Heart Anatomy

Introduction

  • Discussion about control pressures and alveolar pressures during respiration.

  • Noticed inconsistency in red blood cell count in slides.

    • 5,000,000 red blood cells per microliter is incorrect; it should be 5,000,000,000.

Structure and Role of the Heart

  • Overview of the heart's function: circulating blood in systemic and pulmonary circulations.

  • Importance of understanding complicated concepts, with a focus on familiarization.

Circulations

  • Systemic Circulation:

    • Delivers blood to the body.

  • Pulmonary Circulation:

    • Moves deoxygenated blood to the lungs for oxygenation.

External Structures

  • Pericardial Cavity:

    • Space the heart sits in, between the lungs.

    • Left lung has a notch for the heart's accommodation.

  • Heart Orientation:

    • Apex points toward the lower left of the body.

  • Pericardium:

    • Membrane enclosing the heart; similar to pleural membranes around lungs.

  • Epicardium:

    • Layer directly attached to myocardium (muscle layer).

  • Endocardium:

    • Inner lining of the heart chambers similar to endothelial cells in blood vessels.

Internal Structures

  • Overview of heart's chambers and valves:

    • Identification and functionality of atria and ventricles.

    • Importance of recognizing which chamber and valve is which.

Conduction System

  • Electrical Signals:

    • Synchronizes the activities of heart chambers.

  • Overview of cardiac cycle, cardiac output, and Frank-Starling Law:

    • Heart's ability to handle increased blood volume.

Blood Flow and Pressure Changes

  • Cardiac Cycle Overview:

    • Two circulatory systems: systemic and pulmonary.

  • Change in blood pressure:

    • As blood moves through the circulatory system, pressure dynamics shift.

Membranes and Fluid Space

  • Pericardium-related structures:

    • Fatty tissue on the heart.

  • Pericardial Cavity:

    • Acts as a lubricant space between heart and pericardium.

Major Vessels and Structures

  • Major Inflows and Outflows:

    • Superior and inferior vena cavae enter the right atrium.

    • Aorta exits the left ventricle.

    • Pulmonary artery and veins govern flow to/from lungs.

Myocardial Infarction

  • Understanding how blockages in coronary arteries lead to heart attacks.

  • Sensitivity of heart muscle to oxygen deficiency.

  • Damage due to myocardial infarction can lead to permanent heart function impairment.

Blood Movement in Heart Chambers

  • Mechanism of blood flow from atria to ventricles, guided by bicuspid and tricuspid valves.

    • Recognize three names for the left atrioventricular valve: bicuspid, left atrioventricular, mitral.

Electrocardiography (ECG)

  • P, QRS, T Waves:

    • Electrical activity associated with heart function.

  • Changes in these peaks help visualize heart health and function.

Heart Sounds

  • Two sounds of the heartbeat:

    • Lub: Closure of tricuspid and bicuspid valves during ventricular systole.

    • Dub: Closure of semilunar valves as blood exits the heart.

Blood Pressure Dynamics

  • Systolic vs Diastolic Blood Pressure:

    • Normal ranges explained; systolic ~120, diastolic ~80 mmHg.

    • Management of blood pressure under stress and its implications on health.

  • Mean Arterial Pressure (MAP):

    • Calculation: Diastolic Pressure + (1/3 Pulse Pressure).

Summary of Blood Flow Dynamics

  • Blood pressure behavior:

    • Aorta and arteries show pressure fluctuations (pulse).

    • Continuous pressure in capillaries; drops significantly moving into the venous system.

  • Cross-Sectional Area:

    • Blood flow slows markedly across capillary beds due to vast numbers compared to larger vessels.

Heart Failure and Implications

  • Differentiation between heart attack and heart failure.

  • Effects of myocardial infarction on overall heart functionality over time.

  • Changes in cardiac performance under varying physiological conditions.