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

What is the centre of a sacromere called?

A

An M-line

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

What is the structure of a sacromere?

A

Interdigitation of thick (myosin) and thin (actin) filaments

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

Is myosin thick or thin?

A

Thick

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

Is actin thick or thin?

A

Thin

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

What kind of filaments does the H-band contain?

A

Contains thick filaments only

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

What kind of filaments does the I-band contain?

A

Contains thin filaments only

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

What kind of filaments does the A-band contain?

A

Contains both thin and thick filaments (zone of overlap)

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

What three things occur to the bands during muscle contraction?

A
  1. Width of the I-band decreases (thin actin filaments)
  2. Width of the H-band decreases (thick myosin filaments)
  3. Width of the A-band remains constant (thin actin and thick myosin)
17
Q

What three things happen during muscle contraction?

A
  1. Intake of calcium increases
  2. Cross-bridging between thick and thin filaments
  3. Pivoting of myosin heads toward the M-line
18
Q

Which direction are the myosin heads facing when the sacromeres are at rest?

A

Towards Z-line

19
Q

Which direction are the myosin heads facing when the sacromeres are contracting and filament sliding?

A

Towards M-line

20
Q

What are the three steps of nerve stimulation and muscle contraction?

A
  1. Each muscle cell (fibre) is innervated by a motor neuron (nerve cell)
  2. When the neuron fires, it signals the muscle cell to contract
  3. Contraction is an ALL OR NONE phenomenon: the muscle cell either contracts fully, or it does not contract at all
21
Q

When is the lag phase?

A

Between action potential and contraction

22
Q

What does the motor neuron do?

A

Innervates multiple muscle cells

23
Q

How are all muscle cells controlled by?

A

A single motor neuron constitute a motor unit

24
Q

What is a motor unit?

A

Nerve from spinal cord that innervates a muscle fibre

25
Q

What is important to note about motor units?

A

The number of muscle fibers can be big or small

26
Q

What is the amount of muscle tension produced dependent on?

A

The number of motor units that are stimulated

27
Q

What happens when you have more nerves?

A

You have more motor units therefore you generate more force

28
Q

What happens when you have less nerves?

A

You have** less **motor units therefore you have fine control of muscle