Basic science Flashcards
When does gastrulation occur?
Week 3
At what stage does the neural tube close?
Week 4
When does an embryo’s heart begin to beat?
Week 4
When in embryonic development does genitalia become differentiated?
Week 10
What are the three embryonic layers?
Ectoderm
Mesoderm
Endoderm
The CNS is derived from which embryonic layer?
Ectoderm
Most bones and connective tissue are derived from which embryonic layer?
Mesoderm
Where is bilirubin conjugated?
Liver
Which type of ulcers are more common with HSV 1?
Oral lesions
Which type of ulcers are more common with HSV 2?
Genital
During which phase of mitosis do chromosomes align at the centre of the cell?
Metaphase
Cobblestone appearance suggests…
Crohn’s disease
Granulomas are found in which type of IBD?
Crohn’s disease
Crypt abscesses are more common in which type of IBD?
UC
Measles evades the immune system by interacting with which immune cell?
Dendritic cells
What is the mechanism of paracetamol damage to the kidneys?
NAPQI-induced renal papillary necrosis
Studies which compare new diagnostic tests with gold standard tests may suffer from which type of bias?
Workup bias
What are the main phases of the cell cycle?
G1 > S > G2 > M…
At which point in the cell cycle does DNA replication occur?
S
What are the four stages of mitosis?
Prophase
Metaphase
Anaphase
Telophase
What happens during prophase?
chromatin condenses, chromosomes become visible
What happens during metaphase?
Chromosomes line up at centre of the cell
What happens during anaphase?
Sister chromatids move to opposite poles of the cell
What happens during telophase?
Cytoplasm separates, allowing for 2 daughter cells to form
What happens during the urea cycle?
Nitrogenous waste products converted to urea, eliminated by urine
What is the accessory bundle called in WPW syndrome?
Bundle of Kent
What is meant by ‘left shift’ of the oxy-Hb curve?
Increased Hb-O2 affinity and reduced tissue uptake
What is meant by ‘right shift’ of the oxy-Hb curve?
Decreased Hb-O2 affinity and increased tissue uptake
Which factors result in ‘right shift’ of the oxy-Hb curve?
INCREASED temp, CO2, 2,3-DPG, H+, altitude
Which factors result in ‘left shift’ of the oxy-Hb curve?
DECREASED temp, CO2, 2,3-DPG, H+, altitude
What is the effect of CO on the oxy-Hb dissociation curve?
Results in left shift
Which antibody is most involved in plasmodium vivax entry into cells?
Duffy
Which complement deficiencies can give rise to opportunistic infections?
C5-9
Which porphyria is associated with photosensitivity?
Porphyria cutanea tarda
What is the mechanism of action of methylphenidate?
Inhibits dopamine reuptake in basal ganglia
Which enzyme is involved in conjugation of bilirubin?
UDPGT
Which anti-TB drug can affect INR?
Rifampicin
What is the mechanism of action of milrinone?
Inhibition of PDE-III
What is the function of the CFTR?
Movement of chloride from intracellular to extracellular space in lungs
What colour do gram positive organisms stain?
Purple
What colour do gram negative organisms stain?
Pink
Do gram positive or negative organisms have a thicker peptidoglycan wall?
Positive
Give examples of gram positive cocci.
Staph
Strep
Enterococcus
Give examples of gram positive bacilli.
AACDL mnemonic
Actinomyces
Anthrax
Clostridium
Diphtheria
Listeria
Treponema pallidum is which kind of organism?
Gram negative spirochete
What kind of virus is HIV?
Single-stranded RNA reverse transcriptase
What kind of virus is Hepatitis B?
Double-stranded DNA reverse transcriptase
Give examples of DNA viruses.
Smallpox
Parvovirus
Hep B (reverse transcriptase)
Give examples of RNA viruses.
Rotavirus
Coronavirus
Measles
HIV (reverse transcriptase)
Increased PT suggests an issue with which pathway and factor?
Extrinsic pathway, factor 7
Increased APTT suggests an issue with which pathway?
Intrinsic pathway
Which clotting factors are involved in the intrinsic pathway?
8, 9, 11 and 12
Raised PT and APT suggests…
common pathway issue
Which factors are involved in the ‘common pathway’?
Factors 2,5 and 10
Which factors are Vitamin K dependent?
2, 7, 9 and 10
Which factor is deficient in Haemophilia A?
Factor 8 (VIII)
Which factor is deficient in Haemophilia B?
Factor 9 (IX)
Which factor is deficient in Haemophilia C?
Factor 11 (XI)
How is haemophilia C inherited?
AR
What is the mechanism of loop diuretics?
Inhibits Na/K/2Cl co-transporter in thick ascending loop of Henle to increase water excretion
What is the mechanism of thiazide-like diuretics?
Inhibit Na absorption at DCT resulting in water loss
What is the mechanism of aldosterone antagonists?
Block effects of aldosterone in DCT –> reduced activity of Na/K exchanger resulting in water loss
Which ion is most important in cardioplegia solution?
K+
What kind of receptor is Ca-sensing receptor?
GPCR
What are the main roles of PTH in calcium metabolsim?
Stimulates Ca release from bones
Stimulates Ca uptake by kidneys
Conversion of Vit D to active form
What is the main role of Vit D in calcium metabolism?
Increase intestinal absorption of Ca
Give features of hypocalcaemia.
Spasm/parasthesia
Seizures
Arrythmia
Renin is primarily secreted in response to…
Low BP
What is the role of Renin?
hydrolyses angiotensinogen to produce angiotensin I
Which structures are included in a myelomeningocoele?
Meninges, CSF and spinal nerves
Which anti-D immunoglobin is responsible for haemolytic disease of the newborn?
IgG
What is CVID?
Group of hypogammaglobulinaemi syndromes characterised by recurrent infections, increased risk of malignancy and autoimmune disease
What is the underlying issue in Bruton’s agammaglobulinaemia?
Defect in Bruton’s Tyrosine Kinase resulting in severe block in B cell development
How is Bruton’s agammaglobulinaemia inherited?
X-linked recessive
Which immune cell is affected in DiGeorge Syndrome?
T cells
What is the most common cause of SCID?
Genetic
Recurrent bacterial infections, eczema and thrombocytopaenia suggests…
Wiskott-Aldrich Syndrome
How is Wiskott-Aldrich syndrome inherited?
X-linked
What is the most abundant Ig sub-class in serum?
IgG
Which is the first immunoglobulin secreted in acute infection?
IgM
Basophilic stippling suggests…
Lead poisoning
What is the mechanism of Na valproate?
Increased GABA activity
What is the mechanism of Carbemazepine?
Binds to Na+ channels to increase refractory perior
What is the mechanism of Lamotrigine?
Na+ channel blocker
Which anti-epileptic(s) are P450 inhibitor?
Valproate
Which anti-epileptics are P450 inducers?
Lamotrigine, Carbamazepine, Phenytoin
Which eye drops are typically used to dilate the pupils?
Atropine
Which is the only vaccine to be given intra-dermally?
BCG
Prostaglandin is produced by…
Cyclo-oxygenase
What is the mechanism of UVB phototherapy?
Induction of pyridimine dimerisation
Where is melatonin produced?
Pineal gland
Which part of the bone is most susceptible to osteomyelitis?
Metaphysis
Which part of the bone is most susceptible to osteomyelitis?
Metaphysis
When is a serious case review initiated (England)?
Child dies or serious injury and abuse suspected
What are the most common causes of meningitis in > 3 months?
Neisseria meningitidis
Strep pneumoniae
H influenzae
What are the CSF findings in bacterial meningitis?
Raised protein, low glucose, increased polymorphs
What are the CSF findings in viral meningitis?
Increased or normal protein, normal glucose, increased lymphocytes
What are the CSF findings in fungal/TB meningitis?
Raised protein, low glucose, increased lymphocytes
Is grey or white matter more associated with decision making?
Grey
What is the mechanism of Vigabatrin?
GABA inhibitor
What is the MOA of levetiracetam?
Modulates SVA2 which regulates release of neurotransmitter
What is the MOA of ranitidine?
H2 receptor antagonist
What is the MOA of chlorephenamine?
H1 receptor antagonist
What is the MOA of Domperidone?
Dopamine antagonist
What is the role of leptin?
Decrease food intake and increase energy expenditure
What is the role of Ghrelin?
Increase food intake, fat deposition and GH release
What is the MOA of ethosuximide?
T-type Ca channel blocker
What are the typical CSF findings in GBS?
Protein +++, normal WCC/glucose
Which area is typically affected in IVH?
Germinal matrix
What is the primary mechanism of botulinum toxin?
ACh inhibition
What is the main method of paracetamol metabolism in children < 12?
Sulphate conjugation
Which protein reduces iron transport through enterocytes?
Hepcidin
What is the MOA of rocuronium?
competitive ACh antagonist –> preventing depolarisation
What is the most potent beta-agonist?
Dobutamine
What is the pathological process in SMA?
Anterior horn cell degeneration
Which part of the nephron is defective in Cystinuria?
PCT
Isolated premature development of pubic hair is called…
Premature adrenarche
Bias in which researchers’ ideas/hopes influence result…
observation bias
How are live attenuated vaccines made?
Passed through live foreign host
What is the detrimental gene in MRSA?
MecA
Where is leptin produced?
Adipocytes & P cells of stomach
Where is ghrelin produced?
Enteroendocrine cells in fundus of stomach
Where is somatostatin produced?
Hypothalamus and delta cells of GI tract
Which structure of the visual pathway is affected in a homonymous hemianopia?
Optic tract
Which structure of the visual pathway is affected in a quadrantanopia?
Optic radiation
Which structure is affected in an inferior quandrantanopia?
Superior optic radiation (parietal lobe)
Which structure is affected in a superior quandrantanopia?
Inferior optic radiation (temporal lobe)
What is the mechanism of phototherapy for jaundice?
Photoisomerisation from bilirubin to lumirubin which can be excreted in urine
What are the main functions of the PCT?
Reabsorb ions, water and nutrients, remove toxins and adjust pH
What are the main functions of the DCT?
Selective secretion of ions to maintain blood pH and electrolyte balance
Where in the nephron are aquaporins primarily located?
Descending loop of Henle
What is the main function of the ascending loop of Henle?
Reabsorb Na/Cl
Between which layers is CSF located?
Between arachnoid and pia mater
What is the main location of CSF production?
Ependymal cells in choroid plexus
Where is CSF re-absorbed?
Arachnoid granulations into superior sagittal sinuses
What is the flow of CSF within the ventricles?
Foramen of Munro –> Lateral ventricles –> 3rd ventricle —> Cerebral aqueduct (of Sylvius) –> Foramina of Magendie/Luschka –> 4th ventricle –> sub-arachnoid space
What is the most important enzyme in transporting fatty acids from adipose tissue to mitochondria?
Carnitine acyltransferase I
Histology: Patchy enteropathy with increase in eosinophils and lymphocytes (no increase in inra-cellular lymphocytes).
CMPA
Increase in intraepithelial lymphocyte count on duodenal biopsy suggests…
Coeliac disease
What is the most appropriate test for galactossaemia?
Red blood cell galactose-1-phosphate uridyl transferase activity
Acidosis and raised ammonia suggests…
Organic aciduria
Slightly low factor VIII and raised APTT suggests…
Von-Willebrand disease
Which toxin is most involved in bullous impetigo?
Exfoliative toxin A
Which toxin is most involved in SSSS?
Exfoliative toxin B
What kind of organism is listeria?
Gram positive rod
During which embryonic phase do alveoli start to develop?
Saccular
Which layer of skin is most affected by epidemolysis bullosa simplex?
Basal epidermis
Where is most Vitamin B12 absorbed?
Ileum
Which HLA sub-type is most associated with Ankylosing Spondylitis?
HLA-B27
Unable to prolong APTT with heparin suggests…
AT III deficiency
Where is ADH synthesised?
Hypothalamus