Chapter 10

Composition and Function of Blood

-Connective tissue with blood cells, formed elements, and a fluid matrix, plasma.

Erythrocytes-

Leukocytes-

Platelets-

Plasma-

Many 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.

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

Neutrophils-

Eosinophils-

Basophils-

Agranulocytes- “normal” nuclei, little or no visible granules

Lymphocytes-

Monocytes-

Platelets-

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.

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

-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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