GI- Lecture 1

Question 1

2 main groups of organs in the Digestive system

Answer 1

• alimentary canal (GI tract)

- accesory digestive organs

Question 2

Organs part of the Alimentary canal

Answer 2

• mouth
• pharynx
• esophagus
• stomach
• small intestine

Question 3

Organs part of the accessory digestive organs

Answer 3

• teeth
• tongue
• gall bladder
• salivary glands
• liver
• pancreas

Question 4

Functions of the alimentary canal

Answer 4

• digests food
• absorbs digested fragments through lining into the bloodstream
• excretes end products of digestion

Question 5

The function of accessory digestive organs

Answer 5

produce secretory products like bile, enzymes, and saliva to help digest food

Question 6

What lines the abdominopelvic cavity

Answer 6

serous membranes like the peritoneum

Question 7

Types of peritoneum

Answer 7

• Visceral peritoneum: covers the external surface of digestive organs
• Parietal peritoneum: lines the walls of the abdominal cavity
  visceral is continuous with the parietal

Question 8

What is the Peritoneal cavity

Answer 8

slit-like space btwn the visceral and parietal peritonea

Question 9

What is the Mesentary

Answer 9

fused double layer of the parietal peritoneum

Question 10

Function of the Mesentary

Answer 10

• holds organs in place

- carries blood vessels, lymphatic vessels, and nerves to the organs of the GI tract

Question 11

Peritoneal organs vs retroperitoneal organs

Answer 11

• peritoneal organs: organs with a mesentery that stay in the peritoneal cavity
• retroperitoneal: organs that lost their mesentery and lie posterior to the peritoneal cavity

Question 12

Splanchnic circulation

Answer 12

includes arteries that branch off the abdominal aorta to the digestive circulation & the hepatic portal circulation

Question 13

Arteries & the organs they serve

Answer 13

hepatic artery—> liver
gastric artery—> stomach
splenic artery—> spleen
superior & inferior mesenteric artery—> small and large intestines

Question 14

how much of the cardiac output do arteries get

Answer 14

1/4, increases after you eat

Question 15

Where does the venous return go through from most of the abdominopelvic region

Answer 15

inferior vena cava

* venous return from digestive viscera (organs) is indirect through the hepatic portal circulation

Question 16

Hepatic portal circulation

Answer 16

veins coming from various organs, join up with the hepatic portal vein and empty into the liver

Question 17

Typical 4 layers of the GI tract

Answer 17

• muscularis externa
• submucosa
• serosa
• mucosa

Question 18

Mucosa

Answer 18

• innermost, secretes mucus, digestive enzymes, and hormones

- absorbs the end product of digestion and protect the tract against infection

Question 19

3 sublayers of Mucosa

Answer 19

• surface epithelium: columnar epithelia + goblet cells; secrete enzymes and hormones in stomach and small intestine
• lamina propria: loose connective tissue with isolated lymph nodes; some bunches of these nodules are in key areas (tonsils, appendix)
• muscularis mucosa: a thin layer of smooth muscle; responsible for local movements and causes mucosa to form folds in the small intestine

Question 20

Submucosa

Answer 20

• moderately dense connective tissue
• contains blood, lymphatic vessels, lymph nodes, and nerve fibers
• elastic, allows stomach to regain shape after large meal

Question 21

Muscularis externa

Answer 21

• responsible for the mixing and propulsive movements of the GI
• inner circular layer + outer longitudinal layer
• thickens to form sphincters at organ-organ junctions

Question 22

Serosa

Answer 22

• outermost, protective layer (visceral peritoneum)

- loose CT covered by single layer of squamous epithelial cells

Question 23

What surrounds the esophagus

Answer 23

surrounded by adventitia (fibrous CT that binds esophagus to surrounding tissues) instead of serosa

Question 24

What do retroperitoneal structures have

Answer 24

both a serosa on the side facing the peritoneal cavity & an adventitia on the side against the dorsal body wall