Week 02

Question 1

What is composed of muscle fibres?

Answer 1

Fascicle

Question 2

What is composed of muscle myofibrils?

Answer 2

muscle fibres/cells

Question 3

What is composed of sarcomeres?

Answer 3

Myofibrils

Question 4

What is the mysium?

Answer 4

A sheath of connective tissue allowing gliding between layers

Question 5

Epi means…

Answer 5

above

Question 6

peri means…

Answer 6

around

Question 7

Endo means…

Answer 7

internal, within

Question 8

What is the perimysium?

Answer 8

Sheath that encapsulates groups of muscle fibres into fascicle

Question 9

What is the endomysium?

Answer 9

Sheath that wraps around single muscle fibres (space for capillaries and nerves

Question 10

What is the sarcolemma?

Answer 10

is the cell membrane of a muscle cell.

Question 11

What is the purpose of the sarcolemma? (4)

Answer 11

Propagation of action potential along muscle fiber, transports metabolites, maintains acid balance

Question 12

Function of transverse tubules (T-tubules)?

Answer 12

Transmit action potential into fiber via sarcoplasmic reticulum

Question 13

The Sarcoplasmic reticulum releases and uptakes …

Answer 13

calcium to myofibrils

Question 14

What is the first step of muscle contraction?

Answer 14

Action potential arrives at terminal of neuromuscular junction (NMJ)

Question 15

Once the AP reaches the neuromuscular junction, _______ is released to the receptors

Answer 15

acetyl choline (ACh)

Question 16

After acetyl choline is released, _______ occurs

Answer 16

depolarization (change in ion level)

Question 17

What happens after depolarization in the sarcomere?

Answer 17

AP travels along sarcolemma and down T-tubules

Question 18

What could be a rate limiter for speed of contraction? (6)

Answer 18

• Stimulation strength and frequency from axon terminal
• Calcium kinetics (release and uptake)
• Affinity of calcium to troponin
• Myosin ATPase
• Ability of Myosin machinery to produce force
• Energy supply and type

Question 19

Power =

Answer 19

Power = force x velocity

Question 20

Factors that effect the ability to produce power? (5)

Answer 20

• frequency of stimulation
• fiber types
• number of motor units
• Architectural factors (parallel vs series)
• Fiber length relative to optimal length (length tension relationship)

Question 21

Henneman size principle is…?

Answer 21

Recruitment increases as cell body size increases - smaller start recruiting first (type II - largest)

Question 22

3 benefits of longer fascicle length

Answer 22

• Greater work across ROM
• generate higher shortening speed
• Greater power production capacity

Question 23

Fascicle length can shorten due to

Answer 23

immobilisation and injury.

Question 24

Series design increases….

Answer 24

Contraction speed

Question 25

Parallel design increases….

Answer 25

Force production

Question 26

Pennation angle allows for….

Answer 26

more packing of sarcomeres in parallel (most muscles)

Question 27

Slow twitches do/don’t build on top of the last twitch?

Answer 27

DO (too slow to recover from last twitch quick enough)

Question 28

Fast twitches do/don’t build on top of the last twitch?

Answer 28

DONT (recover too quickly)

Question 29

Muscle fibre type 2a is more aerobic or explosive?

Answer 29

aerobic

Question 30

Muscle fibre type 2x is more aerobic or explosive?

Answer 30

explosive

Question 31

Longer fascicle lengths promotes (3)?

Answer 31

1. Greater work across ROM
2. Generate higher shortening speed
3. Greater power production capacity