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muscle anatomy
muscles
| Question | Answer |
|---|---|
| the ability of skeletal muscle to shorten with force | contractility |
| the capacity of skeletal muscle to respond to a stimulus | exciteability |
| the ability to be stretched | extensibility |
| 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 called the ? | epimysium |
| what is another connective tissue located outside the epimysium?it surrounds and seperates muscles. | fascia |
| a muscle is composed of numerous visible bundles called muscle fasciculi, which are surrounded by loose connective tissue called the ? | perimysium |
| the fasciculi are composed of single muscle cells called ? | fibers |
| each muscle fiber is a single cylindrical cell containing several ? | nuclei |
| each fiber is surrounded by a connective tissue sheath called the ? | 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 ? | actin and myosin myofilaments |
| thin myofilaments. they resemble 2 minute strands of pearls twisted together...... | actin myofilaments |
| thick myofilaments. they resemble bundles of minute golf clubs.... | myosin myofilaments |
| actin and myosin myofilaments for highly ordered units called ? | sarcomere |
| these are joined end to end to form the myofibril? | sarcomere |
| the basic structural and functional unity of the muscle ? | sarcomere |
| each sarcomere extends from one z line to another. each z line is an attachment site for ? | actin |
| the arrangement of actin and myosin give a ________ appearance? | banded |
| on each side of the z line is a light area called an I band, it consists of ? | actin |
| the A band extends the length of the ? | myosin |
| the _ ____ is the darker central region in each sarcomere | a band |
| in the center of each sarcomere is another light area called the _ ____? | h zone |
| the h zone consists of ? | myosin |
| myosin mmyofilaments are anchored in the center of the sarcomere at a dark staining band called the _ ____? | m line |
| the change difference across the membrane is called the ? | resting membrane potential |
| when a muscle cell is stimulated the membrane characteristics change briefly. the brief reversal back of the charge is called _____? | action potential |
| nerve cells that carry action potentials to skeletal muscle fibers ? | motor neurons |
| axons enter the muscled and branch. each branch that connects to the muscle forms a ? | neuromuscular junction |
| a single motor neuron and all the skeletal muscle fibers it innervates are called ? | a motor unit |
| many motor units form a ? | single muscle |
| a __________ is formed by an enlarged nerve terminal resting in an indentation of the muscle cell membrane. | 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 between the presynaptic terminal and the muscle cell is the ? | postsynaptic terminal |
| each presynaptic terminal contains ? | synaptic vesicles |
| synaptic vesicles secrete a neurotransmitter called ? | acetylcholine |
| what diffuses across the snyaptic cleft and binds to the postsynaptic terminal causing a change in the postsynaptic cell ? | acetylcholine |
| the acetylcholine released into the synaptic cleft between the neuron and muscle cell is rapidly broken down by an enzyme called? | acetylcholinesterase |
| what occurs when actin and myosin myofilaments slide past one another causing the sarcomeres to shorten? | muscle contraction |
| when the ________ shortens it causes the muscle to shorten. | sarcomere |
| the sliding of actin myofilaments past myosin myofilaments during contraction is called ______? | sliding filament mechanism |
| contraction of the entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers. | muscle twitch |
| a muscle will not respond to a stimulus until that stimulus reaches a level called ? | threshold |
| when _____ occurs the muscle fiber will contract maximally | threshold |
| when the muscle fiber contracts maximally this phenomenon is called ? | all or none response |
| the 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 which the muscle relaxes is the ? | relaxation phase |
| where the muscle doesn't have time to fully relax? | tetany |
| the increase in number of motor units being activated is called ? | recruitment |
| the portion of the muscle between the origin and the insertion is the ? | belly |
| these contract quickly and fatigue quickly | fast twitch fibers |
| these contract more slowly and are more resistant to fatigue | slow twitch fibers |
| the most stationary end of the muscle | origin |
| the end of the muscle undergoing the greatest movement? | insertion |
| points of attachment of each muscle are? | origin and insertion |
| at these attachment points, the muscle is connected to the bone by the ? | tendon |
| some muscles have multiple ? | origins and heads. |
| this refers to constant tension produced by muscles of the body for long periods of time? | muscle tone |
| isometric | equal distance |
| isotonic | equal tension |
| this results when atp is used during muscle contraction faster than it can be produced in the muscle cells | muscle fatigue |
| 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 |
| when at rest muuscles can't stockpile atp but they can store another high energy molecule... | creatine phosphate |
| anaerobic respiration | without oxygen |
| aerobic respiration | with oxygen |
| muscles that work together to accomplish specific movements are called ? | synergists |
| muscles that work in opposition to one another are called ? | antagonists |
| among a group of synergists, if one muscle plays the major role in accomplishing the desired movement, it is called the ? | prime mover |
| occipito frontalis | raises the eyebrows |
| orbicularis occuli | closes the eye lid |
| orbicularis oris | puckers lips |
| buccinator | flattens the cheeks |
| zygomaticus | smiling muscle |
| levator labii superioris | sneering |
| depressor anguli oris | frowning |
| chewing | mastication |
| four chewing muscles | temporalis, masseter, & 2 types of pterygoids |
| kissing muscles ? | orbicularis oris & the buccinator |
| what happens at a neuromuscular junction? | a chemical referred to as a neurotransmitter is released |
| what muscles are involved in mastication? | buccinator, masseter, and the temporalis |
| what are intrinsic tongue muscles? | the intrinsic tongue muscles lie entirely within the tongue. & also alter the shape of the tongue for talking and swallowing |
| what are extrinsic tongue muscles? | they attach the tongue to other structures... they reposition the tongue |
| what do muscles help produce that is essential for the maintenance of normal body temperature | heat |
| what are the four major muscle characteristics ? | contractility, excitability, extensibility, elasticity |
| what is the location of the skeletal muscles | attached to the bones, or some facial muscles are attached to the skin. |
| what is the location of cardiac muscles ? | they are found in the walls of the heart |
| what is the location of smooth muscles? | they are mostly found in walls of hollow visceral organs |
| what are the three types of muscles? | skeletal, smooth, and cardiac |
| the unique characteristic that sets muscles apart from other body tissue? | contraction, or shortening |
| skeletal muscle is also known as? | striated muscle or voluntary muscle |
| what are the four muscle functions? | produces movement, maintains posture, stabilizes joints, and generated heat |
| specialized smooth endoplasmic reticulum | sarcoplasmic reticulum |
| irritability | ability to recieve and respond to a stimulus |
| graded responses | the way muscles react to stimuli |
| if tthe nerve supply to a muscle is destroyed, the muscle? | loses tone and becomes paralyzed. |
| flexion | movement generally in the sagittal plane |
| extension | movement that increases the angle or distance between two bones |
| rotation | movement of a bone around its longitudinal axis |
| abduction | moving a limb away from the midline |