muscle 2

Question 1

name types of skeletal muscle fibres

Answer 1

fast glycolytic fibers
slow oxidative fibers
fast oxidative fiber

Question 2

describe chicken

Answer 2

stand a lot - leg muscles = generate force over time
fly for short time = lots of force, short time

Question 3

describe fast glycolytic fibers

Answer 3

Myosin with high ATPase activity
no myoglobin (“white muscle”)
For generation of large force over short periods of time.

Question 4

describe slow oxidative fibers

Answer 4

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

Question 5

describe fast oxidative fibers

Answer 5

intermediate properties
fast myosin and oxidative metabolism

Question 6

can muscle fibers switch from fast to slow

Answer 6

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

Question 7

describe Fast glycolytic fibers metabolism

Answer 7

atp cycles through cross bridge fast
Predominantly energy from glycolysis
lactic acid = contirbutes to muscle fatigue

Question 8

describe slow oxidative fibers metabolism

Answer 8

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)

Question 9

describe muscle fatigue generally

Answer 9

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

Question 10

describe cause of fatigue for high intensity short duration activity

Answer 10

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

Question 11

describe cause of fatigue for long duration activity

Answer 11

slow oxidative fibers
Depletion of glycogen
like marathon
internal processes can detect change in concentration

Question 12

what is central command fatigue

Answer 12

Failure of command signals from the CNS
brain can’t try anymore, ability of brain fatigues
also a safety mechanism

Question 13

what is muscle response to exercise

Answer 13

Changes in muscle physiology depend on the type of
exercise

Question 14

describe muscle response for low intensity, long duration exercise

Answer 14

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

Question 15

describe muscle response for high intensity, short duration exercise

Answer 15

increase in the diameter of fast glycolytic fibers and muscle hypertrophy
make more myofibrils = more force it can generate

Question 16

what is muscle soreness due to

Answer 16

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

Question 17

describe smooth muscle

Answer 17

involuntary - not under conscious control = regulating homeostatic mechanisms inside body = function normally

Question 18

describe contraction of smooth muscle

Answer 18

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

Question 19

describe smooth muscle contraction - activation

Answer 19

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

Question 20

what is smooth muscle contarction regulated by

Answer 20

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