LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END COMPUTER PRESENTATIONS FOR KS3 SCIENCE - BIOLOGY ©2003, STEVE PARKER COMPUTER PRESENTATIONS FOR KS3 SCIENCE - BIOLOGY ©2003, STEVE PARKER

1 1 KS3 SCIENCE - BIOLOGY KS3 SCIENCE - BIOLOGY Blood Circulation Blood Circulation

CIRCULATION 2 2

3 3 The Heart is the pump that shifts Blood around the body under pressure The Heart is the pump that shifts Blood around the body under pressure

CIRCULATION 4 4 But the blood must contain oxygen to be much use, so it goes first to the Lungs, before going back to the heart to be pumped to the rest of the body But the blood must contain oxygen to be much use, so it goes first to the Lungs, before going back to the heart to be pumped to the rest of the body

CIRCULATION 5 5 Oxygen dissolves into the blood in the lungs and the blood then goes to the heart Oxygen dissolves into the blood in the lungs and the blood then goes to the heart

CIRCULATION 6 6 The heart then pumps this oxygenated blood around the body The heart then pumps this oxygenated blood around the body

CIRCULATION 7 7 Oxygen is used up by the body and the blood goes back to the heart Oxygen is used up by the body and the blood goes back to the heart

CIRCULATION 8 8 The heart then sends it back to the lungs for more oxygen The heart then sends it back to the lungs for more oxygen

THE HEART 9 9

10 The heart has four separate chambers to deal with blood to and from the lungs and blood to and from the body The heart has four separate chambers to deal with blood to and from the lungs and blood to and from the body

THE HEART 11 Blood vessels coming out of the heart are called Arteries, those going in are called Veins Blood vessels coming out of the heart are called Arteries, those going in are called Veins Aorta Pulmonary Vein Left Atrium Left Ventricle Bicuspid Valve Pulmonary Artery Right Ventricle Tricuspid Valve Vena Cava Right Atrium Semi-lunar valves

THE HEART 12 Oxygenated blood from the lungs enters the heart from pulmonary vein here Oxygenated blood from the lungs enters the heart from pulmonary vein here De-oxygenated blood from the body enters the heart from the vena cava here De-oxygenated blood from the body enters the heart from the vena cava here

THE HEART 13 Contraction of the left and right atriums forces the blood down into the left and right ventricles Contraction of the left and right atriums forces the blood down into the left and right ventricles

THE HEART 14 Then the ventricles contract forcing the blood out of the heart Then the ventricles contract forcing the blood out of the heart Oxygenated blood is sent out to the body to be used Oxygenated blood is sent out to the body to be used De-oxygenated blood is sent out to the lungs to be oxygenated De-oxygenated blood is sent out to the lungs to be oxygenated

THE HEART 15 The heart has a double beat because there are two stages of pumping The heart has a double beat because there are two stages of pumping

BLOOD VESSELS 16

BLOOD VESSELS 17 Arteries carry blood away from the heart to the body, (they carry oxygenated blood, apart from the pulmonary artery) Arteries carry blood away from the heart to the body, (they carry oxygenated blood, apart from the pulmonary artery) Blood in arteries is at at high pressure, so they have thick elastic walls Blood in arteries is at high pressure, so they have thick elastic walls

BLOOD VESSELS 18 Veins carry blood to the heart from the body, (they carry de-oxygenated blood, apart from the pulmonary vein) Veins carry blood to the heart from the body, (they carry de-oxygenated blood, apart from the pulmonary vein) Blood flows through veins at lower pressure, so they have thinner walls and valves to stop back-flow Blood flows through veins at lower pressure, so they have thinner walls and valves to stop back-flow

BLOOD VESSELS 19 Arteries and veins have smaller branches - Capillary walls are only one cell thick to allow oxygen and nutrients to diffuse across the walls Arteries and veins have smaller branches - Capillary walls are only one cell thick to allow oxygen and nutrients to diffuse across the walls

BLOOD CELLS 20

BLOOD CELLS 21 Red Blood Cells make up just under half the blood - they contain Haemoglobin which carries oxygen around Red Blood Cells make up just under half the blood - they contain Haemoglobin which carries oxygen around

BLOOD CELLS 22 A small fraction of blood is Platelets - these are fragments of cells which can clot the blood to patch up any cuts A small fraction of blood is Platelets - these are fragments of cells which can clot the blood to patch up any cuts

BLOOD CELLS 23 White Blood Cells also make up a small fraction of the blood - their main function is to attack foreign bodies to fight disease White Blood Cells also make up a small fraction of the blood - their main function is to attack foreign bodies to fight disease

BLOOD CELLS 24 These all float in a liquid called Plasma, which makes up about half the blood volume and carries Salts, Sugars and Proteins around These all float in a liquid called Plasma, which makes up about half the blood volume and carries Salts, Sugars and Proteins around