Term
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Definition
| attached to & moves bones, occasionally skin or other muscles, striated, voluntary as a rule, , body position and stabilization |
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Term
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Definition
| forms most of heart wall and pumps blood, striated, involuntary |
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Term
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Definition
| built in rhythm, a pacemaker initiates contraction |
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Term
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Definition
| located in the walls of hollow organs, nonstriated, usually involuntary |
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Term
| Functions of Muscular Tissue: 1. Electrical excitability |
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Definition
| The ability to respond to certain stimuli by producing electrical signals known as action potentials. |
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Term
| Properties of Muscular Tissue: 2. Contractility |
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Definition
| ability of muscular tissue to contract forcibly when stimulated by an action potential. |
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Term
| Properties of Muscular Tissue: 3. Extensibility |
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Definition
| The ability of muscular tissue to stretch without being damaged. |
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Term
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Definition
| the ability of muscular tissue to return to its original length and shape after contraction or extension. |
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Term
| Muscle fibers, myofibrils |
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Definition
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Term
| Connective Tissue Components |
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Definition
| surrounds and protects muscular tissue. |
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Term
| Subcutaneous layer/hypodermis |
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Definition
composed of areolar and adipose connective
tissue. |
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Term
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Definition
dense irregular connective tissue that lines the body wall, limbs
and muscles with similar functions as well as fills spaces between muscles |
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Term
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Definition
| C.T. that surrounds the entire muscle. |
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Term
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Definition
| C.T that surrounds a group of muscle fibers. |
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Term
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Definition
| C.T that surrounds and separates individual muscle fibers |
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Term
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Definition
| bundle of 10-100 muscle fibers |
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Term
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Definition
cord-like C.T. of dense regular C.T. that attaches the muscle to the
periosteum of bone. |
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Term
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Definition
broad, flat C.T that connects the muscle to muscle or muscle to
bone. |
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Term
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Definition
C.T. that encloses tendons to reduce friction as they slide
back and forth. Similar to bursae. Cavity between the layers is filled with synovial fluid. |
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Term
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Definition
| generally one artery and one or two veins accompany each nerve that penetrates a skeletal muscle. |
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Term
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Definition
| fusion of 100 or more mesodermal cells in each muscle fiber during embryonic development. |
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Term
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Definition
| muscle growth after birth, an enlargement of existing muscle fibers |
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Term
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Definition
| myoblasts which persist in mature skeletal muscle fibers may fuse with one and regenerate muscle fibers to a small extent |
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Term
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Definition
| replacement of muscle fibers by fibrous scar tissue due to damage or degeneration |
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Term
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Definition
| plasma membrane of a muscle cell. |
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Term
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Definition
tiny invaginations of the sarcolemma tunnel into the
center of the muscle fiber. |
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Term
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Definition
| The cytoplasm of a muscle fiber. |
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Term
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Definition
| Thread-like organelles of contraction |
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Term
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Definition
sleave-like membranous sac that encircle each
myofibril |
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Term
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Definition
| dialated end sacs of the sarcoplasmic reticulum. |
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Term
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Definition
| a transverse tubule and two terminal cisterns |
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Term
| Filaments and the Sarcomere |
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Definition
| filaments are arranged in sarcomeres. The thin and thick filaments overlap one another creating striations. |
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Term
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Definition
| 8 nm in diameter and 1-2 um long |
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Term
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Definition
| 16 nm in diameter and 1-2 um long |
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Term
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Definition
the basic functional units of the myofibril that extend from one Z
disc to the next |
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Term
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Definition
| structural proteins that separate one sarcomere from the next. |
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Term
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Definition
the dark middle part of the sarcomere that extends the entire length of
the thick filament |
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Term
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Definition
| thick and thin filaments lie side by side |
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Term
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Definition
| lighter, less dense area that contains only thin filament |
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Term
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Definition
a narrow region in the center of each A band that contains thick
filaments but no thin filaments. |
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Term
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Definition
structural proteins in the middle of the H zone that hold the thick
filaments together |
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Term
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Definition
| Myofibrils are built from three kinds of proteins: see chart 10.2 |
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Term
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Definition
myosin and actin, are the main components of thick and thin
filaments |
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Term
|
Definition
functions as a motor protein. They bind to myosin sites on actin
molecules during muscle contraction |
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Term
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Definition
Actin molecules join together to form an actin filament, twisted into a
helix. On each actin molecule is a myosin binding site for the myosin head. |
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Term
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Definition
| Two regulatory proteins are also part of the thin filament. |
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Term
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Definition
covers the myosin binding sites on actin when the muscle is
relaxed. |
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Term
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Definition
| Troponin holds tropomyosin in place. |
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Term
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Definition
| Muscle contains a dozen structural proteins which contribute to the alignment, stability, extensibility and elasticity of myofibrils. |
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Term
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Definition
| (gigantic) Each Tintin molecule connects a Z disc to the M line of the sarcomere and helps to stabilize the position of the thick filament. |
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Term
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Definition
| a cytoskeletal protein that links thin filaments of the sarcomere to integral membrane proteins of the sarcolemma, which are attached in turn to proteins in the connective tissue extracellular matrix |
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Term
| The Sliding Filament Mechanism |
|
Definition
| muscle contraction occurs because myosin heads attach to and “walk along” the thin filaments at both ends of the sarcomere, pulling the thin filaments toward the M line and may even overlap. As a result the Z discs move closer together. |
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Term
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Definition
| the Sarcoplasmic reticulum releases calcium ions. Once the myoin binding sites are free the contraction cycle begins. It has four steps: See pages: 312-313 |
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Term
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Definition
| the repeating sequence of events that causes the filaments to slide 1. ATP hydrolysis 2. Attachment of myosin to actin to form crossbridges 3. Power Stroke 4. Detachment of myosin from actin |
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Term
| Excitation-Contraction Coupling |
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Definition
| The events that connect excitation (action potential) to contraction (sliding filaments). |
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Term
| Length-Tension Relationship |
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Definition
• When the sarcomere length is close to resting length the zone of overlap is
maximal for the muscle fiber to develop maximal tension • When there is no overlap of the thick and thin filaments, muscle cannot contract
and the tension is zero • When sarcomere length shortens, the tension decreases with few myosin heads
making contact with thin filament. |
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Term
| The Neuromuscular junction |
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Definition
| NMJ, A synapse between the axon terminals of a somatic motor neuron and the sarcolemma of a muscle fiber. |
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Term
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Definition
| a region where communication occurs between two neurons or between a neuron and a target cell. |
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Term
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Definition
| a small gap at a synapse. |
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Term
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Definition
the chemical communication between the first cell and the
second |
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Term
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Definition
membrane-enclosed sacs located in synaptic end bulbs
containing neurotransmitters |
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Term
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Definition
| the region of the sarcolemma opposite the synaptic end bulb. |
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Term
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Definition
Deep grooves in the motor end plate that increase the surface
area for neurotransmitters |
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Term
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Definition
| Muscle fibers have three ways to produce ATP |
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Term
| Muscle Metabolism 1. Creatine Phosphate |
|
Definition
produced when muscle fibers are relaxed and more ATP is
available than needed for resting muscle metabolism. |
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Term
| Muscle Metabolism 2. Anerobic Cellular Respiration |
|
Definition
ATP producing reactions that do not require
oxygen. |
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Term
| Muscle Metabolism3. Aerobic Cellular Respiration |
|
Definition
Muscular activity that lasts longer than a half a
minute depends increasingly on ACR, oxygen-requiring reactions |
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Term
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Definition
refers to the added oxygen, over and above the resting oxygen
consumption, that is taken into the body after exercise. |
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Term
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Definition
| # of impulses per second. |
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Term
|
Definition
a somatic motor neuron and all the skeletal muscle fibers it
stimulates |
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Term
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Definition
a brief contraction of all the muscle fibers in a motor unit
in response to a single action potential in its motor unit. |
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Term
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Definition
| record of a muscle contraction. |
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Term
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Definition
the delay (2 milliseconds) between the application of the
stimulus and the beginning of contraction. |
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Term
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Definition
| Ca++ binds to troponin, myosin-binding sites are revealed, crossbridges formed and peak tension develops in the muscle fiber. 10-100msec |
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Term
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Definition
Ca++ is actively transported back into the SR, myosin
binding sites are covered and tension in the muscle fiber decreases, 10-100msec |
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Term
|
Definition
The period of lost excitability where the muscle fiber cannot
respond. |
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Term
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Definition
| phenomenon in which stimuli arriving at different times cause larger contractions. |
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Term
| Unfused (incomplete) tetanus |
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Definition
| When a skeletal muscle fiber is stimulated at a rate of 20 to 30 times per second, it can only partially relax between stimuli. |
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Term
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Definition
| When a skeletal muscle fibers is stimulated at a higher rate of 80 to 100 times per second, it does not relax at all. |
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Term
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Definition
| the process in which the number of active motor units increases. |
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Term
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Definition
| a small amount of tautness or tension in the muscle due to weak involuntary contractions of its motor units. |
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Term
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Definition
| a state of limpness in which muscle tone is lost. |
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Term
|
Definition
the tension (force of contraction) developed by the muscle
remains almost constant while the muscle changes its length. |
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Term
| Concentric isotonic contraction |
|
Definition
if the tension generated is great enough to
overcome the resistance of the object to be moved |
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Term
| Eccentric Isotonic Contraction |
|
Definition
when the length of a muscle increases
during a contraction. |
|
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Term
|
Definition
the tension generated is not enough to exceed the
resistance of the object to be moved and the muscle does not change its length. |
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Term
| Types of Skeletal Muscle Fibers |
|
Definition
| classification of skeletal muscle fibers into 3 types: Slow Oxidative (SO) fibers, Fast Oxidative-Glycolytic Fibers (FOG), Fast Glycolytic Fibers (FG). See pages 324-5 and table 10.3 |
|
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Term
|
Definition
| the red-colored protein that binds oxygen in muscle fibers |
|
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Term
|
Definition
skeletal muscle fibers that have a high myoglobin content,
more mitochrondia and more capillaries |
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Term
|
Definition
| skeletal muscle fibers that have a low myoglobin content |
|
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Term
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Definition
speed at which the ATPase in the myosin heads hydrolyzes
ATP |
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Term
| Visceral (single-unit) smooth muscle tissue |
|
Definition
most common type. Fibers
connect to one another via gap junctions. It is autorhythmic. |
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Term
| Multiunit smooth muscle tissue |
|
Definition
| consists of individual fibers, few gap junctions. Stimulation of one multiunit fiber causes contraction of only that fiber |
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Term
| Regeneration of Muscular Tissue |
|
Definition
| Satellite cells divide slowly and fuse with existing fibers to assist both in muscle growth and in repair of damage fibers. |
|
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Term
|
Definition
| All the muscles of the body are derived from mesoderm. They develop on either side of the developing nervous system and undergo segmentation into a series of cube-shaped structures called somites. The somites differentiate into three regions: |
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Term
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Definition
| forms the skeletal muscles of the head, neck, and limbs |
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Term
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Definition
| which forms the connective tissues, including the dermis of the skin |
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Term
|
Definition
| which gives rise to vertebrae. |
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