Physiology Muscle Quiz

acetylcholine (ACh)

acetylcholine (ACh)

a neurotransmitter substance stored in synaptic vesicles; binds to a specific receptor protein on the sarcolemma; made from acetic acid and choline

acetylcholineesterase (AChase)

an enzyme used to decompose the neurotransmitter acetylcholine

sodium

Na+

synaptic cleft

the space found between 2 neurons or a neuron and a muscle fiber (where Acetylcholine uses Achase to break apart into choline and acetic acid)

synaptic vesicle

a sac like organelle that stores neurotransmitter substances like ACh

sarcolema

the technical name for the cell membrane of a muscle cell/fiber

depolarization

the inside of the cell becomes positively charged for a brief period of time

cardiac muscle

found in heart, involuntary contraction, single nuclei, intercalated disks, circulate blood

smooth muscle

found in blood vessels, spindle shaped, single nuclei, involuntary contraction, no striations

skeletal muscle

attached to bone, body movement, voluntary control, striated, multinucleate

reasons for muscle fatigue

lack of oxygen, lactic acid build up, glycogen

Graves disease

immune system disease that affects thyroid gland; anti-bodies attack nerve endings destroying connection between nerve and muscle causing loss of motor function

NMJ Step 1

acetylcholine spills into synaptic cleft

NMJ Step 2

ACh attatches to receptor site causing channels to open and sodium ions to pass through

NMJ Step 3

ACh uses AChase to break apart into acetic acid and choline. Choline is recycled and acetic acid leaves body as waste

NMJ Step 4

Choline passes from synaptic cleft to presynaptic terminal

NMJ Step 5

Choline reattaches to new acetic acid molecules creating acetylcholine and forming a new synaptic vesicle.

epimysium

connective tissue surrounding muscle

fascicle

bundles of muscle cells/fibers

perimysium

connective tissue surrounding fascicles

sarcoplasmic reticulum

special endoplasmic reticulum made of interconnecting tubules surrounding each myofibril

myofibril

small tube like structure within a muscle fiber