Muscle

Question 1

What are the three types of muscle?

Answer 1

Skeletal, smooth and cardiac

Question 2

Which cells replace muscle cells after injury?

Answer 2

Satellite cells - by differentiating to form new muscle fibres

Question 3

Which structure attaches muscle to bone?

Answer 3

Tendon

Question 4

What are the ‘thick’ filaments composed of?

Answer 4

Myosin

Question 5

What are the ‘thin’ filaments composed of?

Answer 5

Actin

Question 6

Which filaments are cross-bridges found on?

Answer 6

Myosin filaments

Question 7

Which molecule partially covers the myosin binding site?

Answer 7

Tropomyosin

Question 8

Which molecule holds tropomyosin in place?

Answer 8

Troponin

Question 9

Which molecule does calcium bind to?

Answer 9

Troponin

Question 10

What happens when calcium is removed?

Answer 10

Tropomyosin blocks the binding site again

Question 11

Which filament are troponin and tropomyosin found on?

Answer 11

Actin ‘thin’ filament

Question 12

Where is calcium released from?

Answer 12

Lateral sac of sarcoplasmic reticulum

Question 13

What is a motor unit made up of?

Answer 13

Muscle fibres and the motor neuron that innervates them

Question 14

What is the name for the force exerted BY a muscle?

Answer 14

Tension

Question 15

What is the name for the force exerted ON a muscle?

Answer 15

Load

Question 16

What is the name for contraction with constant length (e.g. weightlifting)?

Answer 16

Isometric contraction

Question 17

What is the name for contraction with shortening length (e.g. running)?

Answer 17

Isotonic (or concentric) contraction

Question 18

What is the name for contraction with increasing length (e.g. sitting down)?

Answer 18

Lengthening contraction

Question 19

What is the name for the period of time before contraction starts?

Answer 19

Latent period

Question 20

Between which points does contraction time occur?

Answer 20

Between start of tension and time when we have peak tension

Question 21

What are the effects of ATP within the muscle?

Answer 21

1. Binding to myosin dissociates bridges bound to actin - new cycle may begin
2. Powers Ca2+-ATPase in sarcoplasmic reticulum - Ca2+ pumped back into SR, contraction ends

Question 22

True or False: Fatigue prevents muscles using up vast amounts of ATP, which would cause rigour (i.e. muscles would not be able to activate new cross-bridges)

Answer 22

True

Question 23

What are the factors that cause fatigue in long term, low intensity exercise?

Answer 23

Decrease in muscle glycogen, decrease in blood glucose, dehydration

Question 24

Which of oxidative fibres and glycolytic fibres have more mitochondria?

Answer 24

Oxidative fibres

Question 25

What are the 3 types of muscle fibres?

Answer 25

Slow oxidative (I) - resist fatigue
Fast oxidative (IIa) - intermediate resistance to fatigue
Fast glycolytic (IIb) - fatigue quickly

Question 26

“Smooth muscle has tone.”

What does this mean?

Answer 26

A basal level of Ca2+ in cells causes a constant level of tension

Question 27

Name 3 factors affecting contractile activity of smooth muscle.

Answer 27

Any of:

• spontaneous electrical activity in muscle membranes - pacemaker activity
• autonomic neurotransmitters from varicosities
• hormones (e.g. oxytocin)
• local factors (paracrine agents, pH, O2, osmolarity, ions, NO)
• stretch

Question 28

What is another term for a multinucleated muscle cell?

Answer 28

Muscle fiber

Question 29

What structure surrounds a bundle of muscle fibres?

Answer 29

Perimysium

Question 30

What structure surrounds a bundle of muscle fascicles?

Answer 30

Epimysium

Question 31

What structure surrounds a single muscle fibre?

Answer 31

Endomysium

Question 32

What is the term for a bundle of muscle fibres?

Answer 32

Fascicle