Flash Cards

Muscle Stack Cards

Question Answer
the ability of skeletal muscle to shorten with force contractility
the capacity of skeletal muscle to respond to stimulus excitability
the ability to be stretched extensibility
ability to recoil to original resting length after being stretched elasticity
muscles help to… produce heat essential for maintenance of normal body temperature
each skeletal muscle is surrounded by a connective tissue sheath called the… epimysium
what is another connective tissue located outside the epimysium? fascia
what surrounds and separates the muscles? fascia
a muscle is composed of numerous visible bundles called… muscle fasciculi (fascicle)
fasciculi are surrounded by loose connective tissues called… perimysium
fasciculi are composed of single muscle cells called… fibers
muscle cells are called… muscle fibers
each fiber is surrounded by a connective tissue sheath called… endomysium
the cytoplasm of each fiber is filled with… myofibrils
myofibrils are… a threadlike structure that extends from one end of the fiber to the other
myofibrils consist of how many major kinds of protein fibers? two
what are the names for two protein fibers found in myofibrils? actin myofilaments & myosin myofilaments
which myofilament is thin and they resemble 2 minute strands of pearls twisted together? actin myofilaments
which myofilament is thick and resemble bundles of minute golf clubs? myosin myofilaments
actin and myosin form highly ordered units called… sarcomeres
what are the highly ordered units that joine4d end to end to form the myofibril? sarcomeres
what is the basic structural and functional unit if the muscle? sarcomere
each sarcomere extends from… one Z Line (disc) to another Z Line (disc)
each Z Line is an attachment site for… actin
the arrangement of actin and myosin give what kind of appearance? banded appearance
on each side of the Z Line is a light area called… I Band
what does the I Band consist of? actin
the A Band extends the length of… myosin
the A Band is the darker or lighter central region in each sarcomere? darker
in the center of each sarcomere is another light area called… H Zone
the H Zone consists of only myosin or actin myosin
myosin myofilaments are anchored in the ______ of the sarcomere
the outside of most cell membranes is positively charged compared to the inside of the cell membrane, which is negatively charged. the charge difference across the membrane is called the… resting membrane potential
when a muscle cell is stimulated the membrane characteristics change briefly. the brief reversal back of the charge is called… action potential
motor neurons are nerve cells that carry action potentials to _______ muscle fibers
axons enter muscles and branch. each branch that connects to the muscle forms a… neuromuscular
near the center of the cell, each branch is called a… synapse
a single motor neuron and all skeletal muscle fibers it innervates are called a… motor unit
many motor units form what? a single muscle
a neuromuscular junction is formed by an _____________ __________ ___________ resting in an indentation of the muscle cell membrane
enlarged nerve terminal
the enlarged nerve terminal is the… presynaptic terminal
the space between the presynaptic terminal and the muscle cell is the… synaptic cleft
the membrane (or the muscle fiber) of the presynaptic terminal is the… postsynaptic terminal
each presynaptic terminal contains… synaptic vesicles
synaptic terminals secrete a neurotransmitter called… acetylcholine
acetylcholine diffuses across a synaptic cleft and binds to the postsynaptic terminal causing a change in the… postsynaptic cell
when an action potential reaches the nerve terminal, it causes the synaptic vesicles to release acetylcholine into the synaptic cleft by… exocytosis
the acetylcholine diffuses across the synaptic cleft and binds to receptor molecules in the muscle cell membrane. this action is called… sarcolemma
influx initiates an action potential in the muscle cell, which causes it to… contract
the acetylcholine released into the synaptic cleft between the neuron and muscle cell is rapidly broken down by an enzyme called… (HINT: really big word that ends with erase) acetylcholinsterase
acetylcholine breakdown ensures that one action potential in the neuron yields only one action potential in the ______ muscle, and only one contraction of the ______ cell
skeletal; muscle
________ _________ occurs as actin and myosin myofilaments slide past one another causing the sarcomeres to shorten.
muscle contraction
when the sarcomeres shorten, it also causes the ________ to shorten
the sliding of actin myofilaments past myosin myofilaments is called the… sliding filament mechanism
the H & I Bands shorten, but which bands do not change in length? A Bands
what term is a muscle contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers? muscle twitch
a muscle fiber will not respond to stimulus until that stimulus reaches a level called… threshold
threshold is a phenomenon called the… all-or-nothing repsonse
the time between application of a stimulus to a motor neuron and the beginning of a contraction is the… lag phase
the time of contraction is the… contraction phase
relaxation phase is the time during… which the muscle relaxes
if successive stimuli are given you get ________ twitches that occur so frequently the muscle doesn't have time to fully relax.
name the term where the muscle remains contracted without relaxing. tetany
the increase in number of motor units being activated is called… recruitment
what are two major energy requirements? ATP & ADP
what does ATP stand for? adenosine triphosphate
what does ADP stand for? adenosine diphosphate
where is ATP produced? in the mitochondria
ATP is needed for… energy for muscle contraction
is ATP short-lived or long-lived and unstable or stable? short-lived; unstable
is ATP or ADP more stable? ADP
is it necessary for muscle cells to constantly produce ATP? yes
creatine phosphate is… another high-energy molecule that stored
during periods of inactivity as excess ATP is produced in the muscle cell, the energy contained in the ATP is used to… synthesize creatine phosphate
during periods of activity, the energy stored in creatine phosphate can be accessed quickly and used to produce… ATP
what is anaerobic respiration? without oxygen
what is aerobic respiration? with oxygen
what results when ATP is used during muscle contraction faster than it can be produced? muscle fatigue
isometric is… equal distance
isotonic is… equal tension
muscle tone refers to… constant tension
fast-twitch fibers… contract quickly and fatigue quickly
slow-twitch fibers… contract more slowly and are more resistant to fatigue
muscles that work together to accomplish specific movements are called… synergists
muscles that work in opposition to one another are called… antagonists
what are some names that are descriptive about most muscles? according to location, size, orientation of fibers, shape, origin, insertion, and function, etc.

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