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46 Cards in this Set

  • Front
  • Back
Muscle fibers are specialized for _____
contraction
Muscle contraction occurs when ____ and ____ filaments slide past each other
actin
myosin
Muscle _____ is a state of partial contraction
tone
Muscles work ______ to one another
antagonistically
Skeletal muscle is made up of hundreds, sometimes thousands, of muscle cells referred to as muscle _____
fibers
Individual muscle fibers are surrounded by a connective tissue covering called the _____
endomysium
Muscle fibers are arranged in bundles known as ______
fascicles
Each fascicle is wrapped by connective tissue called the _____
perimysium
The muscle is surrounded by a covering of connective tissue called the _____
epimysium
Extensions of epimysium form tough cords of connective tissue called ____
tendons
_____ anchor muscle to bone
tendons
The muscle is surrounded by fibrous connective tissue called ____ that merges with the tissue of the tendon
fascia
The plasma membrane of a muscle fiber has many inward extensions that form a set of ____ _____
transverse tubules
(T tubules)
Each muscle fiber is almost filled with threadlike structures called _____
myofibrils
Myofibrils are composed of smaller structures called muscle _____ that are made of protein threads
filaments
Thick muscle filaments consist mainly of the protein ______
myosin
Thin muscle filaments consist of the protein _____
actin
Myosin and actin are _____ proteins, which means they are capable of shortening
contractile
Myosin and actin filaments are organized into repeating units called _____, the basic units of muscle contraction
sarcomeres
Filaments ______ lengthwise in the muscle fibers
overlap
Overlapping muscle fibers produce the pattern of transverse bands, or _______
striations
A _____ ____ is a nerve that signals a muscle to contract
motor nerve
The junctions of nerve and muscle fibers are called _____ _____
neuromuscular junctions
A motor neuron releases the neurotransmitter _____ which is a signaling molecule
acetylcholine
Acetylcholine is released into the ____ ____ between the motor neuron and muscle fiber
synaptic cleft
Acetylcholine ____ across the synaptic cleft and combines with receptors onfthe surface of the muscle fiber
diffuses
Diffusion of acetylcholine causes ____, or a decrease in the electric charge difference across the plasma membrane of the muscle fiber
depolarization
Depolarization may cause an electrical impulse or ____ ____ to be generated in the muscle fiber
action potential
Excess acetylcholine is broken down by an enzyme called ______
acetylcholinesterASE
Depolarization of the T tubules triggers release of stored ____ ____ from the endoplasmic reticulum
Ca ions
The backup energy storage compound for muscle cells is ____ ____
creatine phosphate
_____ provides the immediate source of energy for muscle contraction
ATP
Glucose is stored in muscle cells in the form of a large energy storage molecule called _____
glycogen
The depletion of ATP results in weaker contractions and muscle ____
fatigue
____ ____ is a waste product produced during anaerobic metabolism of glucose
lactic acid
During muscle exertion, an ____ ___ develops
oxygen debt
In _____ contraction, the force of muscle contraction is greater than the opposing force of the weight, causing the muscles to shorten as they contract
isotonic
In _______ contraction, muscle length does not appreciably change but muscle TENSION may increase greatly (e.g. pushing against a wall)
isometric
Muscles can only ____; they cannot _____
pull
push
The attachment of the muscle to the less movable bone is called its ______
origin
The attachment of the muscle to the more movable bone is its _____
insertion
The muscle that contracts to produce a particular action is known as the ____ or ____ _____
agonist
prime mover
The muscle the produces the opposite movement is the _____
antagonist
____ & ______ are muscles that help the prime mover by reducing unnecessary movement
synergists
fixators
_____ stabilize joints so that undesirable movement does not occur
synergists
_____ stabilize the origin of a prime mover so that its force is fully directed on the bone on which it inserts
fixators