Muscles Flashcards Preview

Anatomy > Muscles > Flashcards

Flashcards in Muscles Deck (55):
1

Fascia

Sheet of fibrous connective tissue that encloses a muscle

2

Aponeuroses

Sheet of connective tissue that attaches muscle to bone and fascia

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Myofibrils

Contractile fibers in muscle cells

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Sarcomere

Structural and functional unit of Myofibril

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Actin

Protein in a muscle fiber that forms filaments that slide between filaments of the protein myosin contracting muscle fibers

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Myosin

Protein that contracts and relaxes muscle fibers with actin

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Troponin

Protein that functions with tropomyosin to block muscle contraction until calcium ions are present

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Tropomyosin

Protein that blocks muscle contraction until calcium ions are present

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Transverse tubule

Membranous channel that extends inward from a muscle fiber membrane and passes through the fiber

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Sarcoplasmic reticulum

Membranous network of channels and tubules in a muscle fiber corresponding to ER

11

Neuromuscular junction

Synapse between a motor neuron and skeletal muscle fiber

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Synapse

Functional connection between axon of one neuron and the dendrite or cell body of another of membrane of another cell type

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Neurotransmitter

Chemicals that an axon end secretes that stimulates a muscle fiber to contract or a neuron to fire an impulse

14

Motor end plate

Specialized part of muscle fiber membrane at neuromuscular junction

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Motor unit

Motor neuron and associated muscle fibers

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Synaptic cleft

Narrow extracellular space between presynaptic and postsynaptic neurons

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Acetylcholine

Type of neurotransmitter transports nerve impulses across synapses

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Sliding filament theory

Mucked contract when actin and myosin filaments move past each other shortening the skeletal muscle

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Myoglobin

Pigmented compound in muscle tissue that stores oxygen

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Oxygen debt

Amount of o required following physical exercise to react accumulated lactic acid to form glucose

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Threshold stimulus

Stimulation level that must be exceeded to elicit a nerve impulse or a muscle contraction

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Latent period

Time between application of stimulus and beginning of response in muscle fiber

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Refractory period

Period following stimulation during which a neuron of muscle fiber will not respond to a stimulus

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Summation

Increased force of contraction by a skeletal muscle fiber when twitches occur before previous twitch relaxes

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Recruitment

Increase in number of motor units activated as stimulation intensity increases

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Tetanic contraction

Continues forceful muscular contraction without relaxation

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Muscle tone

Contraction of some fibers in skeletal muscle at any given time

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Peristalsis

Rhythmic waves of muscular contraction in the walls of certain tubular organs

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Smooth muscle

Type of involuntary muscle tissue in walls of hollow viscera

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Cardiac muscle

Specialized muscle tissue found only in heart

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Myofilaments

Filaments in myofibrils

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Thick filament

Myosin

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Thin filament

Actin

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Z lines

Appear at center of I bands
Have direct attachments to actin

35

Tendon

Cordlike mass of white fibrous connective tissue that connects muscle to bone

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H zone

Consist only of thick filaments

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Crossbridge

Each myosin molecule consists of two twisted pristine stands with globular parts

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Lactic acid threshold

Anaerobic reactions break down glucose into Pyruvic acid which reacts to produce lactic acid

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Syncytium

When the heart contracts as a unit

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Calat-

Something inserted

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Erg-

Work

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Fasc-

Bundle

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-gram

Something written

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Hyper-

Over, more

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Inter-

Between

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Iso-

Equal

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Laten-

Hidden

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Myo-

Muscle

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Reticul-

A net

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Sarco-

Flesh

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Syn-

Together

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Tetan-

Stiff

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-tonic

Stretched

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-troph

Well fed

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Voluntar-

Ones free will