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Chapter 6 Anatomy
muscles
| Question | Answer |
|---|---|
| Contractility | the ability of the 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 muscle is surrounded by a connective tissue sheath called what | the epimysium |
| another connective tissue located outside the epimysium that surround and separates muscles | facsia |
| a muscle is composed of of numerous visible bundles called what | muscle fasciculi |
| Muscle fasciculi are surrounded by loose connective tissue called | the perimysium |
| the fasciculi are composed of single muscle cells called | fibers |
| T or F? Each muscle fiber is a single cylindrical cell containing several nuclei. | True |
| each fiber is surrounded by a connective tissue sheath called the | endomysium |
| the cytoplasm of each fiber is filled with | myofibrils |
| define myofibrils | a thread like structure that extends from one end of the fiber to the other. |
| Myofibrils consist of two major kinds of protein fibers which are | actin and myosin microfilaments |
| define actin microfilaments | thin myofilaments |
| define myosin microfilaments | thick myofilaments |
| actin and myosin myofilaments form highly ordered units called | sarcomeres |
| sarcomeres are joined end to end to form the | myofibril |
| basic structural and functional unit of the muscle | sarcomeres |
| the H zone consists only of | myosin |
| 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 nuerons |
| each branch that connects to the muscle forms a ______ near the center of the cell | neuromuscular junction, or synapse |
| a single motor neuron and all the skeletal muscle fibers it innervates are called a | motor unit |
| many motor units form | a single muscle |
| formed by an enlarged nerve terminal resting in an indentation of the muscle cell membrane | a neuromuscular junction |
| 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 |
| diffuses across the synaptic cleft and binds to the postsynaptic terminal causing a change in the postsynaptic cell | acetylcholine |
| acetylcholine releases into the cynaptic cleft between the neuron and muscle cell is rapidly broken down by | acetylcholineesterase |
| the sliding of actin myofilaments past myosin myofilaments during contaction is called the | sliding filament mechanism of muscle contraction |
| a contraction of an entire muscle in response to a stimulus the causes the action potential in one or more muscle fibers | muscle twitch |
| point at which the muscle fiber will contract maximilly | threshold |
| time between application of a stimulus to a motor neuron and the beginning of a contraction is the | lag phase |
| the time of contraction is the | contraction phase |
| the time during the muscle relaxes is called the | relaxation phase |
| the muscle remains contracted without relaxing | tetany |
| the increase in number of motor units being activated is called | recruitment |
| ATP | adenosine triphosphate |
| atp is needed for | energy for muscle contaction |
| atp is produced in | the mitochondria |
| anaerobic respiration | without oxygen |
| aerobic | 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 creatine 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 |
| 2 types of muscle contraction | isometric and isotonic |
| muscle refers to | constant tension produced by muscles of the body for long periods of time |
| contract quickly and fatigues quickly | fast-twitch fibers |
| contract more slowly and are more resistant to fatigue | slow-twitch fibers |
| the most stationary end of the muscle | origin (head) |
| the end of a muscle undergoing the greatest movement | insertion |
| portion of the muscle between the origin and the insertion | the belly |
| synergists | muscles that work together to accomplish specific movements |
| muscles that work in opposition to one another are called | antogonists |
| occipitofrontalis | raises the eyebrows |
| orbicularis oculi | closes the eyelids and causes "crow's feet" |
| orbicularis oris | puckers the lips |
| buccinator | flattens the cheeks |
| zygomaticus | smiling muscle |
| levator labii superioris | sneering |
| depressor anguli oris | frowning |
| mastication means | chewing |
| 4 pairs of mastication muscles | 2 pair of pterygoids, temporalis, and masseter |
| intrinsic tongue muscles | change the shape of the tongue |
| extrinsic tongue muscles | move the tongue |
| sternocleidomastoid | lateral neck muscle and prime mover. rotates and abducts the head |
| erector spinae | group of muscles on each side of the back |
| flexor carpi | flexes the wrist |
| extensor carpi | extends the wrist |
| flexor digitorium | flexes the fingers |
| extensor digitorium | extends the fingers |
Created by:
samantharuthann