PE Section 2 Revision

Also known as the cardiovascular System.

Consists of two circuits that the blood flows the through, the pulmonary and the systemic. Exercise increases the efficiency of these systems as the heart increases in size and pumps the blood round the body faster, which allows you to exercise for longer without fatigue.

3 components of circulatory system:

• The heart
• The blood
• The blood vessels

The circulatory system has two circuits the pulmonary and the systemic.

• The Pulmonary circuit takes blood to the lungs to be oxygenated. In the lungs the carbon dioxide is removed from the blood, and the oxygen is collected by the haemoglobin in the red blood cells.
• The Systemic circuit takes blood around the body to deliver oxygen, and then takes the deoxygenated blood back to the lungs.

The Heart is a muscular pump, when it beats it pumps blood to the lungs and around the body.

The amount of blood pumped out of the heart can be calculated like this.

Heart rate x Stroke volume = cardiac output.

This output increases when exercising.

The heart has 4 chambers.

• 2 atria to collect the blood.
• 2 ventricles to pump the blood out of the heart.

It also has valves that stop the blood from flowing backwards.

The right side of the heart pumps the de-oxygenated blood to the lungs to pick up oxygen. The left side of the heart pumps oxygenated blood from the lungs around the rest of the body.

There are three types of blood vessels

Arteries

• Carry blood away from the heart.
• They have thick muscular walls.