AQA GCSE FOUNDATION Biology: The Heart and Circulatory System

AQA GCSE Foundation Biology: The Heart and Circulatory System

Understanding the Heart

The heart is a vital organ responsible for pumping blood throughout your body. It's a muscular pump located in the chest, slightly to the left of the center. Let's break down the heart's structure:

1. Chambers:

• Right Atrium: Receives deoxygenated blood from the body.
• Right Ventricle: Pumps deoxygenated blood to the lungs.
• Left Atrium: Receives oxygenated blood from the lungs.
• Left Ventricle: Pumps oxygenated blood to the body.

2. Valves:

• Tricuspid Valve: Controls blood flow between the right atrium and right ventricle.
• Pulmonary Valve: Controls blood flow from the right ventricle to the pulmonary artery.
• Mitral Valve: Controls blood flow between the left atrium and left ventricle.
• Aortic Valve: Controls blood flow from the left ventricle to the aorta.

These valves act like one-way doors, ensuring blood flows in the correct direction.

The Flow of Blood

Let's follow the journey of blood through the circulatory system:

1. Deoxygenated Blood:

• Deoxygenated blood enters the right atrium from the body through the superior and inferior vena cava.
• The tricuspid valve opens, allowing blood to flow into the right ventricle.
• The pulmonary valve opens, and the right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery.

2. Oxygenated Blood:

• In the lungs, carbon dioxide is released, and oxygen is absorbed.
• Oxygenated blood returns to the left atrium via the pulmonary veins.
• The mitral valve opens, allowing blood to flow into the left ventricle.
• The aortic valve opens, and the left ventricle pumps oxygenated blood to the body through the aorta.

This process repeats continuously, ensuring that your body receives a constant supply of oxygen and nutrients.

Understanding the Circulatory System

The circulatory system is a network of blood vessels that transport blood throughout the body. Here are the key components:

• Arteries: Carry oxygenated blood away from the heart.
• Veins: Carry deoxygenated blood back to the heart.
• Capillaries: Tiny blood vessels that connect arteries and veins, allowing for the exchange of gases and nutrients.

Key Points

• The heart is a muscular pump that drives blood circulation.
• Valves control blood flow, ensuring it moves in the correct direction.
• Deoxygenated blood travels to the lungs for oxygenation, while oxygenated blood is delivered to the body.
• The circulatory system comprises arteries, veins, and capillaries, facilitating the transport of blood throughout the body.