Anatomy muscle contractions

sarcomere

repeating patterns of striations along each muscle

actin

thin filaments

myosin

thick filaments

i band

light band, actin filaments held to z line

a band

dark band, myosin fibers/filaments overlapping actin

h zone

only thick filaments

m line

proteins that hold thick filaments in place

titin

attaches myosin to z line

traponin

have 3 subunits, attaches to actin

tropomyosin

long rods, they lay in spiral groves in the actin helix

relaxed tropomyosin

covers binding sites on actin

contracted tropomyosin

uncovers binding sites

3 types of muscle tissue

skeletal, smooth, cardiac

tendon

connective tissue that binds muscle to bone

aponeurosis

broad fibrous sheets connective tissue which attach to bone or surface of adjacent muscle coverings

ligament

fibrous tissue connect bone to bone

epimysium

first layer ct surronding skeletal muscle

perimysium

another layer of ct on skeletal tissue, extends inwards from epimysium and seperates muscle tissue into sections containing fasicals

fasiciles

bundles of skeletal muscle fibers

endmyosium

location of small sections containing fasicles/musce fibers/cells

muscle fiber

muscle cell

myofibril

contractile fibers within muscle cells

motor end plate

specialized portion of a muscle fiber membrane at neruomuscular junction, nuclei and mitochondira abundant

motor unit

a motor neuron and its associated muscle fibers

motor neuron

neuron that transmitts impulses from the centrl nervous system to an effector

neurotransmitter

chemical that an axon end secrets to stimulate a muscle fiver to conreact or a neuron to fire an impulse

synaptic cleft

a narrow extracelllular space between the presynaptic and postsynaptic neurons