MEH

Question 1

microcytic anaemia causes

Answer 1

TAILS

Thalassaemia- mutation in globin genes (alpha or beta globin)
Anaemia of chronic disease- increased hepcidin leads to functional iron deficiency
Iron deficiency- normocytic in early stages then microcytic due to abnormal haem synthesis and insufficient haemoglobin synthesis
Lead poisoning
Sideroblastic anaemia- inherited defect in haem synthesis

Question 2

vit B12 absorption

Answer 2

1. forms complex with HAPTOCORRINS
2. pancreatic proteases digest complex, releasing B12 which binds to INTRINSIC FACTOR
3. once internalised, B12 forms complex with transcobalamin II and is released into bloodstream as complex

storage occurs in the liver, lack of intrinsic factor causes pernicious anaemia

Question 3

cell signalling control of insulin release

Answer 3

Increase in extracellular [glucose] causes it to move through glut 2 transporters into beta cells, more ATP produced, binds to K+ ATPase and inhibits K+ exiting cell, depolarises membrane activating VG Ca2+ channels, Ca2+ moves into cell causing vesicles containing insulin to fuse with outer membrane

Question 4

homocystinuria

Answer 4

issue breaking down METHIONINE
defect in CRYSTATHIONINE BETA SYNTHASE
treatment= low methionine diet (avoid meat, fish, eggs, cheese) also cysteine vit B12, betaine and folate supplements taken (cysteine not produced by crystathionine)
affects CVS, CNS, muscles, connective tissues

Question 5

Phenylketonuria

Answer 5

presence of phenylketones in urine- lack of phenylalanine hydroxylase

phenylalanine accumulates in blood, instead transaminated to phenylpyruvate and phenylketones are produced

symptoms= intellectual disability, developmental delay, seizures, microcephaly. Treatment= low protein, avoid artificial sweeteners, tyrosine supplementation

Question 6

Adrenal gland layers

Answer 6

Go Find Rex, Make Good Sex

layers= Glomerulosa, Fasciculata, Reticularis
produces… Mineralocorticoids, Glucocorticoids, Sex hormones (androgens)

Question 7

Paracetamol overdose

Answer 7

excess paracetamol causes production of toxic metabolite NAPQI
NAPQI causes direct toxicity to liver cells and depletes glutathione levels (glutathione conjugates NAPQI) causing oxidative damage to hepatocytes
Acetylcysteine= antidote- replenishes glutathione levels

Question 8

key regulators of gluconeogenesis

Answer 8

PEPCK and fructose 1,6 bisphosphatase

activated by cortisol/glucagon, inhibited by insulin

activated by fasting/starvation, prolonged exercise, stress

Question 9

signs associated w/ anaemia

Answer 9

abnormal facial bone structure- thalassaemia
koilonychia (spoon shaped nails)- iron deficiency
angular stomatitis (inflammation of corners of mouth)- iron deficiency
glossitis (inflammation+ depapillation of the tongue)- vit B12 deficiency

Question 10

causes of macrocytic anaemia

Answer 10

FAT RBC

Foetus- increased folate requirements during pregnancy
Alcohol- toxicity towards bone marrow + likely secondary B12/folate deficiency
hypoThyroidism- low thyroid hormones affect hormones involved in erythropoiesis
Reticulocytosis- secondary to blood loss, reticulocyte larger than RBC
B12/Folate- deficiency/pernicious, thymidine deficiency, uracil used, constant DNA repair, nucleus never matures
Cirrhosis/chronic liver disease