142 Quiz Flashcards
concentric contraction
muscle shortens in length, total force by active sarcomeres greater than force of load
eccentric contraction
muscle contracts and becomes longer, actively lowering a load, force of load stronger than force of active sarcomeres
isometric contraction
muscle contracts but does not change length, total force is balanced
agonist
prime mover, muscle performing desired reaction
antagonist
capable of opposing the action
tetanus
muscle in maximal state of contraction (summation at max) complete is fused and muscles get no break, forming a plateau.
recruitment
activation of additional motor units to increase muscle strength and force of contraction.
coactivation
both antagonist and agonist, controlled movement or joint stabilization
preload
amount of blood returning to heart from venous circulation, *affected by calcium , if stretches wall of ventricle
afterload
back pressure in arteries preventing blood flow out of the heart, determined by aortic pressure, and diameter of aorta
intropic state/contractility
relative strength of muscle contraction CO=HR*SV (stroke volume)
stroke volume (5-6 L/min is standard, 70 b/min, 80mL)
amount of blood ejected from heart with each individual contraction (depends on preload, afterload, and intropic state
stenosis
narrowing of aorta, raises afterload.
cardiac control center
regulates CO (cardiac output) adjusts HR and SV
ganglion
swelling of neuronal cell bodies
