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Questions and Answers
What is the primary role of the AV node in the heart?
What is the primary role of the AV node in the heart?
Which wave is responsible for ventricular repolarization on an ECG?
Which wave is responsible for ventricular repolarization on an ECG?
What is the normal heart rate range for junctional bradycardia according to the content?
What is the normal heart rate range for junctional bradycardia according to the content?
Which heart sound is associated with the closure of the atrial valves?
Which heart sound is associated with the closure of the atrial valves?
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When interpreting an ECG, how is the heart rate calculated from the QRS complex?
When interpreting an ECG, how is the heart rate calculated from the QRS complex?
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Which type of shock is characterized by the heart's failure to pump blood effectively?
Which type of shock is characterized by the heart's failure to pump blood effectively?
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Which of the following is NOT a clinical symptom associated with shock?
Which of the following is NOT a clinical symptom associated with shock?
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Septic shock is primarily caused by which of the following?
Septic shock is primarily caused by which of the following?
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Which cytokines are commonly released during septic shock?
Which cytokines are commonly released during septic shock?
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What is a common symptom related to hypovolemic shock after significant trauma?
What is a common symptom related to hypovolemic shock after significant trauma?
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What is the primary role of the sinoatrial node in the heart?
What is the primary role of the sinoatrial node in the heart?
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During ventricular systole, what occurs in the heart?
During ventricular systole, what occurs in the heart?
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What can result from a failure of the sinoatrial node?
What can result from a failure of the sinoatrial node?
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What is the normal weight range of the heart in males?
What is the normal weight range of the heart in males?
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Which of the following is NOT a major disease affecting the heart?
Which of the following is NOT a major disease affecting the heart?
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What is the normal wall thickness of the left ventricle?
What is the normal wall thickness of the left ventricle?
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What causes blood to flow from the left atrium into the left ventricle during diastole?
What causes blood to flow from the left atrium into the left ventricle during diastole?
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Which of the following is TRUE about the myocytes in the heart?
Which of the following is TRUE about the myocytes in the heart?
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What condition is characterized by the heart's inability to pump sufficient blood through the body?
What condition is characterized by the heart's inability to pump sufficient blood through the body?
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Which symptom is NOT typically associated with congestive heart failure?
Which symptom is NOT typically associated with congestive heart failure?
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What is a primary cause of heart failure related to the amount of blood the heart is required to pump?
What is a primary cause of heart failure related to the amount of blood the heart is required to pump?
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Which treatment method is NOT typically employed for managing heart failure?
Which treatment method is NOT typically employed for managing heart failure?
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What is the result of right ventricular hypertrophy caused by chronic obstructive pulmonary disease?
What is the result of right ventricular hypertrophy caused by chronic obstructive pulmonary disease?
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Which term describes the dilation of the heart due to volume overload?
Which term describes the dilation of the heart due to volume overload?
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What is a common consequence of the left ventricle working harder to overcome increased pressure in the aorta?
What is a common consequence of the left ventricle working harder to overcome increased pressure in the aorta?
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What condition occurs if large ventricular septal defect (VSD) leads to a reversal of shunt?
What condition occurs if large ventricular septal defect (VSD) leads to a reversal of shunt?
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Which of the following symptoms is associated with right-sided heart failure?
Which of the following symptoms is associated with right-sided heart failure?
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Which statement accurately describes the septum wall formation in atrial septal defect (ASD)?
Which statement accurately describes the septum wall formation in atrial septal defect (ASD)?
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What happens if the ductus arteriosus does not close after birth?
What happens if the ductus arteriosus does not close after birth?
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Which clinical feature is commonly associated with patent foramen ovale (PFO)?
Which clinical feature is commonly associated with patent foramen ovale (PFO)?
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What is a characteristic of Tetralogy of Fallot (ToF)?
What is a characteristic of Tetralogy of Fallot (ToF)?
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Study Notes
Basics
- Normal heart weight: females (250-300 g); males (300-350 g).
- Wall thickness: right ventricle (0.3-0.5 cm); left ventricle (1.3-1.5 cm).
- 90% of the heart's mass is made up of myocytes (heart muscle cells), but they only make up 25% of the cells.
- Heart function relies on the conduction of electrical impulses.
- The sinoatrial node (SA node) is the pacemaker of the heart, located in the right atrium.
- The SA node discharges at 70–80 times/minute and is innervated by vagal and sympathetic nerve fibers.
- The AV node is a "gatekeeper" that prevents too fast depolarization of the heart.
ECG
- Normal ECG strip: 10 seconds
- To calculate heart rate: multiply ventricular depolarization (QRS) count in 10 seconds by 6
- Interpretation: check if the P wave precedes the QRS complex and analyze the ST waves.
Heart Sounds
- First heart tone ("lub"): produced by the vibration of blood against closed atrial valves, marking the start of systole.
- Second heart tone ("dub"): caused by the closure of the aortic and pulmonary valves at the end of systole.
- S2 can sometimes be split into P2 (pulmonary valve sound) and A2 (aortic valve sound) during inspiration (inhaling).
Congestive Heart Failure
- Characterized by the heart's inability to pump sufficient blood throughout the body.
- Caused by factors that impair heart function: myocardial infarction, hypertension, arrhythmias, valve defects, pulmonary hypertension, and so forth.
- Main cause: volume overload, requiring the heart to pump more blood.
- Symptoms: shortness of breath during exercise or at rest, fatigue, pulmonary edema, peripheral edema, ascites, nocturia (urinating at night), and jugular vein distension.
- Treatment: address underlying causes, weight reduction, fluid management, sodium restriction, and medication (antihypertensives, diuretics, beta blockers, and antiarrhythmics).
General Causes of Heart Failure
-
Left side of the heart:
- Hypertensive heart disease: left ventricle works harder to overcome increased pressure in the aorta, leading to left ventricular hypertrophy.
- Coronary heart disease.
- Arrhythmias.
-
Right side of the heart:
- Cor pulmonale: right ventricle hypertrophy or dilation due to impaired lung perfusion.
- Acute cor pulmonale: pulmonary embolism (PE).
- Chronic cor pulmonale: chronic obstructive lung disease, lung tissue loss (tuberculosis, cancer surgery).
- Mechanism: right ventricle works harder to pump blood through the lungs.
- The heart compensates until it fails.
- Cor pulmonale: right ventricle hypertrophy or dilation due to impaired lung perfusion.
Shock
- Three most frequent types of shock:
- Cardiogenic shock: heart failure to pump blood (MI, arrhythmias, PE, heart tamponade).
- Hypovolemic shock: blood volume loss (bleeding, burns, trauma).
- Septic shock: systemic infection (mainly gram-negative organisms – endotoxic shock).
- Other types of shock: anaphylactic shock and neurogenic shock following spinal cord injury.
Clinical Symptoms of Shock
- Anxiety, restlessness, disorientation.
- Hypotension.
- Rapid pulse (tachycardia).
- Cool, clammy, mottled skin.
- Decreased urine production (oliguria).
- Rapid breathing (hyperventilation).
Blood Circulation Before and After Birth
- Before birth, oxygenation occurs through the placenta, not the lungs.
- Fetal blood bypasses the lungs through the foramen ovale between the right and left atria.
- Shortly before/after birth, the foramen ovale closes.
- Blood from the pulmonary artery takes a shortcut through the ductus arteriosus to the aorta.
Atrial Septal Defect (ASD)
- A left-right shunt occurs when the septum wall does not form properly.
- Consequences are usually less severe than ventricular septal defects, with no symptoms before age 30.
- Results in right heart hypertrophy eventually.
- Systolic murmur!
- Paradoxical embolus: thrombosis can travel from the right heart to the left heart and cause a stroke if the foramen ovale doesn't close (patent foramen ovale - PFO).
Patent Ductus Arteriosus (PDA)
- In the fetus, blood from the right heart bypasses the lungs through shortcuts (foramen ovale and ductus arteriosus) directly to the aorta.
- After birth, the ductus arteriosus usually closes within 15 hours.
- If it doesn't close, blood flows from the aorta (with higher blood pressure) into the lungs.
- This increases blood flow through the lungs and decreases oxygenated blood in the aorta.
- The heart has to work harder.
- Clinical feature: machine-like sound over the heart.
- Right-to-left shunts causing cyanosis.
Tetralogy of Fallot (ToF)
- RIGHT-TO-LEFT SHUNT!
- A large VSD will lead to right heart hypertrophy and eventually a reversal of the shunt.
- Deoxygenated blood flows from right to left, causing cyanosis (Eisenmenger's syndrome).
- Prognosis is very poor if this occurs.
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Description
Test your knowledge on the basics of cardiac physiology, including heart weight, wall thickness, and the roles of key cardiac structures such as the SA and AV nodes. Additionally, this quiz covers the interpretation of ECG strips and heart sounds involved in cardiac cycles. Perfect for students studying cardiology or health sciences.