Ch. 1 Muscular, Neuromuscular, Cardiovascular, and Respiratory Systems Flashcards Preview

CSCS > Ch. 1 Muscular, Neuromuscular, Cardiovascular, and Respiratory Systems > Flashcards

Flashcards in Ch. 1 Muscular, Neuromuscular, Cardiovascular, and Respiratory Systems Deck (66):
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epimysium

continous with the tendons at the ends of the muscle

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tendon

attaches the muscle to the bone periosteum

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bone periosteum

a special connective tissue covering all bones

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attachments of limb muscles to bone

proximal (closer to the trunk) & distal (farther from the trunk)

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attachments of trunk muscles

superior (closer to the head) & inferior (closer to the feet)

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origin of muscle

the proximal attachment

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insertion of muscle

its distal attachment

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muscle cells (aka muscle fibers)

long, have lots of nuclei on the edges of the cell, striated appearance

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fasciculi

bundled groups of muscle fibers

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perimysium

the connective tissue holding the fasciculi together

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endomysium

connective tissue that surrounds each muscle fiber

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sarcolemma

the muscle fiber membrane, encircles the endomysium

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motor neuron

nerve cell

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neuromuscular junction

the junction between the nerve cell and the muscle fibers it innervates (aka the moror end plate)

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motor unit

a motor nueron and the muscle fibers it innervates

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sarcoplasm

the cytoplasm of a muscle fiber, contains many cell componets

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myofibrils

hundreds of them dominate the sarcoplasm, contains the apparatus that contracts the muscle cell

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types of myofilament

myosin and actin

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cross-bridges

globular heads that protrude away from the myosin filaments

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sarcomere

the smallest contractile unit of skeletal muscle, repeat the entire length of the muscle fiber, within them the myosin and actin filaments are organized longitudinally

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M-bridge

where adjacent myosin filaments connect

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A-band

where myosin filaments align

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I-band

area where two sarcomeres are adjacent and there are only actin filaments

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Z-line

middle of the I-band, looks dark running through it

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H-zone

where only myosin is present, shrinks during contraction as actin slides over the myosin

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sarcoplasmic reticulum

parallels and surrounds each myofibril, terminates around the z-lines, stores calcium ions

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T-tubules

run perpendicular to the sarcoplasmic reticulum

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triad

the pattern of one t-tubule between two sarcplasmic reticulum vesicles

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action potential

electrical nerve impulse, causes the release of calcium ions from the sarcoplasmic reticulum into the myofibril, which causes tension development in the muscle

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sliding-filament theory

states that the actin filaments at each end of the sarcomere slife inward on myosin filaments, pulling the Z-lines toward the centre of the sarcomere and this shortening the muscle fiber

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What dictates the force production of a muscle?

the number of cross-bridges that are attached to actin filaments at any instant in time

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what is necessary for mysoin cross-bridge cycling with actin filaments?

calcium and ATP

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When does relaxation occur?

when actin and myosin return to their unbound state

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acetylocholine

a neurotransmitter, diffuses across the neuromuscular junction, causing excitation of the sarcolemma, when enough of it is released and action potential is generated

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all-or-none principle

a motor neuron stimulus always stimulates all fibers equally

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troponin

a protein that is situated at regular intercals along the actin filament and has a high affinity for calcium ions

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tropomyosin

a protein that runs along the length of the actin filament in the groove of the double helix

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what does the extent muscle control depend on?

the number of muscle fibers within each motor unit

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twitch

the brief contraction that results from an action potential

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tetanus

when the stimuli are delivered as so high a frequency that the twitches merge and eventually completely fuse

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types of muscle fibers 

slow twitch (Type I), fast twitch (Type IIa and Type IIb/Type IIx)

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recruitment

a means of varying skeletal muscle force involving an increase in force through varying the number of motor units activated

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preloading

the loading of the muscle prior to the motion, helps to fully activate the muscle fibers that are needed for the early range of motion

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proprioceptors

specialized sensory receptors located within joins, muscles, and tendons

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muscle spindles

proprioceptors that consist of several modified muscle fibers enclosed in a sheath of connective tissue, they provide information concerngin muscle length and the rate of change in length

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intrafusal fibers

the modified muscle fibers that make up muscle fibers

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Golgi tendon organs

proprioceptors located in tendons near the myotendinous junction and are in a series with extrafusal muscle fibers

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sarcopenia

the reduction of skeletal muscle in size and strength due as a result of aging or inactivity

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the heart

a muscular organ comprised of two interconnected but separate pumps

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atrium

delivers blood into the ventricles

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ventricle

supply the main force for moving blood through the pulminary and peripheral circulations

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tricuspid and mitral valves (AV valves)

prevent blood flow from the ventricles back into the atria

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semilunar valves- aortic and pulmonary

prevent backflow from the aorta and pulmonary artieries into the ventricles during ventricular relaxation

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sinoastrial (SA) node

the intrinsic pacemaker (where rhythmic electril impluses are normally initiated

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atrioventricular (AV) node

wher the impulse is delayed slightly before passing into the ventricles

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atrioventricular (AV) bundle

conducts the impulse to the ventricles

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myocardium

the heart muscle

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sympathetic and parasympathetic nervous systems

components of the autonomic nervous system (sympathetic nerves accelerates heart beat, parasympathetic slows it)

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bradycardia

a heart beat less that 60 beats/min

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tachycardia

a heart beat higher than 100 beats/min

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electrocardiogram (ECG)

a graphic representation of this activity

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P-Wave

the first wave, genereated by the changes in the electrical potential of cardiac muscle cells that depolarize the atria and result in atrial contraction

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QRS complex

three separate waves, genereated by the electrical potential that depolarizes the ventricles and results in ventircular contraction

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T-wave

cause by the electrical potential genereated as the ventricles recover from the state of depolarization

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repolarization

the recovery of the ventricles or atria from their depolarized state

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