The circulatory system
Also known as the cardiovascular system, your heart, blood vessels and blood itself are three essential components the body needs to survive. The circulatory system consists of two circuits that blood travels through; pulmonary and systemic. Exercise affects these systems, causing the heart to pump blood faster around the body, which in turn allows you to exercise for longer!
The three components are:
It is a double circulatory system. It comprises two separate circuits and blood passes through the heart twice.
The pulmonary circuit carries blood to the lungs to be oxygenated and then back to the heart. In the lungs, carbon dioxide is removed from the blood, and oxygen taken up by the haemoglobin in the red blood cells.
The systemic circuit carries blood around the body to deliver the oxygen and returns de-oxygenated blood to the heart. Blood also carries nutrients and waste.
NB The heart is seen from the front in the diagram. So the right side of the heart is shown on the left of the diagram. The left side is on the right side of the diagram.
The heart is a muscular pump. When it beats it pumps blood to the lungs and around the body. The amount of blood pumped can be calculated:
heart rate [Heart rate: The number of heart beats per minute. ] x stroke volume [Stroke volume: The volume of blood pumped from heart with each beat. ] = cardiac output [Cardiac output: The amount of blood pumped by heart in one minute. Heart Rate x Stroke Volume = Cardiac Output. ]
These increase when exercising. See the 'Exercise and Training' revision bite for effects of exercise on the circulatory system.
The heart has four chambers. The two atria collect the blood. The two ventricles pump the blood out of the heart.
Valves prevent the blood from flowing backwards.
The septum separates the two sides of the heart.
The right side of the heart pumps de-oxygenated blood (blood not containing oxygen) to the lungs to pick up oxygen. The left side of the heart pumps the oxygenated blood from the lungs around the rest of the body.
There are three types of blood vessel:
Blood has four key components:
Red blood cells
White blood cells
When exercising blood does the following things:
Blood pressure [Blood pressure: The force of blood against the artery walls. ] increases when you exercise, but is lower at rest when you are fit. It is also affected by age, smoking, stress, diet and weight.