chapter 9: homeostasis Flashcards
homeostasis
a relatively stable, balanced internal environment that is optimized for cellular activities
motivation
psychological process that induces or sustains a particular behavior
endotherms
we make our own heat inside our bodies using metabolism and muscular activity
ectotherms
animals that get their heat from outside the body
negative feedback
process whereby a system monitors its own output and reduces its activity when a setpoint is reached
set point
a point of reference in a feedback system
allostasis
varying behavioral and physiological adjustments that an individual makes in order to maintain optimal functioning of a regulated system in the face of changing environmental stressors
obligatory losses
unavoidable expenditures of bodily resources that must then be regained from the external environment
intracellular compartments
water that is contained within our cells
extracellular compartments
fluid that is outside of our cells, divided between interstitial fluid and blood plasma
diffusion
molecules of a substance (solute) dissolved in another substance (solvent) with move until a uniform concentration is achieved
osmosis
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
physical force that pushes or pulls water across the membrane
osmotic thirst
a desire to ingest fluids that is stimulated by high concentration of solute (salt) in the extracellular compartment
osmosensory neurons
neurons that specifically monitor the concentration of the extracellular fluid
circumventricular organs
monitor the concentration of extracellular fluid
vasopressin
pituitary hormone which acts on the kidneys to slow the production of urine by increasing the reabsorption of water
aldosterone
a mineral cortical hormone, secreted by the adrenal cortex, that promotes the conservation of sodium by the kidneys
hypovolemic thirst
the concentration of the fluid has not changed, salt and ions are also lost
baroreceptors
a pressure receptor in the heart or a major artery that detects a change in blood pressure
angiotensin ll (All)
hormone produced in the blood by the action of renin and that may play a role in the control of thirst
vagus nerve
transmits signals from the viscera to the brain about saltiness of fluid in the gut
nutrients
chemicals required for the effective functioning, growth, and maintenance of the body
glucose
sugar molecule used by the body and brain for energy
glycogen
complex carbohydrates made by combining glucose molecules for short term store of energy
insulin
pancreatic hormone that lowers blood glucose, promotes energy storage, and facilitates glucose utilization by cells
glucagon
converts glycogen back into glucose
lipid
large molecule (usually fay) that consists of fatty acids and glycerol
basal metabolism
energy used for heat production, maintenance
of membrane potentials, and life sustaining processes
diabetes mellitus
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
ventromedial hypothalamus
hypothalamic region involved in sexual behaviors, eating, and aggression
lateral hypothalamus
hypothalamic region involved in the control of appetite and other functions
arcuate nucleus
hypothalamic nucleus implicated in appetite control by integrating peptide hormone signals from several sites in the body
leptid
peptide hormone released by fat cells
ghrelin
synthesized and released by endocrine cells of the stomach, reaches high levels before eating, drops off after eating, works as an appetite stimulant
PYY3-36
released by intestinal cells, reaches high levels after eating, works as an appetite suppressant
glucagon-like peptide 1 (GLP 1)
increased during a meal, suppresses appetite, blocks effects of ghrelin
POMC neurons
act as satiety neurons when activated, inhibiting appetite and increasing metabolism
NPY neurons
act as hunger neurons when activated, stimulating appetite directly and also inhibiting the POMC neurons and reducing metabolism
cholecystokinin (CCK)
peptide hormone that is released from the gut after ingestion of food that is high in protein and/or fat
orexin
neurons of the hypothalamic appetite system that promote feeding bahavior
endocannabinoid
an endogenous ligand of cannabinoid receptors, thus an analog of cannabis that is produced by the brain
enterotype
each individuals personal combination of gut microbiota
hormones
are molecules released by a cell into the bloodstream,
where they can travel throughout the body to target tissues and
bind to their receptors in the tissue, causing some sort of effect
