GI Cells & Signalling Substances Summary

Question 1

vagal neurons (stim, substance released, target, physiological response)

Answer 1

-stim: higher brain control and long reflexes (e.g. cephalic response)
- release: ACh
- target: ENS neurons
- physiological response: motility and secretion

Question 2

Efferent ENS neurons

Answer 2

• stim: short reflexes or long (vagal neurons)
• release: various, over 30 neurotransmitters
• target: smooth muscle, enteroendocrine, epithelial cells
• response: motility, secretion

Question 3

what are the stomach cells

Answer 3

G, ECL, parietal, chief, D, mucus

Question 4

G

Answer 4

• stim: long reflexes, AA, peptides, distension (e.g. short reflex)
• release: gastrin
• target: parietal cells, ECL cells
• response: acid secretion from parietal cells

Question 5

ECL

Answer 5

• stim: gastrin, neural
• release: histamine
• target: parietal
• response: acid secretion

Question 6

parietal cells

Answer 6

• stim: gastrin, histamine, ACh, GRP (short and long reflex)
• release: HCl, intrinsic factor
• target: lumen on stomach
• response: protection, denaturing proteins, activating zymogens, Vit B12 absorption

Question 7

chief

Answer 7

• stim: HCl, neural reflex
• release: gastric lipase, pepsinogen
• target: fats and proteins
• response: digestion

Question 8

D

Answer 8

• stim: HCl
• release: somatostatin
• target: G cells, ECL cells, parietal cells, chief cells
• response: Inhibit acid secretion, inhibit pepsinogen secretion

Question 9

mucus

Answer 9

• stim: Constitutively, Neural input, irritation (HCl)
• release: mucus, bicarbonate
• target: stomach surface
• response: protection

Question 10

intestinal cells

Answer 10

S, I, K, L, Mo

Question 11

S

Answer 11

• stim: acid entering small intestine
• release: secretin
• target: pancreas duct cells, hepatocytes/cholangiocytes, G cells, ECL cells, parietal cells
• response: Bicarbonate secretion from pancreas duct cells, bile production, inhibits acid secretion from stomach

Question 12

I

Answer 12

• stim: fa and aa
• release: CCK
• target: Pancreas acinar cells, gallbladder, sphincter of oddi, stomach
• response: Digestive enzyme secretion, bile secretion, inhibit acid secretion

Question 13

K

Answer 13

• stim: carbs in small intestine
• release: GIP (glucose-dependent insulinotropic peptide)
• target: stomach beta islets in pancreas
• response: inhibit acid secretion, stim insulin secretion

Question 14

L

Answer 14

• stim: carb in small intestine
• release: GLP-1 (glucagon-like peptide-1)
• target: Stomach, beta islets in pancreas
• response: Inhibit acid secretion, stimulate
  insulin secretion

Question 15

Mo

Answer 15

• stim: unknown, maybe alkaline lumen
• release: motilin
• target: CNS-stomach and small intestine
• response: migrating motor complex

Question 16

pancreas cells

Answer 16

beta islets, alpha islets, acinar cells, duct cells

Question 17

beta islets

Answer 17

• stim: GLP-1, GIP, increased plasma glucose
• release: Insulin
• target: muscle, liver adipocytes
• response: glucose homeostasis, metabolism during fed state

Question 18

alpha islets

Answer 18

• stim: Decrease plasma glucose
• release: glucagon
• target: muscle, liver, adipocytes
• response: glucose homeostasis, metabolism
  during fasted state

Question 19

acinar

Answer 19

• stim: ACh, CCK, gastrin
• release: Digestive enzymes: amylases, lipases, peptidases
• target: duodenum
• response: Digestion

Question 20

duct

Answer 20

• stim: ACh, Secretin
• release: bicarbonate
• target: duodenum
• response: protection (buffering acid)

Question 21

liver/gallbladder cells

Answer 21

hepatocytes/cholangiocytes

Question 22

hepatocytes/cholangiocytes

Answer 22

• stim: CCK, secretin
• release: bile
• target: gallbladder, duodenum
• response: assists in fat digestion

Question 23

small intestine and large intestine cells

Answer 23

M cells, goblet cells

Question 24

M

Answer 24

• stim: foreign antigens
• release: endocytose antigens and present them to immune cells
• target: none
• response: immune protection

Question 25

goblet

Answer 25

- stim: Constitutively, irritation - release: mucus - target: lumen - response: protection

Question 26

salivary gland cells

Answer 26

serous cells, mucus cells

Question 27

serous

Answer 27

- stim: Parasympathetic input - release: Watery solution with amylase - target: mouth - response: Soften, moisten, dissolve food, (taste), carbohydrate digestion, defense

Question 28

mucus

Answer 28

- stim: parasymp - release: mucus - target: mouth - response: Soften, moisten, dissolve food, (taste), carbohydrate digestion, defense