Test 2 Study Guide 6 Flashcards
How is Ca2+ returned to the endoplasmic reticulum and terminal cisternae?
SERCA pumps
sarcoplasmic/endoplasmic reticulum ATPase pumps
When a muscle is stimulated there is a latent period before contraction starts, why?
Takes awhile for the action potentials to open, and for Ca2+ to diffuse to the sarcomeres
Twitch:
A single contraction
Muscle fiber summation:
- Define:
- Why?
- 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
Tetanus:
- Incomplete Tetanus:
- Complete Tetanus:
- 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
Recruitment:
- Define:
- Define:
Adding more muscle fibers from smallest slow twitch to largest fast twitch
Asynchronous activation:
Rotating between different motor units to avoid fatigue
Series elastic component (of muscles):
- What contributes to it:
- Predominant contributor:
- Does it strengthen contractions?
- What contributes to it: Tendon Plasma membane titan - Predominant contributor: Tendon - Does it strengthen contractions? No (it must be counteracted)
Ideal sarcomere length for skeletal muscle:
- 25 um
- This is why muscles contract better when partly bent.
Where is the majority ATP used in muscle?
What uses the rest?
by myosin ATPase in the sarcomere (70%)
SERCA (30%)
At rest where does most muscle energy come from?
Heavy exercise?
Fat
Glycogen/glucose
Why does your muscles switch to aerobic after 2 minutes?
Because then the heart rate will have picked up
- Define:
VO2 max, maximum amount of oxygen you can uptake - Training increases VO2 max by how much?
20%
Maximal oxygen uptake:
- Define:
- Training increases VO2 max by how much?
The percentage of you maximal oxygen uptake at which lactate levels spike is called:
Anaerobic threshold
What breaks down glycogen?
Phosphorylase
The process of glycogen breakdown - When during exercise: Early - Predominately from which organ: Liver
Glycogenolysis:
- When during exercise:
- Predominately from which organ:
Gluconeogenesis:
- When during exercise:
- Predominately from which organ:
- When during exercise:
Late - Predominately from which organ:
Liver
Oxygen is meeting the demand of the muscles
Steady state:
Period before steady state:
Period after steady state:
O2 debt
Recovery (Repayment of O2 debt)
Repayment of O2 debt/recovery is what physiological process?
- 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.
- Function:
phosphocreatine + ADP -> ATP + creatine
Creatine Phosphokinase (CPK): - Function:
Creatine phosphokinase in the blood is indicative of what?
Myocardial infarction
Fast twitch:
- Also called:
- Found in:
- Also called: Type 2 White muscle - Found in: Arms and muscles of eye
Slow twitch:
- Also called:
- Found in:
Slow twitch: - Also called: Type 1 Red muscle - Found in: Soleus
Primarily what causes the high variation in slow twitch fast twitch ratio?
Genetics
Peripheral muscle fatigue:
- predominately due to:
- due to:
- predominately due to: increased extracellular K+ - due to: Lack of oxygen Glycogen depletion ATP decline Ca2+ lost from sarcoplasmic reticulum
Changes in CNS stop muscles before peripheral fatigue stops them
Central fatigue:
Intramuscular triglycerides:
- In fat people:
- In endurance athletes
- In fat people:
There but doesn’t help - In endurance athletes:
There but is used as fuel source
Hypertrophy in muscles is an increase in:
Size in muscle fibers, number of myofibrils within them
Atrophy in the elderly is due to:
- How is the counteracted?
Decreased muscle fibers. Decreased blood capillaries.
- How is the counteracted?
Resistance training
Endurance training benefits:
increase supply of blood to muscle fibers, increase glycogen storage
Satellite cells (in muscle fibers):
- Define:
- What happens as you age?
- Define:
Stem cells, can become muscle cells, and add to muscle cells to repair them. - What happens as you age?
Decreased functionality
Myostatin:
Inhibits satellite cell function and muscle growth
Commissural tracts:
Cross over to the other side of the spinal card
Muscle stretch reflex:
- Define:
- Example:
- Route:
- 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)
Step on a tack reflex is also called:
Double reciprocal innervation
Double reciprocal innervation:
- Alternative name:
- Route:
- 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
