My heart is a muscle and it pumps bloodLike a big old black steam train

My veins are the tracksAnd the city is my brain

- The Cruel Sea (1993)

Animation

Right atrium

Right ventricle

Left atrium

Left ventricle

1

2

3

4

The Chambers

Pump blood to the required destinations

• Right atrium – pumps blood to right ventricle

• Right ventricle – pumps blood to lungs via the pulmonary artery

• Left atrium – pumps blood to left ventricle

• Left ventricle – pumps blood to the body via the aorta

Superior vena cava

Inferior vena cava

Left pulmonaryartery

Left pulmonaryveinRight pulmonary

vein

Aorta1

2

3

4

5

6

7

Right pulmonaryartery

The Blood Vessels

Arteries carry blood from the heart and veins carry blood to the heart

• Superior and inferior vena cava – carry blood from the body to the right atrium

• Pulmonary arteries – carry blood from the right ventricle to the lungs

• Pulmonary veins – carry blood from the lungs to the left atrium

• Aorta – carries blood from the left ventricle to the body

Tricuspid valve

Pulmonary valve

Mitral valve

Aortic valve

1 2

34

The Valves

Valves ensure that blood flows in one direction only

• Tricuspid valve – from right atrium to right ventricle

• Pulmonary valve – from right ventricle to pulmonary artery

• Mitral valve – from left atrium to left ventricle

• Aortic valve – from left ventricle to aorta

Comparative Circulation

• The circulatory system that we share with a number of other animals is called a closed circulatory system, in that the blood never leaves the blood vessels.

• The blood carries the materials to cells and they diffuse in and out, but the blood does not leave.

• In an open system, blood leaving the heart bathes the organs before returning to the heart.

Closed circulatory systems

• A) Fish have one atrium and one ventricle and blood is oxygenated en-route to the body.

• B) Reptiles and amphibian have two atria and one ventricle in which oxygenated and deoxygenated blood mix.

• C) Mammals and birds have the 4 chambered system with which we are familiar.

A B C

Open circulatory systems

• The aorta takes blood from the insect heart distributes blood around the body so that it can surround all the tissues and organs to distribute nutrients before returning to the heart.

• The blood is translucent as it contains no haemoglobin (no oxygen is carried by the blood).

aorta left ventricle pulmonary valve

vena cava aortic valve left atrium

pulmonary veins tricuspid valve right ventricle

mitral valve

pulmonary arteries lungs

right atrium

BODY

The Mammalian

Heart