Cardiovascular and Respiratory Systems Quiz

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Questions and Answers

What is the initial event in the formation of atherosclerosis?

Activation of scavenger receptor in the macrophages

Phagocytosis of LDL cholesterol by the macrophages

Migration of smooth muscle onto subintimal layer

Disruption of the single layer endothelium (correct)

What type of ion current primarily contributes to Phase 2 of the myocyte action potential?

Outward Na currents

Inward K currents

Inward Na currents (correct)

Outward K currents

Which shunt allows oxygenated blood to bypass the liver during fetal circulation?

Truncus arteriosus

Foramen ovale

Ductus venosus (correct)

Ductus arteriosus

What mechanism is primarily responsible for the long plateau phase during Phase 2 of the action potential?

The near equality of current from inward Ca influx and outward K efflux Signup and view all the answers

In the case of acute lung edema, what is the primary mechanism involved?

Increased hydrostatic pressure Signup and view all the answers

What is responsible for the transient repolarization observed in phase 1 of the myocyte action potential?

Transient activation of potassium channel Signup and view all the answers

Which segment of the ECG is typically indicative of left atrial enlargement?

The P wave Signup and view all the answers

What causes the sudden occlusion in acute coronary syndrome?

Thrombosis process at the atherosclerotic plaque Signup and view all the answers

What is the correct sequence of events in the development of atherosclerosis?

Endothelial dysfunction – migration of LDL to intimal layer – oxidation of LDL – migration of smooth muscle cells – formation of foam cells Signup and view all the answers

What is the result of the activation of monocytes in relation to macrophage function?

They transform into macrophages Signup and view all the answers

What effect does inward K current have during the action potential phases?

It leads to repolarization. Signup and view all the answers

How does the ductus arteriosus function in fetal circulation?

It shunts blood from the pulmonary artery to the aorta. Signup and view all the answers

Which aspect of the ECG is assessed to evaluate cardiac ischemia?

The ST segment Signup and view all the answers

Which condition is most likely to lead to myocardial infarction?

Impaired perfusion due to atherosclerotic lesions Signup and view all the answers

How does calcium current affect cardiac muscle contraction?

It initiates muscle contraction. Signup and view all the answers

Which ion plays a significant role in the formation of foam cells during atherosclerosis?

Cholesterol Signup and view all the answers

What is the first step in the process leading to the formation of foam cells in atherosclerosis?

Migration of LDL to intimal layer Signup and view all the answers

Which arrhythmia is characterized by abnormal impulse formation?

Sick sinus syndrome Signup and view all the answers

In which part of the heart's conduction system does the electrical signal experience a delay?

Atrioventricular node Signup and view all the answers

What mechanism is involved in excitation-contraction coupling in cardiac myocytes?

Influx of Na+ triggers release of Ca2+ from the sarcoplasmic reticulum Signup and view all the answers

What does marker 3 on an ECG signify?

Ventricular depolarization Signup and view all the answers

Which artery is associated with the blockage that affects the left anterior descending sulcus?

Left anterior descending artery Signup and view all the answers

What physiological event occurs during the inflow of calcium ions in cardiac myocytes?

It triggers muscle contraction through cross-bridge cycling Signup and view all the answers

Which of the following describes the abnormal heart rhythm known as bradycardia?

Heart rate is consistently below 60 beats per minute Signup and view all the answers

What does a jugular vein pressure (JVP) measurement of 5 + 4 cmH2O indicate about the right atrial pressure?

The estimate right atrial pressure is 9 cmH2O Signup and view all the answers

What does the vertical height of the external jugular vein indicate when JVP is measured as 5 + 4 cmH2O?

The vertical height is 4 cm above the sternal angle Signup and view all the answers

Which statement correctly describes the automaticity of pacemaker cells?

The action potential of pacemaker cells has unique characteristics compared to myocyte action potentials Signup and view all the answers

Which of the following statements about the action potential of pacemaker cells is correct?

The upstroke of phase 0 primarily relies on sodium influx Signup and view all the answers

Which property is NOT typical of the pacemaker cell action potential?

Phase 0 characterized by rapid sodium influx Signup and view all the answers

In patients with congestive heart failure, what does a high jugular vein pressure indicate?

Increased right atrial pressure Signup and view all the answers

What characteristic of pacemaker current distinguishes it from myocyte action potential?

Unique ion channels governing the slow influx Signup and view all the answers

What might be the consequence of action potential properties in pacemaker cells?

Spontaneous depolarization leading to arrhythmias Signup and view all the answers

Which statement about cardiac output in heart failure is accurate?

Increasing preload significantly boosts cardiac output. Signup and view all the answers

What condition may result from elevated LV end-diastolic pressure in heart failure?

Pulmonary congestion. Signup and view all the answers

Which of the following conditions can echocardiography NOT evaluate?

Stenosis of coronary artery. Signup and view all the answers

Cyanosis refers to which condition?

Discoloration from elevated deoxygenated hemoglobin. Signup and view all the answers

What does afterload in cardiac function primarily affect?

The contractile strength at a given length. Signup and view all the answers

In heart failure, how does increased contractility influence stroke volume?

It maintains stroke volume equal to that of a normal heart. Signup and view all the answers

How does excessive preload affect cardiac output during heart failure?

It can lead to decreased stroke volume. Signup and view all the answers

Which factor is crucial for maintaining cardiac output in a failing heart?

Increased contractility. Signup and view all the answers

Study Notes

Atherosclerosis and Coronary Artery Disease

Formation of atherosclerotic plaque in the coronary artery causes coronary artery disease.
Initial Event: Disruption of the single layer endothelium.
Process: LDL (low-density lipoprotein) migration into the intimal layer followed by its oxidation, monocyte adhesion, expression of scavenger receptors, formation of foam cells, and smooth muscle cell migration.

Fetal Circulation

Oxygenated blood leaves the placenta and enters the fetus through the umbilical vein.
Shunts exist to bypass the liver and lungs.
Ductus Venosus bypasses the liver and directs blood to the inferior vena cava.

Acute Lung Edema

Shortness of breath and leg edema are common symptoms.
Mechanism: Increased hydrostatic pressure in the pulmonary capillaries.

Myocyte Action Potential

Phase 1: Brief transient repolarization caused by the transient activation of potassium channels.
Phase 2: Long plateau phase caused by the near equality of current from inward Ca influx and outward K efflux.

Acute Coronary Syndrome

Sudden occlusion of the coronary artery is the primary cause.
Mechanism: Thrombosis due to the rupture of an atherosclerotic plaque.

Arrhythmia

Sick Sinus Syndrome: Abnormal impulse formation from the sinoatrial node.

ECG Interpretation

P Wave: Represents atrial depolarization.
QRS Complex: Represents ventricular depolarization.
T Wave: Represents ventricular repolarization.

Cardiac Contraction

Excitation-contraction coupling: Action potential reaching the myocyte induces contraction by triggering the release of calcium ions into the cytoplasm.
Mechanism: Influx of calcium ions during phase 2 triggers the inhibition of Troponin-Tropomyosin complex, allowing actin and myosin cross-bridging and muscle contraction.

Stroke Volume Regulation

Afterload: The resistance that the ventricle must overcome to eject blood.

Echocardiography

Ultrasound-based diagnostic tool used in cardiac evaluations.
Limitations: Cannot evaluate stenosis of coronary arteries.

Congenital Heart Disease

Cyanosis: A blue-purple discoloration of the skin and mucous membranes caused by an elevated level of deoxygenated hemoglobin.

Jugular Venous Pressure (JVP)

Measurement: Provides an estimate of right atrial pressure.
JVP of 5 + 4 cmH2O: Indicates a right atrial pressure of 9 cmH2O.

Pacemaker Cell Automaticity

Unique Property: The action potential of a pacemaker cell has a gradual upward slope (phase 4) due to the inward "funny" current carried by sodium ions.
Mechanism: This gradual depolarization brings the cell to threshold, initiating the spontaneous firing of action potentials.

Mr. Sederhana

Chest pain: Indicates a possible cardiovascular emergency.

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Description

Test your knowledge on topics including atherosclerosis, fetal circulation, acute lung edema, and myocyte action potentials. This quiz covers essential mechanisms and processes involved in cardiovascular health and respiratory function. Perfect for students in advanced biology or medical courses.