1. Blood

2. Composition of Blood Blood is the body’s only fluid tissue
It is composed of liquid plasma and formed elements
Formed elements include:
Erythrocytes, or red blood cells (RBCs)
Leukocytes, or white blood cells (WBCs)
Platelets

3. Overview of Blood Circulation
Blood leaves the heart via arteries that branch repeatedly until they become capillaries
Oxygen (O2) and nutrients diffuse across capillary walls and enter tissues
Carbon dioxide (CO2) and wastes move from tissues into the blood

4. Overview of Blood Circulation
Oxygen-deficient blood leaves the capillaries and flows in veins to the heart
This blood flows to the lungs where it releases CO2 and picks up O2
The oxygen-rich blood returns to the heart

5. The Human Body Respiratory system Circulatory system Digestive system
Figure 7.1
Oxygen
intake
Elimination of
carbon dioxide
Food and
water intake
The Human Body
Respiratory
system O2
CO2
Nutrients,
salt, water
Water, salts,
metabolic waste
Circulatory
system
Digestive
system
Urinary
system
Metabolic
waste
Transport
to and from
all cells
Elimination of
food residues,
metabolic wastes
Elimination of
excess water, salts,
metabolic wastes

6. Regulation
Body Temperature
Body PH
Fluid Balance

7. Physical Characteristics and Volume
Blood is a sticky, opaque fluid with a metallic taste
The pH of blood is 7.35–7.45
Temperature is 38°C, slightly higher than “normal” body temperature; warms the areas it passes through
Blood accounts for approximately 8% of body weight
Average volume of blood is 5–6 L for males, and 4–5 L for females

8. Components of Whole Blood
Plasma (55% of whole blood)
Buffy coat: leukocyctes and platelets (<1% of whole blood)
Formed elements
Erythrocytes (45% of whole blood) 1
Withdraw blood and place in tube 2
Centrifuge
Hematocrit – the percentage of RBCs out of the total blood volume
Figure 17.1

9. Components of Blood Plasma (makes up 55% of whole blood)
Water
Electrolytes
Proteins (albumins, globulins, clotting proteins)
Hormones
Gases
Nutrients and wastes
Formed elements (makes up 45% of whole blood)
RBCs
WBCs
Platelets

10. Blood Plasma Blood plasma contains over 100 solutes, including:
Proteins – albumin, globulins, clotting proteins, and others
Nonprotein nitrogenous substances – lactic acid, urea, creatinine
Organic nutrients – glucose, carbohydrates, amino acids
Electrolytes – sodium, potassium, calcium, chloride, bicarbonate
Respiratory gases – oxygen and carbon dioxide

11. Maintaining Osmotic Pressure

12. Albumins Smallest/Most abundant blood protein
Exerts greatest colloid pressure
Transport ions, hormones, lipids

13. Globulins
Alpha/Beta – bind and transport water-insoluble molecules and hormones, some metals, and ions
Gamma – a.k.a. antibodies

14. Fibrinogen
Type of clotting protein

15. Formed Elements
Erythrocytes, leukocytes, and platelets make up the formed elements
Only WBCs are complete cells
RBCs have no nuclei or organelles, and platelets are just cell fragments
Most formed elements survive in the bloodstream for only a few days
Most blood cells do not divide but are renewed by cells in bone marrow

16. Hemopoiesis

17. Erythrocytes (RBCs)
Biconcave discs, anucleate, essentially no organelles
97 % hemoglobin (Hb), a protein that functions in gas transport
Contain the plasma membrane protein spectrin and other proteins that:
Give erythrocytes their flexibility
Allow them to change shape as necessary

18. Erythrocytes (RBCs)
Figure 17.3

19. Erythrocyte Function
Erythrocytes are dedicated to respiratory gas transport
Hemoglobin reversibly binds with oxygen and most oxygen in the blood is bound to hemoglobin
Each heme group bears an atom of iron, which can bind to one oxygen molecule
Each hemoglobin molecule can transport four molecules of oxygen

20. Hematocrit & Hemoglobin
Hematocrit: the percentage of whole blood that consists of red blood cells
Men: 43–49% Women: 37–43%
Hemoglobin measurement
Men: 14–18 gm% Women: 12–14 gm%
Low hematocrit or hemoglobin may indicate anemia
High hematocrit may be response to high elevation (less O2 available in atmosphere)
Very high hematocrit—risky because of increased blood viscosity

21. Production of Erythrocytes: Erythropoiesis
A hemocytoblast is transformed into a committed cell called the proerythroblast
Proerythroblasts develop into early erythroblasts
The developmental pathway consists of three phases
Phase 1 – ribosome synthesis in early erythroblasts
Phase 2 – hemoglobin accumulation in late erythroblasts and normoblasts
Phase 3 – ejection of the nucleus from normoblasts and formation of reticulocytes
Reticulocytes then become mature erythrocytes

22. Production of Erythrocytes: Erythropoiesis
Figure 17.5

23. Role of EPO

25. Fate and Destruction of Erythrocytes
The life span of an erythrocyte is 100–120 days
Old erythrocytes become rigid and fragile, and their hemoglobin begins to degenerate
Dying erythrocytes are engulfed by macrophages
Heme and globin are separated and the iron is salvaged for reuse

26. Fate and Destruction of Erythrocytes
Iron is transported by transferrin to liver and spleen
Stored there until it’s return to the bone marrow for recycling
Iron storage proteins: ferritin an hemosiderin

27. Fate and Destruction of Erythrocytes
Heme is degraded to a yellow pigment called bilirubin
The liver secretes bilirubin into the intestines as bile
The intestines metabolize it into urobilinogen
This degraded pigment leaves the body in feces, in a pigment called stercobilin
Globin is metabolized into amino acids and is released into the circulation
Hb released into the blood is captured by haptoglobin and phagocytized

28. Leukocytes (WBCs)
Leukocytes, the only blood components that are complete cells:
Are less numerous than RBCs
Make up 1% of the total blood volume
Can leave capillaries via diapedesis
Move through tissue spaces
Leukocytosis – WBC count over 11,000 per cubic millimeter
Normal response to bacterial or viral invasion

29. Types of Leukocytes Granulocytes Agranulocytes
Granules in the cytoplasm
Agranulocytes
Lack visible cytoplasmic granules

30. Leukocytes Found within body tissues as well as blood
Diapedesis: movement of leukocytes from blood vessels to tissue

31. Leukocytes

32. Basophils Account for 0.5% of WBCs and:
Have large, purplish-black (basophilic) granules that contain histamine
Histamine – inflammatory chemical that acts as a vasodilator and attracts other WBCs (antihistamines counter this effect)
Heparin - inhibits blood clotting

33. Eosinophils Eosinophils account for 1–4% of WBCs
Lead the body’s counterattack against parasitic worms
Lessen the severity of allergies by phagocytizing immune complexes

34. Neutrophils 60% of leukocytes First on the scene to fight an infection
Phagocytize pathogens, especially bacteria

35. Monocytes Monocytes account for 4–8% of leukocytes Macrophages:
They are the largest leukocytes
They leave the circulation, enter tissue, and differentiate into macrophages
Macrophages:
Are highly mobile and actively phagocytic

36. Lymphocytes Account for 25% or more of WBCs and:
Are found mostly enmeshed in lymphoid tissue (some circulate in the blood)
There are two types of lymphocytes: T cells and B cells
T cells function in the immune response
B cells give rise to plasma cells, which produce antibodies

37. Changes in Leukocyte Count
Leukopenia vs Leukocytosis
Allergic reactions/Parasitic reactions - inc. eosinophils
Chronic inflammatory disorders/ TB - inc. monocytes

38. Platelets Platelets are fragments of megakaryocytes
Platelets function in the clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels

39. Thrombopoiesis The stem cell for platelets is the hemocytoblast
The sequential developmental pathway is hemocytoblast, megakaryoblast, promegakaryocyte, megakaryocyte, and platelets
Figure 17.12

40. Hemostasis: Stopping Blood Loss
Three stages
1. Vascular spasm: constriction of blood vessels to reduce blood flow
2. Platelet plug formation: sealing of the ruptured blood vessel
3. Coagulation: formation of a blood clot
Blood changes from a liquid to a gel
Complex series of reactions involving at least 12 different clotting proteins in the plasma

41. Clotting Cascade Damage to blood vessels initiates the process
Platelets release prothrombin activator
Prothrombin activator converts prothrombin (plasma protein) to thrombin (active enzyme)
Thrombin converts fibrinogen (soluble plasma protein) to fibrin (insoluble fibers)
Mass of fibrin, platelets, trapped RBCs forms blood clot
Clot contracts and tightens

42. STEP 1: Blood vessel spasm (vascular spasm)
When vessel damage occurs . . .
STEP 1: Blood vessel spasm (vascular spasm)

43. STEP 2: Platelet plug forms

44. STEP 3: Blood coagulation (clotting)

45. The final key step in blood clot formation is the conversion of fibrinogen into fibrin.

46. Coagulation Intrinsic pathway Extrinsic pathway
Triggered by damage to inside of the vessel
Takes 3-6 min
Extrinsic pathway
Caused by damage to outside the vessel
Takes 15 seconds

49. Clot Retraction
As clot forms, actinomyosin, contracts and squeezes the serum out of the developing clot
Plasmin degrades the fibrin strands through fibrinolysis

50. Undesirable Clotting Thrombus Embolus A clot in an unbroken vessel
Can be fatal in coronary vessels
Embolus
A thrombus that breaks away and floats in the blood stream
Can clog vessels in other areas

51. Hemophilia Deficiency of one or more clotting factors
Unable to form clots sufficiently
Complications
Life threatening hemorrhage
Painful, swollen joints
Infections
Easy bruising

52. Blood Disorders Red blood cells
Anemia: reduction in oxygen-carrying capacity due to inadequate number of red blood cells or inadequate hemoglobin
Iron-deficiency anemia: caused by inadequate intake or malabsorption of dietary iron
Hemorrhagic anemia: caused by blood loss
Pernicious anemia: caused by Vitamin B12 deficiency
Hemolytic anemia: caused by destruction of red blood cells
Anemia due to renal failure
Results from inadequate erythropoietin secretion

53. Sickle Cell Disease

54. Leukemia Excessive proliferation of leukocytes
Cancer begins in bone marrow

55. Human Blood Groups
RBC membranes have glycoprotein antigens on their external surfaces
These antigens are:
Unique to the individual
Recognized as foreign if transfused into another individual
Promoters of agglutination and are referred to as agglutinogens
Presence or absence of these antigens is used to classify blood groups

56. ABO Blood Groups The ABO blood groups consists of:
Two antigens (A and B) on the surface of the RBCs
Two antibodies in the plasma (anti-A and anti-B)
Agglutinogens and their corresponding antibodies cannot be mixed without serious hemolytic reactions

57. Rh Blood Groups
Presence of the Rh agglutinogens on RBCs is indicated as Rh+
Anti-Rh antibodies are not spontaneously formed in Rh– individuals
However, if an Rh– individual receives Rh+ blood, anti-Rh antibodies form
A second exposure to Rh+ blood will result in a typical transfusion reaction

58. Antibody binds to antigen. Antibodies ignore
Figure 7.11
“Self” surface protein
Foreign
cell
Antigen-antibody
complex
Antigen
Antibody
Antibody binds to antigen. Antibodies ignore
the “self” surface proteins but bind to the antigen
of the foreign cell, forming an antigen-antibody
complex.
Antigen-antibody complexes
clump together. Clumping
effectively inactivates the foreign
cells.

59. Type A Type B Type AB Type O Red blood cells Plasma antibodies
Figure 7.12
Type A
Type B
Type AB
Type O
Antigen A
Antigen B
Antigens
A and B
Neither A nor
B antigens
Red blood cells
Plasma antibodies B A
Neither A nor B
A and B
Incidences:
U.S. Caucasians
U.S. African Americans
Native Americans
40%
27% 8%
10%
20% 1% 5% 4% 0%
45%
49%
91%

60. Rh Blood Typing Is Based On the Rh Factor
Rh factor: another antigen found on red blood cell surfaces
85% of Americans are Rh-positive (have the antigen)
15% are Rh-negative
These individuals will respond to Rh-positive blood by producing anti-Rh antibodies

61. Rh Blood Typing Is Based On the Rh Factor
Can be a problem when an Rh-negative women is pregnant with an Rh-positive fetus
Mother may produce anti-Rh antibodies that cross placenta and damage fetal red blood cells
Anti-Rh antibodies from mother cause hemolytic disease of the newborn Rh-positive baby
Risk much higher for second and subsequent pregnancies
Can be prevented by giving mother Rho-GAM (anti- Rh antibodies) during pregnancy and at delivery

62. being tested Antibodies Anti-A Anti-B
Figure 7.14
Blood
being tested
Antibodies
Anti-A
Anti-B
Type A
(Contains antigen A)
Type B
(Contains antigen B)
Agglutinated
blood
Type AB
(Contains antigens
A and B)
Type O
(Contains neither
A nor B antigens)

63. Hemolytic Disease in Pregnancy