1. Blood Composition and Function
General Composition of Blood
Plasma
Formed Elements
Erythrocytes
Leukocytes
Hematopoesis
Hemostasis (Clotting)
Transfusion and Blood Typing
Developmental Aspects of Blood

2. Blood Composition The only fluid tissue in the human body
Classified as a connective tissue
Living cells = formed elements
Non-living matrix = plasma
Color range
Oxygen-rich blood is scarlet red
Oxygen-poor blood is dull red
pH must remain between 7.35–7.45
Blood temperature is slightly higher than body temperature
Hematocrit: Percent of blood volume that is RBCs
47% ± 5% for males
42% ± 5% for females
Figure 10.1

3. Blood Cell Types

4. Blood Composition and Function
General Composition of Blood
Plasma
Formed Elements
Erythrocytes
Leukocytes
Hematopoesis
Hemostasis (Clotting)
Transfusion and Blood Typing
Developmental Aspects of Blood

5. Erythrocytes (Red Blood Cells)
Main function is to carry oxygen
Biconcave disks
Essentially bags of hemoglobin; few organelles
Anucleate (no nucleus)
Outnumber white blood cells 1000:1
Contain the plasma membrane protein spectrin and other proteins
Major factor contributing to blood viscosity

6. Hemoglobin Molecular structure
Protein globin: two alpha and two beta chains
Heme pigment bonded to each globin chain
Iron atom in each heme can bind reversibly to one O2 molecule
Each Hb molecule can transport four O2

7. Sickle Cell Hemoglobin Causes Clotting
Normal hemoglobin = HbA
Sickle cell hemoglobin = HbS (mutation in single amino acid - missense)

8. Pleiotropic Effects Seen if HbS present
HbAHbA = normal
HbAHbS = sickle cell trait
HbSHbS = sickle cell disease/anemia

9. Fetal Hemoglobin Binds O2 More Avidly
Fetal circulation must extract oxygen from maternal circulation
Fetal hemoglobin (HbF) binds O2 more avidly than normal hemoglobin (HbA) does
Replaced by “adult” hemoglobin just after birth

10. Blood Composition and Function
General Composition of Blood
Plasma
Formed Elements
Erythrocytes
Leukocytes
Hematopoesis
Hemostasis (Clotting)
Transfusion and Blood Typing
Developmental Aspects of Blood

11. Leukocytes (White Blood Cells)
Differential
WBC count
(All total 4800 –
10,800/l)
Formed
elements
Platelets
Granulocytes
Neutrophils (50 – 70%)
Leukocytes
Eosinophils (2 – 4%)
Basophils (0.5 – 1%)
Erythrocytes
Agranulocytes
Lymphocytes (25 – 45%)
Monocytes (3 – 8%)
Figure 17.9

12. Leukocyte Levels in the Blood
Normal levels are between 4, ,000 cells per millimeter
Abnormal leukocyte levels
Leukocytosis
Above 11,000 leukocytes/ml
Generally indicates an infection (bacterial, fungal, parasitic)
Also caused by some cancers, (including lymphocyte leukemia), hemhorrage, pneumonia
Leukopenia
Abnormally low leukocyte level (< 3,500/ml)
Commonly caused by certain drugs, radiation
Neutropenia (low neutrophil count) common in cancer patients receiving chemotherapy
HIV-AIDS, TB, malaria, influenza also cause leukopenia
Requires careful sanitation and “gowning up” for medical staff

13. Types of Leukocytes Granulocytes
Granules in their cytoplasm can be stained
Include neutrophils, eosinophils, and basophils
Agranulocytes
Lack visible cytoplasmic granules
Include lymphocytes and monocytes
Figure 10.4

14. Characteristics of Formed Elements of the Blood
N E B

15. Characteristics of Formed Elements of the Blood
L M

16. Blood Composition and Function
General Composition of Blood
Plasma
Formed Elements
Erythrocytes
Leukocytes
Hematopoesis
Hemostasis (Clotting)
Transfusion and Blood Typing
Developmental Aspects of Blood

17. Hematopoiesis Subdivided into erythropoesis and leukopoesis
Erythropoesis ccurs in red bone marrow
Erythropoesis Steps
Ribosome synthesis
Hemoglobin accumulation
Ejection of the nucleus and formation of reticulocytes
Reticulocytes then become mature erythrocytes
Stem cell
Committed
cell
Developmental pathway
Phase 1
Ribosome
synthesis
Phase 2
Hemoglobin
accumulation
Phase 3
Ejection of
nucleus
Figure 17.5
Proerythro-
blast
Early
erythroblast
Late
erythroblast
Reticulo-
cyte
Erythro-
cyte
Hemocytoblast
Normoblast

18. Fate of Erythrocytes Unable to divide, grow, or synthesize proteins
Wear out in 100 to 120 days
When worn out, are eliminated by phagocytes in the spleen or liver
Iron is salvaged for reuse
Heme is degraded to yellow the pigment bilirubin
Liver secretes bilirubin (in bile)) into the intestines
Lost cells are replaced by division of hemocytoblasts

19. Control of Erythrocyte Production
Rate is controlled by a hormone (erythropoietin)
Kidneys produce most erythropoietin as a response to reduced oxygen levels in the blood (hypoxia)
Hypoxia can develop from hemorrhage, low O2 in air, insufficient hemoglobin
Homeostasis is maintained by negative feedback from blood oxygen levels

20. Platelets Important in Clotting
Small fragments of megakaryocytes
Formation is regulated by thrombopoietin
Blue-staining outer region, purple granules
Form a temporary platelet plug that helps seal breaks in blood vessels
Stem cell
Developmental pathway
Hemocyto-
blast
Megakaryocyte
Platelets

21. Blood Composition and Function
General Composition of Blood
Plasma
Formed Elements
Erythrocytes
Leukocytes
Hematopoesis
Hemostasis (Clotting)
Transfusion and Blood Typing
Developmental Aspects of Blood

22. Hemastasis: Blood Clotting
Step Vascular spasm 1
• Smooth muscle contracts,
causing vasoconstriction.
Step Platelet plug formation 2
• Injury to lining of vessel
exposes collagen fibers;
platelets adhere.
Collagen
fibers
• Platelets release chemicals
that make nearby platelets
sticky; platelet plug forms.
Platelets
Step Coagulation 3
• Fibrin forms a mesh that traps
red blood cells and platelets,
forming the clot.
Fibrin
Figure 17.13

23. Hemastasis

24. Undesirable Clotting Thrombus A clot in an unbroken blood vessel
Can be deadly in areas like the heart
Embolus
A thrombus that breaks away and floats freely in the bloodstream
Can later clog vessels in critical areas such as the brain, causing a stroke (CVA)

25. Bleeding Disorders Thrombocytopenia Platelet deficiency
Even normal movements can cause bleeding from small blood vessels that require platelets for clotting
Hemophilia
Hereditary bleeding disorder
Normal clotting factors are missing or deficiency in Vit. K.
mild hemophilia

26. Blood Composition and Function
General Composition of Blood
Plasma
Formed Elements
Erythrocytes
Leukocytes
Hematopoesis
Hemostasis (Clotting)
Transfusion and Blood Typing
Developmental Aspects of Blood

27. Blood Groups and Transfusions
Large losses of blood have serious consequences
Loss of 15 to 30 percent causes weakness
Loss of over 30 percent causes shock, which can be fatal
Transfusions are the only way to replace blood quickly
Transfused blood must be of the same blood group

28. Human Blood Groups Blood contains genetically determined proteins
A foreign protein (antigen) on a donated RBC may be attacked by the immune system
Blood is “typed” by using antibodies that will cause blood with certain proteins to clump (agglutination)

29. Components of Blood of this Type
Human Blood Groups
There are over 30 common red blood cell antigens
The most vigorous transfusion reactions are caused by ABO and Rh blood group antigens
ABO Blood Groups and Alleles
Components of Blood of this Type
anti-A anti-B
anti-B
anti-A

30. Rh Blood Groups and Hemolytic Deaseas of Newborns
Named because of the presence or absence of one of eight Rh antigens (agglutinogen D)
Most Americans are Rh+
The danger is only when the mother is Rh– and the father is Rh+, and the child inherits the Rh+ factor
Dd dd
This baby, if from the second or subsequent pregnancy, could have complications in an Rh- mother
Problems can occur in second and subsequent pregnancies when the baby’s Rh+ blood enters Rh– maternal circulation: erythroblastosis fetalis (hemolytic disease of the newborn)
RhoGAM injections contain anti-Rh antibodies that quickly clear the maternal circulation of Rh protein Dd dd

31. Blood Composition and Function
General Composition of Blood
Plasma
Formed Elements
Erythrocytes
Leukocytes
Hematopoesis
Hemostasis (Clotting)
Transfusion and Blood Typing
Developmental Aspects of Blood