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WorksheetsCardiac Metabolism Quiz
Total questions: 30
Worksheet time: 15mins
During prolonged fasting, which molecule supplements energy production in the heart?
Glucose
Ketone bodies
Lactate
Glycogen
What is the main energy currency molecule in cardiac metabolism?
NADH
ATP
Acetyl-CoA
Oxaloacetate
Which process yields 129 ATP per molecule and predominates during the fasting/steady-state in the heart?
Glycolysis of glucose
β-oxidation of palmitate
Anaerobic glycolysis
Oxidative phosphorylation of lactate
Which molecule is the final electron acceptor in oxidative phosphorylation?
NADH
ATP
Oxygen
Acetyl-CoA
During ischaemia, how much does ATP fall within 1 minute?
10%
25%
50%
75%
Why does anaerobic glycolysis accelerate during ischaemia, and what is its ATP yield per glucose?
Due to increased oxygen, yielding 36 ATP per glucose
Due to lack of oxygen, yielding 2 ATP per glucose
Due to increased fatty acids, yielding 129 ATP per glucose
Due to increased ketones, yielding 4 ATP per glucose
Explain why ketones are considered "brain-sparing" fuel during starvation and how this affects the heart's metabolism.
Ketones are used only by the brain, so the heart uses glucose
Ketones spare glucose for the brain, so the heart burns fatty acids and ketones
Ketones inhibit fatty acid metabolism in the heart
Ketones increase ATP production in the heart
Which blood level and pH combination defines lactic acidosis?
Blood lactate > 5 mmol L⁻¹ and pH < 7.35
Blood lactate < 2 mmol L⁻¹ and pH > 7.45
Blood lactate > 10 mmol L⁻¹ and pH > 7.4
Blood lactate < 1 mmol L⁻¹ and pH < 7.0
What is the significance of myoglobin as a cardiac biomarker?
It rises very early after injury but is not cardiac-specific.
It is highly specific for cardiac tissue and rises late.
It is only detectable after 24 hours.
It is used exclusively for diagnosing reinfarction.
A patient with severe anaemia develops metabolic acidosis. Blood tests show lactate > 5 mmol L⁻¹ and pH 7.2. Explain the likely pathophysiological mechanism.
Tissue hypoxia leads to increased anaerobic glycolysis, resulting in lactate accumulation and consumption of bicarbonate, causing anion-gap metabolic acidosis.
Anaemia causes increased oxygen delivery, reducing lactate production and increasing pH.
Severe anaemia leads to decreased glycolysis, resulting in metabolic alkalosis.
Lactate is converted to glucose, increasing blood pH and causing alkalosis.
Which of the following is considered the gold standard marker for detecting 1 g of cardiac necrosis?
Cardiac troponin I/T
LDH-1
Myoglobin
Creatine kinase
What biochemical change is observed in a cell undergoing reversible injury?
ATP levels are 5-20% of normal
ATP levels are 100% of normal
Glycolytic flux decreases
Lactate levels decrease
In the intrinsic (mitochondrial) pathway of apoptosis, which event occurs first?
Caspase-8 activation
Bax/Bak pore formation
Executioner caspase activation
Formation of apoptotic bodies
Which of the following factors does NOT determine the outcome of ischaemia?
Collateral circulation
Metabolic demand
Oxygen extraction reserve
Blood glucose level
Which of the following best describes the structure of smooth muscle cells?
Spindle-shaped with central nucleus and dense bodies
Striated with multiple peripheral nuclei
Branched with intercalated discs
Cylindrical with Z-discs
During relaxation of smooth muscle, which enzyme is responsible for dephosphorylating myosin?
Myosin light-chain kinase (MLCK)
Myosin light-chain phosphatase (MLCP)
SERCA pump
Adenylate cyclase
Which neurotransmitter and receptor combination causes contraction of smooth muscle in vessels?
Acetylcholine (ACh) acting on M2 receptors
Norepinephrine acting on α1 receptors
Norepinephrine acting on β2 receptors
Acetylcholine (ACh) acting on M3 receptors
Compare and contrast the effects of norepinephrine on smooth muscle in vessels versus bronchi, and explain the physiological significance of these differences.
Norepinephrine causes contraction in vessels (via α1) and relaxation in bronchi (via β2), allowing for blood pressure regulation and airway dilation, respectively.
Norepinephrine causes relaxation in both vessels and bronchi, leading to decreased blood pressure and airway constriction.
Norepinephrine causes contraction in both vessels and bronchi, increasing blood pressure and airway resistance.
Norepinephrine has no effect on smooth muscle in either vessels or bronchi.
Explain how pacemaker-like slow waves in single-unit smooth muscle contribute to the function of organs such as the gastrointestinal tract.
They coordinate whole-sheet contractions for peristalsis and mixing of contents.
They inhibit contraction, leading to muscle relaxation.
They cause random, uncoordinated contractions.
They only occur in multi-unit smooth muscle.
What is the definition of an Adverse Drug Reaction (ADR)?
A beneficial response to a drug at normal doses
A harmful, unintended response at normal doses
An allergic reaction to any medication
A response to an overdose of a drug
Which of the following best describes a Type B (Bizarre) adverse drug reaction?
Dose-related and predictable from pharmacology
Idiosyncratic, dose-independent, immune or genetic
Chronic and related to long-term use
Delayed and related to carcinogenesis
Which patient-specific risk factor is associated with increased drug-drug interactions due to polypharmacy?
Age
Genetics
Polypharmacy
Diet
Explain why elderly patients are at increased risk for adverse drug reactions.
They have increased renal/hepatic reserve
They have immature enzymes
They have decreased renal/hepatic reserve
They metabolize drugs faster
Which genetic factor is associated with abacavir hypersensitivity?
CYP2D6 ultrarapid
HLA-B*57:01
CYP3A4
VKORC1
What is the main difference between an Adverse Drug Reaction (ADR) and an Adverse Drug Event (ADE)?
ADRs include overdoses, ADEs do not
ADEs are a subset of ADRs
ADEs are broader and include overdoses and errors, while ADRs are a subset
ADRs are always predictable, ADEs are not
What should be done before prescribing medication to minimize ADRs?
Check renal and hepatic function
Skip patient history
Prescribe the highest dose
Avoid written warnings
Which of the following is NOT part of the practical checklist for minimizing ADRs?
Encourage patients to report unusual symptoms early
Provide written and verbal warnings for serious effects
Ignore electronic prescribing alerts
Ask about allergies and previous ADRs
Which of the following drugs requires therapeutic drug monitoring due to a narrow therapeutic index?
Digoxin
Paracetamol
Ibuprofen
Amoxicillin
Which energy system is dominant in muscle during the first 0-4 seconds of exercise?
Phosphocreatine
Anaerobic glycolysis
Aerobic β-oxidation
Mixed glycolysis + OXPHOS
Considering the statement "Every drug is a potential poison," discuss how pharmacokinetics and genetics can influence the safety and effectiveness of a medication in a patient.
Pharmacokinetics and genetics affect how a drug is processed and responded to, meaning the same drug can be safe for one patient but toxic for another, requiring careful monitoring and respect for individual differences.
All drugs are equally safe for all patients regardless of genetics.
Pharmacokinetics only affects drug effectiveness, not safety.
Genetics has no impact on drug response.
