muscular system

3 types of muscle

cardiac skeletal smooth

function of muscular system

movement of body and substances and posture

cardiac muscle

in heart pumps blood, involuntary

cardiac muscle cells are

straited and 1 nucleus per cell

cardiac muscle cells connect to

inner related disks

skeletal muscle

attach to bones to produce voluntary body movement

skeletal muscle cells are

started with multiple nucleus

skeletal muscle cells attach to

connective tissue

smooth muscle tissue

surrounds hollow organs fand involontary

smooth muscle cells are

no visible striation and one nucleus

smooth muscle cells attach to

other smooth muscle cells

number of muscles in body

over 600

muscles can only

contract

a muscle is either of 2 things

relaxed or contracted

muscle organization

1) whole muscle 2) muscle fascicles 3) muscle fibers 4) myofibrils 5) actin and myosin filaments

muscle are made of

muscle fibers

muscle fibers are grouped into

fascicles

fascicles are bundled together to form

muscles

fascia

separates muscle and forms tendons

epimysium

surrounds entire muscle

perimysium

surrounds fascicles

endomysium

surrounds each muscle fiber

sarcolemma

muscle fiber membrane

sarcoplasm

cytoplasm of muscle fiber

myofibrils

individual muscle cells

actin

thin filament

myosin

thick filaments

actin and myosin form

dark and light bands

a bAnd

dark thick myosin

i band

Light thin actin

muscle order hierarchy is the same organization as

nerves

sarcomere

contractile unit of a myocyte

myocyte

muscle fiber

sliding filament theory

Signal → Ca²⁺ → bind → pull → ATP release → repeat → relax

neuromuscular junction

where neurons meet muscle fibers

motor end plate

folded muscle membrane that recives signal

chemical released for neurotransmitter

ACh

ACh is stored in

vesicle of neuron

Ash is broken down by

AChE

muscle contraction happens when blank shortens

sarcomere

motor unit

motor neuron and all the muscle fibers it controls

supination

leaning outward

pronation

leaning inwards

abduction

spread out

adduction

not spread out

origin

where muscle is fixed

intersection

movement point