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Ch.6 muscles
| Question | Answer |
|---|---|
| muscle cells | muscle fibers |
| contractility | the ability of skeletal muscle to shorten with force |
| excitability | the capacity of skeletal muscle to respond to a stimulus |
| extensibility | the ability to be stretched |
| elasticity | ability to recoil to their original resting length after they have been stretched |
| each skeletal muscle is surrounded by a connective tissue sheath called the ____ | epimysium |
| ____ is another connective tissue located outside the epimysium | fascia |
| muscle fasciculi are surrounded by loose connective tissue called the ____ | perimysium |
| each fiber is surrounded by a connective tissue sheath called the ____ | endomysium |
| the cytoplasm of each fiber is filled with ___ | myofibrils |
| thin myofilaments (pearls twisted) | actin myofilaments |
| thick myofilaments (golf balls) | myosin myofilaments |
| joined end to end to form the myofibril | sarcomeres |
| the charge difference across the membrane | resting membrane potential |
| the brief reversal back of the charge | action potential |
| nerve cells that carry action potentials to skeletal muscle fibers | motor neurons |
| Each branch that connects to the muscle forms a _____ _____, or _____ near the center of the cell. | neuromusclular junction ; synapse |
| a single motor neuron | motor unit |
| enlarged nerve terminal | presynaptic terminal |
| the space between the presynaptic terminal and the muscle cell | synaptic cleft |
| postsynaptic terminal | muscle fiber |
| secrete a neurotransmitter | synaptic vesicles |
| neurotransmitter | acetylcholine |
| enzyme that breaks down muscle cells | acetylcholinesterase |
| the sliding of actin myofilaments past myosin myofilaments during contraction | sliding filament mechanism |
| ___ ___ is a 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 |
| the time between application of a stimulus to a motor neuron and the beginning of a contraction | lag phase |
| the time of contraction | contraction phase |
| the time during which the muscle relaxes | relaxation phase |
| where the muscle remains contracted without relaxing | tetany |
| the increase in number of motor units being activated | recruitment |
| ATP is produced in the _______ | mitochondria |
| adenosine triphosphate | ATP |
| adenosine diphosphate | ADP |
| high-energy molecule ATP stores | creatine phosphate |
| without oxygen | anaerobic respiration |
| with oxygen (more efficient) | aerobic respiration |
| the amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replenish the depleted stores of creatine phosphate stores in muscle cells | oxygen debt |
| results when ATP is used during muscle contraction faster than it can be produced in the muscle cells | muscle fatigue |
| the length of the muscle does not change, but the amount of tension increases during the contraction process | isometric muscle contraction |
| the amount of tension produced by the muscle is constant during contraction, but the length of the muscle changes | isotonic muscle contraction |
| Muscle tone refers to constant tension produced by muscles of the body for long periods of time. Keeps head up and back straight | muscle tone |
| contract quickly and fatigue quickly | fast twitch fibers |
| contract more slowly and are more resistant to fatigue | slow twitch fibers |
| At these attachment points the muscle is connected to the bone by ____ | a tendon |
| the most stationary end of the muscle | origin |
| the end of the muscle undergoing the greatest movement | insertion |
| the portion of the muscle between the origin and the insertion | the belly |
| muscles that work together to accomplish specific movements | synergists |
| muscles that work in opposition to one another | antagonists |
| if one muscle plays the major role in accomplishing the desired movement it is the _____ | prime mover |
| Occipitofrontalis | raises the eyebrows |
| Orbicularis oculi | closes the eyelids |
| Orbicularis oris | puckers lips |
| Buccinator | flattens cheeks |
| Zygomaticus | smiling muscle |
| Levator labii superioris | sneering |
| Depressor anguli oris | frowning |
| Mastication | chewing |
| Intrinsic Tongue Muscles | change the shape of the tongue |
| Extrinsic Tongue Muscles | move the tongue |
| Sternocleidomastoid | lateral neck muscle and prime mover |
| Erector spinae | group of muscles on each side of the back. Responsible for keeping the back straight and the body erect |
| muscles that move the thorax | thoracic muscles |
| elevate the ribs during inspiration | External intercostals |
| contract during forced expiration | Internal intercostals |
| accomplishes quiet breathing | diaphragm |
| tendinous area of the abdominal wall | linea alba |
| On each side of the linea alba is the ____ | rectus abdominis muscle |
| ______ cross the rectus abdominis at three or more locations, causing the abdominal wall of a well-muscled person to appear segmented | Tendinous inscriptions |
| Trapezius | rotates scapula |
| Serratus anterior | pulls scapula anteriorly |
| Pectoralis major | adducts and flexes the arm |
| Latissimus dorsi | medially rotates, adducts, and powerfully extends the arm |
| Deltoid | attaches the humerus to the scapula and clavicle, and is the major abductor of the upper limb |
| Triceps brachii | extends the forearm |
Created by:
shelbyshepard
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