hllj/quesmed huggingface dataset:
Which of the following hormones stimulate and inhibit very low-density lipoprotein (VLDL) formation?

Options:
explanation: Insulin suppresses lipolysis in adipocytes. This increases free fatty acids which stimulate the assembling and secretion of VLDL. Growth hormone increases adipose lipolysis which suppresses VLDL formation.
name: Stimulated by growth hormone, inhibited by insulin
label: c
answer: no
explanation: Insulin suppresses lipolysis in adipocytes. This increases free fatty acids which stimulate the assembling and secretion of VLDL. Thyroid hormone decreases the secretion of VLDL, and VLDL levels are usually high in those with hypothyroidism (low thyroid hormones).
name: Stimulated by thyroid hormone, inhibited by insulin
label: d
answer: no
explanation: Insulin suppresses lipolysis in adipocytes. This increases free fatty acids which stimulate the assembling and secretion of VLDL. Oestrogen increases VLDL levels due to the enhanced production of apolipoprotein B and triglycerides.
name: Stimulated by insulin, inhibited by oestrogen
label: e
answer: no
explanation: Insulin suppresses lipolysis in adipocytes. This increases free fatty acids which stimulate the assembling and secretion of VLDL. High glucagon levels reduce VLDL production.
name: Stimulated by insulin, inhibited by glucagon
label: a
answer: yes
explanation: Insulin suppresses lipolysis in adipocytes. This increases free fatty acids which stimulate the assembling and secretion of VLDL. High glucagon levels reduce VLDL production.
name: Stimulated by glucagon, inhibited by insulin
label: b
answer: no

Correct answer: a
Fatty acids are broken down to release energy from reserves stored in adipose tissue. This involves mobilisation, activation and degradation.

Which of the following activates fatty acids in the liver?

Options:
explanation: This enzyme mediates the first step of fatty acid synthesis to form malonyl-CoA from acetyl-CoA.
name: Acetyl-CoA carboxylase
label: c
answer: no
explanation: This is a molecule formed by 2 acetyl-CoA molecules. It is not an enzyme.
name: Acetoacetyl-CoA
label: d
answer: no
explanation: This enzyme is responsible for the conversion of 3-hydroxy-3-methylglutaryl-CoA to mevalonate. This reaction is part of the cholesterol synthesis pathway.
name: 3-hydroxyl-3-methylglutaryl CoA (HMG-CoA) reductase
label: b
answer: no
explanation: This enzyme catalyses the reaction between acetoacetyl-CoA and acetyl-CoA to form 3-hydroxyl-3-methylglutaryl CoA (HMG-CoA).
name: 3-hydroxyl-3-methylglutaryl CoA (HMG-CoA) synthase
label: e
answer: no
explanation: Fatty acids are transported to the liver and activated by acyl-CoA synthase in the cytoplasm to form fatty acyl-CoA. Activation of the fatty acyl-CoA traps the fatty acid in the cell. In order for it to cross the mitochondrial membrane, it reacts with carnitine to form acyl-carnitine which passes into the mitochondria.
name: Acyl-CoA synthase
label: a
answer: yes

Correct answer: a
A 58-year-old male presents to the hospital with confusion, ataxia and ocular abnormalities. He is subsequently diagnosed with beriberi.

Beriberi is a deficiency of which vitamin?

Options:
explanation: This is also known as scurvy. It may present with tiredness, irritability, muscle pain and easy bruising.
name: Vitamin C
label: d
answer: no
explanation: This is a deficiency of folate. It may present with fatigue, dizziness, pallor, and headache. Folate deficiency is a cause of macrocytic anaemia.
name: Vitamin B9
label: e
answer: no
explanation: This is a cause of rickets in children and osteomalacia in adults. It is often asymptomatic but may present with bowing of the legs, proximal muscle weakness and gait abnormalities in children.
name: Vitamin D
label: c
answer: no
explanation: This is a deficiency of cobalamin. This may present with shortness of breath, headaches, fatigue, paraesthesia and ataxia (problems with balance and coordination). B12 deficiency is a cause of macrocytic anaemia.
name: Vitamin B12
label: b
answer: no
explanation: This is a deficiency of thiamine. An acute severe deficiency of vitamin B1 may lead to Wernicke's encephalopathy. This is characterised by the classic triad of acute confusion, ataxia, and ocular abnormalities such as nystagmus.
name: Vitamin B1
label: a
answer: yes

Correct answer: a
Which of the following is the mechanism of action by which glucocorticoids reduce asthmatic inflammation?

Options:
explanation: Activation of beta-2 receptors on airway smooth muscle by glucocorticoids stimulates the Gs pathway. This increases the concentration of cAMP which stimulates protein kinase A to decrease calcium mobilisation and sensitivity. This causes muscle relaxation and therefore relieves the bronchoconstriction associated with asthma.
name: Increases beta-2 receptor activation
label: a
answer: yes
explanation: Glucocorticoids decrease the number of mast cells. As mast cells are immune cells, this reduces the inflammatory response produced by the immune system.
name: Increases number of mast cells
label: d
answer: no
explanation: Glucocorticoids reduce endothelial cell leakage. As cell leakage is part of the inflammatory response, glucocorticoids can reduce inflammation by decreasing leakage.
name: Increases endothelial cell leakage
label: c
answer: no
explanation: Glucocorticoids reduce the number of dendritic cells. As dendritic cells are immune cells, this reduces the inflammatory response produced by the immune system.
name: Increases the number of dendritic cells
label: b
answer: no
explanation: Glucocorticoids reduce cytokine release from T cells. Asthma is associated with the cytokines interleukin 4, 5 and 13 (IL-4, IL-5, IL-13) which promote airway eosinophilia and mucus overproduction. Therefore glucocorticoids can reduce inflammation by decreasing cytokine mediators.
name: Increases cytokine mediators of inflammation
label: e
answer: no

Correct answer: a
Which of the following describes the term "function residual capacity"?

Options:
explanation: This describes "respiratory reserve volume".
name: The additional volume of gas that can be expired below tidal volume on maximal expiration
label: d
answer: no
explanation: This describes "residual volume".
name: The volume of gas that remains in the lungs following maximal expiration
label: c
answer: no
explanation: This describes "functional residual capacity".
name: The volume of gas that remains in the lungs following normal quiet expiration
label: a
answer: yes
explanation: This describes "vital capacity".
name: The volume of gas that can be expired following maximal inspiration
label: e
answer: no
explanation: This describes "tidal volume".
name: The volume of air moved into or out of the lungs during quiet breathing
label: b
answer: no

Correct answer: a
Oxygen-haemoglobin binding is affected by several factors.

Which of the following statements is correct?

Options:
explanation: Increased temperature **decreases** Hb-O2 binding affinity, decreasing oxygen saturation at a given partial pressure of oxygen and effectively releasing oxygen from haemoglobin.
name: High temperature increases haemoglobin-oxygen (Hb-O2) affinity and decreases O2 unloading from haemoglobin
label: e
answer: no
explanation: A high pH (alkalosis) **increases** haemoglobin-oxygen binding as it decreases the rate of ligand dissociation. This allows for a higher rate of oxygen binding in the lungs where there is a lower pCO2 and the environment is more alkalotic.
name: High pH decreases haemoglobin-oxygen (Hb-O2) affinity and increases O2 unloading from haemoglobin
label: b
answer: no
explanation: Increased 2,3-diphosphoglycerate (2,3-DPG) **decreases** Hb-O2 binding affinity, decreasing oxygen saturation at a given partial pressure of oxygen and effectively releasing oxygen from haemoglobin.
name: High 2,3-diphosphoglycerate (2,3-DPG) increases haemoglobin-oxygen (Hb-O2) affinity and decreases O2 unloading from haemoglobin
label: d
answer: no
explanation: At the site of respiration, there is a high pCO2 due to the production of waste products. Carbon dioxide increases hydrogen ion concentration which causes acidosis (low pH). This increases ligand dissociation and promotes the release of oxygen from haemoglobin.
name: High pCO2 decreases haemoglobin-oxygen (Hb-O2) affinity and increases oxygen unloading from haemoglobin
label: a
answer: yes
explanation: Increased temperature decreases Hb-O2 binding affinity, decreasing oxygen saturation at a given partial pressure of oxygen and effectively releasing oxygen from haemoglobin.
name: High temperature increases haemoglobin-oxygen (Hb-O2) affinity and increases O2 unloading from haemoglobin
label: c
answer: no

Correct answer: a
What impact do anaemia and carbon monoxide poisoning have on blood oxygen transportation?

Options:
explanation: In anaemia, haemoglobin affinity is unchanged i.e. the percentage of haemoglobin binding sites that are occupied with oxygen remains the same. Therefore, despite there being less haemoglobin overall, the oxygen saturation of haemoglobin remains unchanged. In carbon monoxide poisoning, the number of haemoglobin is unchanged but carbon monoxide displaces oxygen that would normally bind to haemoglobin and causes a low haemoglobin oxygen saturation.
name: Haemoglobin saturation (Hb SaO2) is normal in anaemia and reduced in carbon monoxide poisoning
label: a
answer: yes
explanation: CaO2 is reduced in **both** carbon monoxide poisoning and anaemia. The total arterial oxygen concentration includes the oxygen bound to haemoglobin as well as the oxygen concentration in the plasma. As both anaemia and carbon monoxide affect haemoglobin, the oxygen-carrying capacity is reduced (the plasma oxygen concentration is unaffected however). This reduces the overall arterial oxygen concentration.
name: CaO2 (total arterial oxygen concentration) is reduced in carbon monoxide poisoning and normal in anaemia
label: b
answer: no
explanation: Haemoglobin concentration is reduced in anaemia and **normal** in carbon monoxide poisoning. This is because, in carbon monoxide poisoning, carbon monoxide displaces oxygen at haemoglobin binding sites as it has a higher affinity than oxygen. This reduces the oxygen-carrying capacity, however the number of haemoglobin molecules remains unaffected.
name: Haemoglobin concentration is reduced in both anaemia and carbon monoxide poisoning
label: e
answer: no
explanation: Haemoglobin-oxygen concentration is reduced in **both** anaemia and carbon monoxide poisoning. Carbon monoxide displaces oxygen at haemoglobin binding sites as it has a higher affinity than oxygen. This reduces the oxygen-carrying capacity and hence the haemoglobin-oxygen concentration.
name: Haemoglobin-oxygen concentration is reduced in anaemia and normal in carbon monoxide poisoning
label: d
answer: no
explanation: PaO2 is normal in both anaemia and carbon monoxide poisoning. The partial pressure of oxygen refers to the pressure of oxygen in the plasma, not the overall concentration of oxygen in the blood i.e. it does not include oxygen bound to haemoglobin. As it is only the oxygen bound to haemoglobin (the oxygen-carrying capacity) that is affected in anaemia and carbon monoxide poisoning, the PaO2 is unaffected.
name: PaO2 is reduced in anaemia and normal in carbon monoxide poisoning
label: c
answer: no

Correct answer: a
Which mechanism of respiratory failure correlates to this clinical pattern with the presence of compensatory hyperventilation?

PaCO2 – normal

PaO2 – decreased

Arterial Ph – normal

%SaO2 – decreased

A-a gradient – high

Options:
explanation: Carbon monoxide poisoning is a type of insufficient oxygen-carrying capacity that presents with a low oxygen saturation and a normal PaO2 (it only affects the oxygen that is normally bound to haemoglobin).
name: Carbon monoxide poisoning
label: e
answer: no
explanation: Insufficient ventilation means that carbon dioxide can not be exhaled: this increases PaCO2. As carbon dioxide is acidic, this will cause the arterial pH to decrease. As inhalation is also affected, there is less oxygen in the blood leading to a low PaO2. A lower total arterial oxygen content (CaO2) means that oxygen saturation is also low as there are fewer oxygen molecules to bind to haemoglobin. As the problem is not with oxygen diffusion, the Alveolar-arterial gradient is normal.
name: Insufficient ventilation e.g. COPD
label: b
answer: no
explanation: In the presence of insufficient oxygen, hypoxaemia triggers hyperventilation which normalises carbon dioxide levels (which may have increased due to ventilation or perfusion abnormalities). This also normalises the pH. PaO2 is low as oxygen is unable to diffuse into the circulation, which also causes a low oxygen saturation. A high Alveolar-arterial gradient indicates that the partial pressure of oxygen in the alveoli is higher than in arterial blood as there is an issue with the oxygenation of the blood.
name: Insufficient oxygenation e.g. VQ mismatch
label: a
answer: yes
explanation: Insufficient oxygen-carrying capacity does not affect carbon dioxide levels, therefore PaCO2 is unaffected. PaO2 is also unaffected as this refers to the partial pressure of oxygen in the plasma rather than bound to haemoglobin. In anaemia, haemoglobin affinity is unchanged i.e. the percentage of haemoglobin binding sites that are occupied with oxygen remains the same. Therefore the oxygen saturation of haemoglobin remains unchanged. As oxygenation is not affected in anaemia, the Alveolar-arterial gradient is normal.
name: Insufficient oxygen-carrying capacity e.g. anaemia
label: c
answer: no
explanation: Insufficient oxygen in the atmosphere triggers hyperventilation which decreases PaCO2. As carbon dioxide can release hydrogen ions and cause an acidic environment, the lack of CO2 causes pH to increase (becomes more alkaline). The PaO2 decreases due to a lack of available oxygen which therefore causes a low oxygen saturation. As the problem is not with oxygen diffusion, the Alveolar-arterial gradient is normal.
name: Insufficient oxygen in the atmosphere e.g. altitude
label: d
answer: no

Correct answer: a
Which of the following cells is renin released from?

Options:
explanation: Renin is not released by hepatocytes in the liver. Renin is released from juxtaglomerular cells in the kidneys. This converts angiotensinogen (which is produced by the liver) into angiotensin I.
name: Hepatocytes
label: c
answer: no
explanation: These cells cleave angiotensin 1 into angiotensin 2 through the action of angiotensin converting enzyme ACE).
name: Lung endothelial cells
label: d
answer: no
explanation: The macula densa is a collection of cells which sense the concentration of sodium in the distal convoluted tubule and signal to the juxtaglomerular cells to release renin.
name: Macula densa
label: e
answer: no
explanation: Peritubular cells are the site of erythropoietin (EPO) synthesis which stimulates red blood cell production. It does not release renin.
name: Peritubular cells
label: b
answer: no
explanation: The juxtaglomerular cells are derived from smooth muscle cells in the afferent arteriole and contain granules with the enzyme renin. In response to low sodium, renin indirectly increases vascular tone and sodium reabsorption to increase blood pressure.
name: Juxtaglomerular cells
label: a
answer: yes

Correct answer: a
By what mechanism does Tamm Horsfall protein act to prevent urinary tract infections?

Options:
explanation: This is carried out by the process of exfoliation, which is undertaken by uroepithelial cells in response to infection.
name: Removal of infected cells from the urinary tract
label: e
answer: no
explanation: This is the result of unidirectional urine flow.
name: Physical removal of bacteria from the urinary tract
label: b
answer: no
explanation: This is the action of lysozymes.
name: Cleaves cell wall component, killing bacteria
label: d
answer: no
explanation: Tamm Horsfall protein possesses a mannose-containing side chain which can trap the mannose-sensitive pili or fimbriae of organisms such as *Escherichia coli*.
name: Competitive inhibition of bacterial binding
label: a
answer: yes
explanation: This is the mechanism of action of mucous and mucin within the urinary tract.
name: Traps and prevents bacterial adherence to the epithelium
label: c
answer: no

Correct answer: a
A 36-year-old female presents with a history of episodic coughing with purulent sputum, fever, dyspnoea, and chest pain over the last six days. She gives a history of vomiting and hiccups on and off for 7 years.  She says that she has difficulty swallowing her food and sometimes regurgitates it.

What is the most likely diagnosis?

Options:
explanation: Achalasia is the inability of the lower oesophageal sphincter to relax and the loss of oesophageal peristalsis due to a loss of inhibitory nitrinergic neurons. As a result, patients may experience difficulty swallowing and regurgitation. The history of episodic coughs, purulent sputum, fever, dyspnoea and chest pain is suggestive of an aspiration pneumonia which has occurred secondary to regurgitation.
name: Achalasia
label: a
answer: yes
explanation: Gastro-oesophageal reflux disease may present with regurgitation, chest pain and dysphagia (difficulty swallowing), however this would typically present with heartburn that occurs after having larger meals and is aggravated by lying down or bending forward. GORD is unlikely to cause an aspiration pneumonia or infective symptoms.
name: Gastro-oesophageal reflux disease (GORD)
label: b
answer: no
explanation: Peptic ulcer disease may present with epigastric pain, nausea, vomiting and dyspepsia. It does not present with dysphagia.
name: Peptic ulcer disease
label: c
answer: no
explanation: Dyspepsia describes multiple upper gastrointestinal symptoms which persist for 4 or more weeks. This includes heartburn, burping, bloating, nausea, vomiting and early satiety. It is also known as indigestion. Causes of dyspepsia include GORD, peptic ulcer disease and Barrett's oesophagus.
name: Dyspepsia
label: e
answer: no
explanation: *Helicobacter pylori* is a gram-negative infection which causes peptic ulcers. It may present with abdominal pain, nausea, bloating and loss of appetite.
name: *Helicobacter pylori* infection
label: d
answer: no

Correct answer: a
The tricarboxylic acid cycle (TCA cycle), also known as the Krebs cycle, is the first step of aerobic respiration in an eukaryotic cell. The TSA cycle is regulated by several enzymes.

Which of the following enzymes is inhibited by acetyl-CoA?

Options:
explanation: This enzyme is inhibited by malate and oxaloacetate.
name: Succinate dehydrogenase
label: b
answer: no
explanation: This enzyme is inhibited by ATP and NADH.
name: Isocitrate dehydrogenase
label: c
answer: no
explanation: This enzyme is inhibited by NADH, ATP and succinyl CoA.
name: Alpha-ketoglutarate dehydrogenase
label: d
answer: no
explanation: This enzyme is inhibited by citrate and glutamate.
name: Malate dehydrogenase
label: e
answer: no
explanation: This enzyme is inhibited by NADH, ATP, and acetyl CoA.
name: Pyruvate dehydrogenase
label: a
answer: yes

Correct answer: a
In which parts of the nephron are potassium re-absorption and secretion the highest?

Options:
explanation: Around 65% of potassium is re-absorbed in the proximal tubule, and 20-150% is secreted by the distal tubule and principal cells in the collecting duct.
name: Highest re-absorption in the proximal tubule, highest secretion in the distal tubule and principal cells in the collecting duct
label: a
answer: yes
explanation: Re-absorption of potassium in the proximal tubule is around 65%. However, the thick ascending limb of the loop of Henle is responsible for the absorption of potassium, not secretion.
name: Highest re-absorption in the proximal tubule, highest secretion in the thick ascending limb of the loop of Henle
label: e
answer: no
explanation: The thick ascending limb of the loop of Henle only re-absorbs 25% of potassium. Intercalated cells in the collecting duct secrete 0-5% of potassium.
name: Highest re-absorption in the thick ascending limb of the loop of Henle, highest secretion in the intercalated cells of the collecting duct
label: b
answer: no
explanation: The thick ascending limb only absorbs 25% of potassium in comparison to 65% by the proximal tubule. The highest secretion of potassium is in the distal tubule and principal cells (20-150%).
name: Highest re-absorption in the thick ascending limb of the loop of Henle, highest secretion in the distal tubule and principal cells of the collecting duct
label: d
answer: no
explanation: The re-absorption of potassium in the proximal tubule is around 65% but intercalated cells in the collecting duct only secrete 0-5% of potassium in comparison to the distal tubule and principal cells which secrete >20%.
name: Highest re-absorption in the proximal tubule, highest secretion in the intercalated cells of the collecting duct
label: c
answer: no

Correct answer: a
A 73-year-old male attends his GP as he was alarmed when he found blood in his urine this morning. The urine sample provided by the patient shows macroscopic haematuria and a urine dipstick reveals 2+ protein.

Which of the following is the most likely cause of these findings?

Options:
explanation: Membranous nephropathy is one of the most common causes of **nephrotic syndrome** in adults. Nephrotic syndrome is characterised by proteinuria, hypoalbuminaemia and oedema. It does not present with haematuria.
name: Membranous nephropathy
label: c
answer: no
explanation: Focal segmental glomerulosclerosis is a cause of **nephrotic syndrome** and describes scarring of the glomeruli. Nephrotic syndrome is characterised by proteinuria, hypoalbuminaemia and oedema. It does not present with haematuria.
name: Focal segmental glomerulosclerosis
label: d
answer: no
explanation: Whilst a recent group A Streptococcus infection can cause **nephritic syndrome**, this is very uncommon in adults. Poststreptococcal glomerulonephritis is the most common cause of glomerulonephritis in children.
name: Post-streptococcal glomerulonephritis
label: e
answer: no
explanation: Minimal change disease is one of the most common causes of **nephrotic** syndrome. Nephrotic syndrome is characterised by proteinuria, hypoalbuminaemia and oedema. It does not present with haematuria.
name: Minimal change disease
label: b
answer: no
explanation: ANCA-associated vasculitis is a broad umbrella term for 3 types of vasculitis which affect the glomeruli. They are causes of **nephritic syndrome** which is characterised by haematuria, proteinuria and renal impairment.
name: ANCA-associated vasculitis
label: a
answer: yes

Correct answer: a
An 84-year-old male with diabetes and heart failure has his blood pressure checked by his GP. His BP is found to be 92/70.

Which of the following statements is correct in describing how renal autoregulation corrects hypotension?

Options:
explanation: This would effectively cause a low eGFR and therefore lead to an acute kidney injury (AKI).
name: Angiotensin II acts on afferent arterioles to cause vasoconstriction and prostaglandins act on efferent arterioles to cause vasodilation
label: e
answer: no
explanation: Angiotensin II causes arterial vasoconstriction.
name: Angiotensin II acts on afferent and efferent arterioles to cause vasodilation
label: d
answer: no
explanation: Angiotensin II is a vasoconstrictor whereas prostaglandins are vasodilators.
name: Angiotensin II acts on afferent arterioles to cause vasodilation and prostaglandins act on efferent arterioles to cause vasoconstriction
label: b
answer: no
explanation: Prostaglandins are vasodilators.
name: Prostaglandins act on afferent and efferent arterioles to cause vasoconstriction
label: c
answer: no
explanation: Prostaglandins are produced in response to stimulation of the sympathetic nervous system and cause smooth muscle relaxation, preferentially of the afferent arteriole wall. This causes vasodilation. Angiotensin acts on AT1 receptors to cause vasoconstriction. Both of these actions increase eGFR.
name: Prostaglandins act on afferent arterioles to cause vasodilation and angiotensin II acts on efferent arterioles to cause vasoconstriction
label: a
answer: yes

Correct answer: a