Unit Wordlist and Learning Resources
Unit Wordlist: The Muscular System
The following Terms and Concepts are important in the study of the Muscular System:
| Microscopic Structure:
Thick filament (myosin) Thin filament (actin) Muscle type:
Muscle Actions:
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Major Muscles of the Body:
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Muscle contraction:
excitation-contraction coupling neuromuscular junction (NMJ)
Disruptions in Homeostasis:
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protein that makes up most of the thin myofilaments in a sarcomere muscle fiber
loose, and well-hydrated connective tissue covering each muscle fiber in a skeletal muscle
outer layer of connective tissue around a skeletal muscle
bundle of muscle fibers within a skeletal muscle; surrounded by perimysium
part of the sarcolemma that connects cardiac tissue, and contains gap junctions and desmosomes
sarcolemma of muscle fiber at the neuromuscular junction, with receptors for the neurotransmitter acetylcholine
long, cylindrical organelle that runs parallel within the muscle fiber and contains the sarcomeres
protein that makes up most of the thick cylindrical myofilament within a sarcomere muscle fiber
connective tissue that bundles skeletal muscle fibers into fascicles within a skeletal muscle
longitudinally, repeating functional unit of skeletal muscle, with all of the contractile and associated proteins involved in contraction
plasma membrane of a skeletal muscle fiber
space between a nerve (axon) terminal and a motor end-plate
projection of the sarcolemma into the interior of the cell
the thick myosin strands and their multiple heads projecting from the center of the sarcomere toward, but not all to way to, the Z-discs
thin strands of actin and its troponin-tropomyosin complex projecting from the Z-discs toward the center of the sarcomere
regulatory protein that covers myosin-binding sites to prevent actin from binding to myosin
regulatory protein that binds to actin, tropomyosin, and calcium
striated muscle found in the heart; joined to one another at intercalated discs and under the regulation of pacemaker cells, which contract as one unit to pump blood through the circulatory system. Cardiac muscle is under involuntary control.
striated, multinucleated muscle that requires signaling from the nervous system to trigger contraction; most skeletal muscles are referred to as voluntary muscles that move bones and produce movement
nonstriated, mononucleated muscle in the skin that is associated with hair follicles; assists in moving materials in the walls of internal organs, blood vessels, and internal passageways
movement away from midline in the sagittal plane
movement of the bone toward the midline
movement that decreases the angle of a joint
end of a skeletal muscle that is attached to the structure (usually a bone) that is moved when the muscle contracts
end of a skeletal muscle that is attached to another structure (usually a bone) in a fixed position
a rotational movement of the forearm that turns the palm downward
muscle motion that moves the palm and forearm anteriorly
circular muscle that closes the eye
muscle that compresses the cheek
circular muscle that moves the lips
major muscle that laterally flexes and rotates the head
front part of the muscle that makes up the scalp with a frontal belly (frontalis) and an occipital belly (occipitalis)
muscle that retracts the mandible
posterior part of the muscle that makes up the scalp with a frontal belly (frontalis) and an occipital belly (occipitalis)
muscle that stabilizes the upper part of the back
broad, triangular axial muscle located on the inferior part of the back
shoulder muscle that abducts the arm as well as flexes and medially rotates it, and extends and laterally rotates it
superficial abdominal muscle with fascicles that extend inferiorly and medially
long, linear muscle that extends along the middle of the trunk
thick, fan-shaped axial muscle that covers much of the superior thorax
three-headed muscle that extends the forearm
two-headed muscle that crosses the shoulder and elbow joints to flex the forearm while assisting in supinating it and flexing the arm at the shoulder
muscle that can flex the forearm quickly or help lift a load slowly
muscle motion that moves the palm and forearm anteriorly
pronator that originates on the humerus and inserts on the radius
four muscles (rectus femoris, vastus medialis, vastus intermedius, vastus lateralis) that extend and stabilize the knee
quadricep muscle on the anterior aspect of the thigh
quadricep muscle on the lateral aspect of the thigh
quadricep muscle on the medial aspect of the thigh
quadricep muscle that is between the vastus lateralis and vastus medialis and is deep to the rectus femoris
hamstring muscle
largest of the gluteus muscles that extends the femur
muscle located on the lateral surface of the tibia
most superficial muscle of the calf
wide, flat muscle deep to the gastrocnemius
the neurotransmitter that binds at a motor end-plate to trigger depolarization
heart’s ability to control its own contractions
ability to shorten (contract) forcibly
to reduce the voltage difference between the inside and outside of a cell’s plasma membrane (the sarcolemma for a muscle fiber), making the inside less negative than at rest
ability to undergo neural stimulation
contraction coupling - sequence of events from motor neuron signaling to a skeletal muscle fiber to contraction of the fiber’s sarcomeres
motor neuron and the group of muscle fibers it innervates
synapse between the axon terminal of a motor neuron and the section of the membrane of a muscle fiber with receptors for the acetylcholine released by the terminal
signaling chemical released by nerve terminals that bind to and activate receptors on target cells
action of myosin pulling actin inward towards the center of the sarcomere
single contraction produced by one action potential
a continuous fused contraction
membrane proteins that open sodium channels in response to a sufficient voltage change, and initiate and transmit the action potential as Na+ enters through the channel
addition of successive neural stimuli to produce greater contraction
loss of structural proteins from muscle fibers
replacement of muscle fibers by scar tissue
addition of structural proteins to muscle fibers
loss of muscle function, either complete or partial and in either part or all of the body; caused by damage to the nervous system and the prevention of signals from reaching muscles
