S5 L2 Absorption and digestion, Blood vessels of gut

Question 1

Carbohydrates: Digestion and Absorption

• Lists the names of different length carbohydrate chains
• Which length is absorbed?
• Briefly, glucose must be absorbed with…?
• Carbohydrates of plant origin - how are these absorbed?
• List three monosaccharides

Answer 1

Question 2

Starch:

• What length carbohydrate is this?
• Consists of…
• 2 enzymes needed for digestion
• With this digestion, which molecules do you get?

Answer 2

Question 3

Lactose:

• What is this?
• Where is it found?
• Length chain?
• What does it break down as…
• What is the enzyme
• Where is lactose found?

Sucrose:

• Length chain?
• What enzyme?
• What are the products of sucrose breakdown?

Answer 3

Question 4

List the three monosaccharides

How to absorb monosaccharides?
- Steps of this

Answer 4

Question 5

Protein digestion

• 4 places for protein digestion
• Describe protein digestion

Answer 5

Question 6

Intestines:
- 2 ways water moves across the intestines

• Water secretion into lumen of the gut

Answer 6

Question 7

Vitamin B12

• Symptoms
• Causes

Answer 7

Question 8

Lactose intolerance

• What is this? deficiency in what…
• Symptoms
• Explain the symptoms - how does it lead to these symptoms?

Answer 8

Question 9

Irritable Bowel Syndrome

• Symptoms
• Female:Male ratio
• Which group is more affected?
• Associated with what…

Answer 9

Question 10

Coeliac Disease:

• Cause
• How does g____ damage the m____
• 3 ways m____ is damaged
• Symptoms
• Investigations
• Treatment

Answer 10

• Gliadin fraction of gluten
• Damages mucosa of SI
• High concordance in monozygotic twins
• Malabsorption = cant absorb it - high osmotic pressure within lumen of gut
• Not absorbing things - no nutrients - weight loss
• Sugars reaching gut - fermented = flatulence + distension = abdo pain
(stretch receptors signal pain)
Impaired iron absorption = anaemia
• Hypocalcaemia -> neuro sx
• Repeat GI endoscopy histo look for improvements
• Free from gluten foods

Question 11

Coeliac trunk - Blood supply to ___gut

• Explain the three main branches of the coeliac trunk
• What branches come of these?

Answer 11

Question 12

Superior mesenteric artery (SMA)

• Supplies what…
• 4 branches, supplying what…
• 5th - set of branches…

Answer 12

Superior mesenteric artery (SMA) = midgut
• SMA supplies small intestine (attachment of SI goes from top left to bottom right angle along the posterior part of peritoneal cavity) - SMA comes at an oblique angle from top left to bottom right
• Gives off branches (L) to ileum and jejenum
• Branch of SMA goes to terminal ileum and caecum = iliocolic artery (right lower quad)
• Artery to ascending colon = right colic artery
• Artery to 2/3 of transverse colon = middle colic artery
• Branches of SMA form a continuous connection around the periphery of the large intestine = marginal artery (anastomeses linking togather to form continous blood supply to colon)

Question 13

IMA:
- 3 branches…

Answer 13

Inferior mesenteric artery (IMA) = hindgut
• Comes off at L3 from abdo aorta towards left
• Gives off left colic artery supplying the descending colon
• Sigmoidal arteries supplies sigmoid colon
• IMA renamed as it passes into the pelvis = superior rectal artery - supplies superior portion of rectum
• Anastamoses at the periphery of bower - marginal arteries from IMA
• Joins togather with SMA’s arteries anastamose together at the splenic flexure = watershed are - vulnerable portion when drop of blood pressure - weakest blood supply - ischaemic changes.