AP Ch 8 Muscles

Skeletal Muscle

called striated or voluntary muscle; appear in bundles; crosswise stripes or striations; 40-50% of body weight

Origin

the insertion bone moves toward the what bone

Orbicularis Oris

the kissing muscle, puckers the lips

Oxygen Debt

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

Threshold Stimulus

the minimal level of stimulation required to cause a muscle to contract

Insertion

the muscles attachment to the more movable bone is called it's...

Origin

the muscles attachment to the more stationary bone is called it's...

Motor Neuron

the nerve cell that transmits an impulse to a muscle causing contraction

Muscular Dystrophy

a group of genetic diseases characterized by atrophy of skeletal muscle tissues; Duchenne most common

Supination

a hand position with the palm turned to the anterior position

Motor Unit

a single motor neuron with the muscle cells it innervates is called a...

Poliomyelitis

a viral infection of the nerves that control skeletal muscle movement

Tendons

anchor muscles firmly to bones; made of dense fibrous connective tissue; lubricated by synovial fluid

Antagonists

as prime movers and synergist muscles at a joint contract, what other muscles relax

Myasthenia Gravis

autoimmune muscle disease characterized by weakness and chronic fatigue

Sarcomere

basic functional unit of skeletal muscle

Plantar Flexion

bottom of the foot is directed downward so standing on toes

Zygomaticus

elevates the corners of the mouth and lips, known as the smiling muscle

Trapezius

elevates the shoulders and extends head backward

Muscle Fibers

elongated contractile cells of muscle tissue; grouped into bundles and intricately arranged

Endurance Training

increases a muscles ability to sustain moderate exercise over a long period; sometimes called aerobic training

Strain

injury from overuse or overextension; involves stretching or tearing of muscle fibers

Sprain

injury is near a joint and involves ligament damage

Cardiac Muscle

involuntary muscle; has striations; muscle cells branch frequently; characterized by unique dark bands called intercalated disks

Sternocleidomastoid

located on anterior surface of neck and flexes the head

Tibialis Anterior

located on the anterior, or front, surface of the leg; it dorsiflexes the foot

Abduction

means moving a part away from the midline of the body such as moving arm out to the side

Adduction

means moving a part toward the midline such as bringing arms down to side from elevated position

Myofilaments

microscopic threadlike structures found in skeletal muscle fibers

Hamstring Muscles

muscles that flex lower leg; includes bicep femoris

Smooth Muscle

nonstriated, involuntary and visceral; part of blood vessel walls and hollow internal organs such as digestive tract and ureters

Pronation

occurs when you turn the palm of your hand so that it faces posterior

Temporal

one of the mastication muscles that assists in closing the jaw

Masseter

one of the mastication muscles that elevates the mandible

Myoglobin

red oxygen storing pigment similar to hemoglobin contained in muscle fibers

Tonic Contraction

we are able to maintain our body posture because of a specific type of skeletal muscle contraction called...

Muscular Atrophy

what is the term for decrease and weakness of muscle

Oxygen Debt, Lactic Acid and Muscle Fatigue

what three things happen during strenuous exercise

Quadriceps Group

muscles that extend lower leg

Relaxation

elongation of a muscle is...

True

T or F a weight lifter has larger muscle cells

Adductor Muscles

muscles that adduct thighs

Tetanic Contraction

contraction produced by a series of stimuli bombarding the muscle in rapid succession

Isotonic Contraction

contraction that produces movement at a joint; the muscle changes length; insertion end moves relative to point of origin

Dorsiflexion

dorsum, or top, of foot is elevated with toes pointing upward

Disuse Atrophy

during prolonged inactivity muscles shrink in mass, condition called...

Rotation and Circumduction

movement around a longitudinal axis

Extension

movement that makes the angle between two bones at their joint larger than it was at beginning of movement; straightening

Flexion

movement that makes the angle between two bones at their joint smaller than it was at beginning of movement; bending

Functions of Muscles

movement, posture and heat production

Isometric Contraction

muscle contractions that do not produce movement; the muscle as a whole doesn't shorten; tension within muscle increases

Myopathies

muscle disorders; can range from mild to life threatening

Deltoid

muscle that abducts upper arm; surrounds shoulder joint

Triceps Brachii

muscle that extends forearm

Gluteus Maximus

muscle that extends thigh

Latissimus Dorsi

muscle that extends upper arm; large muscle on (mid) lower back

Biceps Brachii

muscle that flexes forearm

Pectoralis Major

muscle that flexes the upper arm

Iliopsoas

muscle that flexes thigh

Gastrocnemius

muscle that plantar flex foot; known as calf muscle

Antagonist

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

Prime Mover

muscle whose contraction is mainly responsible for producing a given movement

Synergist

muscle whose contractions help the prime mover produce a given movement

Contraction

shortening of a muscle is..

Bursae

small synovial lined sacs containing small amount of synovial fluid; located between some tendons and underlying bones

Neuromuscular Junction

the point of contat between the nerve ending and the muscle fiber is called a...

Myosin

thick myofilaments are formed from what protein

Actin

thin myofilaments are formed from what protein