1. Blood Functions Blood maintains:
Appropriate body temperature by absorbing and distributing heat to other parts of the body
Normal pH in body tissues
Adequate fluid volume in the circulatory system

2. Blood Functions: Protection
Blood prevents blood loss by:
Activating plasma proteins and platelets
Initiating clot formation when a vessel is broken
Blood prevents infection by:
Synthesizing and utilizing antibodies
Activating complement proteins & WBCs to defend the body against foreign invaders

3. Physical Characteristics of Blood
Average volume:
5–6 L for males; 4–5 L for females
The pH is 7.35–7.45
Accounts for approximately 8% of body weight

4. Composition of Blood
Blood is the body’s only fluid tissue (connective tissue)
2 major components
Liquid = plasma (55%)
Formed elements (45%)
Erythrocytes, or red blood cells (RBCs)
Leukocytes, or white blood cells (WBCs)
Platelets – cell fragments

5. 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

6. Blood Plasma Blood plasma components: Water = 90-92% Proteins = 6-8%
Albumins-maintain osmotic pressure of the blood
Globulins-used for transport purposes
Fibrinogen-a clotting protein
Organic nutrients – glucose, carbohydrates, amino acids
Electrolytes – sodium, potassium, calcium, chloride, bicarbonate
Non-protein nitrogenous substances – lactic acid, urea, creatine
Respiratory gases – oxygen and carbon dioxide

7. Formed Elements
Only WBCs are complete cells
RBCs have no nuclei or organelles, and platelets are just cell fragments
Most F.E. survive in the bloodstream for only a few days
Most do not divide but are renewed by cells in bone marrow

8. Erythrocytes (RedBloodCells)
Biconcave disc
Folding increases surface area (30% more surface area)
Anucleate, no centrioles, no organelles
No cell division
No mitochondria means they generate ATP anaerobically
This prevents consumption of O2 being transported
Filled with hemoglobin (Hb) - 97% of cell contents
Hb functions in gas transport
Most numerous of the formed elements

9. Erythrocyte Function
Erythrocytes are dedicated to respiratory gas transport
Hb reversibly binds with oxygen and most oxygen in the blood is bound to Hb
Composition of Hb
A protein called globin
A heme molecule (a metal complex with iron as the central metal atom, that can bind or release molecular oxygen.)
Each heme group bears an atom of iron, which can bind to one oxygen molecule

10. Production of Erythrocytes
Hematopoiesis – blood cell formation
Occurs in the red bone marrow
Axial skeleton and girdles
Epiphyses of the humerus and femur
Marrow contains immature erythrocytes

11. Erythrocyte Disorders
Anemia – blood has abnormally low oxygen-carrying capacity
There are many forms of anemia, each with its own cause.
Anemia can be temporary or long term, and it can range from mild to severe.
Blood oxygen levels cannot support normal metabolism
Signs/symptoms include fatigue, paleness, shortness of breath, and chills

12. Leukocytes (White Blood Cells)
Protect the body from infectious microorganisms
Can leave capillaries
Move through tissue spaces
Many are phagocytic- that engulf and absorb waste material, harmful microorganisms, or other foreign bodies in the bloodstream and tissues.
Two major types of leukocytes
Granulocytes: Neutrophils, Eosinophils, Basophils
Agranulocytes: Monocytes, Lymphyocytes
Leukemia - a cancer of WBC

13. Granulocytes
Contain cytoplasmic granules that stain specifically with Wright’s stain
Are larger and usually shorter-lived than RBCs
Have lobed nuclei
Are all phagocytic cells

14. Granulocytes: Neutrophils
Account for 65-75% of total WBC’s
Neutrophils have two types of granules that:
Contain peroxidases, hydrolytic enzymes, and defensins (antibiotic-like proteins)
Neutrophils are our body’s bacteria slayers

15. Granulocytes: Eosinophils
Eosinophils account for 1–4% of WBCs
Function:
Lead the body’s counterattack against parasitic infections
Lessen the severity of allergies by phagocytizing immune complexes (ending allergic reactions)

16. Granulocytes: Basophils
Account for 0.5-1% of all WBCs
Have large, purplish-black granules that contain histamine
Histamine – inflammatory chemical that acts as a vasodilator and attracts other WBCs (antihistamines counter this effect)

17. Agranulocytes: Lymphocytes
Account for 20-25% or more of WBCs and:
Found mostly in lymphoid tissue (some circulate in the blood)
Most important cells of the immune system
Involved in graph rejection, fighting tumors and viruses
There are two types of lymphocytes: T cells and B cells
T cells - attack foreign cells directly
B cells give rise to plasma cells, which produce antibodies

18. Monocytes Account for 3–7% of leukocytes
They are the largest leukocytes
They have purple-staining, U- or kidney-shaped nuclei
They leave the circulation, enter tissue, and differentiate into macrophages
Increase in # during chronic infections.

19. Platelets Platelets are fragments of megakaryocytes
Platelets function in the clotting mechanism –form a temporary plug that helps seal breaks in blood vessels.
Platelet

20. 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

21. 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 (antigens) and their corresponding antibodies cannot be mixed without serious reactions

22. Group A – has only the A antigen on RBCs (and B antibody in the plasma)
Group B – has only the B antigen on RBCs (and A antibody in the plasma)
Group AB – has both A and B antigens on RBCs (but neither A nor B antibody in the plasma)
Group O – has neither A nor B antigens on RBCs (but both A and B antibody are in the plasma)
The universal donor has Type O negative blood.
The universal recipient has Type AB positive blood.

23. Transfusion Reactions
Transfusion reactions occur when mismatched blood is infused
Donor’s cells are attacked by the recipient’s plasma agglutinins causing:
Diminished oxygen-carrying capacity
Clumped cells that impede blood flow
Ruptured RBCs that release free hemoglobin into the bloodstream
Circulating hemoglobin precipitates in the kidneys and causes renal failure

24. Rhesus (Rh) factor
Is an inherited trait that refers to a specific protein found on the surface of RBCs.
If your blood has the protein, you're Rh(+)— the most common Rh factor. If your blood lacks the protein, you're Rh(-).
Rh factor doesn't affect your health.

25. Rhesus (Rh) factor cont.
When pregnant, blood from the baby can cross into the bloodstream. If you're Rh(-)and your baby is Rh(+) your body will react to the baby's blood as a foreign .
Your body will create antibodies against the baby's Rh-positive blood.
These antibodies usually don't cause problems during a first pregnancy.
The antibodies stay in your body once they have formed. Thus, Rh incompatibility is more likely to cause problems in later pregnancies (if the baby is Rh-positive).
The Rh antibodies can cross the placenta and attack the baby's red blood cells. This can lead to hemolytic anemia in the baby, which is a condition in which red blood cells are destroyed faster than the body can replace them.
Without enough red blood cells, the baby won't get enough oxygen. This can lead to problems and can be fatal.