विज्ञान: हृदय का अध्ययन

Anatomy

• The heart is a four-chambered, muscular organ located in the thoracic cavity, between the lungs.
• It is situated slightly to the left of the center of the chest.
• The heart's walls are composed of three layers: epicardium (outer layer), myocardium (middle layer, made of cardiac muscle), and endocardium (inner layer).
• The four chambers are the two atria (right and left atria) and the two ventricles (right and left ventricles).
• The atria receive blood from veins, and the ventricles pump blood into arteries.
• Atrioventricular valves (tricuspid and mitral valves) separate the atria from the ventricles and prevent backflow of blood.
• Semilunar valves (pulmonary and aortic valves) separate the ventricles from the major arteries and also prevent backflow.
• The heart has its own specialized conduction system, enabling automatic and coordinated contraction to pump blood efficiently.
• The sinoatrial (SA) node is the heart's natural pacemaker.
• The atrioventricular (AV) node is crucial for transmitting the electrical impulses from the SA node to the ventricles.
• The bundle of His and Purkinje fibers are parts of the conduction system that facilitate the coordinated contraction.

Blood Flow

• Blood enters the right atrium from the superior and inferior vena cava, carrying deoxygenated blood from the body.
• From the right atrium, blood flows through the tricuspid valve to the right ventricle.
• The right ventricle pumps the blood through the pulmonary valve into the pulmonary artery, which carries it to the lungs for oxygenation.
• Oxygenated blood returns from the lungs via the pulmonary veins to the left atrium.
• From the left atrium, blood flows through the mitral valve to the left ventricle.
• The left ventricle pumps the blood through the aortic valve into the aorta, the body's largest artery, which distributes oxygenated blood to the rest of the body.
• This continuous cycle is crucial for maintaining blood circulation and oxygen supply throughout the body.

Heart Sounds

• Heart sounds are produced by the closing of heart valves.
• The first sound (lub) corresponds to the closure of the mitral and tricuspid valves.
• The second sound (dub) corresponds to the closure of the aortic and pulmonary valves.
• Listening to heart sounds (auscultation) is a vital part of physical examinations to evaluate heart function and detect abnormalities.

Cardiac Cycle

• The cardiac cycle consists of a series of events that occur during a complete heartbeat.
• It includes phases of diastole (relaxation) and systole (contraction) in both atria and ventricles.
• A complete cardiac cycle is the time between successive contractions of the ventricles.

Function

• The heart's primary function is to pump blood throughout the body, ensuring constant supply of oxygen and nutrients to tissues.
• It maintains blood pressure, facilitating transport of waste products and hormones, performing crucial roles in homeostasis.

Associated Diseases

• Various diseases, conditions, and disorders -including coronary artery disease (CAD), myocardial infarction (MI), valvular heart disease, cardiomyopathy, congenital heart defects, and arrhythmias- can affect the heart.
• These conditions can disrupt the heart's normal function and require appropriate medical interventions.

यह क्विज़ हृदय की संरचना और कार्यप्रणाली पर आधारित है। इसमें आप हृदय के विभिन्न कक्षों, वाल्वों और उसकी विद्युत संचरण प्रणाली के बारे में जानेंगे। सही उत्तर देकर अपने ज्ञान को परखें।