muscle 2 Flashcards
name types of skeletal muscle fibres
fast glycolytic fibers
slow oxidative fibers
fast oxidative fiber
describe chicken
stand a lot - leg muscles = generate force over time
fly for short time = lots of force, short time
describe fast glycolytic fibers
Myosin with high ATPase activity
no myoglobin (“white muscle”)
For generation of large force over short periods of time.
describe slow oxidative fibers
Myosin with low ATPase activity
Myoglobin to facilitate oxygen transport from blood (“red muscle”)
For generation of low levels of force over long periods of time
describe fast oxidative fibers
intermediate properties
fast myosin and oxidative metabolism
can muscle fibers switch from fast to slow
nooo but can switch metabolisms
if do exercise that emphasizes lift heavy weight = fast, switch to glycolytic
if do endurance training = switch to oxidative
cannot swicth types of myosin
all muscles fibers have all type of fiber but some muscles just have more of a certain fiber
describe Fast glycolytic fibers metabolism
atp cycles through cross bridge fast
Predominantly energy from glycolysis
lactic acid = contirbutes to muscle fatigue
describe slow oxidative fibers metabolism
long distance running
slow cross bridge cycle
utilizes glycolysis and op = glucose from blood stream and keeps muscles contraction for a while
generates lots of atp = utilize energy store in glucose molecules
to facilitate utilization of oxygen = have myoglobin - binds o2, inside slow oxidative fibres, facilitates transfer of oxygen to mitochondria for op, slows process down tho, reddish colour (dark meet in chicken)
describe muscle fatigue generally
fatigue protects muscle from damage
It is not caused by depletion of ATP
A number of complex and incompletely understood cellular
mechanisms a-re responsible for muscle fatigue
describe cause of fatigue for high intensity short duration activity
changes in ion gradients - increase in extracellular k+ (k flows out when contract = if lots of contract concentration can go up a lot, stays depolarized so na channels inactive and no propagate ap)
reduction of ph due to build up lactic acid (inside fiber, becomes more acidic = bad since muscles operate within small ph range *proteins)
fast glycolytic fibers
all happens rapidly
describe cause of fatigue for long duration activity
slow oxidative fibers
Depletion of glycogen
like marathon
internal processes can detect change in concentration
what is central command fatigue
Failure of command signals from the CNS
brain can’t try anymore, ability of brain fatigues
also a safety mechanism
what is muscle response to exercise
Changes in muscle physiology depend on the type of
exercise
describe muscle response for low intensity, long duration exercise
aerobic exercise causes increase in fiber mitochondria, increased vascularization, i.e. increased ability of muscle fibers to extract ATP energy through oxidative metabolism.
long distance runner - muscle fibers get better and better at utilizing energy - more efficient and ability to sustain contractions = better
describe muscle response for high intensity, short duration exercise
increase in the diameter of fast glycolytic fibers and muscle hypertrophy
make more myofibrils = more force it can generate
what is muscle soreness due to
inflammation in response to muscle damage
Factors (e.g. insulin-like growth factor 1) released by damaged tissue may be involved in muscle changes in response to exercise
describe smooth muscle
involuntary - not under conscious control = regulating homeostatic mechanisms inside body = function normally
describe contraction of smooth muscle
thick myosin filaments pulling on actin thin filaments
actin and myosin in smooth muscle do not have highly ordered structure of skeletal and cardiac muscle, lacks striations
does not have to go from being relaxed to contracted super fast
actin filaments and myosin across muscle in various points
describe smooth muscle contraction - activation
Activated by calcium release from sr or flowing into cell through membrane calcium channels
calcium binds to calmodulin = activates myosin light chain kinase and kinase phosphorylates and actiavtes smooth msucle myosin
what is smooth muscle contarction regulated by
many extracellualr signals
hormones and neurotransmitters of autonomic nervous system
usually activates metabotropic receptors on smooth muscle by ligand binding
bind substance and activates receptors and biochemical processes on inside of cell
