Skeletal Muscle Physiology 1 01/10/18

Question 1

What are the 5 physiological functions of skeletal muscle/

Answer 1

Maintenance of posture
Purposeful movement in relation to external environment
Respiratory movements 
Heat production
Contribution to whole body metabolism

Question 2

What is the largest type of tissue in the human body?

Answer 2

Muscle

Question 3

How many muscle types are there?

Answer 3

3

Question 4

What are the three types of muscle?

Answer 4

Skeletal
Cardiac
Smooth

Question 5

What are all three muscle types capable of?

Answer 5

Developing tension and producing movement through contraction

Question 6

Which two muscle types are striated?

Answer 6

Skeletal

Cardiac

Question 7

Which muscle type is unstriated?

Answer 7

Smooth

Question 8

Which two muscle types are involuntary?

Answer 8

Cardiac

Smooth

Question 9

Which muscle type is voluntary?

Answer 9

Skeletal muscle

Question 10

What is striation visualized as under a microscope?

Answer 10

Alternating light and dark bands

Question 11

Why are dark and light bands seen?

Answer 11

Alternating Actin (light) and Myocin (light) filaments

Question 12

What innervates skeletal muscle?

Answer 12

Somatic nervous system

Question 13

What innervates cardiac and smooth muscle?

Answer 13

Autonomic nervous system

Question 14

Is the initiation of contraction in skeletal muscle neurogenic?

Answer 14

Yes

Question 15

Is the initiation of contraction of cardiac muscle neurogenic?

Answer 15

No its Myogenic

Question 16

Which has neuromuscular junctions present, cardiac or skeletal?

Answer 16

Skeletal

Question 17

Which has Gap junctions present, skeletal or cardiac?

Answer 17

Cardiac

Question 18

Where is the calcium from in skeletal muscle contraction?

Answer 18

Entirely from sarcoplasmic reticulum

Question 19

Where is the calcium from in cardiac muscle contraction/

Answer 19

Extra cellular fluid

Sarcoplasmic reticulum

Question 20

What is responsible for the gradation of contraction in skeletal muscle?

Answer 20

Motor unit recruitment

Summation of contractions

Question 21

What is responsible for the gradation of contraction in cardiac muscle?

Answer 21

Depends on the extent of the heart filling with blood (preload)

Question 22

Can one motor neurone be responsible for more than one muscle fibre?

Answer 22

Yes it can be responsible for many

Question 23

What is a motor unit?

Answer 23

The motor neurone and all of the muscle fibres that is supplies

Question 24

Is there continuity of cytoplasm between nerve and muscle cells?

Answer 24

No

Question 25

What is the transmitter at a neuromuscular junction?

Answer 25

Acetylcholine

Question 26

What connects cardiac muscle fibres?

Answer 26

Desmosomes and gap junctions

Question 27

What does the number of muscle fibres per motor unit depend on?

Answer 27

``` The functions served by a muscle Fine movements (eye, facial expression) have fewer fibres ```

Question 28

Where power is more important than precision are there many or few motor fibres?

Answer 28

Thousands

Question 29

What are the parts of a muscle?

Answer 29

``` Whole muscle Muscle fibre Myofibril Sarcomere Actin and Myocin ```

Question 30

Which filaments are thick and dark, actin or myocin?

Answer 30

Myocin

Question 31

Are skeletal muscle fibres parallel or perpendicular?

Answer 31

Parallel lol

Question 32

How long is a skeletal muscle cell/fibre?

Answer 32

The entire length of the muscle

Question 33

How are skeletal muscle fibres bundled together?

Answer 33

Connective tissue

Question 34

How are skeletal muscles attached to bones?

Answer 34

Tendons

Question 35

What do bones, joints and muscle form to allow body movements?

Answer 35

Lever systems

Question 36

What does each muscle fibre contain?

Answer 36

Myofibrils

Question 37

What is a myofibril?

Answer 37

Specialised contractile intracellular structures

Question 38

What are actin and myocin arranged into inside myofibrils?

Answer 38

Sarcomeres

Question 39

What are the functional units of muscle?

Answer 39

Sarcomeres

Question 40

What do Z lines seperate?

Answer 40

Sarcomeres

Question 41

What are the 4 zones of a sarcomere?

Answer 41

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

Question 42

What is the A-band made of?

Answer 42

Thick filaments with thin filaments that overlap at both ends of the thick filament

Question 43

What is the H-zone?

Answer 43

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

Question 44

What is the M-line?

Answer 44

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

Question 45

What is the I-Band?

Answer 45

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

Question 46

How is muscle tension produced?

Answer 46

Sliding of actin and myocin filaments

Question 47

What is force generation dependent on?

Answer 47

ATP

Question 48

True/False: ATP is only required for contraction

Answer 48

FALSE | It is also required for relaxation

Question 49

What is required to switch on crossbridge formation?

Answer 49

Calcium

Question 50

What is excitation contraction coupling?

Answer 50

The process whereby the surface action potential results in the activation of the contractile structures of the muscle fibre

Question 51

When is calcium released from the sarcoplasmic reticulum in skeletal muscle?

Answer 51

When the surface action potential spreads down the transverse tubules, this is triggered by spread of action potentials down the T-tubules

Question 52

Explain the excitation of actin/myocin

Answer 52

Ca2+ binds wiith troponin, pulling tropomyosin complex aside to expose the cross-bridge binding site for binding to occur Binding of actin and myocin cross bridge triggers power stroke that pulls the thin filament inwards during contraction

Question 53

Explain the massive diagram about how muscle contraction occurs

Answer 53

Ach is released from axon of a motor neurone, which causes an action potential to go down the T-tubules. This triggers the release of calcium from the sarcoplasmic reticulum. Calcium ions released bind to troponin on actin filaments which means tropomyosin is moved and the cross-bridge binding site is exposed. The myosin cross bridge attaches to the actin and bends, pulling the actin towards the middle, powered by ATP.