Glossary Terms

 

action potential - transient all-or-nothing reversal of a membrane potential

 

bradycardia - a reduction in heart rate from the normal level

 

baroreceptor - a sensory nerve ending that is stimulated by changes in pressure, as those in the walls of blood vessels.

 

chemoreceptor - a sensory receptor specifically sensitive to certain molecules

 

conduit - a pipe or channel for conveying fluids

 

depolarization - The reduction or reversal of the potential difference that exists across the cell membrane at rest

 

dorsal - towards the back

 

endothelium - single cell layer forming the internal lining of blood vessels

 

hemocoel - the space between the endoderm and the ectoderm in some invertebrates

 

inferior vena cava - vein that brings blood from the lower portions of the body to the right atrium

 

interstitial fluid - fluid existing between tissues or cells

 

isometric - an absence of volume change of blood in the contraction of the ventricle in the heart

 

pacemaker - an excitable cell or tissue that fires spontaneously and rhythmically

 

posterior - the back of the body

 

proximal - nearer to the attachment of an extremity or nearer to the point of origin

 

pulmonary - pertaining to or affecting the lungs

 

refractory stage - the period during the repolarization of the cell membrane during which the cell cannot generate another action potential.

 

repolarize - the return of resting polarity of a cell membrane that has been depolarized

 

sinuses - spaces surrounding an organ

 

superior vena cava - vein that brings blood from the upper portions of the body to the right atrium

 

systemic - pertaining to or affecting the body

 

threshold - the membrane potential at which votage sensitive sodium gates open, permitting a rapid influx of sodium ions, which results in the depolarization phase of an action potential.

 

ultrafiltration - the process of filtration of colloidal particles by using pressure or suction and a semipermeable membrane

 

vasoconstriction - contraction of circular muscle of arterioles, decreasing their volume and increasing the vascular resistance

 

vasodilation - a widening of the lumen or interior space of the blood vessels, increasing the blood flow.

 

ventral - towards the belly