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muscular tissue enables the body and its parts to...

move

muscle cells shorten by converting chemical energy into...

mechanical energy

how many types of muscle tissue exist in the body

3

skeletal muscle is also called

striated or voluntary

what % of body weight is skeletal muscle?

40-50%

skeletal muscle contractions are

voluntarily controlled

what does skeletal muscle look like?

crosswise stripes or striations

what kind of muscle tissue composes the bulk of the heart?

cardiac muscle

which kind of muscle cells branch frequently?

cardiac

which muscle tissue is characterized by dark bands called intercalated disks?

cardiac

cardiac muscle cells allow the heart to contract as a ....

unit

smooth muscle is also referred to as....

nonstriated, involuntary, or visceral muscle

how does smooth muscle appear under a microscope?

smooth

where can one fine smooth muscle?

in walls of hollow visceral structures (such as digestive tract, blood vessels, and ureters)

contractions of smooth muscle are?

involuntary

what is the function of all muscles?

contraction (shortening)

attachment to the bone that remains relatively stationary or fixed when movement at the joint occurs

(parts of a skeletal muscle:) origin

the point of attachment to the bone that moves when a muscle contracts

(parts of the skeletal muscle:) insertion

the main part of the muscle

(parts of the skeletal muscle:) body

skeletal muscles are organs composed of...

skeletal muscle cells and connective tissue

how are muscles attached to bones?

by tendons (cords of fibrous connective tissue; sometimes closed in tendon sheaths)

what is the name of the sac that is located between some tendons and underlying bones?

bursae (synovial lined sac)

contractile cells are also referred to as...

muscle fibers (they are grouped into bundles)

fibers contain...

(thick myofilaments) myosin and (thin myofilaments) actin

basic functional (contractile) units; separated by dark bands (z lines)

sacromere

it explains the mechanism of contraction; thick and thin myofilaments slide past each other as a muscle contracts

the sliding filament model

contraction requires?

calcium and ATP

What are the functions of skeletal muscle?

movement, posture, heat production, and fatigue

how do muscles produce movement?

by pulling on bones as a muscle contracts; (insertion bone is pulled closer to origin bone and movement occurs at the joint between the origin and the insertion)

muscle whose contraction is mainly responsible for producing a given movement

a prime mover

muscle whose contractions help the prime mover produce a given movement

a synergist

muscle whose actions oppose the action of a prime mover in any given movement

an antagonist

what type of muscle contraction allows us to maintain a position?

tonic contraction

tonic contractions maintain muscle tone called?

posture

no movement of body parts and use of only few muscle fibers at one time are ?

tonic contraction

to enable best body functioning....

good posture (optimum body positioning) is favored

skeletal muscle tone maintains posture by?

counteracting the pull of gravity

survival depends on the body's ability to maintain?

a constant body temperature

an elevated body temperature and also a common sign of illness is?

fever

when your body temp is too low

hypothermia

what produces the most amount of heat required to maintain normal body temp?

contraction of muscle fibers

reduced strength or muscle
contraction; not enough rest after repeated muscle stimulation; muscle burning due to inadequate oxygen producing lactic acid; oxygen debt; depleted cellular ATP

fatigue

term used to describe the metabolic effort required to burn excess lactic acid that may accumulate during prolonged periods of exercise

oxygen debt

how to pay the debt?

labored breathing after strenuous exercise

what other body systems are important to muscle functioning?

respiratory, circulatory, nervous, muscular, and skeletal systems

name some exs of pathological conditions in other body organ systems that can dramatically affect movement?

multiple sclerosis, brain hemorrhage, and spinal cord injury

before a muscle can shorten and produce movement it must be stimulated by?

nerve impulse

what is a nerve cell that transmits an impulse to a muscle, causing contraction?

a motor neuron

what is the point of contact between a nerve ending and the muscle fiber it innervates?

a neuromuscular junction

what is the combination of a motor neuron and the muscle cell or cells it innervates?

a motor unit

a muscle will contract only if an applied stimulus reaches a minimal level of intensity...this is called?

threshold stimulus

after the threshold stimulus, a muscle fiber will contract completely...this is referred to as?

all or none

different motor units responding to different threshold stimuli permit a muscle as a whole to execute contractions of....

graded force

individual muscle fibers always respond in an All or None mode....T or F?

true: (fibers do, the muscle as a whole does not)

quick, jerky responses to a stimulus; they are laboratory phenomena and do not play a significant role in normal muscular activity?

twitch contractions

sustained and steady muscular contractions caused by a series of stimuli bombarding a muscle in rapid succession

tetanic contractions

contraction of a muscle that produces movement of a joint; the muscle changes length, causing the insertion end of the muscle to move relative to the point of origin

isotonic contractions

what type of contractions shorten muscles?

concentric

which type of contractions allow a muscle to increase in length?

eccentric

most types of body movements are caused by what type of contraction?

isotonic contractions

muscle contractions that do not produce movement; the muscle as a whole does not shorten; tension in the muscle increases

isometric contractions

what improves muscle tone and posture, results in more efficient heart and lung functioning and reduces fatigue?

exercise

what causes disuse atrophy?

prolonged inactivity

regular exercise increases muscle size...this is called?

hypertrophy

contraction of muscles against heavy resistance is; increase in number of myofilaments in each muscle fiber; total mass of muscle increases; does not increase the # of fibers

strength training

what increases a muscle's ability to sustain moderate exercise over a long period; allows more efficient delivery of oxygen and nutrients to a muscle via increased blood flow; does not result in hypertrophy?

endurance training (aerobic training)

facial muscles

orbicularis oculi, orbicularis oris, and zygomaticus

muscles of mastication

masseter and temporal

what muscle flexes the head?

sternocleidomastoid

what muscle elevates the shoulders and extends the head?

trapezious

what muscle flexes the upper arm?

pectoralis major

what muscle extends the upper arm?

latissimus dorsi

what muscle abducts the upper arm?

deltoid

what muscle flexes the forearm?

biceps brachii

what muscle extends the forearm?

triceps brachii

what are the abdominal muscles?

rectus abdominus, external oblique, internal oblique, and transverse abdominis

what are the respiratory muscles?

intercostal muscles and diaphragm

what muscle flexes the thigh?

iliopsoas

what muscle extends the the thigh?

gluteus maximus

what muscle adducts the thighs?

adductor muscles

what muscle flexes the lower leg?

hamstring muscles (semimembranosus, semitendinosus, and biceps femoris)

what muscle extends the lower leg?>

the quadriceps femoris group (rectus femoris and vastus muscles)

what muscle dorsiflexes the foot?

tibialis anterior

what muscle plantar flexes foot?

gastrocnemius

what muscle flexes the foot?

peroneus group

movement that decreases the angle between two bones at their joint: bending?

flexion

movement that increases the angle between two bones at their joint: straightening?

extension

movement of a part away from the midline of the body?

abduction

movement of a part toward the midline of the body?

adduction

movement around a longitudinal axis?

rotation and circumduction

hand positions that result from rotation of the forearm; hand position with the palm turned to the anterior position

supination

hand positions that result from rotation of the forearm; when the palm faces posteriorly

pronation

foot movements; results in elevation of the dorsum or top of the foot

dorsiflexion

foot movements; the bottom of the foot is directed downward

plantar flexion

muscle disorders; can range from mild to life threatening

myopathies

injury from overexertion or trauma; involves stretching or tearing of muscle fibers; accompanied by myalgia, myositis and fibromyositis

strain ( called a sprain when injury is near a joint and involves ligament damage)

painful muscle spasms (involuntary twitching)

cramps

what injuries result from severe muscle trauma and may release cell contents that ultimately cause kidney failure?

crush injuries

stress induced muscle tension can cause

headaches and back pain

viral infection of motor nerves that ranges from mild to life threatening

poliomyelitis

group of genetic disorders characterized by muscle atrophy?

muscular dystrophy

most common muscular dystrophy characterized by rapid progression of weakness and atrophy; it is x linked affecting mostly boys?

duchenne (pseudohypertrophic) muscular dystrophy

autoimmune muscle disease characterized by weakness and chronic fatigue?

myasthenia gravis

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