Deck 3

Question 1

Describe mechanisms of excessive accumulation of fat in the liver

Answer 1

1. Fatty liver due to increased mobilisation of fat from
   adipocytes or hydrolysis of lipoprotein of chylomicron
   triglyceride by lipoprotein lipase in extrahepatic tissue

• Hypoglycemia -> causing increased mobilisation of fat, lipolysis of fats -> increased FFAs are taken up by liver where quantity of FFAs is greater than the livers ability to break them down -> triglycerides start accumulating –> FATTY LIVER

2. Fatty liver due to a decreased transport of VLDL into the blood (metabolic block in the prod. of proteins & phospholipids, transport across structurally & functionally damages plasma membranes).
3. Fatty liver due to excessive chylomicron intake

• High fat, low protein diets (carnivores) -> excessive accumulation of fat by the liver, decreased synthesis of transport proteins for lipids –> FATTY LIVER
• High carbohydrate & energy diet (laying hens, geese) ->
  lipogenesis by the liver beyond its capacity to
  synthesise lipoproteins –> FATTY LIVER

4. Fatty liver due to impaired oxidation of fatty acids

• Hepatotoxins & low protein, choline deficient, essential
  FA deficient diets -> damage & swelling of
  mitochondria -> metabolic block of beta-oxidation of
  FA’s -> accum. of TAG (triacylglycerol) in hepatocytes –>
  FATTY LIVER

5. Fatty liver due to essential FA deficiency

• Deficiency of essential FA’s (in poultry) -> activation of
  FFA synthesis -> fat accum. in liver –> FATTY LIVER

Question 2

What is myxoedema?

Answer 2

Myxoedema = increased accum. of proteins complexed
w/polysaccharides, sulphuric acid and
hyaluronic acid in the subcutaneous
space

• In hyperthyroidism: sodium & water are also retained,
  leading to myxoedema, an
  oedematous deposition of
  polysaccharides.

Question 3

Characterise: - Icterus
- Kernicterus
- Neonatal Jaundice

Answer 3

1. Icterus: jaundice, hyperbilirubinaemia, yellow
   discolouration of scleras & skin
2. Kernicterus: not fully developed blood-brain barrier in
   newborns, unconjugated bilirubin can
   cross into brain & damage ganglia
3. Neonatal Jaundice: immature liver cells (first 7-14
   postnatal days), not fully
   functional conjugation enzymes
   leading to jaundice

Question 4

Problems caused by decreased protein in the blood

Answer 4

1. Hypoalbuminaemia (albumin is contributor to plasma
   oncotic pressure. Can cause ascites (excess fluid in
   abdomen)
2. Decreased synthesis of plasma clotting factors
   (uncontrolled bleeding, more prone to haemorrhage)
3. Decreased synthesis of ceruloplasmin ( copper
   binding protein, microcytic hypochromic anaemia)
4. Decreased transferrin synthesis (iron binding protein,
   microcytic hypochromic anemia)
5. Decreased synthesis of apoproteins by the liver (fatty
   liver, macrocytic anemia)