1. Chapter 21 The Cardiovascular System: The Blood

2. Functions of Blood Transportation Regulation
O2, CO2, metabolic wastes, nutrients, heat & hormones
Regulation
helps regulate pH through buffers
helps regulate body temperature
coolant properties of water
vasodilatation of surface vessels dump heat
helps regulate water content of cells by interactions with dissolved ions and proteins
Protection from disease & loss of blood

3. Components of Blood 55% plasma 45% cells 99% RBCs
< 1% WBCs and platelets

4. Blood Plasma 0ver 90% water 7% plasma proteins albumin
maintain blood osmotic pressure
globulins (immunoglobulins)
antibodies bind to foreign substances called antigens
form antigen-antibody complexes
fibrinogen
for clotting

5. Formed Elements of Blood
Red blood cells ( erythrocytes )
White blood cells ( leukocytes )
granular leukocytes
neutrophils
eosinophils
basophils
agranular leukocytes
lymphocytes = T cells, B cells, and natural killer cells
monocytes
Platelets (special cell fragments)

6. Hematocrit Percentage of blood occupied by cells Anemia Polycythemia
not enough RBCs or not enough hemoglobin
Polycythemia
too many RBCs (over 65%)
dehydration, tissue hypoxia, blood doping in athletes

7. Formation of Blood Cells
Most blood cells types need to be continually replaced
die within hours, days or weeks
process of blood cells formation is hematopoiesis or hemopoiesis
occurs only in red marrow of flat bones like sternum, ribs, skull & pelvis and ends of long bones

8. Red Blood Cells or Erythrocytes
Contain oxygen-carrying protein hemoglobin that gives blood its red color
1/3 of cell’s weight is hemoglobin
Biconcave disk 8 microns in diameter
increased surface area/volume ratio
flexible shape for narrow passages
no nucleus or other organelles
no cell division or mitochondrial ATP formation

9. RBC Life Cycle RBCs live only 120 days
wear out from bending to fit through capillaries
no repair possible due to lack of organelles
Worn out cells removed by fixed macrophages in spleen & liver
Breakdown products are recycled

10. WBC Anatomy and Types
All WBCs (leukocytes) have a nucleus and no hemoglobin
Granular or agranular classification based on presence of cytoplasmic granules made visible by staining

11. WBC Physiology Less numerous than RBCs
1 WBC for every 700 RBC
Leukocytosis is a high white blood cell count
microbes, strenuous exercise
Leukopenia is low white blood cell count
radiation, shock or chemotherapy

12. Complete Blood Count (CBC)
Screens for anemia and infection
Total RBC, WBC & platelet counts; differential WBC; hematocrit and hemoglobin measurements
Normal hemoglobin range
12 to 18g/100mL of blood

13. Platelet Adhesion
Platelets stick to exposed collagen underlying damaged endothelial cells in vessel wall

14. Blood Clotting Blood drawn from the body thickens into a gel
If clotting occurs in an unbroken vessel is called a thrombosis
Substances required for clotting are Ca+2, enzymes synthesized by liver cells and substances released by platelets or damaged tissues

15. Role of Vitamin K in Clotting
Normal clotting requires adequate vitamin K
Produced by bacteria in large intestine

16. Intravascular Clotting
Thrombosis
clot (thrombus) forming in an unbroken blood vessel
may dissolve spontaneously or dislodge & travel
Embolus
clot, air bubble or fat from broken bone in the blood
Low dose aspirin blocks synthesis of thromboxane A2 & reduces inappropriate clot formation

17. Blood Groups and Blood Types
RBC surfaces are marked by genetically determined glycoproteins & glycolipids
agglutinogens or isoantigens
distinguishes at least 24 different blood groups
ABO, Rh, and others

18. ABO Blood Groups
Based on 2 antigens called A and B found on the surface of RBCs
display only antigen A -- blood type A
display only antigen B -- blood type B
display both antigens A & B -- blood type AB
display neither antigen -- blood type O
Plasma contains antibodies or agglutinins to the A or B antigens not found in your blood
anti-A antibody reacts with antigen A
anti-B antibody reacts with antigen B

19. Universal Donors and Recipients
People with type AB blood called “universal recipients” since have no antibodies in plasma
People with type O blood cell called “universal donors” since have no antigens on their cells
theoretically can be given to anyone

20. Anemia = Not Enough RBCs
Symptoms
oxygen-carrying capacity of blood is reduced
fatigue, cold intolerance & paleness
Types of anemia
iron-deficiency =lack of absorption or loss of iron
pernicious = lack of intrinsic factor for B12 absorption
hemorrhagic = loss of RBCs due to bleeding (ulcer)
hemolytic = defects in cell membranes cause rupture
thalassemia = hereditary deficiency of hemoglobin
aplastic = destruction of bone marrow (radiation/toxins)

21. Sickle-cell Anemia (SCA)
Genetic defect in hemoglobin molecule
at low very O2 levels, RBC is deformed by changes in hemoglobin molecule within the RBC
Found among populations in malaria belt
Mediterranean Europe, sub-Saharan Africa & Asia
Person with only one sickle cell gene
increased resistance to malaria

23. Hemophilia Inherited deficiency of clotting factors
bleeding spontaneously or after minor trauma
subcutaneous & intramuscular hemorrhaging
nosebleeds, blood in urine, articular bleeding & pain
Treatment is transfusions of fresh plasma or concentrates of the missing clotting factor

24. Leukemia Acute leukemia Chronic leukemia
uncontrolled production of immature leukocytes
crowding out of normal red bone marrow cells by production of immature WBC
prevents production of RBC & platelets
Chronic leukemia
accumulation of mature WBC in bloodstream because they do not die