Chapter 10
Composition and Function of Blood
-Connective tissue with blood cells, formed elements, and a fluid matrix, plasma.
Erythrocytes-
Leukocytes-
Platelets-
PlasmaMany things are dissolved in plasma, mainly plasma proteins
Albumin-
Clotting proteins-
Antibodies-
Hormones-Changes on a daily/hourly rate to maintain homeostasis, based on diet,
internal and external stressors.
-Also helps to distribute body heat throughout the body.
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Red Blood Cells-Main function is to transport oxygen to all tissues and cells in the body
-Lacks a nucleus and major organelles, packed full of hemoglobin
-Hemoglobin is a protein molecule that binds easily to oxygen, and CO2
-Small disc shaped cells, allow for ease of movement through small
vessels
-One RBC can carry about 1 billion oxygen molecules, more practical
measurement, 12-18 g of Hb per 100 mL of blood.
White Blood Cells-Less numerous than RBC, but crucial to the bodies defense system.
-Have the ability to move in and out of the bloodstream
-WBC’s are classified into two divisions, based on visible granules in the
cytoplasm; granulocytes and agranulocytes.
Granulocytes- have lobed nuclei and darkly staining granules
NeutrophilsEosinophilsBasophils-
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Agranulocytes- “normal” nuclei, little or no visible granules
LymphocytesMonocytesPlatelets-
Blood Cell Formation- hematopoiesis-All formed elements arise from a common type of stem cell, hemocytoblast.
-Hemocytoblasts-
-Lymphoid stem cells-
-Myeloid stem cells-
-RBC live for about-Rate of RBC production is regulated by a hormone called erythropoietin
-Rate of WBC production is regulated by hormones called colony stimulating
factors and interleukins.
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Hemostasis- stoppage of blood flow
A fast and localized response, has three major phases, platelet plug, vascular
spasms, and coagulation.
1. Vascular Spasm Phase-
2. Platelet Plug Phase-
3. Coagulation Phase
Blood Groups and Transfusions
-RBC’s contain membrane proteins (antigens) that are genetically inherited.
-Major antigens are A, B, and Rh
-During development antibodies are formed against the A and/or B antigens not
present on the persons own RBC’s.
-Type A blood
-Type B blood
-Type AB blood
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-Type O blood
-Rh + has Rh antigens, Rh – has no Rh antigens, antibodies are formed
differently.
Developmental Aspects of Blood
-Circulatory system is developed early on
-Blood is flowing through vessels by day 28 of pregnancy
-Infants have a special type of Hb that binds stronger to oxygen.
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