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?

<p>It is relatively thin (A)</p> Signup and view all the answers

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

<p>Conductive myocardium (A)</p> Signup and view all the answers

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

<p>10-50 mL (A)</p> Signup and view all the answers

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

<p>It separates the atria and ventricles (A)</p> Signup and view all the answers

What is one major function of the serous pericardium?

<p>To reduce friction between heart surfaces (D)</p> Signup and view all the answers

Where is the aortic valve best auscultated?

<p>Second intercostal space, R sternal border (C)</p> Signup and view all the answers

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

<p>Isovolumetric ventricular systole (B)</p> Signup and view all the answers

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

<p>Right atrium and left ventricle (B)</p> Signup and view all the answers

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

<p>Diaphragmatic (inferior) (A)</p> Signup and view all the answers

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

<p>Calcium helps in releasing tropomyosin from the actin-binding site. (A)</p> Signup and view all the answers

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

<p>The heart is shaped like a blunt cone roughly â…” the size of a clenched fist. (A)</p> Signup and view all the answers

What defines preload in cardiac physiology?

<p>The volume inside the ventricle at the end of diastole. (D)</p> Signup and view all the answers

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

<p>Ventricular ejection (A)</p> Signup and view all the answers

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

<p>The myosin head cocks to initiate the power stroke. (C)</p> Signup and view all the answers

Where is the tricuspid valve best auscultated?

<p>Right half of the lower end of the sternum (B)</p> Signup and view all the answers

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

<p>Aortic systolic pressure. (D)</p> Signup and view all the answers

What effect does increased afterload have on myocardial contraction?

<p>It decreases the force of contraction and increases workload. (D)</p> Signup and view all the answers

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

<p>Mean: 24 mmHg; range: 15-28 mmHg (D)</p> Signup and view all the answers

Which channels are blocked by calcium channel blocking medications?

<p>L-type calcium channels. (C)</p> Signup and view all the answers

What defines stroke volume in relation to cardiac output?

<p>The volume of blood pumped per contraction. (A)</p> Signup and view all the answers

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

<p>Blood viscosity. (C)</p> Signup and view all the answers

What is the primary factor that directly influences stroke volume?

<p>Preload (B)</p> Signup and view all the answers

How is ejection fraction calculated?

<p>(EDV - ESV)/EDV (C)</p> Signup and view all the answers

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

<p>Increase in systemic vascular resistance (SVR) (B)</p> Signup and view all the answers

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

<p>Connects the inferior vena cava to the umbilical vein. (A)</p> Signup and view all the answers

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

<p>52-72% (A)</p> Signup and view all the answers

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

<p>Insulin (A)</p> Signup and view all the answers

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

<p>Connects the left and right atria. (C)</p> Signup and view all the answers

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

<p>Moderate dysfunction (D)</p> Signup and view all the answers

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

<p>It becomes thicker and more dominant. (A)</p> Signup and view all the answers

Which congenital defect is classified as decreasing pulmonary blood flow?

<p>Tetralogy of Fallot (A)</p> Signup and view all the answers

What is the primary outcome of Eisenmenger syndrome?

<p>Reversal of blood shunting. (D)</p> Signup and view all the answers

Which congenital defect does NOT involve a shunt?

<p>Pulmonary stenosis (A)</p> Signup and view all the answers

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

<p>It aids in the establishment of normal adult blood flow pathways. (C)</p> Signup and view all the answers

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

<p>Smoking during pregnancy (D)</p> Signup and view all the answers

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

<p>Transposition of the great vessels (A)</p> Signup and view all the answers

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

<p>Hypoplastic left heart syndrome (A)</p> Signup and view all the answers

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

<p>They consist of cusps that are endocardial folds. (A), Their free edges attach to chordae tendineae and papillary muscle. (B), They have annular rings that attach to the fibrous skeleton. (D)</p> Signup and view all the answers

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

<p>Aortic diastolic pressure (B)</p> Signup and view all the answers

Which combination of cusps is found on the mitral valve?

<p>Anterior and posterior leaflets (A)</p> Signup and view all the answers

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

<p>Pulmonary valve separates the RV from the main pulmonary artery. (C)</p> Signup and view all the answers

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

<p>Bainbridge reflex (C)</p> Signup and view all the answers

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

<p>Decreases force of contraction (B)</p> Signup and view all the answers

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

<p>Glossopharyngeal (CN IX) (D)</p> Signup and view all the answers

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

<p>When they measure less than 1 cm^2 in area. (B)</p> Signup and view all the answers

Flashcards

Heart Location

The heart is located in the mediastinum, anterior to the descending aorta, esophagus, and major bronchi, from T5-T8. It's shaped like a blunt cone, about two-thirds the size of a clenched fist, and sits two-thirds to the left of the midline, projecting anterior, superior, and to the left.

Heart Valves Auscultation

Heart valves can be listened to (auscultated) in specific locations on the chest, to identify any abnormal noises. The aortic valve is heard in the second intercostal space, right sternal border. The pulmonary valve is heard in the second intercostal space, left sternal border. The mitral valve is located at the apex (or PMI—point of maximal impulse), 5th intercostal space/midclavicular line. Finally, the tricuspid valve is at the lower right sternum.

Isovolumetric Ventricular Systole

During this phase, all four heart valves are closed. The ventricles contract, but the volume of blood in them remains constant.

Ventricular Ejection

The phase where blood is actively pumped out of the ventricles. During this period, the semilunar valves (aortic and pulmonic) are open but all four valves are not at the same time open, the other valves are closed.

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Cardiac Cycle Phase 1

The first phase involves atrial contraction, where both atria simultaneously squeeze to push blood down into the ventricles (ventricular diastole).

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Cardiac Cycle Phase 5

Passive ventricular filling: the passive flow of blood into the ventricles through open AV valves.

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Right Atrium Pressure (RA)

Average pressure in the right atrium is 4 mmHg, with a normal range from 0 to 8 mmHg.

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Right Ventricle Systolic Pressure (RVESP)

Average systolic (contraction) pressure in the right ventricle is 24 mmHg, within a range of 15 to 28 mmHg.

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Fibrous Pericardium

The outermost layer of the heart, a thick, protective connective tissue layer attached to the diaphragm and great vessels.

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Serous Pericardium

A thin, double-layered membrane forming a protective sac around the heart.

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Epicardium

The visceral layer of the serous pericardium; it's the same as the serous visceral layer.

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Myocardium

The muscular middle layer of the heart wall comprising atrial, ventricular and conductive muscle

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LV vs RV Myocardium Thickness

The left ventricle's (LV) myocardium is three times thicker than the right ventricle's (RV), making the RV more susceptible to ischemia/infarction due to lower blood supply.

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Endocardium Structure

The innermost layer of the heart wall, composed of endothelium and subendothelium, continuous with the blood vessels.

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Atrial Muscle

The thin muscle tissue of the heart's atria responsible for their contraction

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Ventricular Muscle

The relatively thicker muscle tissue of the heart's ventricles responsible for stronger contractions. (Contractility)

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Coronary Vessel Ischemia

Small coronary vessels are most susceptible to blockage, due to high pressure, which opposes blood flow.

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Aortic Diastolic Pressure

Optimal aortic diastolic pressure is crucial for proper blood flow to the smallest coronary vessels.

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AV Valves

AV valves (atrioventricular) prevent backflow into atria during ventricular contraction; these valves have cusps, fibrous rings, chordae tendineae, and papillary muscles.

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Semilunar Valve Size (Pulmonary)

The pulmonary valve, separating the right ventricle from the pulmonary artery, typically has an area of 4 cm².

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Mitral Valve Area

The mitral valve, separating the left atrium and ventricle, typically has an area between 2-6 cm².

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Parasympathetic Stimulation (effect)

Parasympathetic stimulation, primarily mediated by acetylcholine, slows heart rate (chronotropy), conduction velocity (dromotropy), and contraction strength (inotropy), and causes coronary vasodilation.

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Baroreceptor Reflex

The baroreceptor reflex, primarily located in the carotid and aortic arches, is crucial for short-term blood pressure regulation.

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Bainbridge Reflex Trigger

The Bainbridge reflex responds to increased volume in the right atrium, causing an increase in heart rate.

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Myosin Length

Myosin filament length remains constant during muscle contraction. Actin filaments shorten.

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Cross-bridge Cycle

The sequence of events where myosin heads bind, rotate, detach, and reattach to actin, producing muscle contraction.

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Excitation-Contraction Coupling

The process linking electrical stimulation of a muscle to the mechanical contraction.

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Preload

Volume inside ventricle at diastole end (LVEDV).

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Afterload

Resistance to ejection during systole.

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Cardiac Output

Heart rate multiplied by stroke volume.

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L-type Calcium Channel

Calcium channel (blocked by calcium channel blocking drugs).

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T-type Calcium Channel

Transient calcium channel.

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Stroke Volume (SV)

The amount of blood pumped out of the left ventricle during a single contraction (systole).

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Ejection Fraction (EF)

The percentage of blood pumped out of the ventricles with each contraction.

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Fetal Circulation

The circulatory system of a fetus, with features adapted for oxygen and nutrient delivery from the mother.

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Foramen Ovale

A natural opening between the atria in a fetus.

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Ductus Arteriosus

A blood vessel in a fetus that connects the pulmonary artery to the aorta.

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Ductus Venosus

A fetal vessel connecting the umbilical vein to the inferior vena cava

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Hyperdynamic EF

Ejection fraction greater than typical, suggesting an increased heart pumping capacity.

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Heart Failure Treatments

Treatments for heart failure address the underlying issues and symptoms to improve cardiac function and reduce symptoms.

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Fetal Shunt Closure

The closing of the ductus venous, foramen ovale, and ductus arteriosus after birth.

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Postnatal Heart Changes

Heart position and size adjustments; right ventricle size decreases; left ventricle becomes dominant; blood flow shifts to adult pathway.

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Congenital Heart Defect Types

Categorized as increasing/decreasing pulmonary flow, obstructing outflow (left/right), or mixed lesion types.

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PDA

Patent Ductus Arteriosus is a congenital heart defect causing increased pulmonary blood flow.

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Eisenmenger Syndrome

Increased pulmonary vascular resistance (PVR) that exceeds systemic vascular resistance (SVR), leading to reversed shunting.

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Increased Pulmonary Flow Defects

Congenital heart defects that result in increased blood flowing to the lungs.

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Obstructive Lesions

Congenital heart defects that restrict blood flow out of the heart. No shunting involved.

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Maternal Risk Factors

Factors like rubella, lupus, diabetes, and alcohol use during pregnancy can increase risk of congenital heart defects.

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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.

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