The Heart Structure and Function
The heart is a complex organ with a specific structure designed to efficiently pump blood throughout the body. This page provides a detailed overview of the heart's anatomy and how it functions within the circulatory system.
The heart is divided into four main chambers: two atria (upper chambers) and two ventricles (lower chambers). The right side of the heart deals with deoxygenated blood, while the left side handles oxygenated blood.
Vocabulary: Atria - The upper chambers of the heart that receive blood from the body or lungs.
Vocabulary: Ventricles - The lower chambers of the heart that pump blood out to the body or lungs.
Blood enters the heart through two major veins:
- The Superior Vena Cava, which brings deoxygenated blood from the upper body.
- The Inferior Vena Cava, which brings deoxygenated blood from the lower body.
These veins connect to the right atrium. From there, blood flows through the tricuspid valve into the right ventricle.
Definition: Tricuspid valve - A valve between the right atrium and right ventricle that prevents backflow of blood.
The right ventricle then pumps the deoxygenated blood through the pulmonary artery to the lungs, where it becomes oxygenated. Oxygenated blood returns to the heart via the pulmonary vein, entering the left atrium.
Highlight: The pulmonary circulation is the part of the circulatory system that oxygenates the blood.
From the left atrium, blood passes through the bicuspid valve (also known as the mitral valve) into the left ventricle. The left ventricle then pumps the oxygenated blood out through the aorta to the rest of the body.
Example: The left ventricle has thicker walls than the right ventricle because it needs to generate more pressure to pump blood throughout the entire body.
The heart's pumping action is controlled by specialized cardiac muscle. This muscle contracts rhythmically without fatigue, ensuring continuous blood flow.
Highlight: Cardiac muscle is unique in its ability to contract continuously without tiring, which is essential for the heart's non-stop function.
Understanding the heart diagram and the flow of blood through its chambers is crucial for answering IGCSE Biology heart questions and GCSE Biology the heart exam questions.
