DUMES - principles Flashcards
what is the law explaining this newborn’s condition where premature baby by 10 weeks, is found to be tachypnoeic. On examination, there is intercostal recession, nasal flaring, and cyanosis. The baby is placed on NCPAP in NICU. Which phenomenon best explains the reason for this baby’s respiratory distress?
law of La Place.
It states that the tension exerted on a spherical wall of set pressure is inversely proportional to that sphere’s thickness.
Alveoli are prone to collapse due to alveolar surface tension. Pulmonary surfactant is a fluid which increases alveolar thickness and thus reduces alveolar surface tension.
when does resp distress syndrome arise?
Respiratory distress syndrome arises in premature newborns with insufficient surfactant
Which neurotransmitter acts on muscarinic receptors and what is its action in the airways?
Acetylcholine, constriction of the airways
Which of the following statements correctly explains the difference between foetal and adult haemoglobin?
Foetal haemoglobin has gamma subunits instead of beta subunits, causing it to have a higher affinity for oxygen than adult haemoglobin
In the foetal circulation, which shunt connects the pulmonary trunk to the aorta?
Ductus arteriosus
Which of the following statements correctly describes the intent of neo-adjuvant treatment?
Neo-adjuvant treatment is given before surgery to shrink the tumour for surgical removal
what is the ductus venosus
The ductus venosus allows oxygenated blood from the placenta to bypass the hepatic circulation
what is the foramen ovale
The foramen ovale shunts oxygenated blood from the right atrium to the left atrium, bypassing the pulmonary circulation.
what is adjuvant treatment
Adjuvant treatment is given after surgery, aimed at reducing the risk of recurrence
Which option is an example of metaplasia?
Squamous epithelium changing to columnar epithelium in response to contact with gastric acid
Which option correctly defines the following:
“Normal genes which stimulate cell division”
Proto-oncogenes
what happens to proto-oncogenes during cancer
In cancer, these proto-oncogenes are changed to oncogenes which enable uncontrolled cell proliferation
what are tumour suppressor genes
Tumour suppressor genes are normal genes that inhibit cell division - loss of both copies of a tumour suppressor gene can allow cancer to develop.
genetic code is unambiguous
each codon specifies a single amino acid or stop codon only
genetic code is degenerate
which means a single amino acid is coded for by more than one codon (e.g leucine, coded for by CUU, CUC, CUA and CUG).
describe the action of ACh, Gastrin and ghrelin
Acetylcholine acts on M3 muscarinic receptors. Gastrin binds to G/CCK2 receptors, histamine acts via H2 receptors and ghrelin is the “hunger hormone” which does not act on parietal cells.
Which of the following options correctly describes a nonsense mutation?
A nonsense mutation causes a premature stop and hence an abnormally short protein.
What is the rate-limiting enzyme for each of the following processes?
1) Glycogenesis (synthesis of glycogen from glucose)
2) Glycogenolysis (breakdown of glycogen from glucose)
3) Gluconeogenesis (synthesis of glucose within the body from non-carbohydrate precursors)
4) Lipogenesis (the metabolic formation of fat)
1) Glycogen synthase
2) Glycogen phosphorylase
3) Fructose 1,6-bisphosphonate
4) acetyl-coA carboxylase
IgA
IgA is found in breast milk, saliva and tears and is transferred to the neonate via colostrum and breast milk.
IgG
IgG is the most abundant immunoglobulin found in blood serum, is dominant in the memory immune response and is transferred across the placenta into the foetal circulation
IgM
IgM is produced first in the adaptive immune response
IgE
IgE mediates Type I hypersensitivity reactions
Which of the following cancers is associated with a c-MYC mutation?
Burkitt’s lymphoma is associated with c-MYC mutations.
You are looking at a patient’s histology slides and find psammoma bodies (pictured below). Which of the following cancers is associated with psammoma body formation?
Psammoma bodies are collections of calcium found in biopsy samples of mesothelioma, a pleural malignancy caused by inhaled asbestos fibres.
