Salivary glands, oesophagus and stomach microanatomy

Question 1

How much serous fluid do we make a day?

Answer 1

Around 7 litres

Question 2

Describe ascites

Answer 2

Blood hydrostatic pressures change and fluid moved from vessels to peritoneal cavities.

Question 3

Where are the myenteric plexus and the submucosal plexus located?

Answer 3

In between inner circular and outer longitudnal muscle layers (muscular externa gut layer).
In between inner circular and submucosa. These are enteric nervous system.

Question 4

Enteric nervous system

Answer 4

Functions independently of the autonomic nervous system. Controls GI function.
Sits between the muscularis externa layers (myenteric plexus) and under the submucosa (meissners plexus). It uses the same NT as the CNS.

Question 5

How much of your saliva do the parotid, submandibular, and sublingual glands produce?

Answer 5

Parotid about 25%
Submandibular about 70%
Sublingual about 5%

Question 6

Describe staining and contents of serous cells, position of nucleus. Presence or absence of myoepithelial cells

Answer 6

Stain dark due to zymogen granules that hold enzyme amalyse. Central nuclei. Myoepithelial cells present. Produce watery fluid

Question 7

Describe staining and contents of mucous cells, position of nucleus. Presence or absence of myoepithelial cells

Answer 7

Produce viscous sticky solution
Nuclei in periphery
Many mucous granules
Absent myoepithilial

Question 8

Describe ductal cells

Answer 8

Many striated mitochondria, lots of active transport occurring. Function is to exchange Na and Cl for K and HCO3-

Question 9

Holy trinity of salivary glands, including functions of salivary glands.

Answer 9

Enzymes, mucous, HCO3-

Key functions lubrication, digestion, protection

Question 10

Function: Lubrication

Describe composition of saliva that achieves this

Answer 10

99% water

Carbohydrate rich glycolproteins (mucins)

Question 11

Function: digestion

Describe composition of saliva that achieves this

Answer 11

Amylase
Lipase
Kallikrein (increases blood flow)

Question 12

Function: protection

Describe composition of saliva that achieves this

Answer 12

Bacterial adhesion to mucous
Bicarbonate ions
Lysozome
Lactoferrin (fights iron dependant bugs)
Immunoglobin A

Question 13

How long is the oesophagus?

Answer 13

25cm

Question 14

What region of the oesophagus is the muscular mucosae absent?

Answer 14

The upper region

Question 15

Oesophageal varices

Answer 15

If patient has portal hypertension there can be back flow of blood into the submucosal blood vessels. Can haemorrhage easily.

Question 16

Achalasia

Answer 16

Failure of smooth muscle fibres in oesophagus to relax. Absent peristalsis. Can result in ‘birds beak’

Question 17

Is the submucosa loose or tightly packed

Answer 17

Loosely packed to allow passage of bolus

Question 18

Fundus

Answer 18

Parietal glands. HCl, IF, pepsinogen, somatostatin.

Question 19

Cardia

Answer 19

Mostly mucous cells

Question 20

Pylorus

Answer 20

Mucous, pepsingogen, gastrin, somatostatin

Question 21

Simple columnar mucous cells

Answer 21

Produce mucous coat that traps HCO3- (made by parietal cells).

Question 22

Undifferentiated stem cells

Answer 22

High rate of replenishment of epithelium in the stomach.

Question 23

Prostglandin E2’s role in the GI tract

Answer 23

Stimulates mucous production

Question 24

H. Pylori

Answer 24

Urease present on bacteria converts urea in the blood into ammonia this attacks the mucous coat and degrades it. The toxins secreted by H. pylori damage the epithelium. They also release ulcerousness and platelet aggregating factor. All cause stomach ulcers

Question 25

Parietal cells

Answer 25

Located in the gastric glands of funds and body. Make HCl (sterilises food, creates an acidic environment), acidic environment activates pepsinogen to pepsin, make IF (cobalamin absorption), produce HCO3- (protective against acid)

Question 26

Chief cells

Answer 26

Make pepsinogen