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

neutrophils eosinophilsbasophilsmonocyteslymphocytes

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 (O2, CO2)• 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?

Which type of leukocyte is it?

Which type of leukocyte is it?

Which type of leukocyte is it?

Which type of leukocyte is it?

Which type of leukocyte is it?

Which type of leukocyte is it?

Which type of leukocyte is it?

Which type of leukocyte is it?