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Questions and Answers
What is the primary function of 3-Hydroxy-methylglutaryl coenzyme A (3-HMG CoA) reductase in the regulation of cholesterol synthesis?
What is the primary function of 3-Hydroxy-methylglutaryl coenzyme A (3-HMG CoA) reductase in the regulation of cholesterol synthesis?
- Inhibiting the synthesis of bile salts
- Controlling the rate of cholesterol synthesis in the liver (correct)
- Regulating the activity of enzymes involved in steroid hormone production
- Activating the transport of cholesterol in lipoproteins
What is the primary mechanism by which the liver takes up LDL?
What is the primary mechanism by which the liver takes up LDL?
- Active transport using ATP-dependent pumps
- Facilitated diffusion through specific protein channels
- Receptor-mediated endocytosis (correct)
- Passive diffusion through the liver cell membrane
What is the role of cholesterol in animal membranes?
What is the role of cholesterol in animal membranes?
- It provides structural integrity and fluidity to the membrane (correct)
- It is involved in the regulation of gene expression
- It is a key component of the electron transport chain
- It acts as a precursor to steroid hormones
What is the fate of cholesterol and other lipids in excess of those needed by the liver?
What is the fate of cholesterol and other lipids in excess of those needed by the liver?
What is the origin of the term 'cholesterol'?
What is the origin of the term 'cholesterol'?
What is the primary mechanism by which nitrates lead to vasodilation in the treatment of angina?
What is the primary mechanism by which nitrates lead to vasodilation in the treatment of angina?
What is the key difference between stable and unstable angina in terms of chest pain?
What is the key difference between stable and unstable angina in terms of chest pain?
What is the primary effect of β-blockers on the heart in the treatment of angina?
What is the primary effect of β-blockers on the heart in the treatment of angina?
What is the primary mechanism of action of Ca2+ channel blockers in the treatment of angina?
What is the primary mechanism of action of Ca2+ channel blockers in the treatment of angina?
What is the primary effect of glyceryl trinitrate on coronary arteries in the treatment of angina?
What is the primary effect of glyceryl trinitrate on coronary arteries in the treatment of angina?
What is the key similarity between unstable angina and myocardial infarction (MI) in terms of pathology?
What is the key similarity between unstable angina and myocardial infarction (MI) in terms of pathology?
What is the primary risk factor for atherosclerosis?
What is the primary risk factor for atherosclerosis?
Which enzyme is inhibited by statins?
Which enzyme is inhibited by statins?
What is the name of the gene responsible for familial hypercholesterolemia?
What is the name of the gene responsible for familial hypercholesterolemia?
What is the normal range for total cholesterol?
What is the normal range for total cholesterol?
What is the cause of angina in coronary heart disease?
What is the cause of angina in coronary heart disease?
What is the purpose of statins in the treatment of cardiovascular disease?
What is the purpose of statins in the treatment of cardiovascular disease?
What is the primary mechanism of action of dabigatran?
What is the primary mechanism of action of dabigatran?
What is the primary reason for avoiding warfarin in the first few months of pregnancy?
What is the primary reason for avoiding warfarin in the first few months of pregnancy?
What is the primary benefit of using bivalirudin in percutaneous coronary artery surgery?
What is the primary benefit of using bivalirudin in percutaneous coronary artery surgery?
What is the primary mechanism by which liver disease affects warfarin therapy?
What is the primary mechanism by which liver disease affects warfarin therapy?
What is the primary reason for monitoring prothrombin time (PT) in patients taking warfarin?
What is the primary reason for monitoring prothrombin time (PT) in patients taking warfarin?
What is the primary effect of high metabolic rate on warfarin therapy?
What is the primary effect of high metabolic rate on warfarin therapy?
What is the mechanism of action of aspirin in the context of antiplatelet therapy?
What is the mechanism of action of aspirin in the context of antiplatelet therapy?
Which of the following antibiotics can decrease vitamin K availability?
Which of the following antibiotics can decrease vitamin K availability?
What is the effect of dipyridamole on platelet aggregation?
What is the effect of dipyridamole on platelet aggregation?
Which of the following drugs can bind to warfarin in the gut and reduce its absorption?
Which of the following drugs can bind to warfarin in the gut and reduce its absorption?
What is the indication for using abciximab?
What is the indication for using abciximab?
Which of the following drugs can be used as a single agent in patients intolerant to aspirin?
Which of the following drugs can be used as a single agent in patients intolerant to aspirin?
Cholesterol is synthesised from Acetyl-CoA in the mitochondria.
Cholesterol is synthesised from Acetyl-CoA in the mitochondria.
LDL is formed from VLDL in the liver.
LDL is formed from VLDL in the liver.
HDL is responsible for transporting cholesterol from the liver to peripheral tissues.
HDL is responsible for transporting cholesterol from the liver to peripheral tissues.
Chylomicrons are involved in transporting dietary fats from the intestine to the liver.
Chylomicrons are involved in transporting dietary fats from the intestine to the liver.
Bile salts are synthesised from cholesterol in the liver.
Bile salts are synthesised from cholesterol in the liver.
Inhibition of myosin light chain kinase leads to decreased vasodilatation
Inhibition of myosin light chain kinase leads to decreased vasodilatation
Atherosclerosis is a sudden symptomatic manifestation.
Atherosclerosis is a sudden symptomatic manifestation.
Platelet-activating factor is involved in the coagulation cascade
Platelet-activating factor is involved in the coagulation cascade
Genetic risk factors include HMG CoA reductase polymorphism and LDL-R gene polymorphism.
Genetic risk factors include HMG CoA reductase polymorphism and LDL-R gene polymorphism.
Nifedipine is a β-blocker
Nifedipine is a β-blocker
Unstable angina is characterized by chest pain on exertion
Unstable angina is characterized by chest pain on exertion
Statins are used to increase LDL receptors.
Statins are used to increase LDL receptors.
A healthy total cholesterol level is ≤ 6 mmol/L.
A healthy total cholesterol level is ≤ 6 mmol/L.
Atenolol is a Ca2+ channel blocker
Atenolol is a Ca2+ channel blocker
Angina is a symptom of atherosclerosis.
Angina is a symptom of atherosclerosis.
Glyceryl trinitrate increases the work done by the heart
Glyceryl trinitrate increases the work done by the heart
Vasodilatation and pain are caused by the release of K+ and H+ ions.
Vasodilatation and pain are caused by the release of K+ and H+ ions.
Warfarin is a direct inhibitor of Factor Xa
Warfarin is a direct inhibitor of Factor Xa
Bivalirudin is an oral anticoagulant used in patients with type 2 HIT
Bivalirudin is an oral anticoagulant used in patients with type 2 HIT
Lepirudin is used in patients with type 2 diabetes
Lepirudin is used in patients with type 2 diabetes
Dabigatran is a vitamin K antagonist
Dabigatran is a vitamin K antagonist
Rivaroxaban is used in conjunction with aspirin and clopidogrel in percutaneous coronary artery surgery
Rivaroxaban is used in conjunction with aspirin and clopidogrel in percutaneous coronary artery surgery
Thrombin is essential for the production of protein C and S.
Thrombin is essential for the production of protein C and S.
Warfarin can be used safely in the first few months of pregnancy
Warfarin can be used safely in the first few months of pregnancy
Hirudins are indirect thrombin inhibitors, relying on ATIII activation.
Hirudins are indirect thrombin inhibitors, relying on ATIII activation.
Fondaparinux is an example of a low-molecular-weight heparin (LMWH).
Fondaparinux is an example of a low-molecular-weight heparin (LMWH).
Heparin is a single substance, not a family of glycosaminoglycans.
Heparin is a single substance, not a family of glycosaminoglycans.
Gut flora can synthesise vitamin K in humans.
Gut flora can synthesise vitamin K in humans.
Enoxaparin is a type of novel anticoagulant.
Enoxaparin is a type of novel anticoagulant.
Study Notes
Hypercholesterolaemia
- Cholesterol is a steroid component of animal membranes and a precursor of steroid hormones, sex hormones, Vit D, and bile salt.
- Cholesterol is synthesised from Acetyl-CoA in the ER, and its synthesis is regulated in the liver by changes in 3-Hydroxy-methylglutaryl coenzyme A (3-HMG CoA) reductase.
- Cholesterol is transported in complex with proteins (lipoproteins) – HDL, IDL, LDL, VLDL, and chylomicrons.
- The liver takes up LDL by receptor-mediated endocytosis.
Angina/Coronary Artery Disease
- Angina is a symptom of coronary heart disease, characterized by chest pain due to increased oxygen demand.
- Stable angina is predictable, whereas unstable angina occurs with less and less exertion or at rest.
- Unstable angina is caused by a platelet and fibrin thrombus with ruptured atheroma, but not complete occlusion.
Treatment for Angina
- Nitrates relax smooth muscle, releasing nitric oxide (NO), which binds to soluble guanylyl cyclase (sGC) and produces cGMP, activating protein kinase G (PKG).
- PKG inhibits myosin light chain kinase (MLCK), leading to vasodilation.
- Î’-blockers have a negative inotropic effect, decreasing the force of the heartbeat and heart rate.
- Ca2+ channel blockers inhibit Ca2+ influx, leading to vasodilation.
Thrombosis
- Thrombosis is a complex process involving the coagulation cascade and platelet activation.
- Platelet-activating factor (PAF) and thromboxane A2 (TXA2) are key players in thrombosis.
Statins
- Statins are lipid-lowering drugs that inhibit HMG CoA reductase in the liver and intestine.
- Statins increase the expression of LDL receptors, leading to increased clearance of LDL from the bloodstream.
- Healthy lipid levels are: total cholesterol ≤ 5mMol/L, non-HDL ≤ 4mMol/L, LDL ≤ 3mMol/L, TC/HDL ratio ≤ 6.
Antiplatelet Drugs
- Aspirin inhibits platelet thromboxane synthesis, irreversibly inhibiting COX-1.
- Aspirin is efficacious in thrombotic stroke evolution and acute myocardial infarction.
- Dipyridamole inhibits platelet aggregation, and its effects are additive to aspirin's.
- ADP receptor (purine P2YX1/12) antagonists, such as clopidogrel, prasugrel, and ticagrelor, can be used in combination with aspirin or as a single agent in patients intolerant to aspirin.
- Glycoprotein IIB/IIIA receptor antagonists, such as abciximab, tirofiban, and eptifibatide, inhibit all platelet activation pathways.
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Description
Test your knowledge of hypercholesterolaemia, cholesterol, and statins in pharmacology. This quiz covers key facts about cholesterol, its synthesis, and its role in the body.
