Homeostasis 3.27.2025 Flashcards
Homeostasis
a relatively, balanced internal enviornment that is optimized for cellular activites
Allostasis
the varying behavioral and physiological adjustments than an individual makes in order to maintain optimal (rather than unchanging) functioning of a regulated system system in the face of changing enviornmental stressors
Intracellular compartment
fluid part of the body contained within cells
Extracellular compartment
the fluid in the space outside of cells, divided between interstital fluid and blood plasma
Water movement
Diffusion
molecules of a substance (solute) dissolved in another substance (solvent) will move until a uniform concentration is achieved
Water movement
Osmosis
passive movement of solvent through a semipermeable membrane between solutions of different solute concentration until both sides become equal
Osmotic pressure
the force that pushes or pulls water across the membrane
Baroreceptors
in blood vessels and the heart detect a drop in pressure
Vasopressin
induces blood vessel constriction and slows the production of urine
hormone
Angiotensin II
regulating blood pressure and fluid balance, causing basoconstricting which stimulates aldosterone release for sodium and water retention and influencing thirst and salt appetite, triggered in the kidneys due to decreased blood volume
Osmosensory neurons
in the hypothalamus, monitor changes in concentration of the extracellular fluid
Aldosterone
Released in response to angiotensin II and stimulate kidneys to conserve sodium, aiding water retention
Nutrient regulation
glucose
principal sugar used for energy
Glycogen
glucose stored in the liver and muscles for the short-term a process regulated by the pancreatic hormone insulin
Glucagon
converts glycogen back into glucose when glucose levels drop
basal metabolism
energy used for heat production, maintenance of membrane potentials, and life-sustaining processes
Diabetes
Diabetes mellitus
failure of insulin to induce glucose. Two types
Type I diabetes
pancreas stops producing insulin
Type II diabetes
reduced tissue sensitivity to insulin
Cephalic phase
insulin released is mediated by the brain in response to seeing, smelling, or tasting food
Digestive phase
insulin is released when food enters the digestive tract
Absorptive phase
specialized liver cells called glucodetectors signal the pancreas to release even more insulin
Arcuate nucleus
arc-shaped hypothalamic nucleus implicated in appetite control; key in integrqating peptide hormone signals from the body
Leptin
released by fat cells into the blood stream to provide information to the brain about long-term energy reserves
Ghrelin
ynthesized and released by endocrine cells of the stomach; reaches high levels before eating and drops off after eating - acts as an appetite stimulant
PYY 3-36
peptide gut hormone believed to act on the
hypothalamic appetite system to suppress appetite; released by intestinal cells; reaches high levels after eating and works as an
appetite suppressant
POMC neurons
act as satiety neurons when activated,
inhibiting appetite and increasing metabolism
NPY neurons
act as hunger neurons, stimulating appetite
and reducing metabolism when activated
Orexin
hypocretin; neuropeptide produced in the
hypothalamus that is involved in switching between sleep states, in narcolepsy, and in the control of appetite; participates in control of feeding behavior
Nucleus of the solitary tract (NST)
common pathway for feeding behavior
Cholecytoskinin (CCK)
peptide hormone that is released by the gut after ingestion of food that is high in protein and/or fat
