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Eastham Ch.6-Muscles
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 |
| FILL IN THE BLANK: myosin myofilaments are anchored in the ______ of the sarcomere | center |
| 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 |
| FILL IN THE BLANK: motor neurons are nerve cells that carry action potentials to _______ muscle fibers | skeletal |
| 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 |
| FILL IN THE BLANK: 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 |
| FILL IN THE BLANK: 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 |
| FILL IN THE BLANK: ________ _________ occurs as actin and myosin myofilaments slide past one another causing the sarcomeres to shorten. | muscle contraction |
| FILL IN THE BLANK: when the sarcomeres shorten, it also causes the ________ to shorten | muscle |
| 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 |
| FILL IN THE BLANK: if successive stimuli are given you get ________ twitches that occur so frequently the muscle doesn't have time to fully relax. | successive |
| 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. |