Muscle SS

3 types of muscle?

smooth, skeletal, & cardiac

functions of muscle?

1. motion 2. regulates organ volume 3. movement 4. stabilized position 5. heat production

characteristics of muscle?

1. excitability (receives/responds to stimuli) 2. contractibility (shortens) 3. extensibility (lengthens) 4. elasticity (returns to og size)

what's fascia?

fibrous connective tissue under skin/around organs

what's the fascia around a single muscle fiber?

endomysium

what's the fascia around a bunch of muscle fibers?

perimysium

what's the fascia around the entire muscle?

epimysium

muscle structure?

muscle → fascicle → muscle fiber → myofibrils

thick filament of a sarcomere?

myosin

thin filament of a sarcomere?

actin

does a myofibril run the entire length of the muscle fiber?

no, runs parallel to each other which increases contraction

what're the 2 muscle types?

slow & fast twitch

slow vs fast twitch?

slow = - oxygen - delayed - doesn't fatigue - endurance, fast = - no oxygen - fast - fatigues - short activity

where are the calcium ions stored?

sarcoplasmic reticulum

what do the calcium ions bind to, to start the contraction?

troponin

what causes myosin power strokes?

atp

what causes myosin to reset?

adp

what stops a muscle contraction?

• calcium being put back into sarcoplasmic reticulum

• when there's no more atp

what's rigor mortis?

in death when calcium ions leak into the sarcoplasm of the muscle cells (sustained/stiff contraction)

cell membrane of a muscle cell?

sarcolemma

cytoplasm of a muscle cell?

sarcoplasm

1st usage of energy the body uses when it is fatigued?

atp (5 seconds)

2nd usage of energy the body uses when it is fatigued?

creatine phosphate (15 seconds)

3rd usage of energy the body uses when it is fatigued?

switches between anaerobic & aerobic respiration

another name for anaerobic respiration?

glycolysis

what does anaerobic respiration (glycolysis) do?

creates pyruvic acid & atp from glucose (lasts 30 seconds & is in the cytoplasm)

what does aerobic respiration do?

creates atp from pyruvic acid & oxygen (& is in the mitochondria)

how much atp does anaerobic respiration produce compared to aerobic?

anaerobic = 2, aerobic = 38

what's the all or nothing principal?

muscles NEED a certain level of stimulus to contract. if level isn't reached, muscle WON'T contract at all

do muscle fibers contract partially?

no

why is there weak muscular action sometimes?

only a few muscle fibers contracted to their full ability

what's oxygen debt?

amount of oxygen necessary to return body systems to normal after heavy exercise

what causes hard breathing needed to pay for oxygen debt?

lactic acid accumulation

what's muscle fatigue?

inability of a muscle to sustain its contractile strength

what does a sustained contraction lead to?

body depletion of oxygen & glycogen

what percent of energy is released as heat to cool the body?

85%

4 different contraction types?

twitch, tetanus, isotonic, & isometric

what's a twitch contraction?

• brief/short contraction - single action potential

what's a tetanus contraction?

• sustained contraction/short relaxation periods - multiple action potentials

what type of contractions are most voluntary movements?

tetanus

what's an isotonic contraction?

creates motion & muscle contracts

what's an isometric contraction?

no motion occurs but muscle still contractions

what's muscle tone?

sustained partial contraction w/ no motion (eg; posture)

what's hypotonia?

decreased muscle tone; flaccid

what's hypertonia?

increased muscle tone; rigid

what's muscular atrophy?

wasting away of muscle tissue b/c of inactivity (decrease in muscle SIZE)

what's muscular hypertrophy?

increase in muscle SIZE b/c of constant/increased usage

characteristics of cardiac muscle?

• involuntary - striated - branches - found in heart

what does cardiac muscle do?

forms 2 networks, atrial & ventricular & pumps blood into heart

why does cardiac muscle have intercalated disks?

they have gap junctions which speed along impulses

differences of cardiac muscle?

• beats continuously - causes it's own contractions

what's autorhythmicity?

cardiac muscle being able to make its own contractions

why does cardiac muscle have a long refractory period?

to avoid tetanus; a stopped heart

characteristics of smooth muscle?

• involuntary - found in organs - not striped/striated - flexible

characteristics of skeletal muscle?

• voluntary - striated - attached to bones - moves the skeleton

2 types of smooth muscle?

visceral & multiunit

visceral smooth muscle?

• continuous network of muscle - entire thing responds to single impulse - found in small bv's, stomach, uterus - more common

multiunit smooth muscle?

• individual fibers contract individually - found in large bv's, hair, airways

differences of smooth muscle

• longer contractile periods (than skeletal) - sustains contraction longer = more tone - stimulated by nervous impulses, hormones, pH - more extensible

how is movement produced?

skeletal muscles pull on bones through tendons

what's the middle part of a muscle called?

the belly

what's antagonistic?

muscles in relation towards another (biceps pull forearm up, triceps put it back)

what's the agonist?

primary muscle that CAUSES the action

what's the synergist?

ASSISTS agonist

what's the antagonist?

relaxed during motion of agonist but RETURNS muscle back to og position

what're fixators?

STABILIZES agonist