chapter 9: homeostasis Flashcards
homeostasis
the active process of maintaining a particular physiological parameter relatively constant
motivation
the psychological process that induces or sustains a particular behavior
endotherm
an animal whose body temperature is regulated chiefly by internal metabolic processes (mammals, birds)
ectotherm
an animal whose body temperature is regulated by, and whose heat comes mainly from, the environment (snakes, bees)
negative feedback
the property by which some of the output of a system feeds back to reduce the effect of input signals
set point
the point of reference in a feedback system; like the temperature at which a thermostat is set
set zone
the range of a variable that a feedback system tries to maintain
intracellular compartment
the fluid space of the body that is contained within cells
extracellular compartment
the fluid space of the body that exists outside the cells
diffusion
the spontaneous spread of solute molecules through a solvent until a uniform solute concentration is achieved
osmosis
the passive movement of a solvent, usually water, through a semipermeable membrane until a uniform concentration of solute (often salt) is achieved on both sides of the membrane
osmotic pressure
the tendency of a solvent to move across a membrane in order to equalize the concentration of solute on both sides of the membrane
hypovolemic thirst
a desire to ingest fluid that is stimulated by a reduction in volume of the extracellular fluid
osmotic thirst
a desire to ingest fluids that is stimulated by loss of water from the extracellular compartment
baroreceptor
a pressure receptor in the heart or a major artery that detects a change in blood pressure
atrial natriuretic peptide (ANP)
a hormone, secreted by the heart, that normally reduces blood pressure, inhibits drinking, and promotes the excretion of water and salt at the kidneys
arginine vasopressin
a peptide hormone from the posterior pituitary that promotes water conservation and increases blood pressure; also called antidiuretic hormone
angiotensin II
a hormone that is produced in the blood by the action of renin and that may play a role in the control of thirst
circumventricular organ
any of multiple distinct sites that lie in the wall of a cerebral ventricle and monitor the composition of the cerebrospinal fluid
aldosterone
a mineralocorticoid hormone, secreted by the adrenal cortex, that promotes the conservation of sodium by the kidneys
nutrient
a chemical that is needed for growth, maintenance, and repair of the body but is not used as a source of energy
glucose
an important sugar molecule used by the body and brain for energy
glycogen
a complex carbohydrate made by the combining of glucose molecules for a short-term store of energy
insulin
a pancreatic hormone that lowers blood glucose, promotes energy storage, and facilitates glucose utilization by cells
glucagon
a pancreatic hormone that converts glycogen to glucose, and thus increases blood glucose
lipid
a large molecule (commonly called fat) that consists of fatty acids and glycerol that are insoluble in water
adipose tissue
tissue made up of fat cells; fat tissue
ketone
a compound, liberated by the breakdown of body fats and proteins, that is a metabolic fuel source
basal metabolism
the consumption of energy to fuel processes such as heat production, maintenance of membrane potentials, and all the other basic life-sustaining functions of the body
diabetes mellitus
a condition, characterized by excessive glucose in the blood and urine and by reduced glucose utilization by body cells, that is caused by the failure of insulin to induce glucose absorption
glucodetector
a specialized type of liver cell that detects and informs the nervous system about levels of circulating glucose
ventromedial hypothalamus (VMH)
a hypothalamic region involved in eating and sexual behaviors
lateral hypothalamus (LH)
a hypothalamic region involved in the control of appetite and other functions
arcuate nucleus
an arc-shaped hypothalamic nucleus implicated in appetite control
leptin
a peptide hormone released by fat cells
ghrelin
a peptide hormone produced and released by the gut
PYY3-36
a peptide hormone, secreted by the intestines, that probably acts on hypothalamic appetite control mechanisms to suppress appetite
NPY neuron
a neuron, involved in the hypothalamic appetite control system, that produces both neuropeptide Y and agouti-related peptide
POMC neuron
a neuron, involved in the hypothalamic appetite control system, that produces both pro-opiomelanocortin and cocaine- and amphetamine-related transcript
orexin
a neuropeptide produced in the hypothalamus that is involved in the switching between sleep states, in narcolepsy, and in the control of appetite; also called hypocretin
nucleus of the solitary tract (NST)
a complicated brainstem nucleus that receives visceral and taste information via several cranial nerves
cholecystokinin (CCK)
a peptide hormone that is released by the gut after ingestion of food that is high in protein and/or fat
endocannabinoid
an endogenous ligand of cannabinoid receptors; thus, a marijuana analog that is produced by the brain
liposuction
the surgical removal of fat tissue
bariatric
having to do with obesity
anorexia nervosa
a syndrome in which individuals severely deprive themselves of food
bulimia nervosa
a syndrome in which individuals periodically gorge themselves, usually with “junk food,” and then either vomit or take laxatives to avoid weight gain
binge eating
the rapid intake of large quantities of food, often poor in nutritional value and high in calories
