MUSCULAR SYSTEM

MUSCULAR SYSTEM

composed of muscle cells and tissues that brings about movement of an organs or body party

SKELETAL MUSCLE

attached to the bone. voluntary movements. striated. Moves skeleton, maintains posture

CARDIAC MUSCLE

only exist in the heart. involuntary movement. Striated with intercalated discs. Pumps blood

SMOOTH MUSCLE

Walls of organs (stomach, intestines, blood vessels). Involuntary. Nonstriated. Moves substances through organs

MUSCLE FIBER CELL

a single long muscle cell inside the muscle

MYOFIBRIL

long thread-like structures inside each fiber

SARCOMERES

the function unit inside a myofibril. this is where contraction happens

ACTIN

thin filament

MYOSIN

thick filament

NEVER ACT CALMLY, APES MIGHT ALWAYS RELAX

(NACA MAR)

nerve impulse, acetylcholine, calcium, actin and mysin bind, atp, relax

NERVE IMPULSE

Brain sends a nerve impulse down a motor neuron.

ACETYCHOLINE

tells the muscle fiber to contract by triggering calcium release from a storage area inside the cell called the sarcoplasmic reticulum.

CALCIUM

Calcium binds to troponin (a protein on actin), which moves tropomyosin out of the way → myosin can now grab actin.

TROPOMYOSIN

Troponin shifts tropomyosin so myosin can bind actin.

ACTIN & MYSIN BIND

Myosin and actin slide past each other to shorten the sarcomere

ATP

The energy molecule muscles need for contraction and relaxation.

RELAX

Relaxation when calcium returns

MUSCULAR SYSTEM

responsible for movement, posture, and heat production.

It works closely with the skeletal system (to move bones) and the nervous system (to control contractions).