hllj/quesmed huggingface dataset:
Which of the following vessels supplies blood to the proximal transverse colon?

Options:
explanation: The coeliac trunk supplies the foregut - the oesophagus to the ampulla of Vater.
name: Coeliac trunk
label: c
answer: no
explanation: The inferior mesenteric artery supplies the hindgut - the distal one-third of the transverse colon to the rectum.
name: Inferior mesenteric artery
label: b
answer: no
explanation: The internal iliac artery supplies the pelvic viscera, structures of the pelvic wall, perineum, gluteal region and thigh.
name: Internal iliac artery
label: e
answer: no
explanation: The left renal artery would supply the left kidney, and would not supply any of the gastrointestinal tract.
name: Left renal artery
label: d
answer: no
explanation: The blood supply to the gastrointestinal tract is divided in line with its' embryological origin. The foregut (oesophagus to the sphincter of Oddi) is supplied by the coeliac trunk, the midgut (sphincter of Oddi to the proximal two-thirds of the transverse colon) is supplied by the superior mesenteric artery, and the hindgut (everything distal to the distal one-third of the transverse colon) is supplied by the inferior mesenteric artery.
name: Superior mesenteric artery
label: a
answer: yes

Correct answer: a
A 48-year-old woman presents to A&E with palpitations, weakness, and shortness of breath. An arterial blood gas is performed which demonstrates a potassium level of 7.0. As part of the initial management, she is given IV calcium gluconate.

What is the role of calcium gluconate in the management of this patient's hyperkalaemia?

Options:
explanation: This is incorrect as it is the mechanism of bicarbonate, which does also have a role in the treatment of hyperkalaemia.
name: Shift of potassium intracellularly by raising pH
label: b
answer: no
explanation: This is incorrect as it is the mechanism of insulin when given to patients with hyperkalaemia. This also forms a vital part of the initial management for this patient, but calcium gluconate is typically given first as it is cardioprotective, and arrhythmias are the primary cause of mortality. Dextrose is usually given with insulin in these patients to minimise the risk of hypoglycaemia. This is a similar mechanism to salbutamol, which may also be used in hyperkalaemia.
name: Shift of potassium ions into cells via activation of Na/K ATPase
label: c
answer: no
explanation: This is the mechanism of calcium resonium. This prevents the body from absorbing excess potassium in the GI tract. It may be given PR or orally, and may be given alongside other treatments.
name: Prevention of potassium absorption in the GI tract
label: d
answer: no
explanation: This is correct. Calcium gluconate is administered as a first-line agent in patients with severe hyperkalaemia to protect cardiomyocytes and prevent life-threatening arrhythmias. Calcium increases the threshold potential, restoring the normal gradient between threshold potential and resting membrane potential, which is typically elevated in hyperkalaemia.
name: Stabilisation of cardiomyocyte membrane potentials
label: a
answer: yes
explanation: This is incorrect. This is the mechanism of diuretics such as loop diuretics. Although this may result in a fall in potassium over time, it would not provide a reduction fast enough to be used in the immediate management of this patient.
name: Decreased renal potassium reabsorption
label: e
answer: no

Correct answer: a
Which of the following cell types cannot perform phagocytosis?

Options:
explanation: Basophils are not phagocytic. When stimulated, basophils release histamine - a potent vasodilator - to promote inflammation and draw in other immune cells to neutralise a target.
name: Basophils
label: a
answer: yes
explanation: Dendritic cells play an important role in linking the innate and adaptive immune systems. They are specialised to phagocytose and process antigens by converting proteins into and presenting major histocompatability complex (MHC) molecules which can be recognised by T-cells.
name: Dendritic cells
label: e
answer: no
explanation: Eosinophils are phagocytic and can engulf antibody-marked substances. Despite this, eosinophils more commonly release an array of inflammatory mediators to aid in the inflammatory process.
name: Eosinophils
label: c
answer: no
explanation: Macrophages are specialised cells which detect, phagocytose and destroy harmful organisms. They can be found in almost every tissue (e.g. alveolar macrophages) and use receptors such as toll-like receptors to recognise products of bacteria and other microorganisms.
name: Macrophages
label: b
answer: no
explanation: Neutrophils are the most abundant white blood cell type in humans. They are typically the first white blood cells to reach sites of inflammation and phagocytose pathogens and release antimicrobial factors to combat them.
name: Neutrophils
label: d
answer: no

Correct answer: a
A 61-year-old man has recently been diagnosed with colorectal cancer. He asks his doctor for more information.

Which of the following mechanisms allows cancer cells to evade growth suppression?

Options:
explanation: Switching on telomerase enables replicative immortality of the cell, preventing senescence and telomere shortening. Whilst this is key in cancer, it is unrelated to evading growth suppression.
name: Switching on telomerase
label: c
answer: no
explanation: Inactivation of the p53 tumour suppressor gene is a frequent event in tumorigenesis. Usually, the p53 gene plays a role in controlling cell division and cell death. Inactivation of this gene removes one of the protective factors in cancer development by allowing cancer cells to be unsuppressed. It can occur by various cellular stresses such as hypoxia and DNA damage.
name: Inactivation of tumour protein p53 (TP53)
label: a
answer: yes
explanation: Induction of vascular endothelial growth factor (VEGF) allows for induction of angiogenesis, which is another hallmark of cancer but unrelated to evading growth suppression.
name: Induction of vascular endothelial growth factor (VEGF)
label: b
answer: no
explanation: Secretion of TGF-β allows cells to avoid immune destruction and proliferate with greater freedom. Whilst this is key in cancer, it is unrelated to evading growth suppression.
name: Secretion of transforming growth factor beta (TGF-β)
label: d
answer: no
explanation: Production of IGF survival factor allows cancer cells to resist planned cell death and continue to proliferate. Whilst this is key in cancer, it is unrelated to evading growth suppression.
name: Production of Insulin-like growth factor survival factor
label: e
answer: no

Correct answer: a
DNA repair involves a collection of mechanisms by which the cell maintains the integrity of its genetic code.

Which of the following is a repair mechanism for double strand breaks that creates defective DNA?

Options:
explanation: This repair method can only be used to fix single-strand defects. It involves recognising DNA damage, incising on either side to remove the damaged fragment, adding new nucleotides by DNA polymerase, and then sealing the lesion with DNA ligase.
name: Base excision repair
label: b
answer: no
explanation: This repair method can be used to fix double-stranded defects but works differently to non-homologous end joining as there is a copying process involving homologous recombination from the second chromosome, restoring the original complete sequence. It does therefore not create defective DNA.
name: Homologous recombination
label: e
answer: no
explanation: This repair method can only be used to fix single-strand defects. It works similarly to base excision repair but is used for bulkier and larger lesions of multiple bases, removing the affected nucleotides with DNA helicase and then repairing with DNA polymerase and ligase.
name: Nucleotide excision repair
label: c
answer: no
explanation: This mechanism ligates two broken ends together, resulting in a region of DNA with altered segments due to missing nucleotides. This loss of nucleotides occurs due to degradation from both ends. It is used for fixing double-strand breaks specifically, not single-strand defects, and the loss of nucleotides can cause different proteins to be transcribed as a result.
name: Non-homologous end joining
label: a
answer: yes
explanation: This repair method can only be used to fix single strand defects. When there is an error in a newly made strand, mismatch proofreading proteins bind. DNA repair protein MutS binds to the mismatched base pair and DNA repair protein MutL scans nearby DNA and triggers strand removal to the mismatch.
name: Mismatch repair
label: d
answer: no

Correct answer: a
A 24-year-old female has become pregnant for the first time. At her booking visit, she asks about the chances of her baby being born with a genetic condition.

Which of the following is an imprinting syndrome?

Options:
explanation: This is mainly caused by expansion of the CGG trinucleotide sequence in the 5' UTR of the FMR1 gene on the X chromosome, not imprinting. It silences the FMR1 gene, causing learning difficulties, macrocephaly, a long face, and large ears.
name: Fragile X syndrome
label: d
answer: no
explanation: This is caused by trisomy of chromosome 18, not imprinting. Clinical features include micrognathia, low-set ears, rocker bottom feet and overlapping of fingers.
name: Edward's syndrome
label: e
answer: no
explanation: Down syndrome is caused by trisomy of chromosome 21, not imprinting. The clinical features include single palmar creases, upslanting palpebral fissures, epicanthic folds and small ears.
name: Down syndrome
label: b
answer: no
explanation: This is caused by trisomy of chromosome 13, not imprinting. The clinical features are microcephaly, cleft lip/palate and scalp lesions.
name: Patau syndrome
label: c
answer: no
explanation: Imprinting syndromes occur when one of the parental alleles is inherited but 'turned off' or 'stamped'. In PWS, there is deletion of the paternal copy of chromosome 15q11-q13, leading to language, motor and developmental delays, and excessive weight gain.
name: Prader-Willi syndrome
label: a
answer: yes

Correct answer: a
Adipose tissue can be divided into brown and white adipose tissue.

Which of the following enzymes accounts for the brown colouration of brown adipose tissue?

Options:
explanation: Monoamine oxidases are a family of enzymes that catalyse the oxidation of monoamines. They are involved in breakdown of digestive products and also act as monoamine neurotransmitters. They do not cause the brown colouration of brown adipose tissue.
name: Monoamine oxidase
label: e
answer: no
explanation: Alkaline phosphatase is an enzyme found in many forms, most commonly in the liver and bone. It is a diagnostic biomarker in diseases such as hepatitis or osteomalacia. It does not cause the brown colouration of brown adipose tissue.
name: Alkaline phosphatase
label: d
answer: no
explanation: Brown adipose tissue is present during foetal life but diminishes after the first decade of life. It has high levels of cytochrome oxidase in the mitochondria, which plays a role in energy production in aerobic cells by catalysing the last step of respiration. Cytochrome oxidase enzymes account for its brown colouration.
name: Cytochrome oxidase
label: a
answer: yes
explanation: Xanthine oxidase is a form of xanthine oxireductase, catalysing the oxidation of xanthine to uric acid and the general catabolism of purines. It is unrelated to adipose tissue.
name: Xanthine oxidase
label: b
answer: no
explanation: Alanine transaminase is an enzyme found most commonly in the liver, used as a clinical biomarker for liver health. It does not cause the brown colouration of brown adipose tissue.
name: Alanine transaminase
label: c
answer: no

Correct answer: a
A 44-year-old is seen in the emergency department with severe pain due to a fracture of his right humerus.  He requests some analgesia through the fastest-acting means available.

Which of the following routes of administration enables the drug to work most quickly?

Options:
explanation: In most cases, oral medications do not take effect until they reach the stomach and are absorbed into the blood stream. Modified release preparations are designed to have a longer duration of action than regular oral morphine, however they must still be absorbed from the gastro-intestinal tract and reach the bloodstream before taking effect.
name: Oral morphine (modified release)
label: b
answer: no
explanation: Transdermal medications, that are applied to the external surface of the skin, generally work for extended periods of time and do not begin action as quickly as intravenous drugs.
name: Transdermal fentanyl patch
label: e
answer: no
explanation: This question tests knowledge of routes of administration. Intravenous medications are injected directly into the bloodstream, bypassing first pass metabolism in the liver and bowel. It is therefore extremely fast acting.
name: Intravenous tramadol
label: a
answer: yes
explanation: Topical ibuprofen gel must penetrate the skin before it is able to take effect. It therefore takes longer to work than intravenous medications.
name: Topical ibuprofen gel
label: d
answer: no
explanation: In most cases, oral medications do not take effect until they reach the stomach and are absorbed into the blood stream. Oral morphine must be absorbed from the gastro-intestinal tract and reach the bloodstream before taking effect.
name: Oral morphine
label: c
answer: no

Correct answer: a
A 23-year-old man is given a new drug in a clinical trial. It has been observed to follow 1st order kinetics with a rate constant of k=0.01386.

Which of the following represents the half life of this new drug?

Options:
explanation: The half-life of a drug when following first-order kinetics is to divide 0.693 by the constant k. This is the same for any first-order kinetics. Therefore, 0.693/k = 50.
name: 90 minutes
label: d
answer: no
explanation: The half-life of a drug when following first-order kinetics is to divide 0.693 by the constant k. This is the same for any first-order kinetics. Therefore, 0.693/k = 50.
name: 50 minutes
label: a
answer: yes
explanation: The half-life of a drug when following first-order kinetics is to divide 0.693 by the constant k. This is the same for any first-order kinetics. Therefore, 0.693/k = 50.
name: 110 minutes
label: e
answer: no
explanation: The half-life of a drug when following first-order kinetics is to divide 0.693 by the constant k. This is the same for any first-order kinetics. Therefore, 0.693/k = 50.
name: 35 minutes
label: b
answer: no
explanation: The half-life of a drug when following first-order kinetics is to divide 0.693 by the constant k. This is the same for any first-order kinetics. Therefore, 0.693/k = 50.
name: 70 minutes
label: c
answer: no

Correct answer: a
Intracellular signalling can take a variety of forms. In G-protein coupled receptors (GPCRs), activation of a cell surface receptor causes a cellular response through activation of a G-protein.

Which of the following best describes the speed of action of a GPCR?

Options:
explanation: Tyrosine Kinase receptors act within minutes to hours. They are involved in cell to cell communication and a wide range of biological functions. By contrast, GPCR signalling is much faster than this, acting within seconds.
name: Minutes to hours
label: c
answer: no
explanation: GPCRs are membrane proteins used to convert extracellular information into a cellular response. They act within seconds, as is necessary for functions like vision, taste, and olfaction.
name: Seconds
label: a
answer: yes
explanation: Although ion channels act within milliseconds, GPCR signalling is slightly slower. The rapid action of ion channel signalling is necessary for muscle contraction in the skeletal muscle and cardiac muscle.
name: Milliseconds
label: b
answer: no
explanation: GPCR signalling occurs within seconds.
name: Days
label: e
answer: no
explanation: Nuclear receptors act within hours. These are activated by steroid hormones and other signals, which are found inside the cell. By contrast, GPCR signalling is much faster than this, acting within seconds.
name: Hours
label: d
answer: no

Correct answer: a
A 41-year-old man presents to A&E feeling extremely unwell. An arterial blood gas is taken, which shows:


||||
|--------------|:-------:|------------------|
|pH|7.33|7.35 - 7.45|
|PaO₂|9.6 kPa|11 - 15|
|PaCO₂|6.7 kPa|4.6 - 6.4|
|Bicarbonate|32 mmol/L|22 - 30|

Which of the following correctly describes the acid-base imbalance?

Options:
explanation: Remember ROME

Resp = Opposite

eg. low pH + high pco2 = acidosis OR high pH + low pco2 = alkalosis

Metabolic = Equal

eg. low pH + low bicarb = acidosis OR high pH + high bicarb = alkalosis

This patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis. This option is therefore incorrect.
name: Metabolic alkalosis
label: d
answer: no
explanation: There is a 5 step process to interpreting ABGs:

1) How is the patient? (Clinical judgement is needed here but as preclinical medics it is still simple to interpret ABGs)

2) Is the patient hypoxaemic? The pO2 on air should be >10 kPa

3) Is the patient acidaemic (pH <7.35) or are they alkalaemic (pH >7.45)? This tells you whether this is an acidosis or alkalosis.

To ascertain metabolic or respiratory causes, steps 4 and 5 are key.

4) Respiratory - pCO2 reading. >6.0 kPa suggests respiratory acidosis (or compensating for metabolic alkalosis). <4.7kPa suggests respiratory alkalosis (or compensating for metabolic alkalosis).

5) Metabolic - bicarbonate reading. <22 mmol/L suggests metabolic acidosis (or compensating for respiratory alkalosis). >26 mmol/L suggests metabolic alkalosis (or compensating for respiratory acidosis).

This patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis.
name: Respiratory acidosis
label: a
answer: yes
explanation: Remember ROME

Resp = Opposite

eg. low pH + high pco2 = acidosis OR high pH + low pco2 = alkalosis

Metabolic = Equal

eg. low pH + low bicarb = acidosis OR high pH + high bicarb = alkalosis

This patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis. This option is therefore incorrect.
name: Metabolic acidosis
label: c
answer: no
explanation: Remember ROME

Resp = Opposite

eg. low pH + high pco2 = acidosis OR high pH + low pco2 = alkalosis

Metabolic = Equal

eg. low pH + low bicarb = acidosis OR high pH + high bicarb = alkalosis

This patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis. This option is therefore incorrect.
name: Respiratory alkalosis
label: b
answer: no
explanation: Remember ROME

Resp = Opposite

eg. low pH + high pco2 = acidosis OR high pH + low pco2 = alkalosis

Metabolic = Equal

eg. low pH + low bicarb = acidosis OR high pH + high bicarb = alkalosis

This indicates a normal anion gap, as seen in diarrhoea, addison's and gastrointestinal causes of bicarbonate loss.

The patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis. This option is therefore incorrect.
name: Hyperchloraemic metabolic acidosis
label: e
answer: no

Correct answer: a
The kidneys play a vital role in maintaining the balance of fluid and electrolytes.

Which of the following hormones directly regulates sodium reabsorption in the distal convoluted tubule (DCT)?

Options:
explanation: Desmopressin is a synthetic version of vasopressin, used to treat conditions such as cranial diabetes insipidus and nocturnal enuresis. It regulates water reabsorption in the DCT and collecting duct, by increasing the insertion of aquaporin-2 receptors into the DCT and collecting duct cells. This in turn leads to the reabsorption of water back into the bloodstream. Although this can indirectly influence sodium levels through dilutional effects, vasopressin does not work directly on sodium transporters.
name: Desmopressin
label: d
answer: no
explanation: Renin cleaves angiotensinogen to form angiotensin I. This, if subsequently converted to Angiotensin II, causes the release of aldosterone from the adrenal cortex. Thus although renin increases the expression of aldosterone, which subsequently regulates sodium reabsorption, it does not directly lead to sodium reabsorption in the DCT.
name: Renin
label: c
answer: no
explanation: Vasopressin, also known as antidiuretic hormone or ADH, is a hormone secreted by the pituitary gland. It regulates water reabsorption in the DCT and collecting duct, by increasing the insertion of aquaporin-2 receptors into the DCT and collecting duct cells. This in turn leads to the reabsorption of water back into the bloodstream. Although this can indirectly influence sodium levels through dilutional effects, vasopressin does not work directly on sodium transporters.
name: Vasopressin
label: b
answer: no
explanation: Prostacyclin is a vasodilator and platelet activation inhibitor, unrelated to sodium reabsorption.
name: Prostacyclin
label: e
answer: no
explanation: Aldosterone is a mineralocorticoid hormone produced by the adrenal cortex. It plays a key role in maintaining fluid balance, primarily through its role in regulating sodium reabsorption. In the distal convoluted tubule, aldosterone upregulates the expression of sodium chloride co-transporters (NCC). These increase the reabsorption of both sodium and chloride.
name: Aldosterone
label: a
answer: yes

Correct answer: a
Erythropoietin (EPO) is a renally secreted hormone.

Which of the following best describes the effect of EPO?

Options:
explanation: Incorrect: EPO acts on the bone marrow to stimulate red blood cell production, increasing the capacity of for oxygen carriage.
name: Increasing iron absorption to allow for production of more red blood cells
label: d
answer: no
explanation: This is correct. EPO stimulates the bone marrow to produce more red blood cells, often as an adaptive response to hypoxia. Detection of low oxygen occurs at the bifurcation of the carotid arteries and renal cortex. EPO is produced in response to increase oxygen carrying capacity and correct the hypoxia.
name: Stimulation of bone marrow to produce more red blood cells
label: a
answer: yes
explanation: Incorrect: EPO acts on the bone marrow to stimulate red blood cell production, increasing the capacity of for oxygen carriage.
name: Mediating gaseous exchange in the alveoli, increasing oxygen uptake
label: b
answer: no
explanation: Incorrect: EPO acts on the bone marrow to stimulate red blood cell production, increasing the capacity of for oxygen carriage.
name: Stimulate conversion of fibrinogen to fibrin to aid clotting in response to injury
label: e
answer: no
explanation: Incorrect: EPO acts on the bone marrow to stimulate red blood cell production, increasing the capacity of for oxygen carriage.
name: Enhancing circulatory competence by improving peripheral flow
label: c
answer: no

Correct answer: a
Caspases are enzymes that play a crucial role in programmed cell death (apoptosis). They include both 'initiators' that initiate the apoptosis signal and 'executioner' that carry out proteolysis.

Which of the following caspases are the 'executioner' caspases?

Options:
explanation: Caspases 2, 8, and all 9 are 'initiator' caspases. Initiators begin the process of apoptosis, particularly by converting pro-executioner caspases into active executioner caspases. However they do not directly carry out proteolysis themselves.
name: Caspase 2, 8, 9
label: b
answer: no
explanation: Caspase 3 is an 'executioner' but 8 and 9 are 'initiator' caspases.
name: Caspase 3, 8, 9
label: c
answer: no
explanation: These are the executioner caspases, causing nuclear fragmentation, cytoskeletal disruption, membrane alterations and organelle reduction.
name: Caspase 3, 6 and 7
label: a
answer: yes
explanation: Caspase 6 is an 'executioner' but 7 and 8 are 'initiator' caspases.
name: Caspase 6, 7, 8
label: d
answer: no
explanation: Caspase 3 is an 'executioner'. However caspases 1 and 5 are not directly involved in apoptosis.
name: Caspase 1, 3, 5
label: e
answer: no

Correct answer: a