Flashcards in Chapter 11: Muscular System Deck (123)
40-50 stimuli per second produces what? describe
complete tetanus; muscle has no time to relax between stimuli
producing internal tension; but external resistance causes it to stay at the same length or become longer (NO MOVEMENT)
muscle shortens as it maintains tension
muscle lengthens as it maintains tension
ATP supply depends on availability of: (2)
organic energy sources (glucose & fatty acids)
2 pathways of ATP synthesis? which yields the most ATP?
aerobic respiration (use oxygen) yields more ATP (36 per molecule) anaerobic fermentation (without the presence of oxygen)
For short intense exercises how is oxygen supplied?
via myoglobin for limited aerobic respiration
What enzymes are used by muscles for transfer of phosphate? (2)
myokinase (makes cyclic AMP)
creatine kinase (uses creatine phosphate)
What system is used for nearly all energy used for short bursts of intense activity?
After the phosphagen system-> a muscle enters ___ ____ which uses ___ to produce _____. How many ATPs are gained?
Anaerobic fermentation; glucose ; lactic acid
2 ATPs per molecule
long term energy uses which synthesis pathway?
What happens during fatigue? (4)
-ATP synthesis decline as glycogen consumed
-ATP shortage; slows down Na-K pumps
-lactic acid lowers pH of sarcoplasm
-motor nerve fibers use up ACh
endurance? how is it determined?
ability to maintain high intensity exercise for more than 4-5 minutes; by one's max oxygen uptake
How can you "beat" fatigue? (2)
-taking oral creatine (increases level of creatine phosphate in tissue: increase speed of ATP regeneration)
-carbohydrate overload (extra glycogen packed in)
slow oxidative muscle fibers (3)
-slow twitch, red, type I fibers
-abundant in mitochondria, myoglobin
-adapted for aerobic respiration & fatigue resistance
fast glycolytic muscle fiber
-fast twitch, white, type II fiber
-quick response, but not fatigue resistance
properties of cardiac muscle? (5)
-contraction w/ regular rhythm
-must contract in unison
-contractions must last long to expel blood
-must work in sleep
-tightly resistant to fatigue
Cardiac muscles are _____ and contain _____
in cardiac muscle, myocytes are joined at notched linkages called what?
Cardiac muscles contain _____, so they can contract without need for nervous stimulation
built in pacemaker
How are damaged cardiac muscle cells repaired?
via fibrosis (not capable of mitosis-very little)
which synthesis is used almost exclusively by cardiac muscle?
Smooth muscle does not contain?
t-tubule or sarcomere structure
characteristics of smooth muscle (3)
-capable of mitosis & hyperplasia
-injured muscle can regenerate well
-some lack nerve supply
Describe myocyte structure in smooth muscle?
-no visible striations
-Z discs are replaced by dense bodies
Which type of smooth muscle is more widespread? does it require a nerve supply?what does it use
single unit smooth muscle; NO; gap junctions
Smooth muscle can contract in response to ____. Such as (3)
-hormones, CO2, stretch, oxygen deficiency
Does stimulation mean contraction in smooth muscle?
NO; relax arteries or contract bronchiles
What do the smooth single units contain?
autonomic nerve fibers varicosities