Sliding Filament Theory, Skeletal Muscle Structures, Muscle Tissue Review

Myofilament

Contractile proteins known as actin and myosin

Actin

Thin filament

Myosin

Thick filament

Sarcomere

The functional unit of the Myofibril - where contraction takes place

ATP

when this molecule binds, the myosin heads release from the actin

H Zone

Myosin only; Shortens/gets smaller during muscle contraction

Z Line

Border that separate sarcomere

I band

thin filaments only; gets smaller as a contraction

A band

where actin and myosin overlap; stays the same size druing contraction

Troponin

calcium binding site on actin

Tropomyosin

covers myosin binding sites on the actin molecules

calcium

binds to the troponin; pulls the tropomyosin out of the way to reveal myosin binding sites

Crossbridges

myosin heads attach to actin

sliding filament theory

the concept that a sarcomere shortens as the thick and thin filaments slide past one another

Acetylchoine

An excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle is ________.

action potential

nerve impulse

Primary function of muscle

movement

Epimysium

surrounds entire muscle

Perimysium

The connective tissue that surrounds fascicles.

Endomysium

Connective tissue surrounding an individual muscle fiber

Sarcolemma

plasma membrane of a muscle fiber

Sarcoplasm

cytoplasm of a muscle fiber

sarcoplasmic reticulum (SR)

specialized smooth endoplasmic reticulum, which stores, releases, and retrieves Ca++

Sarcomere

contractile unit of a muscle fiber

Actin

thin filaments

Myosin

thick filament

actin and myosin filaments

proteins which form the contractile units of skeletal muscle

neuromuscular junction (NMJ)

the space between a motor neuron and a skeletal muscle fiber

action potential

nerve impulse/signal

T-tubules (transverse tubules)

spread the action potential into the interior of the muscle fiber

Z line (disc) of sarcomere

ends of sarcomere;

anchor for thin filaments

H zone of sarcomere

Middle region of sarcomere that contains only thick filaments

M line of sarcomere

center/middle of sarcomere

I band of sarcomere

contains only thin actin filaments

A band of sarcomere

contains all of the thick myosin filaments plus any overlapping think actin filaments

skeletal muscle tissue

voluntary muscle; attached to bones; striated

smooth muscle tissue

involuntary muscle, lines hollow organs, non-striated

cardiac muscle tissue

involuntary muscle, found only in the heart; striated

striated muscle (definition)

A muscle that appears banded/striped

non-striated muscle tissue (definition)

A muscle that does not have bands/stripes

muscle fiber

long slender skeletal muscle cells

cardiac muscle tissue (picture)

smooth muscle tissue (picture)

skeletal muscle tissue (picture)

function of all muscle tissue

contraction // movement

Skeletal muscle fibers are multinucleate

Skeletal muscle fibers have many nuclei

Energy for muscle contraction

ATP

actin

A contractile protein that is part of the thin filaments in muscle fibers

Myosin

The contractile protein that makes up the thick filaments of muscle fibers

reason for/cause of striations

regular arrangement/ organization of protein filaments (actin & myosin)

muscle tissue(s) that are striated

skeletal and cardiac

muscle tissue(s) that are involuntary

cardiac and smooth

muscle tissue(s) that are voluntary

skeletal

muscle tissue(s) that are non-striated

smooth

Three (3) types of muscle tissue

skeletal, cardiac, smooth