chapter 9

Flashcards for lecture review.

Homeostasis

Temperature regulation and other biological processes that keep certain body variables within a fixed range.

Homeostasis

Various biological processes that keep body variables within a fixed range.

Set point

A single value that the body works to maintain.

Negative feedback

Processes that reduce discrepancies from the set point.

Allostasis

The adaptive way in which the body anticipates needs depending on the situation.

Basal metabolism

Energy used to maintain a constant body temperature while at rest.

Poikilothermic (ectothermic)

Idea that the body temperature matches that of the environment.

Homeothermic (endothermic)

Use of internal physiological mechanisms to maintain an almost constant body temperature.

POA/AH

An area in the preoptic area/anterior hypothalamus that body temperature regulation is predominantly dependent upon.

Fever

Raised set point for body temperature

Homeostasis

Keeps certain body variables within a fixed range by reacting to changes.

Allostasis

Acts in advance to prevent or minimize changes.

Vasopressin (ADH)

Released by posterior pituitary, constricts blood vessels (raises BP), promotes water reabsorption in kidneys, produces concentrated urine

Osmotic thirst

Results from eating salty foods

Hypovolemic thirst

A thirst resulting from loss of fluids due to bleeding or sweating

OVLT (organum vasculosum laminae terminalis) and the subfornical organ (SFO)

Detect osmotic pressure and sodium content of the blood

Angiotensin II

Constricts blood vessels to compensate for a drop in blood pressure

Sodium-specific hunger

Strong craving for salty foods

Aldosterone

Causes the kidneys, salivary glands, and sweat glands to retain salt.

Digestive system function

Breaks down food into smaller molecules that the cells can use

Insulin

Enables glucose to enter the cell.

Glucagon

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

Type 1 Diabetes

Low insulin, high blood sugar

Type 2 Diabetes

Insulin present, but cells resist it

Leptin

Signals the brain to increase or decrease eating.

Arcuate nucleus

A part of the hypothalamus containing two sets of neurons, one sensitive to hunger signals and the other to satiety signals

Ghrelin

Neurotransmitter released in the brain that acts on the hypothalamus to increase appetite and triggers stomach contractions.

Paraventricular nucleus

Part of the hypothalamus that inhibits the lateral hypothalamus, an area important for eating

Melanocortin

Chemical important in limiting food intake

Ventromedial hypothalamus (VMH)

Output from this area inhibits feeding; damage to this nucleus leads to overeating and weight gain