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Flashcards in Physiology Deck (63):
1

What are the 3 kinds of muscle?

Cardiac (heart)
Smooth (stomach)
Skeletal (limbs)

2

What is the largest type of human tissue?

Muscle

3

What are muscles capable of?

developing tension
producing movement
contraction

4

What types of muscle are striated?

Skeletal and cardiac

5

What are the dark and light bands within muscle?

Dark = thick myocin
Light = thin actin

6

What nervous system innervates skeletal muscle?

Somatic

7

What is a motor unit?

A single alpha motor neurone

8

TRUE or FALSE
Muscle that serve fine movements have less fibres per motor unit

TRUE

9

Does skeletal muscle contain gap junctions?

No, but cardiac muscle does

10

Does skeletal muscle have neuromusclular junctions?

Yes, but cardiac muscle does not

11

In skeletal muscle, where does Ca++ come from?

Entirely from the sarcoplasmic reticulum, in cardiac its also from ECF

12

How is the potential transmitted in alpha motor neurons cause muscle contraction?

Excitation contraction coupling

13

What is excitation contraction coupling?

process where the surface action potential results in activation of the contractile mechanism of the muscle fibre.

14

When in skeletal muscle is Ca++ released?

When the surface action potential spreads down the transverse (T)-tubules

15

What are T-tubules?

They are extensions of the surface membrane that dip into the muscle fibre

16

What is the neuromuscular junction transmitter?

Acetylcholine

17

What does each muscle fibre contain?

Myofibrils

18

How are actin and myocin arranged, and where?

In sarcomeres within each myofibril

19

What are the 4 zones of a sarcomere?

A-band, H-zone, M-line and I-band

20

What is the A-band?

Thick filaments along with the portions of thin filaments that overlap in both ends of thick filament

21

What is the H-zone?

Lighter area within middle of A-band where thin filaments don't reach

22

What is the M-line?

It extends vertically down the middle of the A-band within the centre of the H-zone

23

What is the I-band?

Consists of remaining portion of thin filaments that do not project in A-band

24

What is Ca++ needed for?

to switch on cross bridge formation

25

What is motor neurone recruitment?

stimulation of more motor units resulting in a stronger contraction.

26

What does synchronous motor units recruitment during submaximal contractions help to prevent?

Muscle fatigue

27

What 4 things help dictate the tension developed during muscle fibre contraction?

1. Frequency of stimulation
2. Summation of contractions
3. Length of muscle fibre at onset of contraction
4. Thickness of muscle fibre

28

What prevents a tetanic contraction?

A long refractory period

29

What is a twitch?

a single contraction of the muscle

30

How much tension does a twitch produce?

Very little

31

TRUE OR FALSE
With increasing frequency of stimulation
the tension increases

TRUE

32

What are the two types of contraction?

Isotonic and Isometric

33

Explain isotonic contractions

For body movements and moving objects.
Muscle tension remains constant as the muscle length changes.

34

Explain Isometric contractions

Used for supporting objects in fixed positions and for maintaining body posture.

35

Give an example of a disease which involves chronic degeneration of contractile elements

Muscular dystrophy

36

Give an example of a disease which involves abnormalities in muscle ion channels

Myotonia

37

Give an example of inflammatory myopathies

Polymyosytis

38

Give 2 examples of endocrine myopathies

Cushing syndrome
Thyroid disease

39

Give 2 examples of toxic myopathies

Alcohol
Statins

40

What is a reflex action?

A stereotyped response to a specific stimulus

41

What type of reflex is the stretch reflex?

Monosynaptic reflex

42

The stretch reflex is an example of what?

Negative feedback

43

What type of change does the stretch reflex resist against?

Passive

44

What does the stretch reflex help maintain when walking?

Posture

45

What is the stretch reflex coordinated by?

Simultaneous relaxation of antagonist muscle

46

What spinal segments and peripheral nerve control the Knee jerk?

L3, L4, Femoral nerve

47

What spinal segments and peripheral nerve control the ankle jerk?

S1, S2, Tibial nerve

48

What spinal segments and peripheral nerve control the Biceps jerk?

C5, C6, Musculocutaneous nerve

49

What spinal segments and peripheral nerve control the Brachioradialis?

C5, C6, Radial nerve

50

What spinal segments and peripheral nerve control the Triceps jerk?

C6, C7, Radial nerve

51

What are muscle spindles and what are they known as?

Specialised muscle fibres and intrafusal fibres

52

What are ordinary muscle spindles referred to as?

Extrafusal fibres

53

What are the neurones that control muscle spindles called?

Gamma (y) motor neurones

54

What are slow-twitch fibres?

Slow oxidative type 1 fibres, used for prolonged relatively low aerobic activities

55

What are intermediate -twitch fibres?

fast oxidative type IIa fibres used for both aerobic and anaerobic and are useful in prolonged relatively moderate work

56

What are fast-twitch fibres?

Fast glycolytic type IIx fibres, anaerobic metabolism and are mainly used for short-term high intensity activities

57

What are the 3 types of joints?

1. Synovial
2. Fibrous
3. Cartilaginous

58

What unites bone in a fibrous joint?

Fibrous tissue

59

What unites bone in a cartilaginous joint (Amphiarthrosis)?

Cartilage

60

What separates bones in synovial joints?

A cavity containing synovial fluid and united by a fibrous capsule

61

What produces synovial fluid inside the synovial membrane?

Synovial cells (Fibroblasts)

62

What covers the articular surfaces of bones?

Cartilage

63

What is synovium?

derived hyaluronic acid (mucin) a polymer of disaccharides