BLOOD

Components of Blood Red blood cells = erythrocytes White blood cells = leukocytes Cell fragments = platelets Liquid = plasma

In your 5 liters of blood… 4-6 million erythrocytes per cubic mm 5-10,000 leukocytes per cubic mm 130,000 – 360,000 platelets per cubic mm There are: 45% cells 55% plasma Mostly erythrocytes Fewer leukocytes and platelets Dissolved substances

Erythrocytes Biconcave discs Carry oxygen in hemoglobin Lack nuclei Cannot reproduce Live about 4 months Cell count used in disease diagnosis

Production and Destruction Nutrients necessary include vitamin B12, folic acid, iron Cell count is kept at constant level Production controlled by the hormone erythropoietin After 4 months, destroyed in liver and spleen Byproduct is bilirubin Too much bilirubin leads to jaundice

Leukocytes Protect against infection and disease Can leave the bloodstream to fight infection Have a nucleus Cell count used to diagnose disease

Relative numbers of Leukocytes

Platelets Cell fragments Also called thrombocytes Essential for blood clotting Lack nuclei Live about 10 days

Plasma 92% water Contains dissolved substances: Plasma proteins including albumins, globulins, and fibrinogen Blood gases (O 2, CO 2 ) Plasma nutrients: amino acids, simple sugars, lipids from digestive tract

Plasma Nitrogenous substances such as urea, uric acid. These are toxic wastes that must be excreted in urine Electrolytes: sodium, calcium, phosphate, etc.

Cholesterol: good or bad? It’s normal to have some It is needed to form cell membranes, hormones, and some other tissues But a high level is a risk for heart disease

Cholesterol: good or bad? Lipoproteins carry cholesterol in the blood plasma LDL is “BAD” (Low density) HDL is “Good” (high density)

Neutrophil

Eosinophil

Basophil

Monocyte

Lymphocyte

Which type of leukocyte is it?