Test 2 Study Guide 6

Question 1

How is Ca2+ returned to the endoplasmic reticulum and terminal cisternae?

Answer 1

SERCA pumps

sarcoplasmic/endoplasmic reticulum ATPase pumps

Question 2

When a muscle is stimulated there is a latent period before contraction starts, why?

Answer 2

Takes awhile for the action potentials to open, and for Ca2+ to diffuse to the sarcomeres

Question 3

Twitch:

Answer 3

A single contraction

Question 4

Muscle fiber summation:

• Define:
• Why?

Answer 4

• Define:
  increase in tension (strength of contraction) that results when a muscle fiber is unable to relax between twitches.
• Why?
  More Ca2+ is in the cell, more sarcomeres are involved

Question 5

Tetanus:

• Incomplete Tetanus:
• Complete Tetanus:

Answer 5

• Incomplete Tetanus:
  Spacing of shocks still allows time for relaxation
  Contraction are no longer becomes stronger
• Complete Tetanus:
  Shock frequency is fast muscles cannot relax at all, maximal contraction strength

Question 6

Recruitment:

- Define:

Answer 6

• Define:

Adding more muscle fibers from smallest slow twitch to largest fast twitch

Question 7

Asynchronous activation:

Answer 7

Rotating between different motor units to avoid fatigue

Question 8

Series elastic component (of muscles):

• What contributes to it:
• Predominant contributor:
• Does it strengthen contractions?

Answer 8

- What contributes to it:
Tendon
Plasma membane
titan
- Predominant contributor:
Tendon
- Does it strengthen contractions?
No (it must be counteracted)

Question 9

Ideal sarcomere length for skeletal muscle:

Answer 9

2. 25 um

- This is why muscles contract better when partly bent.

Question 10

Where is the majority ATP used in muscle?

What uses the rest?

Answer 10

by myosin ATPase in the sarcomere (70%)

SERCA (30%)

Question 11

At rest where does most muscle energy come from?

Heavy exercise?

Answer 11

Fat

Glycogen/glucose

Question 12

Why does your muscles switch to aerobic after 2 minutes?

Answer 12

Because then the heart rate will have picked up

Question 13

• Define:
  VO2 max, maximum amount of oxygen you can uptake
• Training increases VO2 max by how much?
  20%

Answer 13

Maximal oxygen uptake:

• Define:
• Training increases VO2 max by how much?

Question 14

The percentage of you maximal oxygen uptake at which lactate levels spike is called:

Answer 14

Anaerobic threshold

Question 15

What breaks down glycogen?

Answer 15

Phosphorylase

Question 16

The process of glycogen breakdown
- When during exercise:
Early
- Predominately from which organ:
Liver

Answer 16

Glycogenolysis:

• When during exercise:
• Predominately from which organ:

Question 17

Gluconeogenesis:

• When during exercise:
• Predominately from which organ:

Answer 17

• When during exercise:
  Late
• Predominately from which organ:
  Liver

Question 18

Oxygen is meeting the demand of the muscles

Answer 18

Steady state:

Question 19

Period before steady state:

Period after steady state:

Answer 19

O2 debt

Recovery (Repayment of O2 debt)

Question 20

Repayment of O2 debt/recovery is what physiological process?

Answer 20

• Oxygen replacement in hemoglobin and myoglobin

- The metabolism of lactic acid. Once this is done, you stop breathing hard, and the lactic acid is gone.

Question 21

• Function:

phosphocreatine + ADP -> ATP + creatine

Answer 21

Creatine Phosphokinase (CPK):
- Function:

Question 22

Creatine phosphokinase in the blood is indicative of what?

Answer 22

Myocardial infarction

Question 23

Fast twitch:

• Also called:
• Found in:

Answer 23

- Also called:
Type 2
White muscle
- Found in:
Arms and muscles of eye

Question 24

Slow twitch:

• Also called:
• Found in:

Answer 24

Slow twitch:
- Also called:
Type 1
Red muscle
- Found in:
Soleus

Question 25

Primarily what causes the high variation in slow twitch fast twitch ratio?

Answer 25

Genetics

Question 26

Peripheral muscle fatigue:

• predominately due to:
• due to:

Answer 26

- predominately due to:
increased extracellular K+
- due to:
Lack of oxygen
Glycogen depletion
ATP decline
Ca2+ lost from sarcoplasmic reticulum

Question 27

Changes in CNS stop muscles before peripheral fatigue stops them

Answer 27

Central fatigue:

Question 28

Intramuscular triglycerides:

• In fat people:
• In endurance athletes

Answer 28

• In fat people:
  There but doesn’t help
• In endurance athletes:
  There but is used as fuel source

Question 29

Hypertrophy in muscles is an increase in:

Answer 29

Size in muscle fibers, number of myofibrils within them

Question 30

Atrophy in the elderly is due to:

- How is the counteracted?

Answer 30

Decreased muscle fibers. Decreased blood capillaries.
- How is the counteracted?
Resistance training

Question 31

Endurance training benefits:

Answer 31

increase supply of blood to muscle fibers, increase glycogen storage

Question 32

Satellite cells (in muscle fibers):

• Define:
• What happens as you age?

Answer 32

• Define:
  Stem cells, can become muscle cells, and add to muscle cells to repair them.
• What happens as you age?
  Decreased functionality

Question 33

Myostatin:

Answer 33

Inhibits satellite cell function and muscle growth

Question 34

Commissural tracts:

Answer 34

Cross over to the other side of the spinal card

Question 35

Muscle stretch reflex:

• Define:
• Example:
• Route:

Answer 35

• Define:
  maintain muscles at their optimal length
• Example:
  Knee jerk reflex
• Route:
  Sensory -> opposing muscle (flexion removes pressure) (polysynaptic)
  Sensory -> back to same muscle -> relaxes stretched muscle (monosynaptic)

Question 36

Step on a tack reflex is also called:

Answer 36

Double reciprocal innervation

Question 37

Double reciprocal innervation:

• Alternative name:
• Route:

Answer 37

- Alternative name:
Crossed-extensor reflex
- Route:
leg 1 steps on tack
Leg 1 flexor flexed, extensor relaxed
Leg 2 flexor relaxed, extensor flexed
Uses interneurons in all steps