MedSoc SAQ Flashcards
Explain the process of alcohol metabolism in the liver
- Alcohol is metabolised to acetaldehyde by alcohol dehydrogenase
- Acetaldehyde is metabolised to acetate by acetaldehyde dehydrogenase
- Acetate is broken down into CO2 and water
Describe the steps of bilirubin metabolism
- Unconjugated bilirubin binds to albumin to be transported to the liver
- UDP glucoronyl transferase catalyses the addition of glucoronic acid, forming conjugated bilirubin
- Conjugated bilirubin dissolves into bile, and is reduced to urobilinogen in the small intestine
- Urobilinogen can be reabsorbed into the blood and oxidised to urobilin
- Urobilin can be recycled into bile or excreted in urine
- Urobilinogen can also be oxidised into stercobilin by intestinal bacteria and excreted in faeces
Why would an unhealthy liver lead to bruising?
The liver produces bile salts that are essential for vitamin K absorption. Clotting factors 10, 9, 7 and 2 rely on vitamin K for their synthesis
Explain the effects of low albumin in the blood
Albumin is a plasma protein that maintains oncotic pressure. A decrease in albumin causes a decrease in oncotic pressure, resulting in net movement of water out of the blood into the interstitial fluid. Oedema.
How are changes in osmolality of extracellular fluid detected?
Osmoreceptors in the hypothalamus
Describe how antibodies are specific to one antigen?
Antibodies bind to antigens via the variable region, which determines the specificity of the antibody.
Describe ketogenesis
- High rates of fatty acid oxidation create overwhelming amounts of acetyl-CoA for the Kreb’s cycle
- Two molecules of acetyl-CoA are converted into acetoacetyl-CoA by thiolase
- Acetoacetyl-CoA is converted into acetoacetate
- Acetoacetate is converted into acetone and betahydroxybutyrate
Give some examples of multifactorial diseases
Type 2 diabetes, spina bifida, schizophrenia
Explain how a girl can be a carrier of an X linked recessive disorder
The mutated gene is located on the X chromosome. A female can be a carrier as they have two X chromosomes, so one can be affected but it is not enough to produce the affected phenotype
What shape are red blood cells, and why are they this shape?
Biconcave disc, to increase the surface area to volume ratio. This makes oxygen exchange more efficient.
What is a single nucleotide polymorphism?
A DNA sequence variation occurring when a single nucleotide in the genome sequence is altered, with the alteration present in at least 1% of the population
What is preload?
The initial stretching of the cardiac myocytes prior to contraction
What is afterload?
The pressure the left ventricle must overcome to eject blood in systole
Name some risk factors for coronary artery disease
Smoking, obesity, male sex, age, family history
Describe oesophageal innervation
The oesophagus is innervated by the vagus nerve. The upper portion of the oesophagus has voluntary (striated) fibres. The lower portion of the oesophagus has involuntary (smooth) fibres. The middle third has a mix of the two.