unit 6 Flashcards by sophie selander

skeletal muscle

attached to bone
striated
multinucleate
very long
voluntary
slow to fast contraction
no rhythm
attached by tendon to bone
*maintains body temp and stabilizes joints

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smooth muscle

walls of hollow visceral organs
uninucleate
involuntary
very slow contraction
yes rhythm

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cardiac muscle

shorter and branching
heart
striated
uninucleate
intercalated discs
involuntary
slow contraction
some rhythm

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muscular system

contraction and shortening of muscles due to movement of microfilaments; moves bones and substances

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endomysium

encloses a single muscle fiber; connective tissue (thin covering); fascia to tendons

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perimysium

wraps around fascicle of muscle fibers

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fascicle

bundle of muscle fibers

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epimysium

covers entire muscle

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tendon

cord; formed by fascia (outside of epimysium); collagen; crosses joints; connects muscle to bone

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aponeurosis

sheet; specialized flat tendon; attaches indirectly to bone, cartilage, or connective tissue coverings

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sarcolemma

specialized plasma membrane

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myofibrils

long organelle inside muscle cell (a bands and I bands) that give striated look

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a bands

myosin myofilaments; thick; heads form cross bridges to actin; full length of band

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I bands

actin myofilaments; thin; attached to z disc; only a space

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sarcoplasmic reticulum

stores and releases calcium; type of smooth; specialized endoplasmic reticulum

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sarcomere

contracting unit of muscle fibers; extends from one z band to another

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action potential

electrical current generated along muscle fiber membrane and is the signal to trigger a contraction

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motor neuron

allows contraction

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motor unit

one motor neuron and all skeletal muscle cells stimulated by that neuron

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neuromuscular junction

gap between nerve ending and muscle cell

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synaptic cleft

space between motor neuron and muscle fiber

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axon terminal

end of nerve

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motor end plate

position on cell where the nerve fiber connects

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graded response

different degrees of skeletal muscle shortening

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tetanus

response to prolonged stimulation; fused (complete-so rapid that no relaxation is detected) and unfused (incomplete-smoother and stronger)

isotonic contraction

myofilaments are able to slide past each other; shortening

isometric contraction

muscle filaments are pitted against immoveable object while trying to slide; can't shorten past certain point

muscle tone

continuous low level of contraction; firm, healthy muscles

three pathways for atp regeneration during muscle activity

1. direct phosphorylation of adp by creative phosphate 2. aerobic pathway 3. anaerobic glycolysis and lactic acid formation (burning muscles)

oxygen debt

rapid, deep breathing to restore oxygen

muscle fatigue

muscle activity is strenuous and prolonged; lack of oxygen

causes of muscle fatigue

lack of oxygen decrease atp supply ion imbalances

aerobic exercise

endurance; jogging; stronger, more flexible muscles with greater resistance to fatigue; helps digestions and metabolism and coordination

resistance exercise

isometric; weight lifting; increase in muscle size and strength

origin

fixed, immovable attachment; superior to insertion

insertion

movable attachment

prime mover

produces the movement (agonist)

antagonist

opposed or reverses movement

sygernist

reduces undesirable or unnecessary movement; aids prime mover

fixator

immobilizes origin of prime mover so all tension is exerted at insertion

flexion

bending at joint

extension

straightening at joint

adduction

toward body

abduction

away from body

lateral rotation

away from body

medial rotation

toward body

dorsiflexion

flexes foot

plantar flexion

points foot

inversion

foot inwards

eversion

ankle outwards

pronation

palm down

supination

palm up

7 criteria in naming muscles

1. direction of muscle fibers 2. size 3. location 4. number of origins 5. location of origin and insertion 6. shape 7. action

importance of nerve supply and exercise in keeping muscles healthy

if the nerve supply is lost, the muscle is no longer stimulated; loses tone and leads to paralysis - flaccid

changes in aging muscles

connective tissue increases; muscle tissue and strength decreases; becomes stringy

nutrients to bones cells

perforating canals central canals canaliculi lacuna (cave where bone cells live) osteocyte (bone cell)

muscular system pt 2

maintains posture and body position stabilizes joints generates heat

myofibrils pt 2

made of proteins; muscle fiber -> myofibril -> myofilaments

sliding filament theory

slide thin and thick over to shorten muscle; H and I temporarily disappear with overlapping

cross bridge cycle needs

calcium and atp for contraction

skeletal muscles function

irritability contractibility extensibility elasticity

neurotransmitter

chemical released by nerve in axon terminal (acetylcholine)

hypertrophy vs atrophy

building; weakening

bursa

freely movable

posterior vs anterior

extender; flexor (front = flex)

flaccid

soft; hanging loosely

ALS (amyotrophic lateral sclerosis)

A nervous system disease that weakens muscles and impacts physical function

myasthenia gravis

a chronic autoimmune disorder in which antibodies destroy the communication between nerves and muscle, resulting in weakness of the skeletal muscles

anaerobic glycolysis

process of breaking down glucose in the absence of oxygen

opposition

resistance

lactic acid

produced in muscle cells and red blood cells

creatine phosphate

atp provides energy for a muscle contraction and is regenerated by direct phosphorylation by cp

muscles that move bones and are under conscious control

voluntary

muscle tissue that isn't under conscious control

involuntary

acetylcholine

chemical released when nerve impulse reaches nerve ending

acetylcholine binds to the muscle cell membrane causing a temporary rush of what into muscle cell

sodium

acetylcholine binds to the muscle cell membrane causing a temporary rush of what into muscle cell

sodium

twitch

single contraction

aerobic respiration

lasts about 20 seconds; most energy at rest and light exercise

anaerobic respration

using glucose and other nutrient fuels; intense exercise - burning sensation

direction of muscle fibers

rectus abdominus

relative size

gluteus maximus

location

temporalis

number of origins

triceps brachii

location of origin and insertion

sternocleidomastoid

shape

deltiod

action

adductor Magnus

unit 6 Flashcards

(87 cards)