Feature

Details

Location

Situated between the left ventricle and the aorta.

Structure

Composed of three cusps (leaflets) that open and close to regulate blood flow.

Function

Prevents backflow of blood into the heart and ensures efficient systemic circulation.

Cause

Description

Age-related calcification

Progressive buildup of calcium deposits on the valve, leading to stiffening and narrowing.

Congenital valve abnormalities

Conditions like a bicuspid aortic valve increase susceptibility to stenosis.

Rheumatic fever

Leads to scarring and deformation of the valve.

Infective endocarditis

Infection damages the valve structure, causing dysfunction.

Stage

Details

Valve Narrowing

Progressive narrowing due to calcification or fibrosis.

Pressure Overload

The left ventricle works harder to pump blood through the narrowed valve causing hypertrophy.

Reduced Cardiac Output

Limited blood flow leads to reduced oxygen delivery to the body.

Heart Failure

Long-term strain results in weakening of the heart muscle.

Aspect

Details

Introduction

The heart is a muscular organ that pumps blood throughout the body.

Central to the circulatory system, it ensures oxygen and nutrients reach all body tissues.

2. Anatomy

Location: Mediastinum between the lungs and behind the sternum.

Size and Weight: About the size of a fist; weighs approximately 250-350 grams.

Structure

Layers of the Heart Wall:

 Epicardium: Outer protective layer.

Myocardium: Thick muscular middle layer.

Endocardium: Inner layer lining the chambers and valves.

Chambers

Right Atrium (RA): Receives deoxygenated blood from the body via the vena cava.

Right Ventricle (RV): Pumps deoxygenated blood to the lungs through the pulmonary artery.

Left Atrium (LA): Receives oxygenated blood from the lungs via pulmonary veins.

Left Ventricle (LV): Pumps oxygenated blood to the body via the aorta.

Valves

Atrioventricular Valves: Tricuspid (RA-RV) and Mitral (LA-LV) prevent backflow.

Semilunar Valves: Pulmonary (RV-lungs) and Aortic (LV-body) control blood flow.

Blood Supply

Coronary Arteries: Deliver oxygen-rich blood to the heart muscle.

Cardiac Veins: Remove deoxygenated blood from the heart tissue.

Conduction System

Components:

Sinoatrial (SA) Node: Heart's natural pacemaker; initiates electrical impulses.

Atrioventricular (AV) Node: Delays impulses allowing atrial contraction.

Bundle of His and Purkinje Fibers: Spread impulses to ventricles for contraction.

Functions

Pumping Blood: Maintains systemic and pulmonary circulation.

Regulating Blood Pressure: Adjusts force and rate of contraction.

Homeostasis: Maintains oxygen, nutrient delivery and waste removal.

Cardiac Cycle

Systole: Contraction phase; ventricles pump blood.

Diastole: Relaxation phase; chambers refill with blood.

Common Disorders

Coronary Artery Disease (CAD): Narrowing of coronary arteries.

Arrhythmias: Irregular heartbeats due to electrical issues.

Heart Failure: Inability of the heart to pump effectively.

Diagnostic Tools

Electrocardiogram (ECG): Records electrical activity.

Echocardiogram: Uses ultrasound to visualize heart structures.

Cardiac MRI and CT: Advanced imaging techniques.

PRACTICE QUESTION

Q.Consider the following statements regarding the Aortic Valve:

1. The aortic valve is a semilunar valve that prevents backflow of blood from the aorta into the left ventricle.
2. It typically has three cusps.
3. The aortic valve opens during diastole to allow blood flow into the aorta.

Which of the statements given above is/are correct?

(a) 1 only

(b) 1 and 2 only

(c) 2 and 3 only

(d) 1, 2, and 3

Answer: (b)

Explanation:

Statement 1 is correct. The aortic valve ensures one-way blood flow from the left ventricle to the aorta.

Statement 2 is correct. The valve typically has three cusps but congenital anomalies like a bicuspid valve can occur.

Statement 3 is incorrect. The aortic valve opens during systole, not diastole, to allow blood ejection into the aorta.