The Circulatory SystemThe Circulatory System

Heart, Blood, Blood VesselsHeart, Blood, Blood Vessels

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The HeartThe Heart

Pump for the bloodPump for the blood

In the chest, between In the chest, between the lungs, protected by the lungs, protected by breastbone, ribs, breastbone, ribs, spine.spine.

Size of the owners fist.Size of the owners fist.

Structure of the heartStructure of the heart

Hollow insideHollow inside Divided in two lengthways by septumDivided in two lengthways by septum Has 4 chambersHas 4 chambers Upper chambers = left and right atria (atrium)Upper chambers = left and right atria (atrium) Lower chambers = left and right ventriclesLower chambers = left and right ventricles Valves separate the atria from the ventricles and Valves separate the atria from the ventricles and

prevent backflow of bloodprevent backflow of blood

Structure of the HeartStructure of the Heart

Blood Flow through HeartBlood Flow through Heart

DeoxygenatedDeoxygenated blood gathered from all around the blood gathered from all around the body flows into the body flows into the R atriumR atrium in veins called the in veins called the vena cavavena cava..

It then flows through the It then flows through the tricuspid valvetricuspid valve into the into the R ventricleR ventricle..

The R ventricle contracts the tricuspid closes and The R ventricle contracts the tricuspid closes and the blood flows out other valves into the the blood flows out other valves into the pulmonary arterypulmonary artery which takes it to the lungs to which takes it to the lungs to have oxygen added and to have carbon dioxide have oxygen added and to have carbon dioxide removed.removed.

Blood Flow through HeartBlood Flow through Heart The The oxygenatedoxygenated blood returns to the blood returns to the L atriumL atrium in in

the the pulmonary veinspulmonary veins.. It then goes through the It then goes through the bicuspid valvebicuspid valve into the into the L L

ventricle.ventricle. The L ventricle contracts, closes the bicuspid The L ventricle contracts, closes the bicuspid

valve and the blood goes out through valves into valve and the blood goes out through valves into the the aortaaorta the largest artery in the body. the largest artery in the body.

The aorta splits into many branches and takes The aorta splits into many branches and takes blood to every blood to every body cellbody cell..

The cells take food and oxygen out of the blood The cells take food and oxygen out of the blood and put carbon dioxide and other waste into it.and put carbon dioxide and other waste into it.

Then the whole process begins again.Then the whole process begins again.

Flow of blood through the Flow of blood through the heartheart

Blood circulation in Blood circulation in the bodythe body

Coronary circulationCoronary circulation

The cells that make up the wall of the heart need The cells that make up the wall of the heart need a supply of blood.a supply of blood.

This blood is carried by a special artery called the This blood is carried by a special artery called the coronary artery a branch from the aorta.coronary artery a branch from the aorta.

If these blood vessels get blocked with fat a If these blood vessels get blocked with fat a person is suffering from coronary heart diseaseperson is suffering from coronary heart disease

Coronary arteryCoronary artery

The bloodThe blood

4-5 litres4-5 litres Plasma (yellow liquid)Plasma (yellow liquid) Red blood cellsRed blood cells White blood cellsWhite blood cells Platelets Platelets

Red blood cellsRed blood cells Contain a red Contain a red

pigment called pigment called haemoglobinhaemoglobin

OxygenOxygen sticks to the sticks to the haemoglobin and haemoglobin and gets carried in the gets carried in the bloodstreambloodstream

To make To make haemoglobin the haemoglobin the body needs Ironbody needs Iron

White blood cellsWhite blood cells Fewer but bigger Fewer but bigger

than red blood cellsthan red blood cells They attack and kill They attack and kill

harmful bacteria and harmful bacteria and viruses and viruses and fight fight diseases.diseases.

They make anti-They make anti-bodies that fight bodies that fight disease.disease.

PlateletsPlatelets

These make the blood These make the blood clotclot so not too much so not too much blood is lost when we blood is lost when we get cut.get cut.

Functions of bloodFunctions of blood

Transport: oxygen, food, waste products, heat, Transport: oxygen, food, waste products, heat, chemicals.chemicals.

Prevents infection, fights disease.Prevents infection, fights disease. Prevents blood loss by clottingPrevents blood loss by clotting

Blood VesselsBlood Vessels

Tubes that the blood flows throughTubes that the blood flows through Three typesThree types Arteries, Capillaries, VeinsArteries, Capillaries, Veins

ArteriesArteries Largest vesselsLargest vessels Walls made of 3 layersWalls made of 3 layers11 outer connective tissue outer connective tissue 22 middle muscle middle muscle 33 inner endothelium cellsinner endothelium cells Mainly carry oxygenated blood (pure)Mainly carry oxygenated blood (pure) Carry blood away from the heart Carry blood away from the heart Blood in arteries is under great pressure so their Blood in arteries is under great pressure so their

walls need to be strong and elastic.walls need to be strong and elastic. The pulse is the gush of the blood through an artery The pulse is the gush of the blood through an artery

near the skin surface after each heartbeat.near the skin surface after each heartbeat.

CapillariesCapillaries Smallest vesselsSmallest vessels Arteries divide again and Arteries divide again and

again an eventually form again an eventually form capillaries.capillaries.

Very thin walls made of Very thin walls made of endothelial cellsendothelial cells

Thin walls allow substances Thin walls allow substances to get out of and into the to get out of and into the bloodblood

Capillaries join up to make Capillaries join up to make veinsveins

VeinsVeins Walls are thinner than arteries Walls are thinner than arteries

but lumen is biggerbut lumen is bigger Same 3 layers in walls as arteriesSame 3 layers in walls as arteries Blood under low pressure so Blood under low pressure so

valves needed to prevent valves needed to prevent backflowbackflow

Mostly carry deoxygenated blood Mostly carry deoxygenated blood (impure)(impure)

Carry blood towards the heartCarry blood towards the heart

Take Your PulseTake Your Pulse