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chapter 6 muscles
| Question | Answer |
|---|---|
| the ability of skeletal muscle to shorten with force | contractility |
| the capacity of skeletal muscle to respond to a stimulus | excitability |
| the ability to be stretched | extensibility |
| the ability to recoil to their original resting length after they have been stretched | elasticity |
| muscles help to produce ____________ essential for maintenance of normal body temperature | heat |
| each skeletal muscle is surrounded by a connective tissue sheath | epimysium |
| connective tissue located outside the epymysium | fascia |
| muscle composed of numerous visible bundles called muscle ____________ | fasciculi |
| fasciculi is surrounded by loose connective tissue called | perimysium |
| muscle cells are called muscle ___________ | fibers |
| each fiber is surrounded by a connective tissue sheath called | endomysium |
| the cytoplasm of each fiber is filled with | myofibrils |
| a threadlike structure that extends from one end of the fiber to the other | myofibrils |
| myofibrils consist of 2 major kinds of protein fibers called ________ | actin myofilaments & myosin myofilaments |
| thin myofilaments | actin myofilaments |
| thick myofilaments | myosin myofilaments |
| the basic structural and functional unity of the muscle | sacomere |
| the outside of most cell membranes are _________ charged | positively |
| the inside of a cell membrane is __________ charged | negatively |
| the charge difference across the membrane is called the ____________________ | resting membrane potential |
| the brief reversal back of the charge is called _______________ | action potential |
| nerve cells that carry action potentials to skeletal muscle fibers | motor neurons |
| each branch that connects to the muscle forms a _____________________ near the center of the cell | neuromusclular junction or synapse |
| single motor neuron and all the skeletal muscle fibers it innervates are called ________ | motor unit |
| the enlarged nerve terminal is the | presynaptic terminal |
| the space between the presynaptic terminal and the muscle cell is the | synaptic cleft |
| the muscle fiber is the | postsynaptic terminal |
| each presynaptic terminal contains | synaptic vesicles |
| synaptic vesicles secrete a neurotransmitter called | acetylcholine |
| the sliding of actin myofilaments past myosin myofilaments during contraction is | sliding filament mechanism |
| contraction of an entire muscle is response to a stimulus that causes the action potential in one or more muscle fibers | muscle twitch |
| muscle fibers will not respond to stimulus until that stimulus reaches a level called | threshold |
| muscle fiber will contract maximally | all or none response |
| the time between application of a stimulus to a motor neuron and the beginning of a contraction is | lag phase |
| the time of contraction is the | contraction phase |
| the time during which the muscle relaxes is the | relaxation phase |
| where the muscle remains contracted without relaxing | tetany |
| the increase in number of motor units being activated is called | recruitment |
| ____ is needed for energy for muscle contraction | ATP |
| ATP is produced in the | mitochondria |
| ATP degenerates to the more stable | ADP |
| high energy molecule | creatine phosphate |
| without oxygen | Anaerobic respiration |
| with oxygen | aerobic respiration |
| _______ the amount of oxygen needed in chemical reactions to convert lactic acid to glucose | oxygen debt |
| ______ results when ATP is used during contraction | muscle fibers |
| the 2 types of muscle contractions | isometric & isotonic |
| equal distance | isometric |
| equal tension | isotonic |
| constant tension produced by muscles of the body for long periods of time | muscle tone |
| contract quickly and fatigue quickly | fast twitch fibers |
| the points of attachment of each muscle are its _____ & _______ | origin & insertion |
| at these attachment points the muscle is connected to the bone by a | tendon |
| (head) 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 is the | belly |
| muscles that work together to accomplish specific movements are called | synergists |
| muscles that work in opposition to one another are called | antagonists |
| if one muscle plays the major role in accomplishing the desired movement | prime mover |
| raises the eyebrows | occipitofrontalis |
| closes the eyelids | orbicularis oculi |
| puckers the lips | orbicularis oris |
| flattens the cheeks | buccinator |
| what are the kissing muscles | orbicularis oris & buccinator |
| smiling muscle | zygomaticus |
| sneering | levator labii superioris |
| frowning | depressor anguli oris |
| chewing | mastication |
| how many pairs of mastication muscles are there | 4 |
| what the mastication muscles | 2 pair pterygoids, temporalis, & masseter |
| change the shape of the tongue | intrinsic tongue muscles |
| move the tongue | extrinsic tongue muscles |
| lateral neck muscle and prime mover | sternocleidomastoid |
| sheetlike muscle that covers the anterolateral neck | platysma |
| group of muscles on each side of the back | erector spinae |
| muscles that move the thorax | thoracic muscles |
| elevate the ribs during inspiration | external intercostals |
| contract during forced expiration | internal intercostals |
| dome chaped muscle | diaphragm |
| rotates scapula | trapezius |
| pulls scapula anteriorly | serratus anterior |
| adducts and flexes the arm | pectoralis major |
| medially rotates, adducts, and powerfully extends the arm | latissmus dorsi |
| attaches the humerus to the scapula and clavicle , and is the major abductor of the upper limb | deltoid |
| extends the forearm | triceps brachii |
| flexes the forearm | biceps brachii |
| flexes and supinates the forearm | brachioradialis |
| flexes the wrist | flexor carpi |
| extends the wrist | extensor carpi |
| flexes the fingers | flexor digitorum |
| extends the fingers | extensor digitorum |
| buttocks | gluteus maximus |
| extends the leg | quadriceps femoris |
| flexes the thigh | satorius |
| posterior thigh muscles | hamstring |
| form the calf muscle | gastrocnemius and soleus |