Term
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Definition
| Consists of bundles of specialized contractile fibers held together by connective tissue. Three types of muscles in mammals. |
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Definition
| Responsible for volunatry movements. Innervated by the somatic nervous system. |
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Term
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Definition
| Each is a multinucleated cell created by the fusion of several mononucleate emryonic cells. Nuclei found at periphery of the cell. |
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Term
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Definition
| Each is a multinucleated cell created by the fusion of several mononucleate emryonic cells. Nuclei found at periphery of the cell. |
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Term
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Definition
| Filaments that are embeded in skeletal muscle fibers. Enveloped by a modified endoplasmic reticulum. Further divided into sarcomeres. |
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Term
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Definition
| Contractile units within myofibrils |
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Term
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Definition
| Modified endplasmic retriculum that stores calcium ions; envelops myofibrils. |
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Term
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Definition
| cytoplasm of a muscle fiber. |
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Term
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Definition
| cell membrane of a muscle fiber. Capable of propagating an action potential, connected to the T system. |
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Term
| transverse tubules (T system) |
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Definition
| Oriented perpendicular to myofibrils. T system provides cahnnels for ion flow throughout the muslce fibers; can propogate action potentials. |
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Term
| Red fibers (Skeletal muscle) |
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Definition
| Slow-twitch fibers. Have a high myoglobin content, and mitochondria. Derive energy from aerobic respiration, capable of sustained and vigorous activity. |
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Term
| White fibers (Skeletal muscle) |
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Definition
| Fast-twitch fibers. Anaerobic and contain less myoglobin and fewer mitochondria. Have a greater rate of contraction than red fibers. They fatigue more easily. |
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Term
| Thin filament of sarcomere |
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Definition
| chains of globular actin molecules associated with troponin and tropomyosin. |
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Term
| Thick filaments of sarcomere |
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Definition
| composed of organized bundles of myosin molecules; each with a head and tail region. |
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Term
| Organization of sarcomere: Z lines |
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Definition
| define boundaries between sarcomeres, and anchor the thin filaments. |
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Term
| Organization of sarcomeres: M line |
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Definition
| Line that runs down the center of the sarcomere. |
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Term
| Organization of sarcomeres: I band |
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Definition
| Region of filament containing thin filaments only. |
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Term
| Organization of sarcomeres: H zone |
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Definition
| Region of sarcomere containing thick filaments only |
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Term
| Organization of sarcomeres: A band |
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Definition
| Region of sarcomere: spans the entire lengtho f the thick filaments and any overlapping portion of the thin filaments. |
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Term
| Contraction of muscle: Sarcomere zone changes |
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Definition
| During contraction, A band is not reduced in size; H zone and I band are. |
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Term
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Definition
| Link between the nerve terminal (synaptic bouton) and the sarcolemma of the muscle fiber. |
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Term
| Shortening of the sarcomere |
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Definition
| Once an AP is generated, conducted along the sarcolemma and the T system, into the interior of the fiber. The sarcoplasmic reticulum releases calcium ions into the sarcoplasm, causing myosin-binding sites to be exposed. Myosin molecules bind to the binding sites, forming actin-myosin cross bridges, causing myosin to pull on the actin molecules, and draw the thin filaments toward the center of the H zone, and shorten the sarcomere. |
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Term
| Role of calcium in skeletal muscle contraction |
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Definition
| Once inside the sarcoplasm, calcium binds to the troponin molecules, causing tropomyosin strands to shift, and exposing the myosin-binding sites on the actin filaments. |
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Term
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Definition
| After death, ATP is no longer producedd and the myosin heads can't detach from actin, and the muscle cannot relax. |
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Term
| Relaxation phase of sarcomere contraction |
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Definition
| calcium is pumped back into the sarcoplasmic reticulum. Myosin dissociates from the thin filament, sarcomere returns to original width. |
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Term
| Stimulus intensity of muscle fibers |
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Definition
| Individual fibers exhibit all-or-none rsponse. Whole muscle does not exhibit this. Strength of the contraction can increase as stimulus strength is increased by involving more fibers. |
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Term
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Definition
| continual low-grade contractions of muscle; essential for both voluntary and involuntary muscle contraction. |
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Term
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Definition
| Response of a signle muscle fiber to a brief stimulus at or above the threshold stimulus. Consists of a latent period, contraction period, and relaxation period. |
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Term
| Frequency summation: Tetanus. |
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Definition
| When muscle contractions begin to combine, becoming stronger and more prolonged. Become continuous sometimes. |
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Term
| Skeletal muscle in a nutshell |
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Definition
Striated
Voluntary
Somatic innervation
Many nuclei per cell
Calcium required for contraction |
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Term
| Cardiac Muscle in a nutshell |
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Definition
Striated
Involuntary
Autonomic innervation
1-2 nuclei per cell
Calcium required for contraction. |
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Term
| Smooth muscle -- other stuff |
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Definition
| Responsible for involuntary actions; innervated by ANS. Found in digestive tract, bladder, uterus, blood vessel walls. Contain one centrally located nucleus. Filaments (actin & myosin) lack organization of skeletal sarcomeres, and hence the striations. |
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Term
| Smooth muscle contractions |
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Definition
| Result from the sliding of actin and myosin over one another via calcium regulation. Slower, capable of being sustained longer than skeletal muscle contractions. Have both inhibitory and excitatory synapses. Demonstrates myogenic activity. |
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Term
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Definition
| Property of reflexively contracting without nervous stimulation (smooth and cardiac muscle). |
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Term
| Smooth Muscle in a nutshell |
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Definition
Non-striated
Involuntary
Autonomic innervation
1 nucleus per cell
Calcium required for contraction. |
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Term
| Cardiac Muscle: Other stuff |
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Definition
| Present in muscle tissue of the heart. Possess characteristics of skeletal and smooth muscle fibers. FIlaments arranged in sarcomeres, and has a striated appearance. Only one or 2 nuclei. Innervated by ANS, serves only to modulate its beat. Myogenic. |
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Term
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Definition
| High-energy storage compound. Produced during resting periods via a reaction that transfers ATP phosphate group to creatine. |
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Term
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Definition
| Hemoglobin-like protein, found in muscle tissue. Has a high oxygen affinity. Binds to oxygen from bloodstream, holds onto it until available oxygenis depleted. Acts as additional oxygen reserve. |
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Term
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Definition
| Major function is to bind and support other tissue. COmposed of sparsely scattered population of cells in an amorphous ground substance. |
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Definition
| Found throughout the body; binds epithelium to underlying tissues. Is the packing material that holds organs in place. Has three kinds of proteinaceous fibers. |
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Term
| Proteinaceous fibers in loose connective tissue |
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Definition
Collagenous fibers: collagen; have good tensile strength
Elastic fibers: elastin, endow resilience
Regular Fibers: branched, tightly woven fibers that join connective and adjoining tissue. |
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Term
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Definition
| Cell type in loose CT: secrete substances that are components of extracellular fibers |
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Definition
| Major cell type in loose CT: engulf bacteria and dead cells via phagocytosis. |
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Definition
| Has high proportion of collagenous fibers. Organized into parallel bundles that give fibers great strength. |
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Definition
| Composed of dense connective tissue; attaches muscle to bone. |
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Term
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Definition
| End of the muscle attached to the stationary bone. (Proximal end) |
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Term
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Definition
| End of the muscle attached to the bone that moves during contraction (distal end). |
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Term
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Definition
| End of the muscle attached to the bone that moves during contraction (distal end). |
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Term
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Definition
| Assist the principle muscles during movement |
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Term
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Definition
| Contracts to decrease the angle of a joint |
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Term
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Definition
| Will contract to straighten the joint |
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Term
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Definition
| Moves a part of the body away from the body's midline. |
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Term
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Definition
| Moves a part of the body toward the midline. |
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