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76 terms

BIOL 121 Chp 10 Vocab: Muscle Tissue

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
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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 glycolysis
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