Physiological Psychology Ch10

Vagus nerve

(cranial nerve X) conveys info about the stretching of the stomach walls, providing major basis for satiety. A way the stomach conveys satiety to the brain.

poikilothermic

(from Greek roots meaning "varied heat".) Amphibians, reptiles, and most fish are this; that is their body temperature matches the temperature of their environment. they lack the ability to shiver or sweat "cold blooded"

Leptin

(from Greek word leptos, meaning slender) produced by the body's fat cells; signals the brain to increase or decrease eating.

Allostasis

(from greek word meaning "standing" and "variable.") the adaptive way in which the body changes its set points depending on the situation.

How does the idea of allostasis differ from homeostasis?

Homeostasis is a set of processes that keep certain body variables within a fixed range. Allostasis is an adjustment of that range, increasing it or decreasing it as circumstances change.

aldosterone

Indicates low sodium. when body sodium reserves are low the adrenal glands produce this hormone; which causes the kidneys, salvitory glands, and sweat glands to retain salt.

Insulin

Pancreatic hormone that enables glucose to enter the cell. When someone is getting ready for a meal, this hormone levels rise, letting some of the blood glucose to enter the cells in preparation for the rush of additional glucose about to enter the blood.

Recovery after damage to the lateral hypothalamus

Stage 1 aphagia and adipsia Stage 2: anorexia Stage 3. adipsia Stage 4. near-recovery

Homeostasis

Walter B. Cannon introduced the term to refer to temperature regulation and other biological processes that keep body variables within a fixed range. EX: like a set thermostat

Prader-Willi syndrome

a genetic condition marked by mental retardation, short stature, and obesity. People with this syndrome have blood levels of ghrelin four to five times higher than average. (ghrelin is related to food deprivation)

Set point

a single value that the body works to maintain

Osmotic thirst

a thirst resulting from eating salty foods

Hypovolemic thirst

a thirst resulting from loss of fluids due to bleeding or sweating. when you need to restore lost salts and not just water. Thirst based on low volume.

anti-diuretic hormone (ADH)

also known as Vasopressin because it enables the kidneys to reabsorb water from urine and therefore make the urine more concentrated.

cholecystokinin(CCK)

any kind of food in the duodenum also releases this hormone; which limits meal size in two ways 1st constricts the sphincter muscle between the stomach and duodenum, causing stomach to hold its contents and fill more quickly than usual. 2nd stimulates the vagus nerve to send signals to the hypothalamus, causing cells there to release a neurotransmitter that is a shorter version of the CCK molecule itself.

Phentermine

appetite suppressant drug that blocks reuptake of norepinephrine and dopamine and therefore prolongs their activity.

"Fen-phen" Fenfluramine

appetite suppressant drug that increases the release of serotonin and blocks its reuptake

OVLT and Subfornical organ (SFO)

areas important for detecting osmotic pressure and the salt content of the blood. the OVLT receives input from receptors of in the brain itself and fro receptors in the digestive tract, enabling the brain to anticipate an osmotic need before the rest of the body experiences it.

Ways the lateral hypothalamus contributes to feeding

changing the response to taste, facilitating ingestion and swallowing, and increasing food-seeking behaviors and also controls stomach secretions.

Splanchnic nerves

conveys info about the nutrient contents of the stomach. A way the stomach conveys satiety to the brain.

Sham-feeding

experiments, everything an animal swallows leaks out of a tube connected to the esophagus or stomach. allowing animals to eat and swallow without becoming satiated. Meaning taste and other mouth sensations contribute to satiety, but they are not sufficient.

melanocortin

hormone with receptors in the para ventricular nucleus are important for limiting food intake, and deficiencies of this receptor lead to overeating.

lateral hypothalamus

includes a "train station" of neurons. controls insulation secretion, alters taste responsiveness, and facilitates feeding in other ways. an animal with damage to this area refuses food and water, averting its head as if the food were distasteful.

Ghrelin

increases eating by making you hungry when your stomach is empty. it is released during a period of food deprivation, where it triggers stomach contractions.

Angiotensin II

indicates low blood volume. stimulates neurons in areas adjoining the third ventricle. like vasopressin, it constricts the blood vessels compensating for the drop in blood pressure. also helps trigger thirst.

supraoptic nucleaus and paraventricular nucleus (PVN)

info is relayed to these areas of the hypothalamus, which control the rate at which the posterior pituitary releases vasopressin.

Ventromedial hypothalamus (VMH)

inhibits feeding; therefore damage to this nucleus leads to overeating and weight gain. damage results in eating normal sized meals unusually frequently.

Why is our body set at 37degrees C

its a trade-off between the advantages of high temperature for rapid movement and the disadvantages of high temperature for protein stability.

Homeothermic

mammals and birds; these animals use physiological mechanisms to maintain a nearly constant body temperature despite changes in the temperature of the environment. An animal Generates heat in proportion to its total mass, but it Radiates heat in proportion to surface area.

Syndromal obesity

obesity that results from a medical condition.

sodium-specific hunger

preference/craving for salty tastes.

negative feedback

processes that reduce discrepancies from the set point. EX: calcium deficiency in blood, storage deposits from bones release calcium.

Lateral preoptic area

receptors also relay info to this area and surrounding parts of the hypothalamus which control drinking.

cytokines

released by leukocytes to attack the intruders when bacteria or other intruders invade the body. They also stimulate the Vagus nerve, which sends signals to the hypothalamus increasing the release of chemicals called prostaglandins; which gives you a fever.

Vasopressin

released by your posterior pituitary; this hormone raises blood pressure by constricting blood vessels which helps compensate for the decrease blood volume due to dehydration.

Siburtramine

replaced fenfluramine and decreases meal size and binge eating by blocking the re-uptake of serotonin and norepinephrine.

What would happen to someones appetite if insulin levels and glucagon levels were both high?

result would be decreased appetite.

Glucagon

stimulates the liver to convert some of its stored glycogen to glucose to replenish low supplies in the blood.

Basal metabolism

the energy used to maintain a constant body temperature while at rest. Which requires about twice as much energy as do all other activities combined. (about 2/3rds of our total energy)

Duodenum

the part of the small intestine adjoining the stomach. It is the first digestive site that absorbs a significant amount of nutrients.

Osmotic pressure

the tendency of water to flow across a semipermeable membrane from the area of low solute concentration tot eh area of higher concentration.

The brains receptors for osmotic pressure and blood volume

these neurons are in areas surrounding the third ventricle of the brain, where no blood-brain barrier prevents blood-borne chemicals from entering the brain

neuropeptide Y (NPY) and agouti-related peptide (AgRP)

these transmitters block the satiety actions of the paraventricular nucleus,in some cases provoking extreme overeating.

Preoptic area/ anterior hypothalamus (POA/AH)

this and a couple other hypothalamic areas send output to the hind-brains raphe nucleus, which controls the physiological mechanisms such as shivering, sweating, and changes in blood flow to the skin.

Would adding salt to the body's extracellular fluids increase or decrease osmotic thirst?

this would increase osmotic thirst because it would draw water from the cells into the extracellular spaces.