CHAPTER 4 | INTERNAL REGULATION

Question 1

• regulation of body temperature
• set point

Answer 1

HOMEOSTASIS

Question 2

temperature = environment

Answer 2

poikilothermic

Question 3

constant temperature

Answer 3

homeothermic

Question 4

releases vasopressin (vascular pressure) that raises blood pressure by constricting blood vessels

Answer 4

posterior pituitary

Question 5

• eating salty foods, high solute concentration outside cells that causes loss of water from cells
• relieved by drinking water
• OLVT (third ventricle)
• vasopressin secretion to conserve water

Answer 5

Osmotic Thirst

Question 6

type of thirst: bleeding or sweating
- low blood volume
- relieved by water with solutes
- receptors measuring blood pressure in the veins, subfortical organ
- angiotensin ii

Answer 6

Hypovolemic Thirst

Question 7

tendency of water to move across semipermeable membranes from the area of low solute concentration to the area of higher concentration

Answer 7

osmotic pressure

Question 8

notices osmotic pressure and sodium
content of the blood (weak blood-brain barrier)

Answer 8

receptors around third ventricle

Question 9

input from digestive tract to foresee osmotic need before the rest of the body experiences it

Answer 9

OVLT (Organum Vasculosum Laminae Terminalis)

Question 10

• some neurons increase thirst and some suppress it
• combines with the input from the OVLT, stomach,
  and other areas to provide input to the
  hypothalamus (supraoptic nucleus and
  paraventricular nucleus) to control vasopressin

Answer 10

Subfornical Organ (SFO)

Question 11

anticipation of needs
- drinking all at once when eating salty meals
- knowing when to stop drinking upon anticipation that thirst has been satisfied

Answer 11

allostasis (osmotic thirst)

Question 12

helps the brain in producing melatonin

Answer 12

tryptophan

Question 13

stomach sends satiety messages to the brain through

Answer 13

splanchnic nerves

Question 14

releases oleoylethanolamide (OEA) that
stimulates the vagus nerve

Answer 14

duodenum

Question 15

limits meal size by constricting the sphincter muscle between the stomach and duodenum and stimulating the vagus nerve to send signals to the hypothalamus

Answer 15

cholecystokinin (CCK)

Question 16

• enables glucose to enter the cells
• rises when someone gets ready for a meal in
  preparation for the rush of additional glucose
• decreases appetite since too much glucose is
  already in the cells

Answer 16

insulin

Question 17

hunger and the presence of energy deficit: eating provides energy resources to return the body to its optimal level

Answer 17

energy set point / set point assumption

Question 18

defines the set point

Answer 18

set-point mechanism

Question 19

detects deviations from the set point

Answer 19

detector mechanism

Question 20

eliminates deviation

Answer 20

effector mechanism

Question 21

• eating is controlled by a system designed to maintain blood glucose set point (nature of regulation through setpoint system)
• people feels hunger when blood glucose level
  drop significantly below the set point
• satiation occurs when eating returns blood
  glucose level to normal set point
• short-term regulation

Answer 21

GLUCOSTATIC THEORY

Question 22

• set point for body fat: deviations create
  compensatory adjustments in eating that return
  levels of body fat to set point
• body weight stay relatively constant
• long-term regulation

Answer 22

LIPOSTATIC THEORY

Question 23

• humans are not normally driven to eat by internal energy deficits but are drawn to eat by the anticipated pleasure of eating

Answer 23

POSITIVE INCENTIVE PERSPECTIVE

Question 24

• food deprivation leading to stomach contractions
• acts on the hypothalamus to decrease appetite
  and acts on the hippocampus to enhance learning

Answer 24

ghrelin

Question 25

- inhibits the lateral hypothalamus for satiety - damage leads to insensitivity to satiety signals

Answer 25

PARAVENTRICULAR NUCLEUS (PVN)

Question 26

arcuate nucleus sends excitatory signals to the paraventricular nucleus through the secretion of melanocortin

Answer 26

BRAIN MECHANISMS: satiety

Question 27

arcuate nucleus sends inhibitory signals to the paraventricular nucleus through the secretion of GABA, neuropeptide Y (NPY), and agouti-related peptide (AgRP)

Answer 27

BRAIN MECHANISMS: hunger

Question 28

- controls insulin secretion, alters taste responsiveness, and facilitates feeding in various ways - damage leads to food and water aversion, possibly leading to death

Answer 28

BRAIN MECHANISMS: LATERAL HYPOTHALAMUS

Question 29

- inhibits feeding - damage leads to overeating and weight gain

Answer 29

ventromedial hypothalamus (VMH)

Question 30

insulin, leptin, glucose, CCK, and other hormones

Answer 30

homeostatic control of feeding

Question 31

evolution predisposed people to eat enthusiastically whenever good food was available

Answer 31

obesity

Question 32

- under consumption of essential nutrients - eating so little leading to health threatening weight loss - perceive themselves as fat despite thin appearance - about 4 % of diagnosed cases result in death due to complications from starvation - high rate of suicide

Answer 32

ANOREXIA NERVOSA

Question 32

factors affecting obesity

Answer 32

psychological distress & prenatal environment

Question 33

(1) periods of not eating, (2) bingeing (huge amount of food in short periods of time), (3) efforts to eliminate consumed calories by purging (e.g., vomiting, excessive use of laxatives) or excessive exercise

Answer 33

BULIMIA NERVOSA

Question 34

antidiuretic hormone (ADH), enables the kidneys to reabsorb water from urine

Answer 34

vasopressin

Question 35

conserving water by excreting more concentrated urine and decreasing sweat

Answer 35

Water regulation