1. The Blood

2. The Blood
Definition
Blood is a connective tissue, made of fluid (plasma) and cellular elements (RBC, WBC, and platelets)
Its volume is 5-6 L in males and 4-5 L in females
It is slightly alkaline, with a pH of ~ 7.4
Its color varies from bright to dark red
It has a salty metallic taste

3. The Blood
Functions
The blood is an organ that reaches all the other tissues
Transports oxygen and nutrients
Removes CO2 and other by-products of cell activity
Participates in the defense against infection
Participates in hemostasis
Participates in body heat distribution and regulation

4. Marieb and Hoehn Human Anatomy & Physiology seventh edition Pearson Benjamin Cummings

5. The Blood
Plasma
Straw colored fluid made of water (~90%), other contents include:
Proteins make the bulk of the solutes:
Albumens (60%), manufactured in the liver are the most abundant
Globulins (36%) are immune bodies
Fibrinogen (4%) for blood clotting
Nutrients: glucose, amino acids, lipids, cholesterol
Electrolytes: Na+, K+, Ca++, Mg++, H+, Cl-, HCO3-, PO4--, SO4--
Waste: urea, creatinine, uric acid, bilirubin
Gases: O2 , CO2 , N2
Protein
Plasma without clotting factors is called “serum”

6. Peripheral blood smear
Marieb and Hoehn Human Anatomy & Physiology seventh edition Pearson Benjamin Cummings

7. Electron micrograph of blood smear
Pathophysiology McCance & Huether fifth edition Elsevier Mosby

8. The Blood
RBC
An RBC is a 7.5 micron disc shaped body with a central depression
NO nucleus NO mitochondria
AN RBC contains hemoglobin
Antigens on RBC cell membrane determine blood type
RBCs function is gas exchange: O2 to the tissues and CO2 to the lungs

9. The Blood RBC Development of RBCs
Hypoxia → erythropoietin (kidney)→ red marrow of long bones→
The normal number of RBCs is million/mm3 in the female and
million/mm3 in the male
The normal values for Hgb are gm/dl for females and
14-16 gm/dl in males
Amino acids, lipids, carbohdrates, iron, vitamin B12 and folic acid are essntial for hemoglobin synthesis

10. The Blood RBC Hemoglobin has a remarkable ability to bind with oxygen
forming oxyhemoglobin
It can also release the oxygen to the tissues becoming deoxyhemoglobin

11. The Blood RBC Destruction Life span ~ 120 days
RBCs are phagocytosed by the reticulo-endothlial cells of the spleen

12. RBC Anemia is reduced RBC count The Blood Disorders of RBCs
Anemias can be caused by
RBC loss or reduced production
Hemorrhage, hemolysis, depressed bone marrow
Reduced hemoglobin content of RBCs
Iron, intrinsic factor, folic acid, or B12 deficiency
Congenital hemoglobin defects
Thalassemia, sickle cell anemia, spherocytosis

13. Normal and sickle cell RBC
In sickle cell disease hemoglobin S replaces the β chain
In thalassemias, the α or β chains can be absent or defective
Marieb and Hoehn Human Anatomy & Physiology seventh edition Pearson Benjamin Cummings

14. White Blood Cells (WBC)
The Blood
White Blood Cells (WBC)
Function
Lymphocytes are the effectors of the immune function
WBCs main function is to fight bacterial infections
WBCs are the only nucleated blood formed elements
They exercise their functions in the tissues not the blood stream
WBC migrate to the tissue spaces
WBC destroy the bacterial cell wall
Life span 1 – 9 days

15. The Blood White Blood Cells (WBC)
Lymphocytes, the smallest and second most abundant
T cells (80%) mediate cellular immunity
B cells mediate humoral immunity
Monocytes, the largest, migrate to the tissues and become
macrophages involved in cellular immunity

16. White blood cells, the granulcytes
Davidson’s The Priciples and Practice of Medicine, eigthteenth edition Churchill Livingstone

17. Monocytes and lymphocytes
Davidson’s The Priciples and Practice of Medicine, eighteenth edition Churchill Livingstone

18. The Blood Blood Coagulation
Coagulation is a natural mechanism that acts to diminish blood loss from hemorrhage
Coagulation occurs in three Stages
Platelet plug
The cascade leading to fibrin (clot) formation
Clot retraction and repair (PDGF)

19. The Blood Blood Coagulation The Platelets Platelets are cell fragments
Their life span is 8-14 days

20. The structure of a platelet
Davidson’s The Priciples and Practice of Medicine, eighteenth edition Churchill Livingstone

21. Initial vasoconstriction and platelet plug
Vander’s Physiology eighth edition Mc Graw Hill v

22. Calcium ions are essential for the coagulation cascade
Intrinsic and extrinsic coagulation pathways
Calcium ions are essential for the coagulation cascade
Vander’s Physiology eighth edition Mc Graw Hill

23. The role of the liver in blood coagulation
Vander’s Physiology eighth edition Mc graw Hill

24. EM of a blood clot: RBC’s and fibrin
NIBSC?Science Photo Libraray – Taken from Vander Physiology eighth edition Mc Graw Hill

25. The Blood Blood Types RBC’s have surface antigens
RBC’s can be grouped according to the presence or absence of certain antigens
There are many RBC antigens but only a A, B, AB and the Rh are of
clinical significance
Each one of the four types can be Rh positive or negative
Donor blood is mixed with recipient serum to decide compatibility, donor cell clumping indicate incompatibility

26. Major blood groups
A certain group posseses its antigen on the RBC surface and antibodies against the others
Marieb and Hoehn Human Anatomy & Physiology seventh edition Pearson Benjamin Cummings

27. The Blood
Rh Factor
There are no preformed Rh antibodies in Rh- individuals
They develop after exposure to Rh+ factors (antigens)
This explains the fact that an Rh+ fetus of an Rh- mother
does not usually suffer
But the Rh- mother can be sensitized to the Rh+ antigens during the first pregnancy, especially during delivery
Subsequent fetuses can suffer from the mother’s Rh antibodies passed
to it and its blood hemolyzes
This can be prevented by giving the mother serum that blocks the Rh+
factors antigenicity

28. The Blood
Rh Factor
Eighty five percent of the population have Rh antigens (Rh+)
There are several Rh groups (factors, antigens)
Three groups: Rh, C, D, and E, are of clinical importance
An Rh- mother may develop antibodies against her Rh+ fetus
The Rh- mother antibodies can pass to the Rh+ fetus resulting in hemolysis of its RBCs, a condition know as erythroblastosis fetalis
This sequence usually occurs after the first pregnancy