Anatomy and Physiology Muscular System

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How much of the body is made up of muscle?

About 40%

antagonists and synergists?

Antagonists: directly oppose prime movers Synergists: muscles that contract at the same time as the prime mover

Thin filaments and thick filaments are the?

actin; myosin

What is the role of calcium ions (Ca++) in muscle contraction

binds troponin molecules in the thin filaments; initiates the chemical reactions that produce a contraction

Identify the *connective tissue membrane that covers individual muscle fibers, *the membrane that surrounds groups of skeletal muscle fibers (fascicles), and *the membrane that covers the muscle as a whole

endomysium; perimysium; epimysium

Name the type of muscles that generally function as joint stabilizers

fixator muscles

What muscle type helps maintain overall body posture when prime movers produce motion in the extremities

fixator muscles

what is the action of the sternocleidomastoid muscle

flexes the head

Name some features of the muscle cell that are not found in other types of cells

increase of mitochondria, presence of T tubules (brings the nerve impulse go all the way through the muscle fiber), contains myofibrils (has sarcomeres), several nuclei

Name the skeletal muscles that produce respiratory movements

internal (exhale) intercostal muscles, external (inhale) intercostal muscles and diaphragm

What is the difference between isotonic and isometric contractions? Concentric and eccentric?

isotonic- "the same" "tension" changing the length of the muscle isometric- "the same" "length" contracting the muscle not changing the length concentric- when the muscle shortens during the movement eccentric-occurs when the contracting muscle lengthens

Why is the traid relationship between T tubules and the SR important

it is important because it allows an electrical impulse traveling along a T tubule to stimulate the membranes of adjacent sacs of the SR

What are the three major functions of the skeletal muscles

movement, heat production (produce heat through respiration of cells; large part in homeostasis), posture (the continued partial contraction of many muscles makes this possible)

What group of muscles facilitates chewing movements

muscles of mastication

What is the perineum?

muscles of the pelvic floor in the anal triangle

Which muscle of facial expression has two parts, one lying over the forehead and the other covering the back of the skull

occipitofrontalis

Identify the point of attachment of a muscle to a bone that *does not move when the muscle contracts and one that *does move when the muscle contracts

origin; insertion

What causes the striations observed in the skeletal muscle fibers

overlapping thick and thin filaments

Name three types of fiber arrangements seen in skeletal muscle

parallel, convergent (coverage to narrow attachment), pennate (oblique [single father]), bipennate (double feather), sphincter (circular)

What name is used to describe a muscle that directly performs a specific movement

prime mover

Name the tough connective tissue cord that serves to attach a muscle to a bone

tendon sheaths

Describe the structure of thin and thick myofilaments, and name the kinds of proteins that compose them

thin filament- actin: troponin and tropomyosin thick filament- myosin: "doubled" heads

What is the neuromuscular junction (NMJ) and how does it work

type of connection called a synapse and is characterized by a narrow gap (synaptic claft) across which neurotransmitter molecules transmit signals


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