12 Ingested Behavior Flashcards
Ingestive behavior
Eating or drinking.
Homeostasis
Process by which the body’s substances and characteristics (such as temperature and glucose level) are maintained at their optimal level.
System variable
Variable that is controlled by a regulatory mechanism, such as temperature in a room.
Set point
Optimal value of the system variable in a regulatory mechanism.
Detector
In a regulatory process, a mechanism that signals when the system variable deviates from its setpoint.
Correctional mechanism
In a regulatory process, the mechanism that is capable of changing the value of the system variable.
Negative feedback
Process whereby the effect produced by an action serves to diminish or terminate that action; a characteristic of records were systems.
Satiety mechanism
Brain mechanism that causes cessation of hunger or thirst, produced by adequate and available supplies of nutrients and water.
Intracellular fluid
Fluid contained within cells.
Extracellular fluid
All body fluids outside cells: interstitial fluid, blood plasma, and cerebrospinal fluid.
Intravascular fluid
Fluid found within the blood vessels.
Interstitial fluid
Fluid that bathes the cells, filling the space between the cells of the body (the “interstices”).
Isotonic
Equal in osmotic pressure to the contents of the cell. Cell placed in isotonic solution neither gains or loses water.
Hypertonic
Characteristic of a solution that contains enough salute that it will draw water out of the cell placed in it, through the process of osmosis.
Hypotonic
Characteristic of a solution that contains a little solid that is so placed in it will absorb water, through the process of osmosis.
Hypovolemia
Reduction in the volume of the intravascular fluid.
Osmometric thirst
Thirst produced by an increase in the osmotic pressure of the interstitial fluid relative to the intracellular fluid, thus producing cellular dehydration.
Osmoreceptor
Neuron that detects changes in the solute concentration of the interstitial fluid that surrounds it.
OVLT (organum vasculosum of the lamina terminalis)
Circumventicular organ located anterior to that anteroventral portion of the third ventricle; served by fenestrated capillaries and thus lacks a blood-brain barrier.
Subfornical organ (SFO)
Small organ located in the confluence of the lateral ventricles, attached to the underside of the fornix; contains neurons that detect the presence of angiotensin in the blood and excite neural circuits that initiate drinking.
Volumetric thirst
Thirst produced by hypovolemia.
Renin
Hormone secreted by the kidneys that causes the conversion of angiotensinogen in the blood into angiotensin.
Median preoptic nucleus
Small nucleus situated around the decussation of the anterior to commissure; plays a role in thirst stimulated by angiotensin.
Glycogen
Polysaccharide often referred to as animal starch.
Stored in the liver and muscle.
Short-term store of nutrients.
Insulin
Pancreatic hormone that facilitates entry of glucose and amino acids into cells, conversion of glucose into glycogen, and transport of fats into adipose tissue.
Glucagon
Pancreatic hormone that promotes the conversion of liver glycogen into glucose.
Triglyceride
Form of fat storage in adipose cells.
Consists of a molecule of glycerol joined with three fatty acids.
Glycerol
Substance (glycerine) derived from the breakdown of triglycerides, along with fatty acids. Can be converted by the liver into glucose.
Fatty acid
Substance derived from breakdown of triglycerides, along with glycerol; can be metabolized by most cells of the body except for the brain.
Fasting phase
Phase of metabolism during which nutrients are not available from the digestive system; glucose, amino acids, and fatty acids are derived from glycogen, protein, and adipose tissue during this phase.
Absorptive phase
Phase of metabolism during which nutrients are absorbed from the digestive system; glucose and amino acids constitute the principle source of energy for cells during this phase, and excess nutrients are stored in adipose tissue in the form of triglycerides.
Ghrelin
Peptide hormone released by the stomach that increases eating; also produced by neurons in the brain.
Duodenum
First portion of the small intestine, attached directly to the stomach.
Glucoprivation
Dramatic fall in the level of glucose available to cells; can be caused by a fall in one level of glucose or by drugs that inhibit glucose metabolism.
Lipoprivation
Dramatic fall in the level of fatty acids available to cells; usually caused by drugs that inhibit fatty acid metabolism.
Hepatic portal vein
Vein that transports blood from the digestive system to liver.
Gastric fistula
Tube that drains out the contents of the stomach.
Cholecystokinin (CCK)
Hormone secreted by the duodenum that regulates gastric motility and causes the gallbladder (cholecyst) to contract; appears to provide satiety signal transmitted to the brain through the vagus nerve.
Peptide YY 3-36 (PYY)
Peptide released by the gastrointestinal system after a meal in amounts proportional to the size of the meal.
Ob mouse
Strain of mice whose obesity and low metabolic rates are caused by a mutation that prevents the production of leptin.
Leptin
Hormone secreted by adipose tissue; decreases food intake increases metabolic rate: primarily by inhibiting NPY-secreting neurons in the arcuate nucleus.
Decebration
Surgical procedure that severs the brainstem, disconnecting the hindbrain from the forebrain.
Melanin-concentrating hormone (MCH)
Peptide neurotransmitter found in a system of lateral hypothalamic neurons that stimulate appetite and reduce metabolic rate.
Orexin
Peptide new transmitter found in the system of lateral hypothalamic neurons that stimulate appetite and reduce metabolic rate.
Neuropeptide Y (NPY)
Peptide neurotransmitter found in the system of neurons of the arcuate nucleus that stimulate feeding, insulin and glucocorticoid secretion, decrease the breakdown of triglycerides, and decrease body temperature.
Arcuate nucleus
Nucleus in the base of the hypothalamus that controls secretions of the anterior pituitary gland; contains NPY-secreting neurons involved in feeding in control of metabolism.
Paraventricular nucleus (PVN)
Nucleus of the hypothalamus located adjacent to the dorsal third ventricle; contains neurons involved in control of autonomic nervous system and the posterior pituitary gland.
Agouti-related protein (AGRP)
Neuropeptide the acts as antagonist at MC4 receptors increases eating.
CART
Cocaine- and amphetamine-regulated transcript; peptide neurotransmitter found it a system of neurons of the arcuate nucleus that inhibit feeding.
Alpha-melanocyte-stimulating hormone (alpha-MSH)
Neuropeptide that acts as an agonist at MC4 receptors and inhibits eating.
Melanocortin 4 receptor (MC4R)
Receptor found in the brain that binds with alpha-MSH and a agouti-related protein; plays a role in good control of appetite.
