GI Tract

Question 1

Functions: chemical & mechanical digestion, absorb nutrients, and excrete unabsorbed material

Answer 1

GI Tract

Question 2

not an endocrine gland, but endocrine cells are dispersed throughout
There are more than 20 distinct endocrine cell types, and they secrete more than 30 peptide hormones

Answer 2

GI Tract

Question 3

General Functions of GI Hormones

Answer 3

• Stimulate secretion of acids and enzymes necessary for digestion
• Modulate hormone release from the pancreas
• Act on smooth muscle to move food through GI tract
• Signal to brain to regulate food intake

Question 4

pancreatic hormone
that reduces blood glucose

Answer 4

insulin

Question 5

most are peptide hormones

Answer 5

GI tract

Question 6

2 families of GI hormones

Answer 6

Gastrin/Cholecystokinin

Secretin

Question 7

Location: G cells in the stomach

Answer 7

Gastrin

Question 8

Function: stimulates gastric acid (HCl) secretion

Answer 8

Gastrin

Question 9

Gastric distention (food in stomach)

Answer 9

triggers secretion of Gastrin

Question 10

Amino acids (products of protein digestion)

Answer 10

triggers secretion of Gastrin

Question 11

Smell, taste, or thoughts of food (parasympathetic stimulation)

Answer 11

triggers of secretion Gastrin

Question 12

low pH (too acidic)

Answer 12

inhibits the secretion of Gastrin

Question 13

secretin does what to the secretion of Gastrin?

Answer 13

inhibits

Question 14

Location: S cells in duodenum

Answer 14

secretin

Question 15

Function: stimulates bicarbonate &
digestive enzymes from pancreas and
bile from gallbladder

Answer 15

Secretin

Question 16

Secretion is triggered by:
* low pH (high acidity)

Answer 16

Secretin

Question 17

Secretion is inhibited by:
* pH >4.5 Contact of intestinal mucosa
with acidic food

Answer 17

secretin

Question 18

Location: I cells in duodenum

Answer 18

Cholecystokinin (CCK)

Question 19

Function: augments secretin to further
stimulate release of digestive enzymes
and bile from the pancreas and
gallbladder (digests fat and protein)

Answer 19

Cholecystokinin (CCK)

Question 20

Secretion is triggered by:
* Food (fats and proteins)

Answer 20

Cholecystokinin (CCK)

Question 21

Secretion is inhibited by:
* Stops when stimuli is removed (digestive products move on)

Answer 21

Cholecystokinin (CCK)

Question 22

Location: K cells in duodenum

Answer 22

Gastric inhibitory polypeptide (GIP)

Question 23

Function: stimulates insulin secretion from
pancreas (prepares body for incoming
glucose) and inhibits gastric secretions in
non-human animals

Answer 23

Gastric inhibitory polypeptide (GIP)

Question 24

glucose and fat triggers the secretion of this hormone

Answer 24

Gastric inhibitory polypeptide (GIP)

Question 25

secretion is inhibited when the stimuli is removed (digestive products move on)

Answer 25

Gastric inhibitory polypeptide (GIP)

Question 26

The GI hormones discussed to this point (GIP, CCK, Secretin, Gastrin) are all secreted in response to eating and are associated with

Answer 26

digestion

Question 27

(parasympathetic nervous system) regulates involuntary processes like digestion. Here, it conveys muscular distension in the stomach to the brain, triggering a full sensation

Answer 27

vagus nerve

Question 28

the two primary hormones that convey more specific information to the brain to control appetite

Answer 28

Leptin and Ghrelin

Question 29

the only peripheral orexigenic (appetite stimulating) signal thus far known.

Answer 29

Ghrelin

Question 30

Location: GI tract (primarily stomach), some from brain & peripheral neurons

Answer 30

Ghrelin

Question 31

Function: increases food intake & stimulates gastric contraction and emptying (accelerates movement of food)

Answer 31

Ghrelin

Question 32

Regulation: produced by an empty stomach (increases just before eating) and is suppressed by eating (fats and carbohydrates)

Answer 32

Ghrelin

Question 33

increases food intake

Answer 33

Ghrelin

Question 34

decreases food intake

Answer 34

Leptin

Question 35

Location: adipose tissue

Answer 35

leptin

Question 36

Function: decreases food intake and increases energy expenditure (increases basal metabolic rate)

Answer 36

Leptin

Question 37

Regulation: body fat (circulating leptin correlates with the size of body fat stores)

Answer 37

Leptin

Question 38

produce lots of leptin but the brain stops acknowledging the signal

Answer 38

leptin resistance

Question 39

Increases hunger and slows metabolism even though fat stores are sufficient One of the main biological contributors to obesity

Answer 39

Leptin resistance

Question 40

Causes of Leptin Resistance

Answer 40

1. Desensitization due to chronically high leptin 2. Obesity causes inflammation: * Produce cytokines that interfere with leptin signaling *Increase C-reactive protein (CRP) from liver -> binds leptin, preventing it from crossing the blood-brain barrier

Question 41

Coordinates activity of both the nervous system and the pituitary, controlling body temperature, thirst, hunger, and other homeostatic systems

Answer 41

Hypothalamus

Question 42

“Switchboard” Receives signals from circulation & regulates the feeding center

Answer 42

Arcuate Nucleus of the Hypothalamus

Question 43

Feeding Center (hunger sensation)

Answer 43

Lateral Hypothalamic Area

Question 44

inhibits the appetite

Answer 44

anorexigenic neurons

Question 45

stimulates the appetite

Answer 45

orexigenic neurons

Question 46

one of the most potent stimulators of feeding

Answer 46

Neuropeptide Y (NPY)

Question 47

Co-express NPY and AgRP

Answer 47

Orexigenic Neurons

Question 48

NPY and AgRP

Answer 48

increase food intake & decrease energy expenditure stimulated by Ghrelin

Question 49

Co-express POMC and CART

Answer 49

Anorexigenic Neurons

Question 50

POMC and CART

Answer 50

suppress food intake & increase energy expenditure stimulated by leptin