Cardiovascular System Overview

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Questions and Answers

What determines the preload in the ventricle?

Contractility of the heart

Venous return to the ventricle (correct)

Blood left in the left ventricle at the end of diastole

Aortic systolic pressure

Which statement regarding afterload is correct?

Afterload is the volume inside the ventricle at the end of diastole.

Increased afterload leads to decreased force of contraction. (correct)

Afterload does not affect the workload of the heart.

A decrease in afterload will reduce the workload of the heart.

What role does calcium play in muscle contraction?

It binds to the troponin complex, allowing myosin to bind to actin. (correct)

It reduces the cross-bridging cycle.

It inhibits the troponin complex.

It decreases the release of neurotransmitters.

What happens to the myosin head during the power stroke?

It rotates 45 degrees, pulling the actin with it. Signup and view all the answers

How is cardiac output calculated?

Heart rate times stroke volume Signup and view all the answers

What is the main effect of L-type calcium channels being blocked?

Decreased force of contraction Signup and view all the answers

What occurs when ATP binds to the myosin head?

Myosin head detaches from actin. Signup and view all the answers

What primarily correlates with left ventricular function as measured by ejection fraction?

Stroke volume relative to total volume Signup and view all the answers

What is the role of chordae tendineae in the function of AV valves?

To prevent regurgitation from ventricles into atria Signup and view all the answers

Which semilunar valve separates the right ventricle from the main pulmonary artery?

Pulmonary valve Signup and view all the answers

What is the significance of optimal aortic diastolic pressure?

It ensures coronary perfusion of the smallest vessels Signup and view all the answers

Which of the following statements about the mitral valve is correct?

It is located between the left atrium and the left ventricle. Signup and view all the answers

Which cranial nerve is responsible for the afferent signal from the carotid baroreceptors?

Glossopharyngeal nerve (CN IX) Signup and view all the answers

What effect does acetylcholine have on heart function?

Decreases heart rate Signup and view all the answers

Which feature distinguishes the pulmonary valve from the aortic valve?

It consists of right, left, and anterior cusps. Signup and view all the answers

What reflex is primarily influenced by stretch signals in the right atrium due to increased volume?

Bainbridge reflex Signup and view all the answers

What is the primary function of the fibrous pericardium?

Protects the heart and prevents overdistension Signup and view all the answers

What is the position of the heart relative to the midline of the body?

Approximately ⅔ to the left of the midline Signup and view all the answers

Which layer of the heart wall is primarily responsible for contractility?

Myocardium Signup and view all the answers

How does the myocardium of the left ventricle differ from that of the right ventricle?

Right ventricle myocardium functions under lower pressure Signup and view all the answers

Which phases of the cardiac cycle involve the aortic and pulmonic valves being open?

Phase 3 and Phase 4 Signup and view all the answers

Where is the tricuspid valve best auscultated?

Right half of the lower end of the sternum Signup and view all the answers

What component separates the muscle mass of the atria and ventricles?

Fibrous skeleton Signup and view all the answers

What occurs during isovolumetric ventricular systole?

All four valves are closed Signup and view all the answers

Which part of the heart muscle has the property of automaticity?

Conductive muscle Signup and view all the answers

What is the role of the pericardial cavity?

Reduces friction between heart layers Signup and view all the answers

Which chamber of the heart has the lowest mean pressure?

Right Atrium Signup and view all the answers

What is the average range of left atrial mean pressure?

4-12 mmHg Signup and view all the answers

During which phase does the heart experience passive ventricular filling?

Phase 5 Signup and view all the answers

Which layer of the heart wall is continuous with the tunica intima of great vessels?

Endocardium Signup and view all the answers

The anatomical shape of the heart can be described as a:

Blunt cone roughly the size of a clenched fist Signup and view all the answers

Which heart valve is auscultated at the apex or PMI?

Mitral Valve Signup and view all the answers

What is defined as the amount of blood ejected from the left ventricle during systole?

Stroke volume Signup and view all the answers

Which formula is used to calculate stroke volume?

EDV - ESV Signup and view all the answers

What percentage range corresponds to normal ejection fraction?

52-72% Signup and view all the answers

Which alteration in the nervous system is related to heart function?

Decreased vagal tone Signup and view all the answers

What is the role of the foramen ovale in fetal circulation?

Allows blood to flow between the atria Signup and view all the answers

What change occurs in circulation with the clamping of the umbilical cord at birth?

Dramatic increase in systemic vascular resistance Signup and view all the answers

Which neurohumoral change is associated with heart failure?

Increased catecholamines Signup and view all the answers

What is the function of the ductus arteriosus in fetal circulation?

Joins the pulmonary artery to the aorta Signup and view all the answers

Which defect is categorized as increasing pulmonary blood flow?

Atrial septal defect Signup and view all the answers

What occurs in Eisenmenger syndrome?

Increased pulmonary vascular resistance exceeding systemic resistance Signup and view all the answers

Which of the following is an example of an obstructive lesion?

Pulmonary stenosis Signup and view all the answers

Which maternal risk factor is associated with congenital heart defects?

Age over 40 Signup and view all the answers

Which lesion is typically associated with a decrease in pulmonary blood flow?

Hypoplastic left heart syndrome Signup and view all the answers

Which condition involves mixing of desaturated and saturated blood?

Transposition of the great vessels Signup and view all the answers

In postnatal development, what happens to the size of the right ventricle?

It decreases relative to the left ventricle Signup and view all the answers

Which congenital defect typically leads to hypoxia and cyanosis?

Tetralogy of Fallot Signup and view all the answers

Study Notes

Cardiovascular and Lymphatic System

The heart is located in the mediastinum, anterior to the descending aorta, esophagus, and major bronchi, from T5-T8. It's roughly 2/3 the size of a clenched fist and positioned 2/3 to the left of the midline.
Heart surfaces include sternocostal (anterior), diaphragmatic (inferior), and base (posterior).
Heart valves are best auscultated at specific locations: Pulmonary (2nd intercostal space, left sternal border), Aortic (2nd intercostal space, right sternal border), Mitral (apex or PMI; 5th intercostal space, midclavicular line), and Tricuspid (right half of the lower end of the sternum).
The cardiac cycle includes phases: atrial systole/ventricular diastole (fast and slow filling), isovolumetric ventricular systole (passive), ventricular ejection (fast and slow), isovolumetric ventricular relaxation (with S2 heart sound), and passive ventricular filling.
Mitral and tricuspid valves open during passive ventricular filling; aortic and pulmonic valves open during ventricular ejection and close during isovolumetric ventricular relaxation.
Normal cardiac pressures:
RA: Mean 4 mmHg, range 0-8 mmHg
RVESP: Mean 24 mmHg, range 15-28 mmHg
RVEDP: Mean 4 mmHg, range 0-8 mmHg
LA: Mean 7 mmHg, range 4-12 mmHg
LVESP: Mean 130 mmHg, range 90-140 mmHg
LVEDP: Mean 7 mmHg, range 4-12 mmHg

Mechanical and Electrical Events

Atrial contraction occurs just after the P-wave.
Tricuspid closes and RV contracts just after the QRS-complex.
RA relaxes and venous filling occurs after the T-wave.
'a' wave (end diastole): RA contraction
'c' wave (early systole): TV bulging into RA
'x' descent (mid systole): relaxation of RA
'v' wave (late systole): rapid filling of RA
'y' descent (early diastole): early ventricular filling

Layers of the Heart Wall

Fibrous pericardium: heavy connective tissue surrounding the heart that protects it.
Serous pericardium: visceral (epicardium) and parietal layers, reducing friction.
Myocardium: atrial, ventricular, and conductive muscle tissue. The LV is 3 times thicker than the RV.
Endocardium: Endothelial lining of the heart chambers.

Cardiovascular Function

Coronary blood flow (80-90% during diastole): 225-250 mL/min (4-7% of CO).
CPP (Coronary perfusion pressure) : DBP-LVEDP, important for autoregulation between 50-120 mmHg.
Coronary flow is autoregulated between 50-120 mmHg.

Conduction System

SA node is the normal pacemaker, located at the junction of the superior vena cava and the right atrium, and setting the heart rate to 100 bpm.
AV node: 40-60 bpm ("Nodal rhythm") slower conduction than SA node at 200 mm/sec located in the lower right atrium near the fibrous skeleton.
AV bundle of His and Purkinje fibers have the fastest conduction speed (4000 mm/sec).

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Description

This quiz covers key concepts related to the cardiovascular and lymphatic system, including the anatomy of the heart, heart valves, and the cardiac cycle. Understand the positions of the heart and auscultation points for heart valves. Test your knowledge of these fundamental topics in cardiovascular physiology.