Blood(made of 45% formed elements)

Red Blood Cells (RBC's)

Called Erythrocytes Small boconcave discs Loses nucleus when mature Each cell contains hemoglobin Heme (with iron, Fe) + globin Made in red bone marrow (skull, ribs,

vertebrae, end of long bones)

RBC formation

Hemoglobin in red blood cells responsible for carrying O

2

Hemoglobin increase O2 carrying capacity

60 times Red Blood Cells live approx 120 days Eventually destroyed by liver and spleen Hemoglobin also helps carry CO

2

High altitudes or blood loss..

Renal erythropoeitinis released This raises the O

2 capacity of the blood

This also causes the blood to thicken Athletes will use this substance to enhance

performance It is illegal (due to the dangers of blood

thickening)

White Blood Cells

Called Leukocytes 8 – 10 times larger than the RBC's Contain a nucleus (irregularily shaped) Exist in far fewer numbers than RBC's Most are neutrophils (immune cells that

engulf invaders) Leukemia: a form of cancer characterized

by uncontrolled production of leukocytes

Granulocytes WBC's with granules in cytoplasm Have irregular shaped (many lobed)

nucleus called polymorphonuclear Formed in red bone marrow 3 kinds:

Neutrophils Eosinophils Basophils

Destro bacteria, viruses, dead tissue by engulfing (phagocytes)

Agranulocytes

WBC's with no granules in cytoplasm Have a circular nucleus 2 kinds:

Monocytes (huge, phagocytotic) Lymphocytes (20 – 30% WBC's,

produced in lymphoid tissue, responsible for immunity, produce antibodies)

Platelets Called thrombocytes Are actually fragments of huge cells Huge cells come from red bone marrow They are anucleate Blood stream has more than a trillion Responsible for blood clotting (combined

with certain plasma proteins) Haemophiliac: a person whose blood

doesn't clot