Week 5

Question 1

Single crossbridge:
-ATP cost
-Force generation (pN)
-Length change (nm)

Answer 1

-ATP cost: 1
-Force generation: 3.2 pN
-Length change: 10 nm

Question 2

Muscular strength vs muscular endurance

Answer 2

Muscular strength: Force a muscle can exert in one maximal effort
Muscular endurance: Ability to perform repeated/sustained contractions

Question 3

What two factors is muscle strength mostly determined by?

Answer 3

1. Muscle size
   -More mass means more crossbridges, leading to more force
2. Neural drive

Question 4

What two factors is muscle endurance mostly determined by?

Answer 4

1. Increased capillarization
2. Increased mitochondria
   density/function

Question 5

3 Muscle fiber types

Answer 5

1. Type I, slow oxidative
2. Type IIa, slow glycolytic
3. Type IIx, fast glycolytic

Question 6

Which type is better for muscle endurance?

Answer 6

Type I, as it has more capillaries & mitochondrial density

Question 7

What does slow twitch muscle look like?

Answer 7

Appears red, due to high myoglobin content

Question 8

Hypertrophy vs Hyperplasia

Answer 8

Hypertrophy: Increase in size of muscle fibres due to increase in myofibrils (most muscle growth due to hypertrophy)
Hyperplasia: Increase in number of actual muscle fibres

Question 9

How are new myofibrils made?

Answer 9

With amino acids delivered to muscle

Question 10

Satellite cells and muscle growth

Answer 10

-Exercise stimulates muscle
-Muscle protein synthesis generates new myofibrils within existing fibres
-Satellite cells (muscle stem cells) multiply/differentiate to form new nuclei or aid in tissue repair

Question 11

What does muscle respond to stimulus-wise?

Answer 11

-Metabolite accumulation
-Detection of mechanical forces
-Inflammation