Biology 322 Human Anatomy I Blood

Blood: Volume: Components: Formed Elements: Plasma: pH:

Erythrocytes Primary Function – Biconcave disks million per cubic millimeter billion per milliliter (cubic cm) Slightly higher in men Normally survive

Leukocytes (White blood cells) Five different types of cells All formed in bone marrow 4,000 to 10,000 per cubic millimeter or 4,000,000 to 10,000,000 per milliliter (cubic centimeter)

Each type has specific functions, but in general: Leukocytes function in body defenses by: Engulfing & digesting invading organisms & debris Directly killing invading cells Producing antibodies Secreting chemicals which activate other immune cells Secreting chemicals which promote inflammation

Leukocytes Grouped into two Categories Abundant, distinct granules = Few, small granules =

Granular Leukocytes Named according to how these granules react to routine lab stains ("Wright's Stain" is most common) The nucleus of each type also has a characteristic shape and/or density Three types:

Neutrophils Granules Nucleus Also called

Eosinophils Granules Nucleus

Basophils Granules Nucleus Outside of circulation:

Agranular Leukocytes Two unrelated types of leukocytes, neither of which has abundant granules: The nucleus of each type also has a characteristic shape and density

Monocytes Nucleus Cytoplasm Outside of circulation:

Lymphocytes Nucleus Varying amounts of cytoplasm

Lymphocytes Two types of Lymphocytes

All leukocytes formed in bone marrow, then enter blood But:

Since they generally function outside of the circulatory system, primarily in the connective tissues of other organs, All leukocytes can leave (and most can also reenter) the blood vessels by a process called

Platelets 250,000 to 500,000 per cubic millimeter or 250,000,000 to 500,000,000 per milliliter (cubic centimeter)

Platelets Fragments