The circulatory system transports blood around the body which contains red blood cells, white blood cells, platelets suspended in plasma. Red blood cells contain hemoglobin and carry oxygen, while white blood cells help fight infection and platelets help with clotting. The heart pumps blood through arteries and veins with a dual circulation system. Blood vessels have valves to prevent backflow. The circulatory and lymphatic systems work together to fight infection, transport nutrients and remove waste throughout the body.

1. HUMAN BODY CIRCULATORY SYSTEM

2. COMPOSITION OF BLOOD RED CELLS WHITE CELLS PLATELETS floating in a liquidcalled PLASMA

3. COMPOSITION OF BLOOD

4. COMPOSITION OF BLOOD

5. RED BLOOD CELLS Biconcave discs No nuclei Spongycytoplasmenclosed in anelasticcellmembrane Red pigmentcalledhaemoglobin Are madebythe red bonemarrow of certainbones in theskeleton: ribs, vertebrae and breastbone

6. Red bloodcells: hystology

7. Red bonemarrow

8. HAEMOGLOBIN

9. Haemoglobin (Hb) Hb + O₂ oxyhaemoglobin (OHb) In places wherethe O₂ concentrationislow, OHbbreaksdown and releasesitsO₂. Where?? Oxygenatedblood : containsmainlyOHb. Deoxygenatedblood : withlittleOHb.

10. Oxyhaemoglobin

11. Red bloodcells After 4 months HbIron BilirubinStored in theliver Bile

12. WHITE CELLS Differenttypes Largerthan red cells Theyhavenuclei They are made in thesamebonemarrowthat red cells Thetwo more numeroustypes are: - Phagocytes - Lymphocytes

13. White bloodcells

14. White bloodcells

15. White bloodcells: Phagocytes Theycollect at thesite of aninfection, engulfing (ingesting) and digestingharmful bacteria. Theypreventthe spread of infectionthroughthebody.

16. Phagocytes

17. White bloodcells: LymphocytesProduction of antibodies (proteins)

18. PLATELETSTheyhelptoclottheblood

19. PLASMA Ions: sodium, potassium, calcium, chloride, hydrogen carbonate. Proteins: fibrinogen (clotting), albuminand globulins (antibodies). Foodsubstances: aa, glucoseand fats. Hormones Urea

21. Functions of theblood Homeostaticfunctions Transport Defenceagainstinfections - Clotting - White cells

22. Functions of blood: Transport

23. THE HEART

24. HumanHeart 4 chambers: - 2 atria (thin-walled) - 2 ventricles (thick- walled) Veins: deoxygenatedbloodexceptpulmonaryvein Arteries: Oxygenatedbloodexceptpulmonaryartery Valves: They stop bloodflowingbackwards. Coronaryarteries: Theysupplytheheartmusclewithfood and oxygen.

25. Humanheart

26. Valves of the heart

27. CONTROL OF THE HEART BEAT At rest: normal heartrate, 50-100 beats per minutes. Duringexercise: 200 beats/min Theheart beat isinitiatedbythepacemaker, a smallgroup of specializedmusclescells at the top of therightatrium.

28. Control of theheart beat Bloodpressure↑ ↓ heartrate Bloodpressure↓ ↑ heartrate ↓ O₂ concentration ↑ CO₂ concentration Hormone adrenaline

29. THE CIRCULATION

30. CIRCULATION

31. BLOOD VESSELS

32. Bloodvessels

33. Arteries, veins: hystology

34. LYMPHATIC SYSTEM

35. Lymphaticsystem Thin-walledvesselscalledlymphatics. Theyemptytheircontentsintothebloodsystem. The fluid iscalledlymph. Most of thelymphflowresultsfromthevesselsbeingcompressedwhenthebodymusclescontract in movementssuch as walkingorbreathing. There are valves, whichforcethe fluid in onedirection: towardstheheart. Lymphnodes: storage of lymphocytes. There are alsophagocytes. Lymphaticorgans:Spleenandthymus

36. Lymphnodes: part of thebodydefencesystem

37. Lymphaticorgans: spleen and thymus

38. SPLEEN: functions Removeworn-out red cells, bacteria and cellfragmentsfromtheblood. Produce lymphocytes and antibodies.

39. THYMUS: functions Particularlyimportantlymphoidorgan in thenewborn: - controlsthedevelopment of thespleen and thelymphnodes. - produces lymphocytes (immunity) Afterpuberty, importantimmunologicalorgan, althoughitbecomessmaller. - storage of whitecells - production of a largepopulation of lymphocytes T.

40. Bloodfunctions: DEFENCE AGAINST INFECTIONS WHITE CELLS: - Phagocytes: - at thesites of a wound - in thebloodcapillaries - in lymphnodes ingestharmful bacteria and stop thementeringthe general circulation - Lymphocytes:Production of antibodies CLOTTING

41. CLOTTING Whentissueisdamaged and bloodvesselscut Plateletsclumptogether and block thesmallercapillaries. Fibrinogenfibrin(network of fibresacross thewound) Red cellsbecometrapped in thisnetwork and form a bloodclot. ↓ entry of harmful bacteria prevents furtherloss of blood

42. Clotting

43. Bloodclotting

44. ATHEROMA and THROMBOSIS

45. CORONARY HEART DISEASES

46. Possible causes of coronaryheartdiseases SMOKING FATTY DIET STRESS LACK OF EXERCISE