CH. 20: Muscular System Flashcards
makes up walls of hollow organs ie stomach, intestines, and uterus; operates INVOLUNTARILY and responsible for peristalsis
Smooth (visceral) muscle
makes up the myocardium of the heart wall; functions INVOLUNTARILY and responsible for heart’s pumping action
cardiac muscle
attached to bones and operates VOLUNTARILY; maintains posture and generates a large proportion of body heat; all these voluntary muscles together make up the muscular system
skeletal muscle
composed of individual cells, referred to as FIBERS b/c they are so long and thread-like
Muscles
these muscles are held together in ________(bundles) by connective tissue
fascicles
sheath of connective tissue that covers each muscle
fascia
attaches the muscle to a bone
tendons
skeletal muscles are stimulated to contract by _____ __________ of the nervous system
motor neurons
the synapse (junction) where a branch of a neuron meets a muscle cell
neuromuscular junction (NMJ)
A neurotransmitter released from small vesicles (sacs) in an axon branch at the neuromuscular junction
acetylcholine (ACh)
ACh interacts with the muscle cell membrane to prompt ______ ________
cellular contraction
two special protein filaments in muscle cells that interact to produce the contraction
actin and myosin
______ and ___________ are needed for contraction
ATP and calcium
state of firmness aka muscle tone
tonus
_____ work in pairs to produce movement at the joints
muscles
as one muscle, the __________, contracts, an opposing muscle, the ________, must relax
agonist; antagonist
any muscle that assists the agonist to produce an action
synergist
point where the muscle is attached to a stable part of the skeleton
origin
point where a muscle is attached to a moving part of the skeleton
insertion
closing the angle at a joint
flexion
opening the angle at a joint
extension
movement away from the midline of the body
abduction
movement toward the midline of the body
adduction
turning of a body part on its own axis
rotation
