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Anatomy
muscles eastham
Question | Answer |
---|---|
The ability of skeletal muscle to shorten with force is | Contractility |
The capacity of skeletal muscle to respond a stimulus is | Excitability |
The ability to be stretched is | Extensibility |
Ability to recoil to their original resting length after they have been stretched is | Elasticity |
Muscles help produce heat essential for maintenance of normal | Body temperature |
Epimysium | Each skeletal muscle is surrounded by a connective tissue sheath |
Fascia | Is another connective tissue located outside the epimysium, it surrounded and sperates muscles |
Muscle is composed of numerous visible bundles called | Muscle fasciculi |
Fascicle are surrounded by loose connective tissue called | Perimysium |
The fasciculi are composed of single muscle cells called | Fibers |
Each fiber is surrounded by a connective tissue sheath called | Endomysium |
The cytoplasm of each fiber is filled with | Myofibrils |
Myofibrils | Threadlike structure that extends from one end of the fiber to the other |
Myofibrils consist of two major kinds of protein fiber | Actin myofilaments Myosin myofilaments |
Action myofilaments | Thin myofilaments, resemble two minute strands of pearls twisted together |
Mysoin myofilaments | Thick myofilaments, resemble bundlesbof minute golf clubs |
Action and myosin myofilaments form highly ordered units called | Sarcomeres |
Sarcomeres are joined end to end to form the | Myofibril |
The sarcomere is the basic structural and functional unity of the | Muscle |
The arrangement of actin and mysoin give a | Banded appearance |
Each side of the Z line is a light area called the | I band, consists of actin |
A band extends the length of | Mysoin |
In the center of each sarcomere is a light area called the | H zone |
H zone only consists of | Mysoin |
Mysoin myofilaments are anchored in the center of the sarcomere at a dark staining band called | M line |
The charge difference across the membrane is called | Resting membrane potential |
Motor neurons | Nerve cells that carry action potentials to skeletal muscle fibers |
Axons enter the muscle and | Branch |
Each branch that connects to the muscle forms | Neuromuscular junction or synapse |
A single motor neuron and all the skeletal muscle fibers it innervates are | Motor unit |
Many motor units form a | Single muscle |
Neuromuscular junction | Formed by an enlarged nerve terminal resting in an indentation of the muscle cell membrane |
The enlarged nerve terminal is | Presynaptic terminal |
The space between the presynaptic terminal and the muscle cells is | Synaptic cleft |
The space between the presynaptic terminal and muscle fiber Is | Postsynaptic terminal |
Each presynaptic terminal contains | Synaptic vesicles |
Each presynaptic terminal contains synaptic vesicles that secreate a synaptic clet called | Acetylcholine |
When an actin potential reaches the nerve terminal it causes the synaptic vesicles to | Realese acetylcholine into the synaptic cleft by exocytosis |
The acetylcholine diffuses across the synaptic cleft binds to receptor molecules in the | Muscle cell membrane |
The combination of acetylcholine with its receptor causes an influx of sodium ions into the | Muscle fiber |
The acetylcholine released into the synaptic cleft between neuron and muscle cell is | Rapidly broken down by an enzymes |
Occurs as actin and mysoin myofilaments slide past one another causing sarcomeres | To shorten |
When sarcomeres shorten it causes the | Muscle to shorten |
The sliding of action myofilaments past mysoin myofilaments during contraction is called | Sliding filament mechanism of muscle contraction |
Muscle twitch | A contraction of an entire muscle in response to as stimulus that causes the sctin potential in one or more muscle fibers |
A muscle fiber will not respond to stimulus until the stimulus reaches a level called | Threshold |
Once the stimulus reaches the threshold level | Muscle fibers will contract maximally |
Phenomenon is called | All or none response |
Time between application of a stimulus to a motor neuron and the beginning of a contraction is the | Lag phase |
Time of contraction is the | Contraction phase |
Time during the which the muscle relaxes is the | Relaxation phase |
Tetany | Where the muscle remains contracted without relaxing |
The increase in number of motor units being actiaved is called | Recruitment |
ATP (adenosine triphosphate) | Needed for energy for muscle contraction |
ATP is prodeced in | The mitochondria |
Shot lived and unstable | ATP |
Degenerates to the more stable | ADP (adenosine diphosphate) |
When at rest they can't stockpile ATP but they can store another high energy molecule called | Creating phosphate |
Anaerobic respiration | Without oxygen |
Aerobic respiration | With oxygen |
Oxygen debt | The amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replenish the depleted stores of creating phosphate stores in muscle cells |
Muscle fatigue | Results when ATP is used during muscle contraction faster than it can be produced in the muscle cells |
Two types of muscle contraction | Isometric Istonic |
Isometric | (Equal distance) length of the muscle does not change, but amount of tension increases during contraction process |
Isotonic | (Equal tension) the amount of tension produced by the muscle is constant during contraction, but the length of the muscle changes |
Muscle tone | Refers to constant tension produced by muscles of the body for long periods of time |
Fast-twitch fibers | Contract quickly and fatigue quickly, well adpated to perform anaerobic metabolism. Ex. White meat of chicken breast |
Slow-twitch fibers | Contract more slowly and are more resistant to fatigue, they are better suited for aerobic metabolism. Ex.dark meat legs of chicken |
Attatcmen points of the muscle is connected to the bone by | A tendon |
Origin(head) | The most stationary end of the muscle |
Insertion | The end of the muscle undergoing the greatest movement |
The portion of the muscle between the orgin and the insertion is | The belly |
Muscles that work together to accomplish specific movements are | Synergists |
Muscles that work in opposition to one another are | Antagonists |
Amount a group of synergits, if onemuscke plays the major role in accomplishing the desired movement | It is the prime mover |