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Anatomy Chapter 19 Mucular system
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Antagonistic pairs of muscles
when one muscle moves in one direction, its antagonist moves in the opposite direction
Synergistic pairs
muscles work together to bring about movement.
Muscle tone
partial contraction of muscle.
-Unconscious action
-Keeps muscles in a constant state of readiness
-Dictates posture
Tonus
Slight tension in the muscle that is always present, even when at rest.
Flacid (atonic)
used to describe someone when muscle tone is lacking
Adenosine Triphosphate (ATP)
a chemical used in muscle contraction.
Lactic Acid
a waste product resulting from breakdown of ATP
-causes the tired and sometimes burning feeling of muscle fatigue.
Muscle Structure
bundles of long muscle fibers
-contract (shorten) when stimulated
-relax (return to their original position) when stimulus subsides.
Fascia
a fibrous sheath that covers, supports, and separates muscles.
-Contains the muscle's blood, lymph, and nerve supply.
Myoglobin
a red pigment in muscles
Tendon
attaches muscles to bone.
Achilles tendon
strongest tendon in the body
Hamstrings
tendons located behind the knee.
-Responsible for extending the hips and flexing the knees.
Aponeurosis
a wide, flat connective tissue that connects muscle to bone
Neuromuscular junction
Where the muscle fiber and nerve ending meet
-where synapse occurs
Acetylcholine
released at the neuromuscular junction.
-used by the nerve endings to send an impulse across the synapse to the muscle.
-causes muscle to contract.
Cholinesterase
breaks down excess acetylcholine and stops overstimulation of muscle.
Isotonic contraction
when a muscle shortens and thickens as it contracts.
-happens when you life a heavy object.
Isometric contraction
muscle length does not change but muscle tension increases
-happens when pushing against an immovable object, like a wall.
Twitch
jerky response to a stimulus
Tetany
abnormal contraction of muscle caused by “rapid fire” impulses.
voluntary muscles
-skeletal muscles
-striated- have light and dark bands of fiber
involuntary muscle
-smooth- makes up most organs of body
-cardiac- in heart
-appears striated under microscope
Contractility
ability of a muscle to shorten and thicken upon stimulus.
Extensibility
The ability of a muscle to stretch
Elasticity
ability of a muscle to return to its original length after stretching
Irritability
ability of a muscle to respond to stimulation.
Prime mover
muscle responsible for movement when a group of muscles is contracting at the same time
Fixator
specialized synergists that stabilize the nonmoving part of a prime mover
Origin
where a muscle begins or is attached to a bone.
-a fixed attachment
Insertion
where a muscle ends
-more movable.
Deltoid
shoulder muscle that looks like an upside down delta.
Abductor
muscle that moves a bone away from midline.
Adductor
muscle that moves a bone toward the midline.
Levator
muscle that lifts a bone.
Depressor
muscle that lowers a bone
Flexor
muscle that bends a joint
Extensor
muscle that straightens a joint
Rotator
muscle that moves a joint on its axis
Sphincter
a ringlike muscle that closes an opening
Strain
overstretching or tearing of muscle fibers
Sprain
stretching or tearing of a ligament or joint
Myalgia
muscle pain
Hernia
when a visceral organ bulges through a weakness in a muscular wall.
Torticollis (wryneck)
causes head to tilt to affected side
Author
lorikuzma
ID
70050
Card Set
Anatomy Chapter 19 Mucular system
Description
Mucular system
Updated
2011-03-02T03:33:41Z
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