1. Blood

2. Functions of Blood
Helps maintain homeostasis of all body organs and tissues
Transportation/Distribution
Oxygen from the lungs
Nutrients - digestive tract  body cells
Metabolic wastes  elimination sites
Hormones

3. Functions of Blood (cont’d)
Protection
Prevents blood loss
Clotting mechanism
Prevents infection
Phagocytic white blood cells (WBC)
Antibodies – specialized proteins

4. Functions of Blood (cont’d)
Regulation
Body temperature by absorbing and distributing heat
Acid-base balance of body fluids
Buffers neutralize harmful effects of too much CO2, lactic acid, etc.

5. Functions of Blood (cont’d)
Regulation(cont’d)
Normal pH in body tissues
Adequate fluid volume in the circulatory system

6. Blood Only fluid tissue - CT Color Slightly alkaline Temperature
Varies from scarlet (oxygen rich) to dull red (oxygen poor)
Slightly alkaline
pH 7.35 – 7.45
Temperature
38oC or 100.4oF
About 8% of body wt.
Volume
5-6 L (11 pints) healthy males
4-5 L healthy females

7. Blood Composition
Formed elements and plasma (matrix)

8. Plasma Liquid portion of blood 55% of blood 90% water
Carry cells nutrients

9. Plasma (cont’d) Dissolved substances Plasma Proteins Albumin
Regulates osmotic balance, pH buffering
Fibrinogen
Clotting of blood
Globulin
Defense (antibodies) and lipid transport

10. Plasma (cont’d) Dissolved substances(cont’d)
Salts (electrolytes) - Na, K, Ca, Mg
Regulates osmotic balance, pH buffering, and regulation of membrane permeability

11. Plasma (cont’d) Dissolved substances(cont’d) Transported substances
Nutrients
glucose, fatty acids, vitamins, amino acids
Waste products of metabolism
urea, uric acid
Respiratory gases
Oxygen and CO2
Hormones

12. Formed Elements 45% of blood
Red blood cells (RBC), white blood cells (WBC), platelets

13. Erythrocytes RBC Most abundant formed element
Transport oxygen to cells and small amounts of CO2 from cells
Contain hemoglobin
Iron-containing protein
Actually transports oxygen
Gives blood its color

14. Erythrocytes (cont’d)
Anucleate (lack nucleus)
Very few organelles
Shaped like biconcave discs
Flattened discs with depressed centers
4-6 million cells per mm3 of blood

15. Erythrocytes (cont’d)
Life cycle
Produced only in red marrow in bone
Production regulated by special cells in kidneys (major role) and liver
Release hormone erythropoietin
Stimulates production of RBC

17. Erythrocytes (cont’d)
Life cycle (cont’d)
Live only about 120 days
Approx. 10 billion cells die each hour
Recycling
Macrophages (WBC)
Hemoglobin breaks down
Biliverdin and bilirubin - bile pigments that color stools and urine
Iron is recycled to form new hemoglobin

19. Leukocytes WBC Far less numerous (4,000 to 11,000 per mm3)
Fight infections
Only complete cells in blood
May live for years
Phagocytes - eat invading substances
Antibodies - help destroy substances
May leave the vessels – diapedesis

20. Types of Leukocytes Granulocytes Agranulocytes
Contain granules in cytoplasm
Polymorphonucleated
Many shaped nuclei
Agranulocytes
Lack visible granules
Nuclei closer to the norm

21. Granulocytes Neutrophils 40-70% of WBCs
Phagocytic removal of foreign particles and damaged cells

22. Granulocyte (cont’d) Eosinophils 1-4% Phagocytic removal of allergens
Kill parasitic worms

23. Granulocytes(cont’d)
Basophils
1% or less
Promotes inflammation by secreting histamine

24. Agranulocytes Lymphocytes 20-45%
Produce antibodies for the removal of toxins and viruses

25. Agranulocytes (cont’d)
Monocytes
4-8%
Active phagocytic removal of large foreign particles and damaged cells
Long-term “clean-up team”

26. Platelets Thrombocytes Form clots Fragments of cells Live 7 - 11 days
About 300,000/mm3

27. Hemostasis The stoppage of bleeding following a blood vessel accident
Three-step process occur in rapid sequence
Blood vessel spasm
Platelet plug formation
Coagulation

28. Blood Vessel Spasm Smooth muscle in vessel cut or torn
Muscle stimulated to contract
Draws open ends of vessel wall together - minimizing loss
This lasts less than 30 minutes
Provides time for hemostatic mechanisms to take effect

29. Platelet Plug Formation
Platelets arrive at the site of vessel breakage
Increase in size; take on irregular shape with a sticky surface

30. Platelet Plug Formation (cont’d)
Release chemicals that attract more platelets – form platelet plug
Release serotonin causing vessels to constrict
Normally followed by coagulation

31. Coagulation
Conversion of fibrinogen into long threads of protein - fibrin

32. Coagulation (cont’d)
Begins when injured vessel walls and platelets release thromboplastin which interacts with Ca ions to convert prothrombin (protein in plasma) into thrombin

33. Coagulation (cont’d) Thrombin works as an enzyme
Combining fibrinogen elements together to form fibrin (fibers)

34. Coagulation (cont’d)
A mass of fibrin form a netting - traps the formed elements
Forms blood clot
Process takes 3 to 6 minutes to complete

35. Coagulation (cont’d) Permanent repair begins
Fibrinolysis begins - clot dissolves

36. Undesirable Clotting
Thrombus – clot develops and persists in an unbroken blood vessel.
May prevent blood flow
Embolus – a thrombus breaks away and floats freely
Anticoagulants – heparin, coumadin, aspirin, warfarin

37. Blood Groups
Classified on the basis of genetically determined proteins (antigens) on RBC membranes.
Complementary antibodies may or may not be present in blood.
Antibodies act to agglutinate (clump) and rupture foreign RBCs.
Over 30 common RBC antigens in humans.

38. ABO Blood Groups Blood type Antigen Antibodies Give to Receive from A
A, AB
O, A B
Anti-A
B, AB
O, B AB
A & B
None
A, B, AB, O O
Anti-A & Anti-B

40. Rh System Antigen known as Rh - first discovered in Rhesus monkey
If present = Rh-positive (85%)
If not = Rh-negative (15%)
Anti-Rh antibodies not naturally present in blood in Rh-neg people.
Body can produce antibodies if exposed to +

41. Disorders
Anemia - reduction in no. of RBCs or amount of hemoglobin per unit of blood
Polycythemia - increase in RBCs (high blood pressure, clots, and hemorrhage)

42. Disorders (cont’d)
Sickle cell anemia - RBCs are sickle shaped containing abnormal hemoglobin (Rarely live beyond 40).
Hereditary disease.

43. Disorders (cont’d)
Bacteremia - acute infection of the blood stream (fever, chills, skin rash)
Thrombocytopenia – insufficient circulating platelets. Spontaneous bleeding.
Hemophilia – several different hereditary bleeding disorders – lack of clotting factors. Partial or complete.

44. Disorders (cont’d)
Leukocytosis - elevated number of WBCs. Indicates infection in body.
Leukemia – Cancer of the blood. Bone marrow becomes cancerous. Huge no. of WBCs produced.
Leukopenia – abnormally low WBC count

45. Disorders (cont’d)
Malaria - infection of the bloodstream caused by Plasmodium (chills, fever, anemia, spleen enlargement, death).
2nd most common infectious disease in world.

46. Disorders (cont’d)
Erythroblastosis fetalis – incompatibility between maternal (Rh-) and fetal (Rh+) blood.
Baby cyanotic, anemic.
Death possible, if not treated.
Preventable with drug RHoGAM.

48. Disorders (cont’d)
Hemorrhage - severe loss of blood due to injury - internal or external (Can result in shock)

49. Disorders (cont’d)
Shock - disturbance of blood circulation reducing the blood to vital tissues
Hypovolemic shock - decreased blood volume due to loss of formed elements and/or plasma
Cardiogenic shock - failure of the heart
Vascular shock - lowered ability of blood vessels to transport blood