lecture 5: muscle physiology

Question 1

skeletal muscle order

Answer 1

1: muscle
2: fascicle
3: fibre
4: myofibril

Question 2

what muscle insets directly into the bone?

Answer 2

the soleus

Question 3

skeletal muscle function

Answer 3

muscle shortening = more overlap

muscle lengthening = less over lap , longer

(the amount of overlap increase or decrease is between the actin and myosin)

Question 4

muscular strength

Answer 4

force a muscle or muscle group can exert in one maximal effort (how many cross bridges can be activated)

Question 5

muscular endurance

Answer 5

ability of muscles or muscle groups to perform repeated or sustained contractions

Question 6

what is muscular strength determined by?

Answer 6

muscle size (CSA)
- neural drive

bigger muscle = more cross bridges
more cross bridges = more force

Question 7

muscle endurance is determined by

Answer 7

• metabolic adaptations
• increased capillarization
• increased mitochondria density/function

Question 8

muscle types

Answer 8

• contractile function of muscle is dependent on fibre type
• in humans, skeletal muscle characterized by :
  1. fast (type 2)
  
  • type 2x (fastest)
  • type 2a (pretty fast)
    
    2. slow (type 1)

Question 9

muscle growth

Answer 9

• tissues can grow through hypertrophy and/or hyperplasia
• accomplished with an increased number of myofibrils per fibre

Question 10

hypertrophy

Answer 10

increase in the size of individual muscle fibres

Question 11

hyperplasia

Answer 11

increase in the number of muscle fibres
- muscles do not really increase the number of muscle fibres

Question 12

amino acids delivered to the – are used to form muscle proteins that comprise new –

Answer 12

1. muscle
2. myofibrils

Question 13

myonuclear domain theory

Answer 13

apart of muscle growth
- each nucleus of a muscle cell is responsible for a finite volume of cell space
- in order for a muscle fibre to grow (hypertrophy), the number of nuclei needs to increase

Question 14

satellite cells

Answer 14

• apart of muscle growth
• quiescent cells that activate and enter the fibre
• aid in tissue repair and or donate their nuclei

Question 15

muscle growth stimulus

Answer 15

muscle responds (in specific ways) in response to overload
- responds to
- metabolite accumulation
- mechanical forces
- immune signalling
(inflammation)

Question 16

resistance training

Answer 16

• muscle function is derived from its unique structure
• muscular strength based on muscle size and activation
• muscular endurance based on capillary and mitochondria density
• muscle adapts to exercise stimuli by generation of myofibril muscle proteins and satellite cell differentiation into nuclei
• muscle adaptation stimulated by accumulation of metabolites, detection of mechanical forces, and inflammation