Muscles

Question 1

What do muscles do (function)?

Answer 1

Produce movement
Maintains posture + position
Protection
Heat production (thermogenesis)
Driving circulatory system (vascular pump)

Question 2

What are the 3 types of muscle?

Answer 2

Smooth muscles - involuntary
Cardiac muscles - involuntary
Skeletal muscles - voluntary

Question 3

Muscle contraction - what is the relationship between external force and muscle force?

Answer 3

• When external force = muscle force, muscle length will stay constant (isometric contraction)
• When external force < muscle force, muscle can be shortened by contracting (concentric contraction)
• When external force > muscle force, muscle can be lengthened by contracting (eccentric contraction)

Question 4

Hierarchical structure of muscle

Answer 4

1) Muscle
2) Muscle fascicle
3) Muscle fibre
4) Myofibrils
5) Sarcomeres
6) Myofilaments - actine and myosin (inter-digitated)

Question 5

Sliding filament model terminology - Binding sites

Answer 5

positions on actin filaments where myosin heads can attach

Question 6

Sliding filament model terminology - Cross-bridges

Answer 6

temporarily formed mechanical bridges between actin binding sites and myosin heads

Question 7

Sliding filament model terminology - Power stroke

Answer 7

a ‘nod’ of the myosin head that applies force to the actin filament via the cross-bridge