PSYB64 Physiological Psychology
Chapter 9 Vocabulary Terms
homeostasis: A physiological state of equilibrium or balance.
set point: A value that is defended by regulatory systems, such as core temperature or a particular body
motivation: The process of activating and directing behavior.
endotherm: An animal that can use internal methods, such as perspiration or shivering, to maintain
ectotherm: An animal that relies on external methods, such as moving into the sun or shade, for
maintaining body temperature.
fever: A carefully controlled increase in the body’s thermal set point that is often helpful in ridding the
body of disease-causing organisms.
pyrogen: A chemical produced by bacteria or viruses that contributes to the production of a fever
hyperthermia (heat stroke): A life-threatening condition in which core body temperature increases
beyond normal limits in an uncontrolled manner.
hypothermia: A potentially fatal core body temperature below 31 degrees C/87.8 degrees F.
preoptic area (POA): A part of the hypothalamus involved in a number of regulatory functions.
solute: A chemical dissolved in solution.
solution: A fluid containing solutes.
electrolyte: A substance that has broken up into ions in solution.
interstitial fluid: A type of extracellular fluid surrounding the body’s cells.
isotonic: Having the same concentration of solutes as a reference solution.
osmosis: The movement of water to equalize concentration on two sides of a membrane.
hypotonic: Having a relatively lower concentration of solutes than a reference solution.
hypertonic: Having a relatively higher concentration of solutes than a reference solution.
kidney: One of a pair of structures located in the lower back responsible for maintaining fluid balance
and for producing urine.
osmotic thirst: Thirst produced by cellular dehydration.
hypovolemic thirs:t Thirst that results from a decrease in the volume of the extracellular fluid.
diabetes mellitus: A disease characterized by insulin deficiency, resulting in hunger, excess sugar in
blood and urine, and extreme thirst.
osmoreceptors: A receptor that detects cellular dehydration.
organum vasculosum of the lamina terminalis (OVLT): An area located around the third ventricle in
the brain that detects cellular dehydration.
baroreceptor: A receptor in the heart and kidneys that measures blood pressure.
antidiuretic hormone (ADH): A hormone that promotes retention of fluid by signaling the kidneys to
reduce urine production and by stimulating the release of renin. Also known as vasopressin.
vasopressin: Another name for antidiuretic hormone (ADH).
renin: A substance released by the kidneys that converts angiotensinogen into angiotensin II.
angiotensinogen: A blood protein converted into angiotensin II by renin.
angiotensin II: A hormone that constricts blood vessels to maintain blood pressure and triggers the
release of aldosterone.
aldosterone: A hormone that signals the kidneys to retain sodium.
subfornical organ (SFO): An area of the brain, located near the junction of the two lateral ventricles,
that regulates drinking.
median preoptic nucleus: An area of the hypothalamus that is involved with drinking behavior.
nucleus of the solitary tract (NST): A structure in the medulla that pr