Chapter 12 - Ingestive behaviours Flashcards Preview

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Flashcards in Chapter 12 - Ingestive behaviours Deck (48):
1

the process by which the body's substances and characteristics are maintained at their optimal level

homeostasis

2

a variable that is controlled by a regulatory mechanism
ex: temperature in a heating system

system variable

3

the optimal value of the system variable in a regulatory mechanism

set point

4

a polysaccharide often referred to as animals starch; stored in the liver and muscle; constitutes the short-term store of nutrients
- complex, insoluble carbohydrate

glycogen

5

a pancreatic hormone that facilitates entry of glucose and amino acids into the cell, conversion of glucose into glycogen, and transport of fates into adipose tissue
- a peptide hormone produced by the pancreas

- Promotes use of glucose as 1o energy source.
- Promotes conversion of fuels to storable forms; glucose to glycogen and fat, amino acids to proteins.
- Promotes storage of glycogen in liver and muscle, fat in adipose tissue, and protein in muscles.

insulin

6

a pancreatic hormone that promotes the conversion of liver glycogen into glucose
- opposite effects of insulin
- stimulates conversion of glycogen to glucose

glucagon

7

a substance derived from the breakdown of triglycerides, along with fatty acids; can be converted by liver into glucose

glycerol

8

the form of fat storage in adipose cells; consists of a molecule of glycerol joined with three fatty acids

triglyceride

9

a substance derived from the breakdown of triglycerides, along with glycerol; can be metabolized by most cells of the body expect the brain

fatty acid

10

the 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

- decrease in insulin
- increase in glucagon

fasting phase

11

the 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
- nutrients absorbed from the bloodstream to meet body needs (energy source)

- increase in insulin, decrease in glucagon

absorptive phase

12

preparoty stage, begins with sensory (head) cues) ie: sight, smell, thought of food. ends with beginning of absorption in bloodstream.

- increase in insulin
- decrease in glucagon

cephalic phase

13

a peptide hormone release by the stomach that increases eating; also produced by neurons in the brain
- stimulate thoughts about food
- released by digestive system
- levels go up before a meal, down after

ghrelin

14

the first portion of the small intestine, attached directly to the stomach
- contains receptors that control secretion of ghrelin

duedenum

15

internal state of an animal seeking food

hunger

16

animals are drawn to eat not by energy deficits but, by the anticipated pleasure of eating

positive incentive theory

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anticipated pleasure of a behaviour

positive incentive value

18

a dramatic fall in the level of glucose avaliable to cells; can be caused by a fall in the blood level of glucose or by drugs that inhibit glucose metabolism.

glucoprivation

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a dramatic fall in the level of fatty acids available to cells; usually caused by drugs that inhibit fatty acid metabolism

lipoprivation

20

the vein that transports blood from the digestive system to the liver

hepatic portal vein

21

a tube that drains out the contents of the stomach

gastric fistula

22

a hormone secreted by the duodenum that regulates gastric motility and causes the gallbladder to contract; appears to provide a satiety signal transmitted to the brain through the vagus nerve
- released by small intestine in response to presence of fats that control the rate of stomach emptying
- inhibits gastric contractions, causes plyorus to constrict
- acts on receptors between stomach and duodenum.

CCK

23

a peptide released by the gastrointestinal system after a meal in amounts proportional to the size of the meal
- only nutrients cause release

PYY

24

a strain of nice whose obesity and low metabolic rate are caused by a mutation that prevents the production of leptin

ob mouse

25

a hormone secreted by adipose tissue; decreases food intake and increases metabolic rate, primarily by inhibiting NPY-secreting neurons in the arcuate nucleus
- weight gained, increase in fat mass, more released
- weight lost, fatty tissue reduces, decreased amount circulating in body

leptin

26

small amounts of food consumed before a meal increase hunger rather than reduce it

appetizer effect

27

as you eat one food, the positive-incentive value of all foods declines a bit, but plummets for that particular food. You will be satiated for that food but are likely to begin eating again if offered a different food
Two kinds of effects:
1) brief effects that influence food selection within a meal 2) enduring effects influencing selection from meal to meal.
Some foods immune: rice, bread, potatoes, sweets, green salads can be eaten daily with only slight drop in palatability (is the hedonic reward provided by foods or fluids that are agreeable to the "palate" in regard to the homeostatic satisfaction of nutritional, water, or energy needs.)

Sensory-specific satiety

28

Mechanism for adjustment of energy efficiency in response to body fat levels is

diet-induced thermogenesis

29

levels at which factors that contribute to body weight reach an equilibrium

settling (balance) point

30

a surgrical procedure that severs the brain stem, disconnecting the hindbrain from the forebrain

decerebration

31

a peptide neurotransmitter found in a system of the lateral hypothalamic neurons that stimulate appetite and reduce metabolic rate

MCH (melanin-concentrating hormone)

32

a peptide neurotransmitter found in a system of the lateral hypothamic neurons that stimulate appetite and reduce metabolic rate

orexin

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a peptide neurotransmitter found in a system of neurons of the arcuate nucleus that stimulate feeding, insulin and glucocorticoid secretion, decrease the breakdown of triglycerides and decrease body temperature

NPY

34

a nucleus in the base of the hypothalamus that controls secretion of the anterior pituitary gland; contains NPY-secreting neurons involved in feeding and control of metabolism

arcuate nucleus

35

a nucleus of the hypothalamus located adjacent to the dorsal third ventricle; contains neurons involved in the control of autonomic nervous system and the posterior pituitary gland

PVN

36

a neuropeptide that acts as competitive antagonist at MC-4 receptors and increases eating

AGRP

37

cocaine and amphetamine-regulated transcript; a peptide neurotransmitter found in a system of the arcuate nucleus that inhibits feeding

CART

38

a neuropeptide that acts as an agonist at MC-4 receptors and inhibits eating

a-MSH

39

a receptor found in the brain that binds with a-MSH and agouti-related protein; plays a role in control of appetite

MC-4R

40

appetite supressing chemicals

anorexigens

41

a disorder that most frequntly afflicts young women; exaggerated concern with being overweight that leads to excessive dieting and often compulsive exercising; can lead to starvation

anorexia nervosa

42

bouts of excessive hunger and eating, often followed by forced vomiting or purging with laxatives; sometimes seen in people with anorexia nervosa

bulimia nervosa

43

regulates cell cycling, growth and division according to nutrient availability.

mTOR

44

potent inhibitor of mTORC1.

RAP

45

We showed that acute injection of RAP, which induces a transient suppression of mTOR, can have a long-lasting effect on the set point for body weight, suggesting a novel role of mTOR in body weight regulation.
Moreover, a single injection has distinct advantage as it can avoid side effects of chronic RAP administration such as glucose intolerance.
We propose that RAP and related compounds could be used as tools to investigate how the defended level (apparent set point) of body weight is determined and to complement other weight loss strategies.

mTOR/RAP/body weight summary

46

deletion of several genes in segment of chromosome 15
involved in production of proteins critical to normal functioning of the hypothalamus
- caused by random accident that occur during production of fathers sperm

Prader-Willi Syndrome

47

brain recieves hunger signals through

vagus nerve

48

fall in blood glucose levels, stimulates hunger

hypoglycemia