GI System Roane

Question 1

What is the purpose of microvilli on gastric epithelial cells?

Answer 1

Increase surface and facilitate absorption

Question 2

What are the 4 main processes when eating food?

Answer 2

Motility: mixing and moving food through the alimentary canal (regulated by neurons, hormones, chemicals)

Secretion: adding acids, bases, and enzymes to the food (regulated by neurons, hormones, chemicals)

Digestion: breaking food into small molecules (passively)

Absorption: Moving food into circulation (passively)

Question 3

What is a Bolus? which path does food take?

Answer 3

Unit of food per swallow -> through Esphalgus (Air goes through traechae=

Question 4

What is the Chyme?

Answer 4

Acidic fluid passes from the stomach to the small intestine
gastric juices and partly digested food

Question 5

What does the small intestine consist of?

Answer 5

25 ft tubule divided into 3 parts:
- Duodenum, jejunum, Ileum

Question 6

What are the accessory organs involved in digestion?

Answer 6

Salvary glands, Liver, gall bladder, pancreas (in the back)

Question 7

What happens to food before absorption?

Answer 7

They are broken down into monomers

Carbohydrates -> Disaccharides -> Monosaccharides (glucose, fructose?

Protein -> Polypeptide -> Amino acids

Triglycerids -> Monoglycerids + Fatty acids

Question 8

The sequence of Digestion:

Answer 8

Mouth -> Esophagus -> Stomach -> small intestine -> Colon (part of large intestine) -> Rectum -> Anus

Question 9

Where is most of the food absorbed?

Answer 9

Duodenum of the small intestine

Question 10

How much fluid gets absorbed into the blood (small intestine)?

Answer 10

6700 ml per day

Question 11

Where do the blood and absorbed nutrients go first?

Answer 11

To the liver

Question 12

The layers of the gastrointestinal tract:

Answer 12

Inside to outside:
1) Epithelium + Lamina propia
2) Muscularis mucosa - muscle layer
3) Submuscosa - connective tissue, rich in blood vessels and glands
4) Submocasal plexus - layer of neurons
5) circular layer of muscles
6) Myenteric plexus - a layer of neurons
7) Longitudinal layer - muscles
8) Surosa - continuous layer of connective tissue

Question 13

Which nerve of the parasympathetic NS controls the intestines?

Answer 13

The vagus nerve

Question 14

Describe one single intestinal villus:

Answer 14

-columnar epithelium with microvilli with Brush border -> adsorbs nutrients

-Enteroendocrine cells -> secrete hormones

-Lacteal (between arteriole and venule): receive digested fats

-Goblet cells: secrete mucus

Question 15

What is special about the intestine in terms of nerves?

Answer 15

It has so many neurons it is considered a second brain

-Smooth muscles form a functional syncytium -> one cell gets activated and spread the signal to adjacent cells

Question 16

What are Peyer’s patches?

Answer 16

Lymph node-like structures in the lower part of the small intestine for immune response to bacteria

Question 17

How are accessory organs (liver, gall bladder) involved in digestion?

Answer 17

Bile is produced in the liver -> travels through the left and right bile ducts to the small intestine, excess bile will be stored in the gall bladder

The pancreas secrets enzymes to digest food

Question 18

EXAM - Anatomy of accessory organs !!!
How does the secretion of accessory organs reach the small intestine?

Answer 18

Through the Ampulla of Vater and Sphincter of Oddi