Lecture 14: GI Tract

Question 1

Where is gastrin synthesized and what is its action?

Answer 1

Stomach- Gastric acid secretion

Question 2

Where is ghrelin synthesized and what is its action?

Answer 2

Stomach- stimulates appeptites and inhibits lipid metabolism

Question 3

Where is Gastric inhibitory polypeptide synthesized and action?

Answer 3

small intestine- inhibits gastric acid secretion, stimulates insulin release

Question 4

Cholecystokinin (CCK) is synthesized where and what is its action?

Answer 4

small intestine- secretion of pancreatic enzymes, bicarbonate release, contraction of gall bladder (release of bile –> duodenum)

Question 5

where is secretin synthesized and what is its action?

Answer 5

duodenum- increases bicarbonate and water secretion from the pancreas and inhibits gastric acid secretion

Question 6

Where is motilin synthesized and what is its action?

Answer 6

small intestine- increases gastric intestinal motility

Question 7

Where is pancreatic polypeptide synthesized and what is its action?

Answer 7

Pancreas- opposes CCK, relaxes gallbladder, inhibits pancreatic secretions

Question 8

Where is somatostatin synthesized, what is its action?

Answer 8

GI tract- inhibits the release of GI hormones

Question 9

What is the characteristic features of the duodenum?

Answer 9

Brunner’s Glands

Question 10

What is the characteristic feature of the jejunum

Answer 10

Large plicae circulares (transverse folds of the submucosa)

Question 11

What is the characteristic feature of the ileum

Answer 11

Peyer’s patches

Question 12

What are the cells of the small intestine? (5)

Answer 12

enterocytes- secretion/ absorption
goblet cells- antimicrobial (lysozymes)
M-cells- antigen presenting
stem cell- found in intestinal crypts
APUD

Question 13

What APUDs are secreted by the pancreas (3)

Answer 13

secretin, CCK, PP

Question 14

What are glycocalyx and where are they found?

Answer 14

collectively known as the brush border - in the pancreas

Question 15

Where are enterocytes and what do they do?

Answer 15

secrete enterokinase (trypsinogen –> trypsin) they are found in the glycocalyx of the pancreas

Question 16

What are the two functions of bile?

Answer 16

1. to emulsify fat

2. excretion of cholesterol and bilirubin in feces

Question 17

what are lacteals?

Answer 17

lymph capillaries

Question 18

what kind of lipids get absorbed in the lymph?

Answer 18

long-chain lipids (chylomicron)

Question 19

What is a chylomicron?

Answer 19

lipid protein particles which make protein coat of long-chain lipids made of triglyceride and lipoprotein

Question 20

What is the function of the colon/rectum?

Answer 20

Absorption of water, production of feces

Question 21

Describe ulcerative colitis

Answer 21

Path: primarily in colon/rectum, it only effects mucosa.
Symptoms: Ab. pain, bloody stool, anemia, fatigue
Rx: corticosteroid (preduison), 5-aminosalicylates

Question 22

Describe Crohn’s Disaese

Answer 22

IBD, can effect any part of the GI tract and it effects the entire wall.
Diagnostic: String Sign (thickening of wall), pain in lower right quad
Rx: nutrition, cortico steroids, surgery

Question 23

What muscle is used in involuntary control of defecation? Describe the sequence

Answer 23

Internal anal sphincter
enternic and autonomic neurons sense that poop has filled colon –> reflexes internal anal sphincter –> feces in rectum = urge to poo

Question 24

What muscle is used in voluntary control of defecation?

Answer 24

external anal sphincter

also diaphram and ab. muscles

Question 25

What is the difference in venous drainage above and below the pectinate line?

Answer 25

above- superior rectal v. --> inferior mesenteric --> hepatic portal below- inferior vena cava (caval system)

Question 26

The molecules that form HCl in the stomach begin where and ultimately form the HCl where?

Answer 26

H+ and Cl- are first in the cytoplasm of the parietal cell, they then form HCl in the canaliculi

Question 27

What are the four layers of the wall of the trachea?

Answer 27

Mucousa, submucousa, Carilagenous layer, adventitia

Question 28

What are the five layers of bronchi

Answer 28

mucosa, muscularis, submucosa, cartilage layer, adventitia

Question 29

Describe what a pink puffer is

Answer 29

emphysema - less surface area for gas exchange, and less vascular bed for gas exchange. Body compensates by hyperventilation

Question 30

Describe what a blue bloater is

Answer 30

chronic bronchitis - body response to obstruction by decreasing ventilation and increasing cardiac output, residual lung space gradually increases

Question 31

describe pneumonia

Answer 31

Inflammatory condition of the lung especially affecting the alveoli, also disrupts gas exchange and capillary beds VIRAL- lymphocytes BACTERIAL - neutrophils

Question 32

Describe cystic fibrosis

Answer 32

CFTR Cl- transporter works differently in different tissue. | the muco- cillary elevator is dehydrated and malfunctions