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