Cardiovascular
Question 1:
Which of the following correctly describes the histology of heart muscle?
A) Similar to skeletal muscle
B) Contains intercalated discs
C) Multinucleated
D) Lacks striations
E) Contains desmosomes
Question 2:
What is the mediastinum, and what structures are found within it?
A) A part of the small intestine; surrounded by the mesentery & allows the passage of blood vessels
B) The central compartment of the thoracic cavity; contains the heart and major blood vessels
C) A region in the brain; contains the hypothalamus
D) The central compartment of the thoracic cavity; contains the lungs and major blood vessels
E) An area of the abdominal cavity; contains the liver & kidneys
Question 3:
What triggers the release of renin in the control of blood volume and blood pressure?
A) High concentration of sodium in the blood
B) Decreased blood pressure in the kidneys
C) Low concentration of potassium in the blood
D) Activation of the parasympathetic nervous system
E) Hormones released by the kidneys
Question 4:
Which of the following contains the correct composition of blood?
A) 45% plasma (<1% white blood cells, platelets, proteins, water & gases), 55% red blood cells
B) 45% plasma (water, proteins, gases), 55% red blood cells (<1% white blood cells & platelets)
C) 55% plasma (proteins, water & gases) & 45% red blood cells (<1% white blood cells, platelets)
D) 55% plasma (<1% white blood cells, platelets, water, proteins, gases) & 45% red blood cells
E) 55% plasms (<1% white blood cells, platelets, proteins, water & gases) & 45% haemoglobin
Question 5:
Which terminology describes the force which the left ventricle must pump blood against during systole?
A) Pre-load
B) Contractility
C) Loading phase
D) Mean Arterial Pressure
E) Afterload
Question 6:
Which type of metabolite is preferred by the heart for energy?
A) Glucose
B) Amino acids
C) Free fatty acids
D) Ketones
E) Phosphocreatine
Question 7:
What is the role of the foramen ovale in fetal circulation?
A) It allows blood to bypass the pulmonary circulation by shunting blood from the right atrium to the right ventricle.
B) It allows blood to bypass pulmonary circulation by shunting blood from the pulmonary artery and the descending aorta.
C) It allows blood to bypass the pulmonary circulation by shunting blood from the right atrium to the left atrium.
D) It allows blood to bypass the hepatic circulation by shunting blood from the hepatic vein to the inferior vena cava.
E) It allows blood to bypass the pulmonary circulation by shunting blood from the left atrium to right atrium.
Question 8:
Which of the following nodes of the conduction system of the heart are primarily responsible for coordinating heartbeats?
A) SA node alone
B) AV node alone
C) SA node initiates heartbeat & AV node coordinates heartbeat
D) AV node initiates heartbeat & SA node coordinates heartbeat
E) SA node & AV node both initiate & coordinate heart beats in equal amounts
Question 9:
What is the essential role of calcium in cardiac contraction?
A) Calcium helps maintain the resting membrane potential.
B) Calcium is responsible for the depolarisation of action potential.
C) Calcium triggers the interaction between actin and myosin.
D) Calcium is required for the formation of ATP.
E)) Used for exchange of Sodium into cell
Question 10:
In the context of the cardiovascular system, what principle does Starling’s law emphasise?
A) Regulation of blood pressure
B) The relationship between preload & afterload & indicating how an increased afterload reduces preload
C) The relationship between preload and stroke volume, indicating that an increase in preload results in a greater stroke volume
D) The effects of the sympathetic and parasympathetic nervous systems on the heart
E) Contractile force of heart
Question 11:
What is peripheral vascular disease?
A) A disorder affecting the heart valves
B) A condition leading to abnormal blood clotting
C) A condition affecting heart chambers.
D) A condition characterised by the widening of blood vessels outside of the heart, typically in the legs.
E) A condition characterised by the narrowing of blood vessels outside of the heart, typically in the legs.
Question 12:
What is Virchow’s Triad?
a) The stages of platelet activation
b) The factors that contribute to thrombosis: stasis of blood flow, endothelial injury, and hypercoagulability.
c) The interactions between clotting factors and platelets
d) The phases of fibrinolysis
e) The three antagonists of Vitamin K
Question 13:
Which part of the ECG represents ventricular repolarisation?
A) P wave
B) PR interval
C) QRS complex
D) T wave
E) QT interval
Question 14:
How does the lymphatic system help maintain fluid balance in the body?
A) By regulating blood pressure
B) By removing excess blood from arterioles and venules.
B) By returning excess interstitial fluid to the bloodstream.
D) By regulating the movement of lymph through the heart
E) By allowing movement of fluid from bloodstream to interstitial fluid.
Question 15:
Which of the following factors is essential for blood clot formation in response to injury?
A) Vasoconstriction
B) Thrombin activation
C) Endothelin
D) Protein C
E) Prostacyclin
Question 16:
Within the cardiovascular system, what is the primary function of aldosterone?
A) Accelerating heart rate
B) Vasoconstriction of blood vessels
C) Enhancing sodium reabsorption in the kidneys and facilitating potassium excretion.
D) Increasing blood pressure
E) Causing release of ADH
Question 17:
Which of the following statements accurately describes arterial vasoconstriction?
A) It increases blood flow to the tissues.
B) It increases the diameter of arteries, increasing vascular resistance and raising blood pressure.
C) Constricting arterioles in place of damaged vessels.
D) It enhances venous return to the heart.
E) It decreases the diameter of arteries, increasing vascular resistance and raising blood pressure.
Question 18:
In the context of blood clot formation, what is the role of thrombin?
A) It promotes vascular spasms.
B) It converts soluble fibrinogen into insoluble strands of fibrin.
C) It inhibits platelet activation.
D) It promotes platelet aggregation.
E) Activates prothrombinase
Question 19:
In the context of oxygen transport, explain the significance of the oxygen dissociation curve. What factors influence the position of this curve, and how does it relate to tissue oxygenation?
A) The curve represents the heart’s oxygen supply, influenced by heart rate.
B) The curve depicts the relationship between oxygen saturation and partial pressure, influenced by factors like pH and temperature. It impacts oxygen unloading to tissues.
C) The curve shows how oxygen levels vary with altitude, influenced by atmospheric pressure.
D) The curve represents oxygen binding to haemoglobin, influenced by carbon dioxide levels.
E) None of the above are true
Question 20:
During embryological development, the heart undergoes significant changes. What key event occurs during the transition from fetal to postnatal circulation?
- Closure of the ductus arteriosus, redirecting blood flow away from fetal pathways.
- Development of the foramen ovale, allowing blood to bypass the lungs in utero.
- Formation of the umbilical vein, facilitating exchange of gases and nutrients with the placenta.
- Maturation of the hepatic portal system, diverting blood flow from the liver to systemic circulation.
- Closure of the umbilical arteries, redirecting blood flow to the iliac arteries.
Question 21:
In fetal circulation, the foramen ovale plays a crucial role. What physiological mechanism prompts its closure after birth?
A) Increased pulmonary blood flow and pressure lead to its closure.
B) Increased pressure in the left atrium triggers its closure.
C) Elevated oxygen levels in the left atrium triggers its closure.
D) Hormonal changes at birth such as reduced prostaglandin levels trigger its closure.
E) All of the above
Question 22:
In the conduction system of the heart, the bundle of His plays a critical role. What is its function, and where is it located?
A) It initiates the heart’s electrical impulses and is in the left atrium.
B) It conducts impulses from the atria to the ventricles and is in the interventricular septum.
C) It regulates the heart’s response to sympathetic stimulation and is in the right ventricle.
D) It controls the heart’s rate and rhythm and is in the coronary sinus.
E) It causes a delay in impulse transmission to allow the atria to fully empty into the ventricles.
Question 23:
Peripheral circulation is crucial for tissue perfusion. Which factor is NOT directly related to peripheral vascular resistance?
A) Vessel diameter
B) Blood viscosity
C) Total blood volume
D) Vessel length
E) Blood vessel damage
Question 24:
Cardiac contractility relies on the interaction between myofilaments. What roles do troponin and tropomyosin play in this process, and how do changes in calcium levels affect muscle contraction?
A) Troponin and tropomyosin block myosin binding sites, and increased calcium levels lead to muscle relaxation.
B) Troponin and tropomyosin allow myosin binding to actin, and increased calcium levels trigger muscle contraction.
C) Troponin and tropomyosin break down myosin, and decreased calcium levels enhance muscle contraction.
D) Troponin and tropomyosin control heart rate, and increased calcium levels enhance muscle contraction.
E) Troponin and tropomyosin block actin binding site, and increased calcium levels result in muscle relaxation.
Question 25:
In cardiac contractility, calcium plays a pivotal role. Explain how calcium affects the cross-bridge cycle, leading to muscle contraction. What role does the sodium-potassium pump (Na/K pump) play in maintaining calcium levels?
A) Calcium binds to tropomyosin, shifting it to expose myosin binding sites, while the Na/K pump directly removes calcium from the cytoplasm to decrease contraction.
B) Calcium binds to troponin, causing tropomyosin to move and expose myosin binding sites on actin. The Na/K pump indirectly affects calcium levels by maintaining the sodium gradient necessary for the sodium-calcium exchanger to function.
C) Calcium binds to actin, initiating the cross-bridge cycle, while the Na/K pump pumps calcium ions back into the sarcoplasmic reticulum to terminate contraction.
D) Calcium binds to myosin, facilitating ATP hydrolysis and muscle contraction, while the Na/K pump directly exchanges calcium for sodium across the sarcolemma.
E) Calcium binds to troponin, causing tropomyosin to inhibit myosin binding, while the Na/K pump maintains potassium levels to directly control calcium influx.
Question 26:
Starling’s law plays a pivotal role in cardiac function. Explain the principle behind Starling’s law and its significance in regulating stroke volume. How does preload impact stroke volume?
A) Starling’s law describes the relationship between heart rate and cardiac output, with no impact on stroke volume. Preload increases heart rate.
B) Starling’s law relates preload to afterload, influencing heart rate. Preload increases contractility.
C) Starling’s law states that increased preload results in increased stroke volume, enhancing cardiac output. It ensures optimal cardiac performance.
D) Starling’s law indicates that afterload decreases stroke volume, reducing cardiac efficiency. Preload & afterload are inversely related.
E) Starling’s law is related to cardiac output and has no impact on stroke volume. Preload influences heart rate.
Question 27:
Adrenoreceptors and adrenergic signalling play essential roles in cardiac function. Explain how these mechanisms influence calcium levels and, consequently, heart rate and contractility. What are the primary effects of sympathetic and parasympathetic stimulation on the heart?
A) Adrenoreceptors block calcium influx, slowing heart rate. Sympathetic stimulation increases heart rate, while parasympathetic stimulation decreases it.
B) Adrenoreceptors promote calcium influx, enhancing heart rate and contractility. Sympathetic stimulation increases heart rate, while parasympathetic stimulation decreases heart rate.
C) Adrenoreceptors have no effect on calcium levels. Sympathetic stimulation decreases heart rate, while parasympathetic stimulation increases it.
D) Adrenoreceptors inhibit calcium release from the sarcoplasmic reticulum, decreasing heart rate. Sympathetic stimulation decreases heart rate, while parasympathetic stimulation has no effect.
D) Adrenoreceptors promote calcium influx, enhancing heart rate and contractility. Sympathetic stimulation increases heart rate, while parasympathetic stimulation decreases contractility.
Question 28:
In peripheral vascular disease, patients often experience claudication. What causes this symptom, and how does it relate to compromised arterial circulation?
A) Claudication results from venous insufficiency, causing leg pain during exercise.
B) Claudication is caused by impaired lymphatic drainage, leading to limb swelling.
C) Claudication is due to inadequate arterial blood flow during exercise, causing muscle pain in the legs.
D) Claudication occurs due to coronary artery stenosis, leading to chest pain.
E) Claudication occurs due to inadequate arterial blood flow, leading to chest pain.
Question 29:
The electrical conduction system of the heart includes specialised cells. Which cells serve as pacemakers, generating electrical impulses for the heart’s rhythmic contractions?
A) Ventricular myocytes
A) Atrial myocytes
C) Purkinje fibres
D) Atrioventricular (AV) Node
E) Sinoatrial (SA) node cells
Question 30:
What does the T wave on an ECG represent & what stage of myocardial action potential does it correspond to?
A) The T wave represent ventricular depolarisation & corresponds to stage 2 of myocardial action potential.
B) The T wave represents ventricular repolarisation & corresponds to stage 3 of myocardial action potential.
C) The T wave represents ventricular repolarisation & corresponds to stage 2 of myocardial action potential.
D) The T wave represents the ventricular contraction & corresponds to stage 2 of myocardial action potential.
E) The T wave represents the ventricular contraction & corresponds to stage 3 of myocardial action potential.
Question 31:
Haemoglobin is essential for oxygen transport. How does haemoglobin’s affinity for oxygen change in response to factors like pH, temperature, and carbon dioxide levels, and why is this modulation crucial for oxygen delivery?
A) Haemoglobin’s affinity for oxygen decreases in acidic conditions and with increasing temperature, promoting oxygen unloading in metabolically active tissues. Carbon dioxide helps maintain proper pH.
B) Haemoglobin’s affinity for oxygen increases in acidic conditions and with increasing temperature, ensuring efficient oxygen delivery in warm environments. Carbon dioxide has no impact on this process.
C) Haemoglobin’s affinity for oxygen is constant regardless of pH, temperature, or carbon dioxide levels. These factors do not affect oxygen transport.
D) Haemoglobin’s affinity for oxygen increases in alkaline conditions and with decreasing temperature, favouring oxygen unloading in metabolically active tissues. Carbon dioxide plays no role in this process.
E) Haemoglobin affinity does not change.
Question 32:
What primarily determines mean arterial pressure (MAP) in the cardiovascular system, and why is MAP considered more clinically valuable than systolic or diastolic blood pressure alone?
A) MAP is primarily influenced by heart rate, while systolic and diastolic pressures relate to blood vessel diameter. MAP provides a holistic view of overall cardiovascular health.
B) MAP is mainly determined by diastolic pressure, with systolic pressure reflecting vascular resistance. MAP accounts for both cardiac output and vascular resistance, offering a better assessment of perfusion.
C) MAP depends on blood viscosity, while systolic pressure relates to arterial elasticity. MAP is critical for oxygen transport, while systolic and diastolic pressures represent peripheral resistance.
D) MAP is affected by venous return, while systolic and diastolic pressures indicate myocardial contractility. MAP provides an assessment of cardiac output, making it more suitable for clinical evaluation.
E) MAP is determined by carotid sinus. It accounts for oxygenation of the blood.
Question 33:
What does the PR interval represent in an electrocardiogram (ECG), and what physiological events occur during this interval?
A) The PR interval represents atrial depolarisation & ventricular depolarisation & the plateau represents atrial repolarisation.
B) The PR interval reflects atrial depolarisation and the delay at the AV node, allowing the ventricles to fill.
C) The PR interval marks the beginning of the QRS complex, indicating the onset of ventricular contraction.
D) The PR interval represents the time it takes for blood to flow from the atria to the ventricles, influencing stroke volume.
E) PR interval represents isovolumetric contraction.
Question 34:
In the developing embryo, several shunts facilitate blood flow bypassing certain structures. Which of the following statements correctly describes the function of the ductus venosus?
A) The ductus venosus allows oxygen-rich blood from the umbilical vein to bypass the liver and flow directly into the inferior vena cava.
B) The ductus venosus shunts blood from the right atrium to the left atrium, bypassing the non-functional fetal lungs.
C) The ductus venosus diverts blood from the pulmonary artery to the aorta, bypassing the non-functional fetal lungs.
D) The ductus venosus connects the umbilical artery to the inferior vena cava, allowing deoxygenated blood to bypass the liver.
E) The ductus venosus allows oxygen-poor blood from the umbilical artery to bypass the liver and flow directly into the superior vena cava.
Question 35:
What is the primary determinant of stroke volume in the context of the cardiovascular system?
A) Blood pressure
B) Heart rate
C) Preload
D) Afterload
E) Contractility
Question 36:
How does the sympathetic nervous system influence cardiac contractility, and which neurotransmitter is primarily involved?
A) Sympathetic stimulation increases the speed of calcium reuptake into the sarcoplasmic reticulum by releasing acetylcholine.
B) Sympathetic stimulation decreases the speed of calcium reuptake into the sarcoplasmic reticulum by releasing noradrenaline.
C) Sympathetic stimulation decreases the duration of contraction of the heart by releasing noradrenaline.
D) Sympathetic stimulation increases the duration of contraction of the heart by releasing noradrenaline.
E) None of the above.
Question 37:
In the context of the cardiovascular system, what is the primary role of myoglobin, and where is it predominantly found?
A) Myoglobin primarily serves as a structural protein in cardiac muscle cells.
B) Myoglobin is primarily responsible for oxygen transport and is predominantly found in red blood cells.
C) Myoglobin primarily stores oxygen in muscle tissues and is predominantly found in skeletal muscles.
D) Myoglobin is primarily responsible for oxygen transport from the cell membrane to mitochondria and is predominantly found in cardiac & skeletal muscles.
E) Myoglobin builds up myocytes after damage and found in skeletal muscles.
Question 38:
Within the cardiovascular system, which component of the blood vessel walls directly influences vascular resistance by contracting or relaxing?
A) Tunica adventitia
B) Tunica intima
C) Tunica media
D) Tunica externa
E) Tunica albuginea
Question 39:
In the autonomic control of the heart within the cardiovascular system, which receptor subtype is primarily responsible for mediating the effects of the parasympathetic nervous system on heart rate and contractility?
- Alpha-1 adrenergic receptors
- Beta-1 adrenergic receptors
- M2 – Muscarinic acetylcholine receptors
- M3 – Muscarinic acetylcholine receptors
- Beta-2 adrenergic receptors
Question 40:
In the cardiovascular system, what is the primary function of preload, and how does it affect stroke volume?
A) Preload primarily influences heart rate and has no direct impact on stroke volume.
B) Preload is the force exerted by the left ventricle during contraction and directly determines stroke volume.
C) Preload is the resistance against which the ventricles pump, influencing blood pressure & stroke volume.
D) Preload is the volume of blood in the ventricles at the end of diastole, and an increase in preload generally leads to an increase in stroke volume.
E) Preload increases contractility of ventricles thus increasing stroke volume.
Question 41:
In the context of cardiovascular embryology, what does the term “ductus arteriosus” refer to & what does the ductus arteriosus become after birth?
A) A fetal structure that connects the right atrium to the left atrium & becomes ligamentum arteriosum.
B) A fetal blood vessel that connects the pulmonary artery to the aorta, allowing blood to bypass the fetal lungs & becomes ligamentum arteriosum.
C) A fetal blood vessel that connects the pulmonary artery to the aorta, allowing blood to bypass the fetal lungs & becomes ductus arteriosum.
D) A blood vessel that carries oxygenated blood from the placenta to the fetus.
E) The post-natal remnant of ligamentum arteriosus.
Question 42:
Within the context of body fluids and haemostasis, what is the main function of oncotic pressure in capillary circulation?
A) To promote fluid filtration out of capillaries.
B) To maintain blood pressure by constricting blood vessels.
C) To promote fluid reabsorption from interstitial fluid back into venule end of capillaries.
D) To promote fluid release from the arteriole end of capillaries.
E) To promote reabsorption of protein back into veins.
Question 43:
Which of the following is the primary detector of changes in pH, pressure, oxygen saturation & carbon dioxide concentration in the cardiovascular system?
A) Mechanoreceptors
B) Carotid sinus receptors
C) Chemoreceptors
D) Baroreceptors
E) Aortic sinus receptors
Question 44:
In the context of blood pressure regulation, what is systolic blood pressure?
A) The pressure in the arteries during ventricular relaxation
B) The pressure in the arteries during ventricular contraction
C) The pressure in the atria during diastole
D) The pressure in the veins during ventricular relaxation
E) The pressure in SVC.
Question 45:
Which component of blood is primarily responsible for oxygen transport from the lungs to body tissues?
A) Erythrocytes
B) Leukocytes
C) Megakaryocytes
D) Erythropoietin
E) Reticulocytes
Question 46:
Which component ensures the coordinated contraction of the ventricles?
A) Sinoatrial (SA) node
B) Atrioventricular (AV) node
C) Moderator band/septomarginal trabeculae
D) Purkinje fibres
E) Bundle of His
Question 47:
In the context of muscle contraction, what is the primary function of T-tubules?
A) To conduct action potentials deep into the muscle fibre (allow calcium ions to enter cardiomyocytes promoting their release from the sarcoplasmic reticulum).
B) It blocks the myosin-binding sites on actin molecules, preventing muscle contraction.
C) To store calcium ions for muscle contraction.
D) To anchor myosin filaments to the Z-disc.
E) It catalyses the breakdown of ATP into ADP and phosphate to generate energy for muscle contraction.
Question 48:
What is the role of thrombin in the coagulation pathway, and how is it regulated?
A) Thrombin activates Factor X, and its activity is inhibited by antithrombin III.
B) Thrombin converts fibrinogen into fibrin and is inhibited by plasmin.
C) Thrombin activates platelets, and its activity is enhanced by heparin.
D) Thrombin degrades fibrin clots, and its activity is promoted by protein C.
E) Thrombin converts fibrin into fibrinogen and is promoted by plasmin.
Question 49:
What is the primary role of tissue factor (Factor III) in the extrinsic pathway of the coagulation cascade?
A) To activate Factor VII
B) To activate Factor X
C) To activate thrombin
D) To activate Factor IX
E) To activate Factor XII
Question 50:
What is the primary function of von Willebrand factor (vWF) in the coagulation process?
A) vWF enhances platelet adhesion to exposed collagen.
B) vWF inhibits platelet aggregation.
C) vWF activates thrombin.
D) vWF stimulates platelet aggregation.
E) vWF activates antithrombin
Question 51:
Vitamin K is essential for the synthesis of which clotting factors in the liver?
A) Factors VII, IX, and X
B) Factors II, VII, IX, and X
C) Factors II and X
D) Factors V and VIII
E) None of the above
Question 52:
In the common pathway of the coagulation cascade, the conversion of fibrinogen to fibrin is catalysed by which enzyme?
A) Thrombin
B) Factor X
C) Factor IX
D) Tissue plasminogen activator (tPA)
E) Prothrombinase
Question 53:
The extrinsic pathway of the coagulation cascade is initiated by the release of tissue factor (Factor III) from which source?
A) Platelets
B) Endothelial cells
C) Blood plasma
D) Liver
E) Exposed collagen
Question 54:
Platelets play a crucial role in haemostasis. When activated, they release ADP, which has what effect on platelet aggregation?
A) ADP inhibits platelet aggregation by blocking fibrinogen binding to integrin receptors.
B) ADP enhances platelet aggregation by activating GPIIb/IIIa receptors.
C) ADP promotes platelet aggregation by increasing the release of von Willebrand factor.
D) ADP increases platelet aggregation by enhancing the activity of tissue factor.
E) ADP enhances platelet aggregation by activating P2/Y12 receptors.
Question 55:
Thromboxane A2 is a bioactive molecule involved in the regulation of blood clotting. Which of the following statements best describes the role of thromboxane A2 in haemostasis?
- Thromboxane A2 promotes endothelial cell repair and angiogenesis.
- Thromboxane A2 inhibits prostacyclin synthesis, promoting vasoconstriction.
- Thromboxane A2 enhances the release of tissue plasminogen activator (tPA), facilitating clot dissolution.
- Thromboxane A2 activates P2Y12 receptors on platelets, amplifying platelet aggregation.
- Thromboxane A2 binds to Factor VIII, enhancing the intrinsic pathway of coagulation.
Question 56:
Heparin and aspirin are two medications commonly used to prevent abnormal blood clot formation. How do these medications differ in their mechanisms of action?
A) Heparin reduces production of thromboxane A2 decreasing platelet aggregation whereas aspirin increases production of antithrombin-III decreasing coagulation.
B) Both heparin and aspirin work by inhibiting platelet aggregation.
C) Heparin enhances fibrinolysis, while aspirin decreases platelet aggregation.
D) Heparin enhances production of antithrombin-III decreasing platelet aggregation whereas aspirin reduces production of thromboxane A2 decreasing coagulation.
E) Heparin enhances production of antithrombin-III decreasing coagulation whereas aspirin reduces production of thromboxane A2 decreasing platelet aggregation.
Question 57:
Which of the following best describes the role of Protein C in blood clotting and anticoagulation?
A) Protein C inhibits the production of thromboxane A2, a molecule that inhibits platelet aggregation and vasoconstriction.
B) Protein C enhances the activation of factor VIII, a key clotting factor inhibitor.
C) Protein C promotes fibrinolysis by stimulating production of plasmin.
D) Protein C inhibits platelet aggregation by producing prostacyclin.
E) Protein C promotes alpha-2-macroglobulin formation, a molecule that inhibits blood clot formation.
Question 58:
Which branch of the aorta supplies blood to the abdominal organs, including the liver, stomach, and spleen?
A) Right subclavian artery
B) Common carotid artery
C) Inferior mesenteric artery
D) Celiac trunk
E) Superior mesenteric artery
Question 59:
What is the primary role of thrombin in the coagulation cascade?
A) Activating Factor X
B) Converting fibrinogen into fibrin
C) Promoting platelet aggregation
D) Synthesising fibrin clots
E) Activating plasminogen
Question 60:
The posterior descending artery (PDA) is a branch of which major coronary artery?
A) Left anterior descending artery (LAD)
B) Left coronary artery (LCA)
C) Left circumflex artery (LCx)
D) Right marginal artery
E) Right coronary artery
Question 61:
What is the name of the membrane that surrounds the heart?
A) Pericardium
B) Pleura
C) Myocardium
D) Endocardium
E) Epicardium
Question 62:
The coronary sinus drains into which chamber of the heart?
A) Left atrium
B) Right atrium
C) Left ventricle
D) Right ventricle
E) Both atriums
Question 63:
What is the name of the projections on the inner lining of the heart’s ventricles that help prevent backflow of blood into the atria?
A) Pectinate muscles
B) Papillary muscles
C) Chordae tendineae
D) Moderator bands
E) Trabeculae carnae
Question 64:
The anterior interventricular sulcus is a groove on the heart’s surface that marks the course of which coronary artery?
A) Left anterior ascending artery (LAD)
B) Right coronary artery (RCA)
C) Left circumflex artery (LCx)
D) Posterior descending artery (PDA)
E) Left anterior descending artery (LAD)
Question 65:
Which coronary artery is most associated with supplying the sinoatrial (SA) node, often referred to as the “natural pacemaker” of the heart?
A) Left anterior descending artery (LAD)
B) Right coronary artery (RCA)
C) Left circumflex artery (LCx)
D) Posterior descending artery (PDA)
E) Right marginal artery
Question 66:
In the histology of the heart, what is the primary function of the intercalated discs found in cardiac muscle tissue?
A) To store excess glucose
B) To facilitate electrical communication between cardiac muscle cells
C) To allow the passage of calcium ions
D) To generate ATP through oxidative phosphorylation
E) To allow the passage of sodium ions
Question 67:
What embryonic structure eventually develops into the smooth-walled part of the right atrium?
A) Bulbus cordis
B) Sinus venosus
C) Truncus arteriosus
D) Infundibulum
E) Septomarginal trabecula
Question 68:
What is the primary role of the fetal shunt known as the “ductus venosus” during prenatal development?
A) To shunt blood from the right atrium to the left atrium bypassing the lungs
B) To shunt blood from the pulmonary artery to the aorta bypassing the lungs
C) To shunt blood from the pulmonary vein to the inferior vena cava bypassing the liver
D) To shunt blood from the umbilical vein to the inferior vena cava bypassing the liver
E) To shunt blood from the umbilical vein to the superior vena cava bypassing the liver
Question 69:
During heart development, the truncus arteriosus gives rise to which adult structures?
A) The aorta and pulmonary trunk
B) The left and right ventricles
C) The atria and ventricles
D) Ductus arteriosus
E) Ligamentum arteriosus
Question 70:
What term describes the tiny blood vessels that supply oxygen and nutrients to the walls of larger arteries and veins?
A) Coronary arteries
B) Capillaries
C) Pulmonary arteries
D) Vasa vasorum
E) Arterioles
Question 71:
What is the primary function of phospholamban in muscle cells?
A) Phospholamban facilitates muscle contraction by enabling calcium to bind to troponin C.
B) Phospholamban stores calcium ions.
C) Phospholamban regulates calcium ion transport within muscle cells.
D) Phospholamban inhibits SERCA pump resulting in a decreased reuptake calcium ions thus less frequent muscle contraction.
E) Phospholamban stimulates SERCA pump to increase the concentration of calcium ions available for muscle contraction.
Question 72:
In the cardiac action potential, which phase corresponds to the rapid depolarisation of the cell membrane?
A) Phase 0
B) Phase 1
C) Phase 2
D) Phase 3
E) Phase 4
Question 73:
During which phase of the cardiac action potential does the membrane repolarise, returning to its resting membrane potential?
A) Phase 0
B) Phase 1
C) Phase 2
D) Phase 3
E) Phase 4
Question 74:
Which ion plays a crucial role in the plateau phase (Phase 2) of the cardiac action potential, maintaining the membrane potential?
A) Sodium (Na⁺)
B) Potassium (K⁺)
C) Calcium (Ca²⁺) via L-type channels
D) Calcium (Ca²⁺) via T-type channels
E) All of the above
Question 75:
What is the primary significance of the plateau phase (Phase 2) in the cardiac action potential?
A) It allows for sustained muscle contraction.
B) It ensures rapid depolarisation.
C) It represents a period of absolute refractoriness.
D) It prevents calcium entry into the cell.
E) It represents the delay at the AV node allowing atria to empty into ventricles.
Question 76:
During the pacemaker cell action potential, which ion(s) contributes to the depolarisation phase (Phase 0)?
A) Sodium (Na⁺)
B) Potassium (K⁺)
C) Calcium (Ca²⁺) via L-type channels
D) Calcium (Ca²⁺) via T-type channels
E) Chloride (Cl–)
Question 77:
Which phase of the pacemaker cell action potential involves the opening of voltage-gated potassium channels, leading to repolarisation?
A) Phase 0
B) Phase 1
C) Phase 2
D) Phase 3
E) Phase 4
Question 78:
In pacemaker cells, the “funny current” (If) involves the movement of which ions, and it plays a crucial role in the slow diastolic depolarisation?
A) Sodium (Na⁺) and Calcium (Ca²⁺) via T-type channels
B) Potassium (K⁺) and Sodium (Na⁺)
C) Calcium (Ca²⁺) via T-type channels and Calcium (Ca²⁺) via L-type channels
D) Sodium (Na⁺) alone
E) Sodium (Na⁺) and Calcium (Ca²⁺) via L-type channels
Question 79:
What is the sequence of events in Atherosclerosis formation?
A) Atherosclerosis begins with lipid buildup in arteries, leading to macrophage engulfment of LDL particles and the formation of foam cells. T cells subsequently join the process, promoting plaque formation and smooth muscle migration.
B) Atherosclerosis results from excessive red blood cell production, with foam cells and T cells working to prevent plaque formation.
C) Impaired lymphatic drainage causes lipid accumulation and activates an immune response. Monocytes transform into macrophages, which engulf LDL particles, forming foam cells. T cells play a role in later stages, promoting smooth muscle migration during atherosclerosis progression.
D) Atherosclerosis is related to vascular dilatation, with foam cells forming after macrophages engulf LDL particles. T cells join later, contributing to plaque dissolution, while smooth muscle migration is inhibited.
E) Atherosclerosis begins with lipid build-up in arteries, leading to macrophage engulfment of HDL particles and the formation of foam cells. T cells subsequently join the process, promoting plaque formation and smooth muscle migration.
Question 80:
Which subtype of beta-adrenergic receptor is primarily found in bronchial smooth muscle, and what effect does its activation have on airway diameter?
A) Beta-1 receptor; bronchodilation
B) Beta-2 receptor; bronchoconstriction
C) Beta-1 receptor; bronchoconstriction
D) Beta-2 receptor; bronchodilation
E) Beta-2 receptor; neuromodulating effects on bronchial smooth muscles
Question 81:
Which of the following describes the primary effect of alpha-1 adrenergic receptor activation on blood vessels?
A) Vasodilation
B) Decreased peripheral resistance
C) Decreased cardiac output
D) Increased cardiac output
E) Vasoconstriction
Question 82:
Which of the following is a downstream signalling event initiated by the activation of beta-adrenergic receptors in cardiac myocytes?
A) Increased intracellular calcium levels
B) Activation of phospholipase C
C) Inhibition of adenylate cyclase
D) Activation of Protein Kinase A
E) Inactivation of cAMP
Question 83:
Alpha-2 adrenergic receptors are often found on the presynaptic terminals of sympathetic neurons. What is their primary function?
A) Enhancing norepinephrine release
B) Inhibiting norepinephrine release
C) Activating parasympathetic neurons
D) Blocking postsynaptic alpha-1 receptors
E) Vasoconstriction of blood vessels
Question 84:
The aortic arch baroreceptors and carotid sinus baroreceptors play crucial roles in regulating blood pressure. Where do these baroreceptors primarily relay their sensory information to, initiating autonomic responses?
A) The spinal cord
B) The heart’s sinoatrial node (SAN)
C) The medullary cardiovascular control centres
D) The adrenal medulla
E) Cardioregulatory centres in thalamus
Question 85:
Which type of artery is responsible for regulating blood flow into individual organs and tissues and typically exhibits the greatest resistance to blood flow?
A) Elastic arteries
B) Muscular arteries
C) Arterioles
D) Medium arteries
E) Large Arteries
Question 86:
Angiotensin II is a hormone involved in blood pressure regulation. What is its primary action within the cardiovascular system?
A) It causes vasodilation to decrease blood pressure.
B) It promotes fluid retention by the kidneys.
C) It increases heart rate.
D) It induces bronchoconstriction in the lungs.
E) It causes systemic vasoconstriction.
Question 87:
During embryonic heart development, which structure gives rise to the atrioventricular (AV) septum and contributes to the formation of the membranous interventricular septum?
A) Bulbus cordis
B) Truncus arteriosus
C) Endocardial cushions
D) Aorticopulmonary septum
E) Sinus Venosus
Question 88:
What structure divides the primitive atrium into the right and left atria during embryonic development?
A) Atrial septum
B) Septum primum
C) Endocardial cushions
D) Aorticopulmonary septum
E) Bulbus cordis
Question 89:
Fetal hemoglobin (HbF) differs structurally from adult hemoglobin (HbA) in which way?
A) HbF has a higher affinity for oxygen than HbA.
B) HbF contains a higher percentage of beta chains than HbA.
C) HbF is primarily produced in the liver.
D) HbF is less efficient at binding to carbon dioxide.
E) HbF is composed of alpha & gamma subunits whereas HbA is composed of alpha & beta subunits.
Question 90:
What forms the coronary sinus, allowing the drainage of deoxygenated blood from the heart muscle back into the right atrium?
A) Left horn of Sinus Venosus
B) Sphenoidal Sinus
C) Right horn of Sinus Venosus
D) Ductus Venosus
E) Inferior Vena Cava
Question 91:
What is the clinical significance of a patent fossa ovalis in an adult’s heart, and how does it relate to fetal circulation?
A) A patent fossa ovalis is a normal variant in adults.
B) It can cause a right-to-left shunt, leading to cyanosis.
C) It can cause a left-to-right shunt, leading to cyanosis.
D) It facilitates left ventricular filling.
E) No clinical significance, it is just a visual defect.
Question 92:
The “Triangle of Koch” in the heart is crucial for understanding the conduction system. Which structure within this triangle serves as the point of origin for the atrioventricular (AV) node?
A) Atrioventricular orifice
B) Tendon of Todaro
C) Ostium secundum
D) Coronary sinus
E) Mitral Valve
Question 93:
The cardiac plexus is an intricate network of nerves near the heart. Which division of the autonomic nervous system contributes to the cardiac plexus?
A) Sympathetic nervous system
B) Dorsal Root Ganglion
C) Parasympathetic nervous system
D) Autonomic nervous system
E) Somatosensory nervous system
Question 94:
Visceral afferent fibres are responsible for transmitting sensory information from internal organs. Which type of sensory information do these fibres primarily convey from the heart?
A) Temperature
B) Pain
C) Blood pressure
D) pH
E) Rate
Question 95:
The inferior vena cava (IVC) and superior vena cava (SVC) are essential vessels in the circulatory system. However, there is a unique characteristic they share. What is it?
A) They are both valveless.
B) They pass through central tendon at T8 level.
C) They direct blood through Mitral and Tricuspid valve.
D) They have multiple valves.
E) They are made up of multiples vessels
Question 96:
How does the skeletal muscle pump contribute to venous return in the circulatory system, and in which parts of the body is it most actively utilised?
A) It contracts to push blood through arteries; it is most active in the brain.
B) It contracts to push blood through veins; it is most active in the lower limbs.
C) It relaxes to facilitate venous return; it is most active in the heart.
D) It contracts to facilitate arterial blood flow; it is most active in the lungs.
E) It relaxes to facilitate venous return and allow space for blood to move up; most active in lower limbs.
Question 97:
In an electrocardiogram (ECG), the T-wave represents ventricular repolarisation. How does the vector of the T-wave differ between the epicardium and endocardium of the heart?
A) The T-wave vector is the same in both the epicardium and endocardium.
B) The T-wave vector is directed towards the epicardium in both regions.
C) The T-wave vector points away from the epicardium and towards the endocardium.
D) The T-wave vector points away from the endocardium and towards the epicardium.
E) None of the above
Question 98:
In an electrocardiogram, which direction does electrical vector of depolarisation follow:
A) Endocardium to epicardium
B) Epicardium to endocardium
C) Myocardium to pericardium
D) Pericardium to myocardium
E) Epicardium to pericardium
Question 99:
What differentiates the absolute refractory period (ARP) from the relative refractory period (RRP) in cardiac muscle cells, and why are these periods crucial for heart function?
A) ARP is shorter than RRP, and both prevent cardiac arrhythmias.
B) ARP is the time when cells cannot respond to any stimulus, while RRP allows for response to strong stimuli.
C) ARP allows for summation of electrical signals, while RRP prevents electrical propagation.
D) ARP is the time between atrial and ventricular contractions, while RRP corresponds to atrial repolarisation.
E) ARP equal to RRP, RRP prevents cardiac arrythmias
Question 100:
Purkinje fibres play a vital role in the heart’s conduction system. In which layer of the heart are Purkinje fibres primarily found, and how does their location relate to their function?
A) Epicardium; they initiate ventricular contractions.
B) Myocardium; they facilitate rapid and coordinated ventricular depolarisation.
C) Endocardium; they facilitate rapid and coordinated ventricular depolarisation.
D) Pericardium; they initiate ventricular contractions.
E) Myocardium; they facilitate rapid atrial depolarisation.
Question 101:
Angina pectoris is a common symptom of myocardial ischemia. Which type of angina is typically occurs predictably with exertion but is relieved with rest?
A) Prinzmetal’s angina
B) Unstable angina
C) Variant angina
D) Stable angina
E) Common angina
Question 102:
In a patient with chronic liver disease, hypoalbuminemia is detected. This condition is most likely to result in oedema due to:
A) Increased capillary hydrostatic pressure
B) Decreased capillary permeability
C) Reduced lymphatic drainage
D) Reduced plasma oncotic pressure
E) Reduced pulse pressure
Question 103:
In the right ventricle of the heart, which anatomical structures contribute to the coordinated contraction of the papillary muscles before the contraction of the right ventricular walls?
A) Pectinate muscles
B) Trabeculae carneae
C) Chordae tendineae
D) Crista terminalis
E) Moderator bands
Question 104:
Which major vessel originates from the aortic arch and carries oxygenated blood to the upper body, including the head and arms?
A) Pulmonary artery
B) Subclavian artery
C) Brachiocephalic artery
D) Superior vena cava
E) Common carotid Artery
Question 105:
Which cardiac structures are primarily responsible for the formation of pectinate muscles?
A) Left ventricular wall
B) Right atrial wall
C) Right ventricular wall
D) Left atrial wall
E) Posterior Ventricular Wall
Question 106:
What is the main function of trabeculae carneae in the heart?
A) To reinforce the myocardium
B) To conduct electrical impulses
C) To prevent backflow of blood
D) To increase contractile efficiency
E) To allow heart to contract faster
Question 107:
Which of the following structures is responsible for preventing the prolapse of atrioventricular (AV) valves into the atria during ventricular contraction?
A) Papillary muscles
B) Chordae tendinae
C) Trabeculae carneae
D) Moderator bands
E) Pectinate muscles
Question 108:
Which of the following cardiac structures is responsible for the contraction of the papillary muscles in the right ventricle?
A) Trabeculae carneae
B) Chordae tendinae
C) Moderator bands
D) Coronary sinus
E) Mitral valve
Question 109:
Which of the following proteins prevents myosin from binding to actin in resting cardiac muscle cells?
A) Troponin C
B) Myosin light chain kinase
C) Tropomyosin
D) Troponin T
E) Calcium
Question 110:
What is the primary function of the sarcoplasmic reticulum in cardiac muscle cells?
A) To store calcium ions for muscle contraction
B) To store ATP required to break actin-myosin crossbridge
C) To initiate muscle contraction
D) To release calcium required for muscle contraction
E) To initiate the action potential
Question 111:
Which cellular structure in cardiac muscle cells contains the contractile units responsible for muscle contraction?
A) Myofibrils
B) Sarcomeres
C) T-tubules
D) A-band
E) M-band
Question 112:
In cardiac histology, what is the primary function of the endocardium and which components does it consist of?
A) The endocardium provides electrical insulation and is composed of the epicardium and myocardium.
B) The endocardium forms the valves and is made up of connective tissue.
C) The endocardium lines the inner surface of the heart chambers and contributes to smooth blood flow.
D) The endocardium generates contractile forces and consists of atrial and ventricular muscles.
E) To contain the electrical production by the pacemaker cells
Question 113:
Which layer of the pericardium is tough, providing structural support and anchoring the heart in the mediastinum?
A) Fibrous pericardium
B) Parietal pericardium
C) Visceral pericardium
D) Serous pericardium
E) Fibrous tissue
Question 114:
Which layer of the pericardium secretes a small amount of serous fluid into the pericardial cavity to reduce friction between the heart and surrounding structures?
A) Fibrous pericardium
B) Parietal pericardium
C) Visceral pericardium
D) Pericardial cavity
E) Endocardium
Question 115:
Which of the following muscle types exhibits involuntary contractions and striations?
A) Smooth muscle & cardiac muscle
B) Cardiac muscle & skeletal muscle
C) Skeletal muscle & smooth muscle
D) Cardiac muscle alone
E) Smooth muscle alone
Question 116:
Which of the following statements regarding the great cardiac vein is correct?
A) The great cardiac vein primarily drains deoxygenated blood from the right atrium.
B) It runs alongside the right coronary artery.
C) The great cardiac vein drains into the coronary sinus.
D) The great cardiac vein carries oxygenated blood to the lungs for oxygenation.
E) The great cardiac vein drains into the right atrium directly.
Question 117:
Which cardiac vein primarily drains the posterior aspect of the left ventricle and often connects directly to the coronary sinus?
A) Great cardiac vein
B) Middle cardiac vein
C) Small cardiac vein
D) Anterior cardiac veins
E) All of the above
Question 118:
Which cardiac vein courses along the right atrium and usually drains directly into the right atrium rather than the coronary sinus?
A) Great cardiac vein
B) Middle cardiac vein
C) Small cardiac vein
D) Anterior cardiac veins
E) Right marginal vein
Question 119:
The coronary sinus is a dilated venous structure located in which part of the heart?
A) Right atrium
B) Left atrium
C) Right ventricle
D) Left ventricle
E) Aorta
Question 120:
In which region of the human body is the aortic hiatus located?
A) T12
B) T8
C) T4
D) L1
E) T10
Question 121:
Which type of capillaries allows for the most exchange of substances between the blood and surrounding tissues?
A) Continuous capillaries
B) Fenestrated capillaries
C) Sinusoidal capillaries
D) Capillary pericytes
E) None of the above
Question 122:
At which vertebral level does the inferior vena cava (IVC) pierce the diaphragm to enter the thoracic cavity?
A) T12
B) T8
C) L1
D) S1
E) T10
Question 123:
Which of the following cranial nerves is responsible for the “rest and digest” parasympathetic functions in the body, including reducing heart rate and promoting digestion?
A) Vagus nerve (cranial nerve X)
B) Facial nerve (cranial nerve VII)
C) Glossopharyngeal nerve (cranial nerve IX)
D) Accessory nerve (cranial nerve XI)
E) Hypoglossal nerve (cranial nerve XII)
Question 124:
Which transporter is responsible for the exchange of calcium ions (Ca²⁺) out of cardiac muscle cells during the process of muscle relaxation?
A) Sodium-potassium pump (Na⁺/K⁺ pump)
B) Calcium-sodium exchanger (NCX antiporter)
C) Sodium-calcium pump (Na⁺/Ca²⁺ pump)
D) Potassium-calcium cotransporter (K⁺/Ca²⁺ cotransporter)
E) Sarcoplasmic/Endoplasmic Reticulum Calcium ATPase (SERCA pump)
Question 125:
Which channel is primarily responsible for the entry of calcium ions (Ca²⁺) into cardiac muscle cells during the initiation of muscle contraction?
A) T-type calcium channel
B) Calcium-sodium exchanger (NCX antiporter)
C) SERCA
D) L-type calcium channel
E) RyR (ryanodine) receptors
Question 126:
Which structure in cardiac muscle cells plays a crucial role in transmitting electrical signals from the sarcolemma into the interior of the cell, allowing for coordinated contraction?
A) T-tubules (transverse tubules)
B) Z-band
C) Sarcoplasmic reticulum
D) Myosin filaments
E) H-Band
Question 127:
Which of the following best defines pulse pressure?
A) Pulse pressure is the difference between systolic and diastolic blood pressure and reflects the elasticity of arteries.
B) Pulse pressure is the rate at which the heart beats, measured in beats per minute.
C) Pulse pressure is the amount of blood ejected from the left ventricle during systole.
D) Pulse pressure is the resistance of blood flow in the capillaries.
E) Pulse pressure is the difference between the arteriole and venule pressure.
Question 128:
Stroke volume is a key determinant of cardiac output. What is the formula for calculating stroke volume, and how is it related to end-diastolic volume and end-systolic volume?
A) Stroke Volume (SV) = End-Diastolic Volume (EDV) – End-Systolic Volume (ESV). Stroke volume is the amount of blood ejected by the ventricle during systole.
B) Stroke Volume (SV) = End-Systolic Volume (ESV) / End-Diastolic Volume (EDV). Stroke volume represents the ratio of blood volumes between systole and diastole.
C) Stroke Volume (SV) = 2/3 End-Diastolic Volume (EDV) + 1/3 End-Systolic Volume (ESV). Stroke volume represents the ratio of blood volumes between systole and diastole.
D) Stroke Volume (SV) = End-Diastolic Volume (EDV) + End-Systolic Volume (ESV). Stroke volume is the sum of volumes at the end of diastole and systole.
E) Stroke Volume (SV) = End-Systolic Volume (ESV) – End-Diastolic Volume (EDV). Stroke volume is the amount of blood ejected by the ventricle during systole.
Question 129:
In the Wiggers diagram, which wave or phase is associated with atrial depolarisation, leading to atrial contraction?
A) P-wave
B) QRS complex
C) T-wave
D) Ventricular ejection phase
E) QT interval
Question 130:
In the Wiggers diagram, during which phase do the mitral and tricuspid valves open, allowing blood to flow from the atria into the ventricles?
A) Ventricular ejection phase
B) Ventricular relaxation phase
C) Isovolumetric contraction phase
D) Atrial contraction phase
E) Isovolumetric relaxation
Question 131:
During which phase in the Wiggers diagram do the aortic and pulmonary valves open, allowing blood to be ejected into the systemic and pulmonary circulations?
A) Ventricular ejection phase
B) Ventricular relaxation phase
C) Isovolumetric contraction phase
D) Atrial contraction phase
E) Atrial relaxation phase
Question 132:
In the Wiggers diagram, what phase corresponds to the brief moment when all four heart valves are closed, and the ventricles are contracting with increasing pressure, but no blood is being ejected yet?
A) Ventricular ejection phase
B) Ventricular relaxation/rapid ventricular filling phase
C) Isovolumetric contraction phase
D) Atrial contraction phase
E) Isovolumetric relaxation phase
Question 133:
What specific role does the mitral valve play during the cardiac cycle, and what are the immediate hemodynamic effects observed during mitral regurgitation?
A) The mitral valve prevents backflow into the left atrium during systole; mitral regurgitation leads to increased left atrial pressure and pulmonary oedema.
B) The mitral valve allows unidirectional flow into the left atrium during systole; mitral regurgitation leads to decreased left ventricular preload and systemic hypotension.
C) The mitral valve prevents backflow into the right atrium during systole; mitral regurgitation leads to increased right atrial pressure and systemic congestion.
D) The mitral valve allows unidirectional flow into the left atrium during diastole; mitral regurgitation leads to increased left ventricular afterload and aortic stenosis.
E) The mitral valve prevents backflow into the left ventricle during diastole; mitral regurgitation leads to decreased left atrial pressure and systemic oedema.
Question 134:
In the cardiac cycle, when do the aortic and pulmonary valves open?
A) During atrial systole
B) During isovolumetric relaxation
C) During ventricular ejection
D) During atrial diastole
E) During isovolumetric contraction
Question 135:
Which type of cardiac receptor is primarily responsible for detecting changes in blood pressure and relaying this information to the central nervous system?
A) Aortic bodies
B) Carotid sinus
C) Baroreceptors
D) Pacinian corpuscles
E) Mechanoreceptors
Question 136:
Which cardiac proprioceptor type is responsible for detecting changes in blood oxygen levels and carbon dioxide levels and plays a role in regulating ventilation?
A) Free nerve endings
B) Carotid sinus
C) Baroreceptors
D) Ruffini endings
E) Aortic bodies
Question 137:
During the vascular phase of haemostasis, what is the primary role of endothelins, and where are they primarily synthesised?
A) Endothelins promote vasoconstriction and are synthesised in the liver.
B) Endothelins stimulate platelet aggregation and are synthesised in platelets.
C) Endothelins enhance clot coagulation and are synthesised in the liver.
D) Endothelins induce vasoconstriction and are synthesised in endothelial cells.
E) None of the above
Question 138:
Where is heparin primarily derived from, and what is its main function in the context of haemostasis?
A) Heparin is synthesised in the liver and enhances fibrin formation.
B) Heparin is produced by platelets and promotes platelet aggregation.
C) Heparin is derived from mast cells and activates antithrombin III, preventing blood clot formation.
D) Heparin is found in red blood cells and activates procoagulant factors.
E) Heparin is a medication, and it activates thrombin.
Question 139:
Warfarin is frequently used as an anticoagulant. What is its primary mechanism of action, and what substance does it antagonise?
A) Warfarin inhibits platelet aggregation, and its antagonist is aspirin.
B) Warfarin inhibits the synthesis of vitamin K-dependent clotting factors and its antagonist is vitamin K.
c) Warfarin prevents fibrin formation, and its antagonist is tissue plasminogen activator (tPA).
d) Warfarin enhances clot stabilisation, and its antagonist is heparin.
e) Warfarin enhances clot production, antagonises heparin.
Question 140:
Which of the following statements accurately describes the role of the atrioventricular (AV) node in cardiac conduction?
A) The AV node is responsible for initiating the electrical impulse that triggers each heartbeat.
B) The AV node delays the electrical impulse briefly to allow for atrial contraction before ventricular contraction.
C) The AV node acts as a backup pacemaker in case the sinoatrial (SA) node fails.
D) The AV node speeds up the electrical impulse to synchronize atrial and ventricular contractions.
E) AV node relays electrical impulse to SAN.
Question 141:
What is the primary role of HCN (Hyperpolarisation-Activated Cyclic Nucleotide-Gated) channels in pacemaker cells, and how do they contribute to the pacemaker potential?
A) HCN channels generate action potentials in pacemaker cells.
B) HCN channels maintain a stable resting membrane potential in pacemaker cells.
C) HCN channels facilitate the influx of calcium ions during depolarisation in pacemaker cells.
D) HCN channels allow for sodium and potassium ion movement, contributing to the gradual depolarisation in pacemaker cells i.e. funny current.
E) HCN channels allows for binding of HCN and this allows it to generate action potential.
Question 142:
How does sympathetic stimulation affect phase 4 of pacemaker cells, and what is the physiological consequence of this effect?
A) Sympathetic stimulation accelerates phase 4 depolarisation, leading to a slower heart rate.
B) Sympathetic stimulation steepens phase 4 depolarisation, leading to a faster heart rate.
C) Sympathetic stimulation has no effect on phase 4 of pacemaker cells.
D) Sympathetic stimulation decreases the resting membrane potential of pacemaker cells.
E) a & d
Question 143:
How does parasympathetic stimulation affect phase 3 of pacemaker cells, and what is the physiological consequence of this effect?
A) Parasympathetic stimulation accelerates phase 3 repolarisation, leading to a slower heart rate.
B) Parasympathetic stimulation steepens phase 3 repolarisation, leading to a faster heart rate.
C) Parasympathetic stimulation has no effect on phase 3 of pacemaker cells.
D) Parasympathetic stimulation makes phase 3 less steep, which slows down the heart rate.
E) Parasympathetic stimulation makes phase 3 even, allowing for simultaneous contraction.
Question 144:
Which ligament runs from the posterior surface of the sternum to the pericardium and is involved in maintaining the position of the heart within the mediastinum?
A) Ligamentum arteriosum
B) Ligamentum teres
C) Ligamentum venosum
D) Sternopericardial ligament
E) All of the above
Question 145:
What is the most effective mechanism for preventing a rapid decrease in blood pressure when you change from a lying position to standing?
A) Stimulation of aortic arch baroreceptors
B) Stimulation of carotid sinus baroreceptors
C) Stimulation of the parasympathetic nervous system
D) Activation of the renin-angiotensin-aldosterone system (RAAS)
E) Release of noradrenaline
Question 146:
What are platelets derived from?
A) Monocytes
B) Erythrocytes
C) Lymphocytes
D) Megakaryocytes
E) Phagocytes
Question 147:
During exercise, muscle tissue becomes more acidic due to increased metabolic activity. How does the Bohr effect, chloride shift, and bicarbonate buffering system collectively facilitate oxygen delivery and pH regulation in this situation?
A) The Bohr effect shifts the oxygen dissociation curve to the left, increasing oxygen affinity, while the chloride shift transports bicarbonate into red blood cells, releasing oxygen more efficiently.
B) The Bohr effect shifts the oxygen dissociation curve to the right, decreasing oxygen affinity, while the chloride exchanges for bicarbonate out of red blood cells, facilitating oxygen release to muscle tissue.
C) The Bohr effect has no influence on oxygen binding, while the chloride shift enhances bicarbonate formation, leading to decreased oxygen transport during exercise.
D) The Bohr effect shifts the oxygen dissociation curve to the left, decreasing oxygen affinity, while the chloride shift transports bicarbonate into red blood cells, promoting oxygen release in muscle tissue.
E) The Bohr effect shifts the oxygen dissociation curve to the right, increasing oxygen affinity, while the chloride shift transports bicarbonate out of red blood cells, limiting oxygen delivery to muscles.
Question 148:
What factor contributes to a reduced oxygen-binding affinity of adult haemoglobin?
A) Methaemoglobin
B) Reduced temperature
C) Reduced partial pressure of carbon dioxide (PCO2)
D) Elevated pH (alkalosis)
E) High levels of 2,3-diphosphoglycerate (2,3-DPG)
Question 149:
What substance, released from mast cells, activates antithrombin III and plays a vital role in inhibiting blood clot formation?
A) Prostacyclin
B) Histamine
C) Heparin
D) Plasmin
E) Von Willebrand factor
Question 150:
How do local anaesthetics primarily exert their pharmacological effect in nerve cells?
A) By binding to potassium channels
B) By inhibiting calcium influx
C) By enhancing neurotransmitter release
D) By blocking sodium channels
E) By modulating GABA receptors
Question 151:
Which of the following ions has a role as an antihypertensive agent and has shown to reduce blood pressure through various mechanisms?
A) Sodium (Na+)
B) Calcium (Ca2+)
C) Potassium (K+)
D) Chloride (Cl-)
E) Magnesium (Mg2+)
Question 152:
Which ions are targeted in antiarrhythmic therapy to modulate cardiac action potentials and impulse conduction, effectively preventing and treating arrhythmias?
A) Sodium (Na+) and potassium (K+)
B) Calcium (Ca2+) and chloride (Cl-)
C) Sodium (Na+) and calcium (Ca2+)
D) Potassium (K+) and magnesium (Mg2+)
E) Chloride (Cl-) and Sodium (Na+)
Question 153:
In a patient with chronic obstructive pulmonary disease (COPD), which of the following changes is most likely to occur as part of the ventilation-perfusion coupling response in the affected lung areas?
A) Increased ventilation and increased perfusion
B) Decreased ventilation and decreased perfusion
C) Increased ventilation and decreased perfusion
D) Decreased ventilation and increased perfusion
E) No change in ventilation or perfusion
Question 154:
Ejection fraction (EF) is a critical parameter in assessing cardiac function. Which of the following formulas accurately calculates ejection fraction?
A) EF = Stroke volume / End-diastolic volume
B) EF = (Stroke volume / Cardiac output) x 100%
C) EF = (End-diastolic volume / Stroke volume) x 100%
D) EF = (End-diastolic volume + End-systolic volume) / End-diastolic volume
E) EF = (Stroke volume – End-systolic volume) / Stroke volume
Question 155:
During heavy exercise, when oxygen supply to cardiac muscle is limited, what alternative source of energy does the heart predominantly utilise?
A) Glucose
B) Ketones
C) Fatty acids
D) Lactate
E) Amino acids
Question 156:
Under which circumstances does glucose play a larger role as an energy source by the heart?
A) During rest and periods of low physical activity
B) During heavy exercise and increased cardiac workload
C) During fasting and prolonged periods of starvation
D) During anaerobic glycolysis
E) After a meal when glucose levels are elevated
Question 157:
Which of the following molecules plays a crucial role in the excitation-contraction coupling in cardiac muscle cells?
A) Sodium (Na+)
B) Potassium (K+)
C) Calcium (Ca2+)
D) Magnesium (Mg2+)
E) Chloride (Cl-)
Question 158:
Which term describes the force exerted on the left ventricle of the heart immediately before it contracts, primarily determined by the volume of blood in the ventricle at the end of diastole?
A) Afterload
B) Preload
C) Contractility
D) Starling’s law
E) Autonomic control
Question 159:
Which type of adrenergic receptor is primarily responsible for increasing intracellular calcium levels in cardiac myocytes, thereby enhancing contractility?
A) Alpha-1 adrenergic receptor
B) Alpha-2 adrenergic receptor
C) Beta-1 adrenergic receptor
D) Beta-2 adrenergic receptor
E) Dopamine receptor
Question 160:
Which autonomic nervous system division primarily increases heart rate and contractility through the release of norepinephrine and epinephrine?
A) Parasympathetic nervous system
B) Sympathetic nervous system
C) Enteric nervous system
D) Somatic nervous system
E) Central nervous system
Question 161:
Which of the following statements best describes Starling’s law of the heart?
A) It states that the heart rate is inversely proportional to the end-diastolic volume.
B) It describes the relationship between stroke volume and systemic vascular resistance.
C) It explains how sympathetic and parasympathetic nerves control heart rate.
D) It states that stroke volume increases with increasing preload, up to a certain point.
E) It describes the regulation of heart rate by the renin-angiotensin-aldosterone system.
Question 162:
Which term refers to the resistance that the left ventricle of the heart must overcome to eject blood into the systemic circulation?
A) Preload
B) Afterload
C) Contractility
D) Frank-Starling effect
E) Venous return
Question 163:
Which layer of the pericardium is directly attached to the heart muscle, providing a protective covering?
A) Fibrous pericardium
B) Parietal pericardium
C) Visceral pericardium
D) Pericardial cavity
E) Peritoneum
Question 164:
During embryological development, the heart initially forms from which germ layer?
A) Endoderm
B) Ectoderm
C) Paraxial mesoderm
D) Lateral plate mesoderm
E) Intermediate mesoderm
Question 165:
What is the name of the remanent of the structure that connects the pulmonary artery and the aorta in a developing fetus, allowing most of the blood to bypass the non-functional fetal lungs?
A) Ductus arteriosus
B) Fossa ovalis
C) Ductus venosus
D) Ligamentum arteriosum
E) Ligamentum venosum
Question 166:
What is the term for a persistent opening between the right and left atria of the heart, which is a remnant of fetal circulation?
A) Patent ductus arteriosus
B) Ventricular septal defect
C) Patent foramen ovale
D) Aortic stenosis
E) Tetralogy of Fallot
Question 167:
Which molecule plays a critical role in the biochemical closure of the ductus arteriosus after birth due to a decrease in its concentration?
A) Prostacyclin
B) Prostaglandin E1 (PGE1)
C) Arachidonic acid
D) Prostaglandin E2 (PGE2)
E) Cyclooxygenase (COX)
Question 168:
During embryological development of the heart, what is the significance of the fusion of the endocardial tubes?
A) Formation of atrioventricular valves
B) Development of coronary arteries
C) Establishment of the cardiac conduction system
D) Creation of the interventricular septum
E) Maturation of the pericardium
Question 169:
In the fetal circulation pathway in-utero, oxygenated blood from the placenta enters the fetal circulation through which vessel?
A) Umbilical artery
B) Ductus venosus
C) Foramen ovale
D) Umbilical vein
E) Pulmonary vein
Question 170:
How many umbilical veins & arteries are present in the developing fetus?
A) 1 umbilical vein & 1 umbilical artery
B) 2 umbilical veins & 1 umbilical artery
C) 1 umbilical vein & 2 umbilical arteries
D) 2 umbilical veins & 2 umbilical arteries
E) 3 umbilical veins & 1 umbilical artery
Question 171:
In which compartment of the mediastinum is the heart found?
- Superior mediastinum
- Inferior mediastinum
- Anterior mediastinum
- Middle mediastinum
- Posterior mediastinum
Question 172:
What type of epithelium lines the endocardium?
- Simple squamous
- Simple cuboidal
- Simple columnar
- Stratified squamous
- Pseudostratified columnar epithelium
Question 173:
Which of the following surfaces of the heart faces the rib cage?
- Diaphragmatic
- Base
- Apex
- Right pulmonary
- Sternocostal
Question 174:
Which of the following blood vessels has the thickest layer of tunica adventitia?
- Elastic arteries
- Muscular arteries
- Large veins
- Medium veins
- Venules
Question 175:
Which of the following has the greatest number of smooth muscle cells?
- Elastic arteries
- Muscular arteries
- Large veins
- Medium veins
- Venules
Question 176:
Which of the following signalling pathways does angiotensin II utilise to carry out its actions?
- Tyrosine kinase
- Nuclear
- Gs (G-protein coupled receptor)
- Gq (G-protein coupled receptor)
- Gi (G-protein coupled receptor)
Question 177:
Which of the following differences between nodal & contractile action potentials is incorrect?
- Stage 4 action potential in nodal cells correspond to slow depolarisation via the funny current whereas in myocardial cells, it corresponds to the return to resting potential via sodium-potassium pump.
- Stage 0 action potential in nodal cells corresponds to rapid depolarisation by L-type calcium channels whereas it corresponds to T-type calcium channels in contractile cells.
- The generation of action potentials in nodal cells via the funny current is much faster than depolarisation in contractile cells.
- Stage 3 action potentials of both nodal & contractile cells are characterised by repolarisation.
- There are no stage 2 action potentials in nodal cells however in contractile cells, stage 2 corresponds to the plateau phase.
Question 178:
Which of the following words has this definition: the speed of electrical conductivity through purkinje fibres?
- Ionotropy
- Chronotropy
- Dromotropy
- Louistropy
- Hypertrophy
Question 179:
As we age, which component of blood vessels is predominantly lost?
- Elastin
- Collagen
- Smooth muscle cells
- Reticular fibres
- Fibroblasts
Question 180:
Which of the following can be used to indirectly measure central venous pressure (CVP)?
- Common carotid venous pressure
- External jugular venous pressure
- Superior vena cava venous pressure
- Subclavian venous pressure
- Internal jugular venous pressure
Question 181:
Which of the following stages corresponds to peak ventricular contraction whereby the ventricles become physically smaller, taking up less pericardial space allowing blood to be drawn down into the atrium in a JVP waveform?
- X descent 1
- C wave
- X descent 2
- V wave
- Y descent
Question 182:
Where are red blood cells synthesised?
- Yellow bone marrow
- Red bone marrow
- Kidneys
- Liver
- Spleen
Question 183:
Which law is the following statement referring to: When a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its partial pressure. The amount of gas that dissolves in a liquid is also dependent upon the solubility of the gas and the temperature of the liquid?
- Graham’s law
- Fick’s law
- Dalton’s law
- Henry’s law
- Boyle’s law
Question 184:
Which of the following is the first structure to form during the separation of the atrium?
- Foramen secundum
- Septum secundum
- Septum primum
- Foramen primum
- Foramen ovale
Question 185:
If a person experiences a heart attack, through which dermatomes is pain perceived in?
- T1-T4
- T1-T5
- C5-T1
- C1-C4
- L1-L5
Question 186:
Which number corresponds with the superior vena cava?
- 1
- 2/3
- 4
- 5
- 6
Question 187:
Which of the following arteries can be palpated in the anatomical snuff box?
- Brachial
- Carotid
- Radial
- Median
- Ulna
Question 188:
Which of the following is the only blood vessel that is composed of a tunica intima layer only?
- Arterioles
- Capillaries
- Venules
- Muscular arteries
- Medium veins
Question 189:
Which second messenger molecule does noradrenaline utilise in cardiomyocytes?
- cAMP
- Adenylate cyclase
- Ca2+
- IP3
- Phospholipase C
Question 190:
Which of the following statements is incorrect?
- Men have a higher volume of lean tissue compared to women
- Intracellular fluid makes up 2/3 of total body water
- The predominant extracellular cation ion is Na+ (sodium)
- Adipose tissue has a higher fluid content than lean tissue
- The total amount of body of fluid in an average human is 55%-60% & extracellular fluid makes up 20% of our body weight
Question 191:
Which of the following is the predominant component of lymph?
- Proteins (albumin, globulin, fibrinogen, prothrombin, clotting factors)
- Carbohydrates
- Water
- Lipids
- Electrolytes
Question 192:
Which of the following ECG chest leads are classified as septal leads?
- V1-V2
- V3-V4
- V5-V6
- Lead II, III & aVF
- Lead I, aVR & aVL
Question 193:
Which of the following arteries supplies leads II,III & aVF?
- Right coronary artery
- Left coronary artery
- Posterior descending artery
- Left anterior descending artery
- Left circumflex artery
Question 194:
Which of the following is not cause and/or is not a consequence reduced oncotic pressure?
- Reduced albumin synthesis
- Increased interstitial fluid
- Reduced fluid reabsorption
- Oedema
- Increased fluid in the venule end of capillaries
Question 195:
Which of the following may contribute to oedema?
- Reduced capillary (hydrostatic) pressure and salt/water retention
- Increased oncotic pressure (low protein in plasma)
- Increased lymphatic drainage
- Inflammation leading to the release of cytokines & immune cells
- Endothelial repair
Med Wiz 