Digestive System

Question 1

Discuss the physical alterations that lead to vomiting

Answer 1

Vomiting centre located in the medulla oblangata is stimulated in the brain - triggers vomiting reflex

• initiates and controls the act of emesis, involves a series of contractions of the smooth muscles in the GI tract

Question 2

What are some stimuli that cause vomiting?

Answer 2

• severe pain
• distension of the stomach or duodenum
• trauma to the testes, ovaries, bladder or kidney

Question 3

Outline the clinical manifestations that you may observe in a patient who has experienced severe vomiting for several days

Answer 3

• Weight loss
• dehydration
• abdominal pain
• light-headedness

Question 4

Discuss possible causes of upper GI bleeding

Answer 4

• Peptic ulcers: open sores that develop on the inside lining of the stomach and upper portion of small intestine
• oesophageal tears
• oesophageal varices
• esophagitis

Question 5

Discuss possible complications that can result from upper GI bleeding

Answer 5

• anaemia
• diarrhoea due to irritating nature of blood and consequent increase of peristalsis
• elevated BUN due to digestion of blood proteins (UGI bleed)

Question 6

Discuss factors that increase gastric acid production

Answer 6

• increase in the number of parietal/chief cells
• decrease in the inhibition of gastric secretions
• increased sensitivity to food/other stimuli such as; caffeine and histamine
• excessive vagal stimulation

Question 7

Discuss factors that impair mucosal barrier protection

Answer 7

• ischaemia can lead to loss of integrity of the mucosa, smoking can also lead to vasoconstriction reducing blood supply
• sympathetic stimulation
• impaired mucous secretion
• bile or pancreatic enzyme reflux from duodenum
• alcohol consumption

Question 8

Discuss treatments that could be used to alleviate symptoms in celiac disease and lactose intolerance

Answer 8

Celiac: non-gluten diet

Lactose intolerance: oral meds & avoidance of dairy products

Question 9

How does the stomach protect itself from its gastric acid?

Answer 9

The stomach is protected by epithelial cells which produce a bicarbonate-rich solution that coats the mucosa

• bicarbonate is alkaline and neutralises the gastric acid produced by the stomach

Question 10

Explain the pathophysiology of osmotic diarrhoea

Answer 10

Occurs when a substance in the intestine, cannot be absorbed and instead draws water into the lumen via osmosis
Causes:
- Lactase deficiency – where ingested lactose cannot be ingested and hence absorbed in the small intestine
- Sorbitol – a non-absorbable synthetic sugar

Question 11

Explain the pathophysiology of secretory diarrhoea

Answer 11

Excessive mucosal secretion of fluid and electrolytes, or inhibition of sodium chloride absorption
Causes:
- Bacterial endotoxins, such as cholera
- Neoplasms (cancers) that produce hormones that stimulate intestinal secretion
- Gastrinoma
- Thyroid carcinoma