Pathology small bowel

Question 1

What is the primary function of the small bowel?

Answer 1

Absorption

Question 2

What are the functions of enterocytes and goblet cells?

Answer 2

Enterocytes = apsorption
Goblet cells= secrete mucus

Question 3

What is contained in the villi?

Answer 3

Lamina propria with immune cells

Question 4

What is the blood supply to the small bowel?

Answer 4

All superior mesenteric artery ecept upper duodenum which is coeliac artery.

Question 5

What are the 2 main causes of ischemia in the small bowel?

Answer 5

1) Mesenteric arterial occlusion

2) Non occlusive perfusion insufficieny

Question 6

What are the 2 causes of mesenteric arterial occlusion?

Answer 6

Atherosclerosis

Thromboembolism (ususlly from the heart)

Question 7

What are the causes of non occlusive perfusion insufficiency?

Answer 7

1) Shock- in trauma and major haemorrage, blood supply to the bowel is cut off
2) Strangulation obstructing venous return (hernia or adhesion
3) Drugs cocaine causes vasospasm of smooth muscle in the superior mesenteric artery
4) Hyperviscosit

Question 8

Acute ischemia of the small bowel is a surgical emergency. T or F?

Answer 8

True

Question 9

Which part of the small bowel is most efffected by ischemia and why?

Answer 9

Mucosa- it is the most metabollically active part. Necrosis begins in the mucosa and spreads out. If it spreads through the muscle layer. Bowel rupture will result

Question 10

The longer the period of hypoxia in the small bowel the greater the damage and the greater the likelihood f complications. T or F?

Answer 10

True

Question 11

In no occlusive ischemia, when does most of the tissue damage occur?

Answer 11

After reperfusion

Question 12

What is the difference between a mucosal, mural and transmural infarct?

Answer 12

Mucosal- only effecting the mucosa and will resolve to normal
Mural- affecting the mucosa submucosa and possibly some of the mucle layer- repair and organization with fibrous tissue
Transmural- Affecting all layers of the bowel wall and will result in gangrene and possible death

Question 13

What are the possible outcomes for ischemia of the small bowel?

Answer 13

Resolution
Fibrosis, chronic ischemia, mesenteric angina , obstruction
Gangrene, perforation, peritonitis, sepsis and death

Question 14

What is mesenteric angina?

Answer 14

Abdonimal pain due to iscemina following exercise or a large meal

Question 15

What is Meckel’s Diverticulum?

Answer 15

Incomplete regression of vitello- intestinal duct.

Tubular structure, 2 inches long, 2 foot above the illeocecal valve in 2% of people.

Question 16

Most people with Meckel’s Diverticulum are assymptomatic but how can it present?

Answer 16

Bleeding, perforation or diverticulitis which mimics appendicitis

Question 17

Can the diverticulum develop gastric ulcers and why?

Answer 17

Yes because it can contain gastic mucosa

Question 18

Why are tumours of the small bowel rare

Answer 18

Because there is continuous enterocyte shed- they only last 72 hours. Any mutations etc are swept away and lost before they can progress

Question 19

What tumours can metastatise to the small bowel?

Answer 19

Ovary, colon, gastric

Question 20

What are the primary tumours of the small bowel from most to least common. Therey are all rare

Answer 20

Lymphomas- non hodkins type (maltomas (B cell) or T cell lymphomas)
Neuroendocrine tumours (slow growing, locally invasive, produce hormones => carcinoid syndrome (seratonin like substance) headaches, flushing and diarrhoea.)
Carninomas (present late, mets in lymph nodes and liver.)

Question 21

Which cancers are associated with chrons disease?

Answer 21

Carcinoma

Question 22

Which cancers are associated with coeliacs disease?

Answer 22

T cell lymphoma

Carcinomas

Question 23

What are the causes of appendicitis?

Answer 23

Unknown,

Faecoliths (faeces impacted on appendix), Lymphiod hyperplasia, paracites, and tumours

Question 24

What are the characteristic tissue changes in appendicitis?

Answer 24

Acute inflammation -neutrophils (must involve the muscle coat
Mucosal ulceration
Serosal congestion
Pus in lumen

Question 25

What are the complications of appendicitis?

Answer 25

Peritonitis, rupture, abscess, fistula, sepsis and liver abscess

Question 26

What other diseases is coeliac disease associated with?

Answer 26

Type 1 diabetes, especially in children

Thyroid diseases and skin conditions (Dermatitis Herpetiformis)

Question 27

What are the complications of coeliac disease?

Answer 27

Malabsorption esp fats => steatorrhea
Reduced intestinal hormone production => reduced pancreatic secretion and bile flow=> gall stones
Ulerative jejenoilleitis T cell lymphoma
Small bowel carcinoma

Question 28

What are the effects of malabsorbtion?

Answer 28

Loss of weight
Anaemia (Fe, Vit B12, Folate)
Abnormal bloating, failure to thrive in children, vitamin deficiencies