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type of muscle that contracts at the same time as a prime mover to produce a more effective movement


muscles that are within the part being moved. ex muscles that move the hand begin and end in the hand

calcaneal, achilles

common tendon of the gastrocnemous and soleus muscle


tough connective tissue binding together fascicles, which are groups of skeletal muscle fibers

size, location, function, shape, direction, number of heads, points of attachment

7 features used in naming muscles


brachialis is named after what feature


type of muscles that have fibers that converge to a narrow attachment

muscles of facial expression

muscles that have at least one of their points of attachment to the deep layers of the skin over the face or neck


fixed attachment of a muscle

rectus femoris, vastus lateralis, vastus medialis, vastus intermedius

4 parts of the anterior thigh of the quadricep muscle

median nerve

nerve affected in carpal tunnel syndrome


broad, flat sheet of connective tissue usually merging with the fibrous wrappings of another muscle

endomysium, perimysium, epimysium

connective tissue components

tendon, aponeurosis, fascia, tendon sheath

connective tissue components that attach muscles to bone

number of heads or divisions

feature used in naming tricep muscle

lumbricales, interosseous, opponens pollicis

3 examples of intrinsic hand muscles


course sheath covering the muscle as a whole


delicate connective membrane that covers specialized skeletal muscle cells called muscle fibers


strong tough cord that on its other end is continuous with the periosteum of the bone


fibrous ct surrounding the muscle organ and is outside the epimysium and tendon. general term for the fibrous ct found under the skin and surrounding many deeper organs

tendon sheath

tube shaped structures of fibrous ct. have synovial membrane lining which secretes a lubricating fluid and allows tendon to move easily


fibers are parallel to long axis of the muscle


fibers are oblique like the feathers in a plume pen


fibers are double feathered


fibers are curved, as in the sphincters of the face


muscles that when contracting, directly oppose the prime mover, or agonist. they are relaxed while the prime mover is contracting to cause mvmt. important because they provide precision and control during contraction of the prime mover

prime mover (agonist)

muscle or group of muscles that directly performs a specific mvmt. mvmt of the muscle is action or function of that muscle


function as joint stabilizers

masseter, temporalis, medial, lateral pterygoid

muscles of mastication

lateral pterygoid

muscle of mastication that opens the jaw


muscles originating from the outside part of the skeleton moved. muscles originating in the forearm can pull on their insertions in the wrists, hand, and fingers to move them

opponens pollicis

important muscle of the thumb, it allows the thumb to be drawn across the palm to touch the tip of any finger--opposition of the thumb


most superficial muscle of the posterior leg and forms the greater part of the calf; flexes the leg and plantar flexes the foot


broad flat muscle just deep to the gastrocnemius, which helps to extend the foot

maintain posture, heat production, movement

3 major roles muscles play in the body

musculoskeletal system

a single, continuous structure that comprises a coordinated, dynamic framework for the body

skeletal muscles

organs of the muscular system


nonstriated involuntary


type of contraction in which tone remains the same but length changes

sliding filament theory

contraction process that involves the sliding of thin filaments toward the center of each sarcomere which quickly shortens the entire myofibril and the entire muscle fiber


muscle fibers' cytoplasm


striated involuntary; found only in the heart

muscular dystrophy

group of genetic diseases characterized by atrophy of skeletal muscle tissue


abnormal, uncoordinated tetanic contractions of varying groups of muscles

excite, contract, extend

major function of skeletal muscles


performed by smooth muscle tissue; progressive wavelike mvmt that occurs involuntarily in the walls of hollow structures of the body

muscle fibers

continually remake ATP because they only store a small amount; contain mitochondria and have several nuclei


tendon and muscle inflammation


inflammation of a muscle


occurs in the area of a joint and results in ligament damage


muscle pain; usually involve overstretching or tearing of muscle fibers


basic contractile unit of a muscle fiber


individual fibers of a muscle contract out of sync with each other

motor unit

made up of one motor neuron plus the muscle fibers (cell) that attach to it


shrinking of muscle mass

t tubules

allow electrical impulses to travel deep into the cell

excess oxygen

myoglobin are attached to this inside cells

synapse, acetylcholine

what type of connection is a neuromuscular junction & what is released there


almost immediately after the sarcoplasmic reticulum (SR) releases its calcium ions into the sarcoplase, it begins actively pumping them back into the sacs.

intercalated disks

cardiac muscle cells are joined together by these strong specialized junctions


plasma membrane of a muscle fiber


type of contraction where muscle length remains the same but tension increases

2 sr sacs, t tubules

what makes up a triad

myosin, actin, tropomyosin, troponin

4 protein molecules that make up myofilaments


what thick myofilaments are composed of

actin, tropomyosin, troponin

what thin myofilaments are composed of


term given a t tubule sandwiched between 2 sacs of the sr. important because it allows an electrical impulse traveling along a t tubule to stimulate the membranes of adjacent sacs of the sarcoplasmic reticulum


a globular protein that forms 2 fibrous strands twisted around each other to form most of the thin filament


protein that covers the active sites on the actin molecules when the myofilaments are at rest


protein that holds tropomyosin molecules in place


long shafts bundled together to form a thick filament and have "heads" sticking out from the bundle. the heads are chemically attracted to the actin molecules of the nearby thin filaments


ability to be stimulated


ability to contract, or shorten, and produce body movement


ability to extend, or stretch, allowing muscles to return to their resting length


bundles of very fine fibers that extend lengthwise along skeletal muscle fibers and almost fill their sarcoplasm; made up of thick & thin myofilaments

sarcoplasmic reticulum

muscle fibers network of tubules and sacs that is comparable to the ER of other cells;

heat production

muscle cells perform catabolism (breakdown) to provide this function for the body


this constitutes one of the most important parts of the mechanism for maintaining homeostasis of temperature


a neurotransmitter that is released into the synaptic cleft when nerve impulses reach the end of a motor neuron fiber


the process of synaptic transmission and induction of an impulse


binds to troponin molecules causing the tropomyosin to shift and expose active sites on the actin molecules

glucose, oxygen

muscle fibers requires this to perform catabolism


reddish-pigmented protein molecules


aka tetanic contractions; smooth sustained muscle contractions--or continuous contraction

stretch reflex

a response in which the body tries to maintain a constant muscle length. if an increased load is unsustainable, the body will abandon the contraction and force you to relax and drop the load


same tension


same length


contractions that result in the shortening of the muscle being contracted


type of contraction that results in the lengthening of the muscle being contracted

concentric, eccentric

2 types of isotonic contractions

aerobic exercise

increased blood flow as a result of this allows a more efficient delivery of oxygen and glucose to muscle fibers during exercise; causes an increase in the number of mitochondria in the muscle fibers, allowing for the production of more atp for a rapid energy source


painful, involuntary muscle spasms; often occur when a muscle is inflammed

rigor mortis

refers to the stiffness of skeletal muscles sometimes seen shortly after death

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