BIOL 121 Chp 10 Vocab: Muscle Tissue

76 terms by robswatski Teacher

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This flashcard set contains vocabulary terms from Chp 10: Muscle Tissue (Tortora & Derrickson, Principles of Anatomy & Physiology, 13th Ed, Wiley, 2012). Visit my iTunes U site for Anatomy podcasts and PDF files of all of my anatomy photo visual guides! http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewPodcast?id=424629511

myology

the scientific study of muscles

autorhythmicity

a feature of cardiac muscle tissue that allows the generation of action potentials without an external stimulus

sphincter

a ringlike band of smooth muscle that prevents outflow of the contents of a hollow organ

thermogenesis

the production of heat through muscle contraction that helps maintain normal body temperature

excitability

the ability of muscle tissue to receive and respond to stimuli

contractility

the ability of muscle tissue to actively generate force to undergo shortening, which results in body or organ movement

extensibility

the ability of muscle tissue to stretch when pulled

elasticity

the ability of muscle tissue to return to its original shape after being stretched or shortened

muscle fiber

another name for a muscle cell, due to its elongated shape

fascia

a sheet or broad band of dense irregular connective tissue that lines the body and surrounds muscles, holding together those with similar functions

epimysium

the outermost layer of connective tissue that encircles the whole muscle

perimysium

a connective tissue layer that surrounds bundles of 10-100 or more muscle fibers, separating them into fascicles

fascicle

a small bundle of 10-100 muscle fibers

endomysium

a connective tissue layer that surrounds and separates individual muscle fibers from each other

tendon

a cord of dense regular connective tissue composed of parallel bundles of collagen fibers that attaches muscle to bone

aponeurosis

a broad, flat layer of dense regular connective tissue that attaches muscle to bone

tendon sheath

a tube of fibrous connective tissue that surrounds certain tendons, especially those at the wrist and ankle

hypertrophy

muscle growth that enlarges the size of existing muscle fibers

hyperplasia

muscle growth that increases the number of new muscle fibers

fibrosis

the replacement of muscle tissue by scar tissue

sarcolemma

the plasma membrane of a muscle fiber

transverse tubule

a tiny, cylindrical invagination of the sarcolemma of striated muscle fibers that conducts muscle action potentials toward the center of each muscle fiber

sarcoplasm

the cytoplasm of a muscle fiber

myoglobin

a red-colored, iron-containing protein that binds oxygen molecules diffusing into the muscle fiber from interstitial fluid

myofibril

a threadlike structure that extends along the length of a muscle fiber, consisting mainly of thick and thin filaments

sarcoplasmic reticulum

the fluid-filled system of membranous sacs that encircles each myofibril, functioning in the storage and release of calcium ions

muscular atrophy

a wasting away of muscle tissue because of progressive loss of myofibrils due to disuse or denervation

filament

a thick or thin protein within a myofibril that is directly involved in muscle contractility

sarcomere

the basic functional contractile unit of a myofibril

Z disc

the narrow, plate-shaped regions of dense protein that separates sarcomeres from each other

A band

the darker middle area of the sarcomere which extends the entire length of the thick filaments

M line

the supporting proteins that hold the thick filaments together at the center of the sarcomere

myosin

the contractile protein that makes up the thick filaments of muscle fibers

actin

the contractile protein that makes up part of the thin filaments of muscle fibers

tropomyosin

one of the two regulatory proteins that make up part of the thin filament; covers the myosin-binding sites on actin

troponin

one of the two regulatory proteins that make up part of the thin filament; binds to calcium ions and moves tropomyosin away from the myosin-binding sites on actin

sliding filament mechanism

the model that describes how striated muscle shortens during contraction due to the thin filaments sliding past the thick filaments

contraction cycle

the repeating sequence of events that causes the thin filaments to slide past the thick filaments

crossbridge

this forms when the myosin heads attach to actin during muscle contraction

excitation contraction coupling

this relates the conduction of a muscle action potential along the sarcolemma and into the T tubules to the sliding of the thin filaments past the thick filaments

length tension relationship

this describes the strength of a muscle contraction based upon the distance across the sarcomeres

somatic motor neuron

a nerve cell that stimulates the contraction of skeletal muscle fibers

neuromuscular junction

the synapse between a somatic motor neuron and a skeletal muscle fiber

synapse

a region where communication occurs between a neuron and a target cell

synaptic cleft

a small gap at the synapse that separates a neuron and a target cell

neurotransmitter

a chemical that allows a neuron to communicate with its target cell

synaptic vesicle

one of the many membrane-enclosed sacs that are found within a synaptic end bulb

acetylcholine

a neurotransmitter released at the neuromuscular junction that stimulates muscle contraction

motor end plate

the region of the muscle fiber sarcolemma that lies opposite the synaptic end bulbs

creatine phosphate

an energy-rich molecule that is synthesized in a muscle fiber when there is excess ATP

anaerobic cellular respiration

a series of ATP-producing reactions that do not require oxygen

aerobic cellular respiration

a series of oxygen-requiring reactions that produce ATP in mitochondria

muscle fatigue

a muscle's inability to maintain contractility after prolonged activity

recovery oxygen uptake

the extra oxygen, over and above the body's resting oxygen consumption, that is taken into the body after exercise

motor unit

a motor neuron plus all of the skeletal muscle fibers it stimulates

myogram

a visual record of a muscle contraction

twitch contraction

the brief contraction of all the muscle fibers in a motor unit in response to a single action potential in its motor neuron

latent period

the brief delay that occurs between application of the stimulus and the beginning of muscle contraction; the muscle action potential sweeps over the sarcolemma and calcium ions are released from the sarcoplasmic reticulum

contraction period

during this time, calcium ions bind to troponin, myosin-binding sites on actin are exposed, and crossbridges form

relaxation period

during this time, calcium ions are actively transported back into the sarcoplasmic reticulum, myosin-binding sites are covered by tropomyosin, myosin heads detach from actin, and tension in the muscle fiber decreases

refractory period

the time when a muscle fiber receives enough stimulation to contract that it temporarily loses its excitability and cannot respond for a time

wave summation

this occurs when a second stimulus is received before the muscle fiber has relaxed, creating a second contraction that is stronger than the first

unfused tetanus

this occurs when a muscle fiber is stimulated at a rate of 20-30 times per second, and is only allowed to partially relax between stimuli, resulting in a sustained but wavering contraction

fused tetanus

this occurs when a muscle fiber is stimulated at a higher rate of 80-100 times per second, preventing it from relaxing at all, resulting in a sustained contraction in which individual twitches cannot be detected

motor unit recruitment

the process in which the number of active motor units increases, resulting in the production of smooth body movements

muscle tone

a small amount of tautness or tension in muscle due to weak, involuntary contractions of its motor units

isotonic contraction

this describes the constant tension generated by a muscle as it changes its length during body movements or moving objects

concentric isotonic contraction

this is when a muscle shortens and pulls on a tendon to produce movement and to reduce the angle of a joint

eccentric isotonic contraction

this occurs when the length of a muscle increases during a contraction, as in lowering a book that you picked up to place it back on the table

isometric contraction

this is when the tension generated by a muscle is not enough to change its length or to exceed the resistance of the object to be moved; holding a book steady using an outstretched arm is an example

slow oxidative fiber

a type of muscle fiber that is the smallest in diameter, the least powerful, and is dark red in color due to large amounts of myoglobin and many blood capillaries; it is a fatigue-resistant fiber adapted to maintain posture and for aerobic, endurance activities like running a marathon

fast oxidative glycolytic fiber

a type of muscle fiber that is intermediate in diameter and dark red in color due to large amounts of myoglobin and many blood capillaries; used in walking and sprinting

fast glycolytic fiber

a type of muscle fiber that is the largest in diameter, the most powerful, and is pale in color due to the low myoglobin content and few blood capillaries; adapted for intense anaerobic movements of short duration such as weight lifting

cardiac muscle fiber

a contractile cell of the heart

smooth muscle tone

a state of continued partial contraction that can sustain long-term tone in the GI tract and in the walls of blood vessels to maintain blood pressure

stress relaxation response

the initial contraction of smooth muscle fibers that occurs when they are stretched, increasing muscle tension for several minutes, and allowing smooth muscle to undergo great changes in length while retaining its ability to contract effectively

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