9.2 Tum Tum

Question 1

What do parietal cells secrete?
What do the secretions do?
Stimulus?

Answer 1

HCl- make acid
Intrinsic Factor- needed for B12 absorbtion in small intestine
Stimulus- ACh, Gastrin, Histamine

Question 2

What do chief cells secrete? Function?

Stimulus?

Answer 2

Pepsinogen
Becomes pesin(protease, breaks down proteins)
Stimulus- ACh, gastrin

Question 3

What do mucous cells secrete? Function?

Stimulus?

Answer 3

Mucus- protect tissue

Stimulus- mechanical stretch of stomach, prostilglandins

Question 4

What go G-cells secrete? Function?

Stimulus?

Answer 4

Gastrin- Stimulates release of HCl by parietal cells

Stimulus- ACh, protein in stomach

Question 5

What do enterochromaffin-like cells secrete? Function?

Stimulus?

Answer 5

Histamine- Stimulates parietal cells (HCl)

Stimulus- ACh, gastrin

Question 6

What do delta cells secrete? Function?

Stimulus?

Answer 6

Somatostatin- Inhibits parietal, ECL, G-cells
= Less acid
Stimulus- Acid in stomach

Question 7

What is the oxyntic mucosa?

What cells?

Answer 7

Fundus – expanded lateral portion
Body– midportion
contains mucous cells, chief cells, parietal cells, ECL cells
oxyntic = “sharp” reference to acid secretion

Question 8

What is the pyloric region? What cell types?

Answer 8

Pyloric (antrum) region – funnel shaped, continuous with the small intestines through the pyloric sphincter
contains G-cells and D-cells

Question 9

What regulates the motility of the stomach?

Answer 9

Volume: when full, motility and emptying is stimulated
Fluidity: when more broken down, chyme is easier to move and emptying will be stimulated
High levels of Fat, Acid, distension of small intestine will inhibit emptying until the small intestine can process more
Stress: inhibits motility and emptying via SNS

Question 10

What is Barret’s esophagus?

Answer 10

metaplasia of esophageal cells (simple squamous columnar) due to repeated acid injury, precancerous
Chronic reflux disease– Barret’s esophagus- metaplasia (simple squamous–> columnar cells)= precursor to cancer

Question 11

What are the causes of peptic ulcer disease?

Answer 11

H.pylori infection damages stomach mucosa causing erosions and ulcers ranging from mm to cm.
burrows in mucosa, typically pyloric antrum (lowest acid region)
secretes of urea (converted to ammonium), proteases, cytotoxins, phopholipases by H. pylori
hypersecretion of HCl, decreased mucus production, reduced cellular repair
erosion of mucose, diffusion of HCl into stomach will, inflamamation and ulceration
abdominal pain between meals, when stomach is empty
irritated by stress, caffeine, smoking, NSAIDs (suppression of prostaglandin E2)

Question 12

What are the most serious SA of PUD?

Answer 12

perforation: sudden excruciating abdominal pain, abdominal rigidity, vomiting blood

Question 13

What are the morphological changes to the small intestine that increase surface area?

Answer 13

Plicae circulares – circular ridges in the mucosa and submucosa
Villi – finger-like projections of the mucosa
capillaries
lacteals
epithelial (“brush border” and goblet cells
Microvilli – tiny projections of the epithelial cell plasma membrane

Question 14

In order, what are the sections of the small intestine?

Answer 14

Duodenum
Jejunum
Ilieum

Question 15

What is the function of the duodenum?

Answer 15

chemical digestion: majority in the body occurs here, enzymes and bicarbonate from pancreas, bile from the liver, final step = brush border enzymes
Brunner’s glands: alkaline mucous secreting glands to neutralize acid entering from stomach

Question 16

What is the function of the jejunum?

Answer 16

nutrient absorption: majority in the body occurs here

Question 17

What is the function of the ileum?

Answer 17

last segment up to ileocecal valve
majority of Vitamin B12 absorption
return of bile salts to the liver via enterohepatic circulation
Peyer’s Patches: MALT (mucosa associated lymphatic tissue) in the submucosa

Question 18

What is segmentation in the small intestine?

Answer 18

a series of ring-like contractions using circular muscle that mix and propel chyme in the small intestine
** Not propulsive, mixes chyme

Question 19

Where do digestive (brush border enzymes come from)?

Answer 19

Pancreas!

Bound to brush border

Question 20

What are the functions of enterokinase, disachharidases, and amino peptidases?

Answer 20

Enterokinase: activates trypsin
Disaccharidases: breaks down disaccharides into monosaccharides
Aminopeptidases: breaks down peptides into amino acids

Question 21

What is the function of enterogastornes? What are they?

Answer 21

Small intestine regulates the stomach with enterogastrones

CCK, Secretin: give small intestone time to process, helps lower acid

Question 22

What enters gut cells via secondary transporters? By simple diffusion?

Answer 22

Secondary transporters:
Electrolytes
Water
monosaccharides
Amino acids
Diffusion:
Fatty acids, hormones

Question 23

What are some mechanism of diarrhea?

Answer 23

osmotic balance disrupted
inflammation, lack of absorption
secretion of mucus, fluid stimulated
excessive motility of intestines

Question 24

What is celiac disease?

Answer 24

sprue, gluten sensitivity) – hypersensitivity reaction to gluten
unknown mechanism, autoimmune, inflammation, increase in T-cells
serum IgA antitissue transglutaminate (IgA TTG)
biopsy of duodenum or jejunem
gluten peptide: gliaden
damage to intestinal mucosa, destruction of villi, decreased surface area for absorption
impaired absorption of nutrients, vitamins, minerals, bile salts

Question 25

What is a hernia? Where can they occur?

Answer 25

protrusion of an organ through abdominal wall
hiatal hernia: protrusion of stomach through diaphragm
acid reflux to esophagus, common cause of esophagitis, GERD
intestinal hernia: protrusion of small intestine through abdominal wall
weak areas of abdominal wall
incarcerated: trapped between muscle fibers
strangulation: incarceration causes obstruction, cuts off blood supply ischemia
Types:
epigastric
umbilical
inguinal ** especially in males due to larger inguinal canal
obturator
femoral
incisional