1. The Circulatory System I Blood
Chapter 19
The Circulatory System I
Blood

2. Cardiovascular System
The cardiovascular system includes:
Blood
The Heart
Blood Vessels
Large and small arteries and arterioles
Large and small veins and venules
Capillaries

3. Blood
A liquid connective tissue made up of plasma and formed elements.
BLOOD COMPOSITION:
Serum: the liquid portion of blood after it has clotted ( fibrinogen has clotted).
Plasma: liquid portion of blood
Water – 92% by weight
Proteins – 6-9 gm/dl; most abundant plasma solute
Formed elements (rbc, wbc and platelets)

4. Blood fractions

5. Blood

6. Blood Proteins
Albumin is the major contributor to plasma viscosity and osmolarity. Albumin- smallest and most abundant protein; serves to transport plasma solutes and buffer the pH of blood plasma.
Fibrinogen- soluble precursor of fibrin, a sticky protein that forms framework for clotting.
Globulins- 3 classes: alpha (α), beta (β) and gamma (γ) (smallest to largest) in molecular weight.

7. Formed Elements Red blood cells (rbc) = erythrocytes ~45-50% pcv*
White blood cells (wbc) = leukocytes ~ < 1% pcv*
Granulocytes- neutrophils, eosinophils and basophils
Agranulocytes- lymphocytes and monocytes
Thrombocytes = platelets (part of buffy coat)
* = packed cell volume

8. Erythrocytes (RBC’s)
4.2 – 6.2 million per mm3
Cell Structure: biconcave disc 7.5 μm diameter,
X 2 μm thick.
anucleated cells (no nucleus or other cellular organelles)
Production: erythropoiesis is stimulated by erythropoietin, a hormone from kidneys.
-From infancy on, all rbc’s are produced in red bone marrow. They are produced from pluripotent stem cells (PPSC).
Contain 280 million hemoglobin molecules/rbc;
Life span of a rbc ~ days

9. Erythrocytes (RBC’s)

10. Hemoglobin
Hemoglobin (Hgb) is a complex molecular struc-ture of four polypeptide chains: 2 α chains and 2 β chains.
Each α chain contains 141 amino acids; β chain contains 146 amino acids.
One heme group is bound to each chain and contains ferrous iron (Fe+2).
Oxygen binds to Fe+2. Each Hgb molecule binds four oxygen atoms. Therefore each RBC can transport about 4 x 280 million oxygen atoms

11. Hemoglobin molecular structure
Star shapes are heme groups containing Fe+2
Dark blue chain is β, light blue is α

12. Blood types Most familiar blood types are ABO groups and Rh group.
Blood type antigens are carried on red blood cell membranes.
Blood types A,B,O and AB involve the ABO group
O is “universal donor”; AB is “universal recipient”.
Rh factor may be present (+) or absent (-) and immune reactions can result if not properly matched.

13. Hematopoiesis

14. Leukocytes (WBC’s) Cell Structure: 4,800 – 11,000/mm3
-Spherical cells containing a nucleus and other organelles. The nucleus of each cell type varies considerably in leukocytes and is quite conspicuous, thus helps in identifying each cell type.
Production:
-stimulated by two cytokines: (interleukin and colony stimulating factor [CSF]).
-All wbc’s are produced from PPSC by a process called leucopoiesis. WBC’s are produced in red bone marrow and may remain there until needed in the body or they may migrate to other organs for further differentiation.
Percentage ranking: NLMEB

15. Differential Leukocyte Count
Smear a drop of blood over a slide
Stain the blood smear with Wright’s stain
- gentian violet stains nuclei violet
- eosin stains proteins pink
Count 100 leukocytes, tallying each type
neutrophils: 60 – 70% of total count
lymphocytes: 20 – 25 %
monocytes: 3 – 8 %
eosinophils: 2 – 4 %
basophils: 0.5 – 1 % :

16. WBC’s

17. Granulocytes Leukocytes that contain granules in their cytoplasm:
Neutrophils – most plentiful in blood (60 – 70 %)
Eosinophils – 1 – 4% of wbc’s
Basophils- least plentiful of all wbc’s ~ 0.5% wbc’s

18. Neutrophils Nucleus looks like sausage links – multilobed
- about 60% of wbcs: 3,000 to 7,000/mm3
-Life span: 6 hrs – few days
- phagocytize bacteria

20. Eosinophils Bilobed nucleus Account for 1-4% of wbc
Red staining granules
Life span- 8 – 12 days
Kill parasitic worms, active in allergies

21. Basophils Bilobed nucleus “U” or “S” Account for < 0.5% wbc
Dark bluish-purple staining granules
Life span- hrs. - days
Contain histamine, and inflamatory substances

22. Agranulocytes Conspicuous granules are lacking in the cytoplasm.
Composed of: Lymphocytes and Monocytes.
Lymphocytes are most important in immune system in lymph nodes, Peyers patches, and spleen.

23. Lymphocytes Round nucleus fills most of cytoplasm
Account for % of wbc’s
Similar size to neutrophils
Life span- hrs. to years
Two types: “B” and “T”
B cells mature in red bone marrow
T cells start in red marrow and mature in Thymus gland

24. Monocytes Largest wbc’s in circulation Large “U: shaped or kidney
shaped nucleus
Account for 4-8% of wbcs
Life span- months
Active in clotting to plug
holes until clot can form.
Become macrophages after release from red bone marrow into circulation
Macrophages are major phagocytes in body

25. Thrombocytes (platelets)
Cellular fragments very small under microscope.
~ 250,000 platelets/ mm3
Contain serotonin, Ca++,
enzymes and platelet growth
factor.
Stick together to form plugs
and stop bleeding (hemostasis).
Picture is of a megakaryocyte from which
platelets are produced.

26. Blood clot of fibrin and platelets and other blood cells