Stomach

Question 1

What is the abdomen?

Answer 1

• The body cavity between the thorax and the pelvic inlet
• Supported in part by the pelvis
• Wall of abdomen is a multilayered musculoaponeurotic wall
• Contains adipose tissue

Question 2

What is the unhealthiest fat to have?

Answer 2

Visceral fat - around the organs

Question 3

What are the regions of the abdomen?

Answer 3

1. Right hypochondrium
2. Epigastic
3. Left hypochondrium
4. Right lumbar
5. Umbilical
6. Left lumbar
7. Right iliac fossa
8. Suprapubic (hypogastrium)
9. Left iliac fossa

Question 4

Which regions of the abdomen is the stomach located in?

Answer 4

Left hypochondrium and epigastric

Question 5

Which structures are the anterior/superior to the stomach?

Answer 5

Lower ribs/diaphragm and liver

Question 6

Which structures are posterior/inferior to the stomach?

Answer 6

Diaphragm, spleen, left kidney, adrenal gland, pancreas

Question 7

What is the bulk of the stomach called?

Answer 7

The body

Question 8

What is the fundus?

Answer 8

The top of the stomach where gas collects

Question 9

What is the pyloric sphincter?

Answer 9

Controls secretions passing from the stomach to the small intestine

Question 10

When might a pyloromyotomy be performed in babies?

Answer 10

When the pyloric sphincter is too thick - babies have distended stomach, projectile vomitting, not excreting faeces

Question 11

Where does fat collect?

Answer 11

Greater curvature of the stomach (greater omentum attaches to greater curvature)

Question 12

What are the 3 layers of muscle in the stomach?

Answer 12

1. Inner circular
2. Outer longitudinal
3. Oblique layer

Question 13

What are the functions of the stomach?

Answer 13

• Stores swallowed food (temporarily)
• Stomach mixes gastric juice
• Chemical and mechanical functions
• Limited absorption (most absorption occurs in S.I. Alcohol is absorbed in stomach)

Question 14

What is the function of mucus secreting cells in the stomach?

Answer 14

Protect the lining from HCl

Question 15

What is the pH of HCl?

Answer 15

pH 1-2

Question 16

How does pepsinogen get converted to pepsin in the stomach?

Answer 16

HCl (hydrochloric acid) converts pepsinogen (inactive) to pepsin (active).

Question 17

Which cells secrete gastrin?

Answer 17

Endocrine cells

Question 18

What does gastrin do?

Answer 18

Causes gut contraction/motility

Question 19

What are parietal cells?

Answer 19

Eosinophilic (stain pink) ‘egg-shaped’ cells that secrete HCl

Question 20

Which cells secrete HCl?

Answer 20

Parietal (oxyntic) cells

Question 21

Which cells secrete pepsinogen?

Answer 21

Chief cells

Question 22

Where are mucus producing cells located?

Answer 22

Luminal surface and gastric pits

Question 23

Describe how HCl is formed in the parietal cell

Answer 23

• CO2 from blood joins to water forming carbonic acid in the parietal cell
• Under the influence of carbonic anhydrase, carbon acid converted to hydrogen and bicarbonate.
• HCO3- participates in chloride shift in the membrane of the parietal cell: Cl- in for HCO3- out.
• H+ from carbonic anhyrase joins to chloride -> forms HCl-

Question 24

Describe venous drainage of the stomach

Answer 24

• Right and left gastric veins drain to the portal vein
• Short gastric veins and left gastroepiploic drain to the splenic vein, then to the superior mesenteric vein
• Right gastroepiploic drains to the superior mesenteric vein

Question 25

What are oesophageal varices, and how do they occur?

Answer 25

- Enlarged veins in the oesophagus - Often due to obstructed blood flow in the portal vein - All the blood coming from the gut goes to the liver (portal vein) - Any pressure in the liver can cause back pressure onto other veins - Oeseophageal veins -> axygos vein -> superior vena cava - Portal pressure -> inferior vena cava pressure - Blood vessels can become dilated and burst

Question 26

What can be used to treat leaking blood vessels in oesophageal varices?

Answer 26

A tube can be passed down the oesophagus, inflate the tube (applying pressure) -> trying to prevent blood vessels from leaking any more

Question 27

What are the surgical options for weight loss?

Answer 27

Gastric band and gastric bypass

Question 28

What is a gastric band?

Answer 28

A band is placed around the stomach to reduce the amount of food and fluid you can get into the stomach

Question 29

What is a gastric by-pass?

Answer 29

Reduce the stomach and reconnect the duodenum (need to make sure bile can still enter the duodenum from the liver)