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A+P muscles
Muscular System
| Question | Answer |
|---|---|
| muscle | one of four basic tissues of the body, made up of cells that can shorten or cnotract. |
| the three different types od muscle | skeletal muscle, cardiac muscle, smooth muscle |
| tendons | fibrous connective tissue bands |
| aponeuroses | sheets of fibrous connective tissue |
| origin of muscle | more stable site of muscle attachment |
| insertion of muscle | site that undergoes most of the movement when a muscle contracts |
| prime mover (agonist) | muscle or muscle group that directly produces a desired movement |
| antagonist | muscle of muscle group that directly opposes the action of a prime mover |
| synergist | muscle that contracts at the same time as a prime mover and assists it in carrying out its action. |
| fixator | muscles stabilize joints to allow other movements to take place |
| action | flexor muscles ie extensor muscles |
| shape | deltoid means triangular |
| location | ie biceps brachii muscle is located in the brachila region |
| direction of fibers | rectis means straight |
| number of heads or divisions | -cep means head, biceps brachii muscle has two heads |
| attachment sites | origin of the sternocephalicus msucle is the sternum, and its insertion is the back of the head. |
| cutaneous muscles | thin, broad, and superficial and serve only to twitch the skin |
| head and neck muscles | control facial expressions, enable chewing (mastication), move sensory structures, such as the eyes and ears. |
| what do the muscles of the neck help support? | the head and allow the neck to flex, extend, and move the head laterally. |
| masseter muscle | closes the jaw. |
| what two main muscle extend the head and neck? | splenius and trapezius |
| brachiocephalicus muscle | extends the head and the neck and also pulls the front leg forward |
| sternocephalicus muscle | flex the head and neck |
| abdominal muscles | support the abdominal organs, gelp flex the back, participate in various functions that involve straining, play a role in respiration, are arranged in layers. |
| the arrangement of the abdominal muscles layers | external abdominal oblique muscle, internal abdominal oblique muscle, rectus abdominis muscle, transverus abdominis msucle |
| what comes together on the ventral midline at the linea alba? | left and right parts of each muscle |
| superficial muscles of the shoulder region | latissimus dorsi muscle, pectoral muscles, deltiod muscle |
| latissimus dorsi muscle | flexes the shoulder, pectoral muscles, one superficial one deep (adductors of the front leg) |
| deltoid muscle | abducts and flexes the shoulder joint |
| biceps brachii muscle | flexes the elbow joint |
| triceps brachii muscle | extends the elbow joint |
| extensor carpi radialis | extends the carpus |
| deep digital flexor | flexes the digit |
| which muscles group extensor muscles of the hip joint | gluteal and hamstring muscles |
| hamstring muscles | flexors of the stifle joint |
| three muscle of hamstring muscles | biceps femoris muscle, semimembranosus muscle, semitendinosus muscle |
| quadriceps femoris muscle | main extensor muscle of the stifle joint |
| gastrocnemius muscle | extends the hock (ankle) |
| muscles of respiration | increase and decrease the size of the thoracic cavity |
| inspiratory muscles | diapragm and external intercostal muscles |
| expiratory muscles | internal intercostal muscles and abdominal muscles |
| expiration | pushing air out of the lungs |
| skeletal muscle cells | huge, threadlike or fiberlike shape, have mutiple nuclei, contain hundreds or thousands of myofibrils packed together lengthwise composed of protein filaments. |
| organelles between myofibrils in a muscle fiber include | network of sacroplasmic reticulm, T tubules |
| (thin) actin and (thick) myosin | are the two proteins that make up the filaments in the myofibrils |
| A band | dark band, thick myosin filaments |
| I band | light band, thin actin filaments |
| Z line | dark line in the center of the I band |
| * sarcomere | disk that is the attachment site for the actin filaments, area from one Z line to the next Z line, the basic contracting unit of skeletal muscle |
| * What is each myofibril made up of? | many sarcomeres lined up end to end |
| neoromuscular junction | skeletal muscle recieves nerve impulses, where the ends of motor nerve fibers connect to muscle fibers |
| what happens if a nerve supply is interrupted for a lengthy period? | as a result of injury, the muscle will shrink down through atrophy |
| syanptic space | very small space, exists between the end of the nerve fiber and the sarcolema |
| synaptic vesicles | tiny sacs, within the end of a nerve fiber, contain the chemical neurotransmitter, acetylcholine |
| acetylcholine | leads to the contraction of the muscle |
| acetylcholinesterase | enzyme in the synaptic space, removes the acetylcholine (ends effect on that nerve impulse) |
| motor unit | one nerve fiber and all the muscle fibers it innervates |
| muscles that position the eyes | make very small delicate movements |
| muscles that position the eyes have how many muscle fibers | only a few per nerve fiber in each motor unit |
| how many motor units may large powerful muscles have? | hundred or more muscle fibers per motor unit |
| connective tissue layers | exert a lor of force, securely fastneed to the structures (usually bones) they move. |
| endomysium | surrounds skeletal muscle, composed of fine reticular fibers |
| fasicles | groups of skeletal muscle fibers |
| perimysium | tougher connective tissue that bounds fasciles together, composed of reticular fibers and thick collagen fibers. |
| epimysium | fibrous connective tissue surrounds groups of muscle fasicles, composed of tough collagen fibers |
| what are connective tissue layers continuous with? | the tendons or aponeuroses that connect muscle to bones or other muscles |
| connective tissue layers hold muscle firmly together and? | contain the blood vessesls and nerve fibers that supply the muscle fibers |
| when is acetylcholine released into the synaptic space ? | when a nerve impulse comes down a motor nerve fiber and reaches the end bulb |
| where do acetylcholine molecules bind? | to receptors on the surface of the sarcolemma (cell membrane) |
| what happens after acetylcholine molecules bind? | impulse that travels along the sarcolemma and through the T tubules to the interior of the cell wall |
| what does it cause when the impulse reaches the sarcoplasmic reticulum? | the release of stored calcium ions (Ca++) into the sarcoplasm |
| what turns on the contraction process? | when Ca++ diffuses into the myofibrils |
| contraction process | sarcoplasmic reticulum releases its Ca++ then starts pumping it back in again. This pulls the Ca++ out of the myofibrils, contraction process shuts down restores it to its original length |
| muscle contraction and muscle relaxation both require? | energy |
| when a muscle fiber is in a relaxed state what happens? | actin and myosin filaments overlap a little |
| when fibers are stimulated to contract.. | small levers on the myosin filaments, cross briges, racthet back and forth pull the actin filaments, shortening the sarcomere |
| shortening all the end-to-end sarcomeres in a muscle fiber result in? | muscle contraction |
| all-or-nothing principle | an individual muscle fiber either contracts completely, or does not contract at all |
| nervous system controls? | the number of muscle fibers it stimulates for a particular movement |
| to contract small fine movements require? | a few muscle fibers |
| to contract larger more powerful movement require? | the contraction of many muscle fibers |
| muscle contraction three phases | 1 latent phase 2 contracting phase 3 relaxation phase |
| latent phase | brief hesitation between the nerve stimulus and the beginning of the actual contraction, lasts anout 10ms |
| contracting phase | last 40ms |
| relaxation phase | last 50ms |
| maximum contraction efficiency occurs? | if nerve impulses arrive about 0.1 second apart, and results in a series of complex muscle fiber twitches |
| how do muscles contract smoothly? | by carefully timing of the nerve impulses to motor units of the muscle |
| ATP is tha energy source that? | powers the sliding of the actin and myosin filaments |
| creatine phosphate | converts ADP back to ATP |
| thr source of energy used to produce ATP and CP are? | glucose and oxygen |
| how is glucose stored in the fibers? | as glycogen |
| how is oxygen stored in the fibers? | as myoglobin |
| aerobic metabolism | oxygen supply is adequate to keep up with the energy needs of the fiber, and maximum amount of energy is extracted from each glucose molecule |
| anaerobic metabolism | particulary during periods of strenuous activity, the need for oxygen exceeds the available supply and muscle fibers must shift |
| anaerobic metabolism is not as efficient as aerobic metabolism and results in? | lactic acid formation |
| what causes discomfort? | lactic acid accumulation |
| what is energy produced in muscles? | heat |
| how is heat excess eliminated? | by panting/sweating |
| shivering | increase production of heat in spasmodic muscle contractions |
| cardiac muscle | form branching networks, are smaller, have one nucleus per cell |
| intercalated disks | attachments between cardiac muscle cells, transmit impulses from cell to cell to allow large groups of cardiac muscle cells to contract in a coordinated manner |
| how do networks of cardiac muscle cells around the cardiac chambers function? | as is they were each a large single unit instead of a whole bunch od individual cells |
| how do cardiac muscles contract? | w/o any external stimulation, groups of cardiac muscle cells adopt the contraction rate of the most rapid cell in the group, in a rapid wavelike fashion |
| what functions like a "mini nervous system"? | the role of the heart's internal impluse conduction system |
| SA sinoatrial node | "pacemaker" impulse that starts each heartbeat, located in the wall of the right atrium |
| what does the heart impulse follow? | a controlled path through the conduction system of the heart, structures in the system transmit, delay, and redirect |
| where are the nerves to the heart from? | (autonomic nervous system) sympathetic and parasympathetic system |
| sympathetic fibers | stimulate the heart to beat harder and faster as a part of the fight-or-flight response |
| parasympathetic fibers | inhibit cardiac function, causing the heart to beat more slowly and with less force |
| smooth muscle | nonstriated involuntary muscle, veyr different from the other two types of muscles, small spindle shaped, single nucleus |
| two main forms of smooth muscle | visceral smooth muscle and multiunit smooth muscle |
| visceral smooth muscle | large sheets of cells in the walls of some hollow organs |
| multiunit smooth muscle | small, discrete groups of cells |
| actin and myosin filaments in smooth muscle? | actin and myosin filaments crisscross the cell at various angles and are attached at both ends to dense bodies that correspond to the Z lines of skeletal muscle |
| visceral smooth muscle | found in the walls of many internal organs (ie stomach, intestine, uterus, urinary bladder) large, rhythmic waves of contraction |
| visceral smooth muscle contractions | peristalic, parturition |
| how does visceral smooth muscle contract? | w/o need for external stimulation, reacts to streching by contracting more strongly |
| visceral smooth muscle nerve supply consists of? | sympathetic and parasympathetic divisions |
| sympathetic stimulation | decreases activity |
| papsympathetic stimulation | increases activity |
| multiunit smooth muscle | individual smooth muscle cells/small groups of cells, found where small delicate contractions are needed (ie iris of the eye, walls of small blood vessels) |
| contractions of multiunit smooth muscle are not ? | automatic, needs external stimulation |
| what does contractions of multiunit smooth muscle require? | specific impulses from autonomic nerves to contract (from external stimuli), specific and carefully controlled |
Created by:
Marilyn:)
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