Gastro-Intestinal Tract

Question 1

what are the mouth, esophagus, pharynx, stomach, small intestine and large intestine collectively known as?

Answer 1

alimentary canal

Question 2

what are the 4 major tissue layers that make the GIT tract?

Answer 2

1. mucosa
2. submucosa
3. muscularis externa
4. serosa

Question 3

what are the 4 main functions of the GIT?

Answer 3

1. motility
2. secretion
3. digestion
4. absorption

Question 4

what are the 2 types of digestive motility?

Answer 4

1. propulsive movement

2. mixing movement

Question 5

where does most absorption occur in the GIT?

Answer 5

small intestine

Question 6

what are the 2 nervous systems that regulate the functioning of the GIT?

Answer 6

Intrinsic [Enteric Nervous System], Extrinsic [ Autonomic Nervous System]

Question 7

what are the 2 plexuses of the enteric nervous system?

Answer 7

1. Myenteric plexus [Auerbach]

2. Submucosal plexus [plexus of Meissner]

Question 8

what is the difference in function of the parasympathetic and sympathetic nervous systems in the GIT?

Answer 8

PNS= stimulates motility and secretion via Vagus nerve
SNS= inhibits digestion

Question 9

what is the term synonymous to Swallowing?

Answer 9

deglutition

Question 10

what are the 3 phases of swallowing and is each phase voluntary or involuntary?

Answer 10

1. Buccal [oral] phase= voluntary
2. Pharyngeal phase= involuntary
3. Esophageal phase= involuntary

Question 11

what are the 2 sphincters present in the esophagus?

Answer 11

pharyngoesophageal sphincter and gastroesophageal sphincter

Question 12

what are the 3 developments within the stomach that prevent it from digesting itself?

Answer 12

1. epithelial cells with tight junctions
2. thick coat of bicarbonate-rich mucus on wall
3. gastric glands that are impermeable to HCl

Question 13

what are the 4 types of gastric exocrine secretory cells and their functions?

Answer 13

1. Parietal cells = secrete HCl and intrinsic factor
2. G cells= secrete hormones and other substances
3. Chief Cells= pepsinogen
4. Mucous Cells= mucus

Question 14

what are the 3 phases of the regulation of gastric juice secretion?

Answer 14

1. cephalic phase
2. gastric phase
3. intestinal phase

Question 15

what are the 3 ligands that stimulate HCl secretion?

Answer 15

ACh, Histamine, Gastrin

Question 16

what happens at the antrum of the stomach?

Answer 16

mixing occurs

Question 17

what feature of the stomach closes to prevent food from leaving the stomach while mixing occurs.

Answer 17

pyloric sphincter

Question 18

what are the 3 segments of the small intestine?

Answer 18

duodenum, jejunum, ileum

Question 19

true or false. The juice secreted by the small intestine cells contains digestive enzymes

Answer 19

false

Question 20

what stimulates the defecation reflex?

Answer 20

stretch receptors in rectal wall are stimulated by distension.

Question 21

which hormone is released due to the presence of proteins in the stomach?

Answer 21

gastrin

Question 22

which hormone is released due to the presence of acid in the duodenum?

Answer 22

secretin

Question 23

give two functions of the hormone secretin

Answer 23

1. inhibits gastric emptying
2. stimulates liver to release Na2CO3 for neutralization
3. inhibits gastric acid release

Question 24

which hormone stimulates pancreatic acinar cells to secrete pancreatic enzymes?

Answer 24

Cholecystokinin

Question 25

what is the importance of the liver in the digestive system?

Answer 25

secretes bile salts

Question 26

what does the hepatic portal vein do?

Answer 26

carries deoxygenated nutrient rich blood from the GIT to the liver for processing.

Question 27

when and where are bile salts released from the gallbladder and why?

Answer 27

bile salts are released after meals into the duodenum into to break down large fat globules into smaller droplets.

Question 28

true or false. digestion of carbohydrates occurs in the stomach.

Answer 28

false

Question 29

what are chylomicrons?

Answer 29

lipoproteins composed mainly of triglycerides that transport cholesterol, phospholipids and proteins from dietary lipids from intestines via lymphatic system to other parts of the body.

Question 30

name the fat soluble vitamins

Answer 30

A,D,E,K

Question 31

what is the major cause of ulcer formation?

Answer 31

Helicobacter pylori bacteria

Question 32

what causes gallstones?

Answer 32

when the concentration of cholesterol in the bile is greater than the concentration of the phospholipids and bile salt, , the cholesterol crystalizes

Question 33

what is the condition characterized by large, frequent watery stools termed as

Answer 33

diarrhea

Question 34

what causes lactose intolerance?

Answer 34

when lactase does does not properly digest lactose