Met

Question 1

Ferritin

Answer 1

Intracellular protein that acts as a buffer store of iron

Question 2

ALP function

Answer 2

Can cause mobilisation of calcium and phosphate stores in bone to increase serum levels

Question 3

Zonulin functions

Answer 3

Loosens tight junctions between epithelial cells of the gut lining is response to the presence of gliadin

Question 4

Bacteria in Whipple disease

Answer 4

Tropheryma whipplei

Gram positive

Question 5

Whipple disease pathophysiology

Answer 5

Lesions in intestinal walls
Damages billi
Also affects joints, CNS and CV systems

Question 6

Diagnosis of Whipple disease

Answer 6

Duodenal biopsy
PAS positive staining macrophages
Pale yellow mucosa
Thickened mucosal folds

Question 7

Whipple disease treatment

Answer 7

Penicillin, ampicillin, tetracycline, doxycycline

Vitamin supplements

Question 8

Cholera toxin actions

Answer 8

Binds to enterocyte surface and taken up by endocytosis
Acvtiates a G protein that activates adenylyl cyclase
Increase IC cAMP levels
Overactivation of PKA
Phosphorylation of CFTR channel to open it
Large efflux of chloride ions
Water, sodium, potassium and bicarbonate follow
Rapid fluid loss leading to dehydration and diarrhoea

Question 9

Define diarrhoea

Answer 9

Increased frequency of bowel evacuation with abnormally soft or liquid faeces with a volume of greater than 250g

Question 10

Osmotic diarrhoea

Answer 10

Where the presence of unabsorbable products in the small intestine means that water remains in the intestines and is not absorbed
E.g. lactose intolerance

Question 11

Secretory diarrhoea

Answer 11

Where substances are actviely trasnported into the gut lumen causing the secretion of water
E.g. cholera, salmonella

Question 12

Inflammatory diarrhoea

Answer 12

Where bowel inflammation means the bowel is less able to absorb the products of digestion and water effectively
E.g. Crohn’s disease, ulcerative colitis

Question 13

Complications of diarrhoea

Answer 13

Dehydration –> kidney failure, seizures, cerebral oedema, shrivelled skin, delirium, unconsciousness
Acid base imbalance - metabolic acidosis due to excessive bicarbonate loss
Malnutrition
Weight loss

Question 14

Treatment of diarrhoea

Answer 14

ORS - glucose and sodium chloride
Diet - low fat, high fibre
Opiates (imodium) - slow transit time and increases anal sphincter tone
Bile acid sequesterants - prevents bile acids having an osmotic effect

Question 15

Dietary water intake

Answer 15

2000-3000ml/day

Question 16

Salivary secretions per day

Answer 16

1000-2000ml/day

Question 17

Gastric juices per day

Answer 17

1000-2000ml/day

Question 18

Bile secretions per day

Answer 18

500-1000ml/day

Question 19

Pancreatic secretions per day

Answer 19

1000-2000ml/day

Question 20

Intestinal secretions per day

Answer 20

1000-2000ml/day

Question 21

How much water enters the colon per day?

Answer 21

1500ml/day

Question 22

How much water is lost in faeces per day?

Answer 22

100-200ml/day

Question 23

Why is water needed in the gut?

Answer 23

Hydrolysis reactions
Allows substances to be brought into close contact with intestinal walls
Mixes with mucin to make mucous
Propulsion of gut contents by peristalsis

Question 24

How is gastric reflex prevented?

Answer 24

LOS tone
Acute angel where oesophagus enters stomach
Terminal oesophagus being within the abdominal cavity –> pressure collapses it
Contraction of the crural diaphragm exerts a pinch cock action on the oesophagus

Question 25

Pathophysiology of heartburn

Answer 25

Acid entering the oesophagus can get through the epithelium Activates spinal and vagal afferents Travel to the CNS Give the sensation of pain

Question 26

Causes of heartburn

Answer 26

``` TLOSRs Weakened oesophageal epithelium Hypersensitivty to pain Hiatus hernia Increased intra-gastric pressure such as in obesity Decreased intra-abdominal pressure Shortened oesophagus ```

Question 27

Risk factors for heart burn

Answer 27

``` Obesity Fatty foods Cabonated and caffeinated drinks Pregnancy Hiatus hernia Gastroparesis CCBs - relax LOS NSAIDs, SSRIs, bisphosphates, corticosteroids - irritation ```

Question 28

Diagnosis of heartburn

Answer 28

``` Barium meal and x ray for obstructions Endoscopy for oesophagitis and masses Biopsy for Barret's oesophagus Ambulatory acid probe test Manometry ```

Question 29

Treatment of heartburn/GORD

Answer 29

Actacids - neutralise stomach acid PPIs - reduce action of H+/K+ ATPase in the parietal cells H2 receptor antagonists - prevent binding of histamine to H2 receptors on parietal cells to decrease adenylyl cylase activation, cAMP production and therefore proton pump activation Alginates - raft on stomach content surface Baclofen - reduce TLOSRs Macrolides - increase gastric motility Surgery - fundoplication - creation of LOS with stomach

Question 30

Tests for H. pylori

Answer 30

Urea breath test Blood antibodies Stool antibodies Stomach biopsy

Question 31

How does the urea breath test work?

Answer 31

``` Drink containing urea Breath into bag Air tested for CO2 levels Higher than normal CO2 = positive This is because the bacteria convert the urea into ammonia and carbon dioxide ```

Question 32

Effects of hypoxia on EPO production

Answer 32

Decreased renal perfusion in hypoxia Causes release of EPO from kidney Causes increased RBC production in bone marrow

Question 33

HIF-1 in hypoxia

Answer 33

Alpha subunits not degraded in hypoxia HIF-1 can bind to promote regions of genes to promote their transcription Upregulation of genes involved in glycogen breakdown and glycolysis Suppression of mitochondrial fission and promotion of autophagy to reduce oxidative stress Upregulation of VEGF to promote angiogenesis to increase tissue perfusion

Question 34

Changes in glycogen breakdown in exercise

Answer 34

Calcium binds to calmodulin subunit of phosphorylase kinase Activation of glycogen phosphorylase to increase glycogen breakdown AMP also allosterically activates glycogen phosphorylase

Question 35

Entry into TCA cycle in exercise

Answer 35

Controlled by PDC | PDC unregulated by calcium and ADP

Question 36

Actions of AMP

Answer 36

Increases GLUT4 activity in muscles Increases glycogen phosphorylase activity Increases PFK-1 activity by activating AMPK which increases PFK2 action Activates AMPK that inactivates ACC to prevent lipogenesis and promote fatty acid break down