Muscles 1 Flashcards Preview

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Flashcards in Muscles 1 Deck (40):
1

3 types of muscle?

- Skeletal
- Cardiac
- Smooth

2

2 examples of skeletal muscle?

- Voluntary muscles
- Diaphragm

3

2 examples of places in the body you would find smooth muscle?

- Blood vessels
- Sphincters
- Airways

4

Another name for a skeletal muscle cell?

Muscle fibre

5

What are skeletal muscle cells formed from in utero?

Myoblasts

6

How do you identify skeletal muscle in histology?

- Striated
- Multinucleate
- Nuclei pushed to edges of the cell

7

Are skeletal muscles able to repair?

Not well at all
Myoblasts do not replace damaged muscle

8

What 2 ways can skeletal muscle try to repair itself?

- Satellite cells replace damaged ones to form new muscle fibres
- Surrounding muscle fibres undergo hypertrophy

9

How does smooth muscle repair?

Can divide very easily

10

What encircles muscle fibres?

Areolar connective tissue

11

How are muscles attached to bone?

Tendons

12

How does blood reach the muscle in the centre of the muscle?

Deep penetrating vessels

13

What is the Z line

Border between one repeating unit (sarcomere) and another

14

What does titin ensure?

Myosin is always surrounded by actin on six sides

15

How is myosin energised to allow quick on demand contraction?

ATP constantly hydrolysed to ADP and Pi on the myosin head

16

What proteins are attached to actin?

Troponin
Tropomyosin

17

What does tropomyosin do?

Blocks myosin binding sites

18

What does troponin do?

Holds tropomyosin in place

19

How does calcium reveal myosin binding sites?

- Binds to troponin
- Troponin twists and moves the tropomyosin

20

Where is calcium stored in the muscle fibre

Sarcoplasmic reticulum

21

Role of transverse tubes in muscle?

Propegating electrical signals into muscle core

22

What do transverse tubes allow the muscle to do?

Uniform contraction

23

What is the combination of a nerve and a muscle called?

Motor unit

24

If a motor unit is damaged why don't you lose the function of the muscle?

There are multiple motor units for a single muscle

25

What is tension?

Force exerted by a muscle

26

What is load

Force exerted on the muscle

27

What is harder as the load increases?

- Fast contraction
- Generation of the required tension

28

What is isometric contraction

Contraction without shortening of the fibre

29

What is isotonic contraction?

Contraction with shortening of the fibre

30

What is lengthening contraction?

Contraction with lengthening of the fibre

31

What is a twitch response?

A contraction produced by a single action potential

32

How much longer is twitch than an AP?

About 100 times longer

33

What does the fact that twitch is so much longer allow?

Contraction to be sustained for longer

34

If the time between AP's is short what happens with the contractions?

They summate

35

What is tetanus with regards to muscle?

A sustained level of tension in any muscle fibre

36

What is unfused tetanus?

Contraction fluctuates over a period of time

37

What is fused tetanus?

Contraction is sustained over a long period of time

38

Why do we fatigue?

Stops fused tetanus from happening constantly and means that calcium levels aren't constantly high in the cell

39

What is the length tension relationship

The optimum length of a muscle fibre that produces the strongest contraction

40

What does the agonist/antagonist relationship of skeletal muscles allow?

Increased manoeuvrability