Cardiovascular System Overview

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Questions and Answers

What is the primary function of the fibrous pericardium?

Provides a pathway for nerve signals

Facilitates contraction of the myocardium

Reduces friction between heart chambers

Prevents overdistension and protects the heart (correct)

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

The LV is 3 times thicker than the RV (correct)

The RV requires more energy to contract than the LV

The LV is thinner than the RV

The RV moves in a circular motion while the LV does not

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

Myocardium

Fibrous pericardium

Epicardium

Endocardium (correct)

What characterizes the atrial myocardium compared to the ventricular myocardium?

It is relatively thin Signup and view all the answers

Which part of the heart wall layer is primarily responsible for conducting electrical impulses?

Conductive myocardium Signup and view all the answers

What is the normal volume of fluid in the pericardial cavity?

10-50 mL Signup and view all the answers

Which statement about the fibrous skeleton of the heart is correct?

It separates the atria and ventricles Signup and view all the answers

What is one major function of the serous pericardium?

To reduce friction between heart surfaces Signup and view all the answers

Where is the aortic valve best auscultated?

Second intercostal space, R sternal border Signup and view all the answers

Which phase of the cardiac cycle involves all four valves being closed?

Isovolumetric ventricular systole Signup and view all the answers

In which heart chambers is the normal range of pressure measured at 0-8 mmHg?

Right atrium and left ventricle Signup and view all the answers

Which surface of the heart is primarily composed of the left ventricle?

Diaphragmatic (inferior) Signup and view all the answers

What is the role of calcium in the contraction process of muscle fibers?

Calcium helps in releasing tropomyosin from the actin-binding site. Signup and view all the answers

Which of the following statements is true regarding the heart's anatomy?

The heart is shaped like a blunt cone roughly ⅔ the size of a clenched fist. Signup and view all the answers

What defines preload in cardiac physiology?

The volume inside the ventricle at the end of diastole. Signup and view all the answers

During which phase of the cardiac cycle do the aortic and pulmonic valves open?

Ventricular ejection Signup and view all the answers

What happens to the myosin head during the cross-bridging cycle when ATP is hydrolyzed?

The myosin head cocks to initiate the power stroke. 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

How is afterload commonly indexed in the left ventricle during systole?

Aortic systolic pressure. Signup and view all the answers

What effect does increased afterload have on myocardial contraction?

It decreases the force of contraction and increases workload. Signup and view all the answers

What is the normal mean pressure in the right ventricle during systole (RVESP)?

Mean: 24 mmHg; range: 15-28 mmHg Signup and view all the answers

Which channels are blocked by calcium channel blocking medications?

L-type calcium channels. Signup and view all the answers

What defines stroke volume in relation to cardiac output?

The volume of blood pumped per contraction. Signup and view all the answers

Which of the following factors has no impact on cardiac output?

Blood viscosity. Signup and view all the answers

What is the primary factor that directly influences stroke volume?

Preload Signup and view all the answers

How is ejection fraction calculated?

(EDV - ESV)/EDV Signup and view all the answers

What change occurs in the cardiovascular system immediately after birth due to umbilical cord clamping?

Increase in systemic vascular resistance (SVR) Signup and view all the answers

Which statement correctly identifies a function of the ductus venosus during fetal circulation?

Connects the inferior vena cava to the umbilical vein. Signup and view all the answers

What is the ejection fraction range classified as indicating normal heart function?

52-72% Signup and view all the answers

Which of the following hormones is NOT typically increased in the neurohumoral changes associated with heart failure?

Insulin Signup and view all the answers

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

Connects the left and right atria. Signup and view all the answers

Which condition corresponds to an ejection fraction of 30-40%?

Moderate dysfunction Signup and view all the answers

What physiological change occurs in the left ventricular myocardium after birth?

It becomes thicker and more dominant. Signup and view all the answers

Which congenital defect is classified as decreasing pulmonary blood flow?

Tetralogy of Fallot Signup and view all the answers

What is the primary outcome of Eisenmenger syndrome?

Reversal of blood shunting. Signup and view all the answers

Which congenital defect does NOT involve a shunt?

Pulmonary stenosis Signup and view all the answers

What effect does the closure of fetal shunts have on the heart postnatally?

It aids in the establishment of normal adult blood flow pathways. Signup and view all the answers

Which maternal factor is NOT listed as a risk for congenital heart defects?

Smoking during pregnancy Signup and view all the answers

Which defect is associated with mixing of desaturated and saturated blood?

Transposition of the great vessels Signup and view all the answers

Which congenital defect primarily causes right-to-left shunting?

Hypoplastic left heart syndrome Signup and view all the answers

Which feature is unique to the AV valves compared to the semilunar valves?

They consist of cusps that are endocardial folds. Signup and view all the answers

What is the critical pressure for optimal perfusion of the smallest coronary vessels?

Aortic diastolic pressure Signup and view all the answers

Which combination of cusps is found on the mitral valve?

Anterior and posterior leaflets Signup and view all the answers

Which of the following statements about the semilunar valves is correct?

Pulmonary valve separates the RV from the main pulmonary artery. Signup and view all the answers

Which reflex is most directly stimulated by increased volume in the right atrium?

Bainbridge reflex Signup and view all the answers

What effect does parasympathetic stimulation via acetylcholine have on the heart?

Decreases force of contraction Signup and view all the answers

Which cranial nerve is responsible for the afferent pathway of the carotid baroreceptor reflex?

Glossopharyngeal (CN IX) Signup and view all the answers

Which of the following best describes the condition when AV valves are considered stenotic?

When they measure less than 1 cm^2 in area. Signup and view all the answers

Study Notes

Cardiovascular and Lymphatics System

Heart Anatomy:
- Located in the mediastinum, roughly 2/3 to the left of the midline, shaped like a blunt cone.
- Approximately 2/3 the size of a clenched fist.
- Projects anterior, superior, and to the left, posterior to the descending aorta, esophagus, and major bronchi.
- Heart surfaces include sternocostal (anterior), diaphragmatic (inferior), and base (posterior).
Heart Valves Auscultation Locations:
- Pulmonary valve: second intercostal space, left sternal border.
- Aortic valve: second intercostal space, right sternal border.
- Mitral valve: apex (PMI), fifth intercostal space, midclavicular line.
- Tricuspid valve: right half of the lower end of the sternum.
Cardiac Cycle Phases:
- Phase 1: Atrial systole/ventricular diastole (fast and slow filling).
- Phase 2: Isovolumetric ventricular systole (all valves closed).
- Phase 3: Ventricular ejection (fast and slow ejection; aortic and pulmonic valves open).
- Phase 4: Isovolumetric ventricular relaxation (S2 heart sound; aortic and pulmonic valves close).
- Phase 5: Passive ventricular filling (mitral and tricuspid valves open).
Cardiac Pressures (Normal Ranges):
- Right Atrium (RA): 4 mmHg (range 0-8 mmHg).
- Right Ventricular End Systolic Pressure (RVESP): 24 mmHg (range 15-28 mmHg).
- Right Ventricular End Diastolic Pressure (RVEDP): 4 mmHg (range 0-8 mmHg).
- Left Atrium (LA): 7 mmHg (range 4-12 mmHg).
- Left Ventricular End Systolic Pressure (LVESP): 130 mmHg (range 90-140 mmHg).
- Left Ventricular End Diastolic Pressure (LVEDP): 7 mmHg (range 4-12 mmHg).

Mechanical and Electrical Events

Atrial Contraction: Just after P wave.
Tricuspid Closing: Just after P wave.
RV Contraction: Just after QRS.
RA Relaxation: Just after T wave
RV contracts, RA has venous filling: Just after T wave
RA empties: Before P wave.

Layers of the Heart Wall

Fibrous Pericardium: Protective, prevents overdistension, fused to great vessels
Serous Pericardium: Thin, delicate double layer (Parietal and Visceral) reducing friction

Coronary Blood Flow and Pressure

Coronary Blood Flow: 225-250 mL/min (4–7% of CO). Predominantly during diastole.
Coronary Perfusion Pressure (CPP): DBP − LVEDP (autoregulates between 50-120 mmHg) - Directly proportional to CPP and inversely proportional to coronary vascular resistance.

Nervous Control of Heart

Sympathetic: Increases Heart Rate (HR), Contractility (inotropy), Speed of contraction (dromotropy). Affects Coronary/Vascular (vasoconstriction)
Parasympathetic: Decreases HR, Contractility, and Speed of contraction. Affects Coronary/Vascular (vasodilation).

Conduction System

SA Node: Normal pacemaker (100 bpm) located at the junction of the superior vena cava (SVC) and right atrium (RA).
AV Node: (40-60 bpm) Located in the lower RA , part of the conduction system.
AV Bundle of His and Purkinje Fibers: Conducts action potentials at high speeds to the ventricles, allowing coordinated contraction.

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Description

This quiz covers the anatomy of the heart, including its location and size, as well as the auscultation points for heart valves. Furthermore, it delves into the phases of the cardiac cycle, detailing the processes of atrial and ventricular activity. Test your knowledge on these essential aspects of cardiovascular physiology.