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A+P muscles

Muscular System

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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