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Website:m-learning.zju.edu.cn. Blood. LiDongMei may75119@163.com. Overview of Blood. Blood is a fluid connective tissue. Its total volume is about 5 liters. It has many functions. Blood is made of two parts: blood cells and plasma. Main Functions.
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Website:m-learning.zju.edu.cn Blood LiDongMei may75119@163.com
Overview of Blood • Blood is a fluid connective tissue. • Its total volume is about 5 liters. • It has many functions. • Blood is made of two parts: blood cells and plasma.
Main Functions • Transport of nutrients and oxygen to cells. • Transport of wastes and carbon dioxide away from cells. • Delivery of hormones and other regulatory substances to and from cells and tissues. • Maintenance of homeostasis. • Transport of humoral agent and cells of the immune system.
Plasma • Its main component is water. • Plasma proteins (albumin, globulins, fibrinogen) • Other solutes
What do blood cells include? • Erythrocytes neutrophils granulocytes eosinophils • Leukocytes basophils agranulocytes lymphocytes monocytes • Platelets
Erythrocytes(E, RBC) • No nucleus, no organelles • Average diameter 7.2μm • Packed with protein hemoglobin(Hb). • biconcave disks. • Quite flexible. • Function: oxygen and carbon dioxide transporting
Reticulocytes • The immature form in which erythrocytes are released into the circulation fromthe bone marrow. • Blue net or granules , ribosomes • Lower concentration of Hb • Final maturation occurs within 24~48 hours. • Less than 1% of circulating RBC.
Leukocytes-granulocytes • Possess two types of granules: specific granules and azurophilic granules. • Granulocytes have nuclei with two or more lobes. • Include the neutrophils, eosinophils, and basophils.
Neutrophils • 60~70% of the leukocyte count • 12~15 um in diameter • Spherical, with a nucleus consisting of two to five lobes. • Neutrophil cytoplasm is lightly eosinophilic and contains two types of granules. • Specific granules: more,small,weakpink, contain bactericidal enzymes. • Azurophilic granules: less • The active phagocytes of bacteria and other foreign agents.
Eosinophils • 1~4% of the leukocyte count • 9~12 um in diameter • Nuclei are bilobed. • Their specific granules are distinctive, uniform in size, more, big, red. • Associated with allergic reactions, parasitic infections.
Eosinophils • Specific granules: major basic protein (MBP), eosinophil cationic protein(ECP), eosinophil peroxidase(EPO) and eosinophil-derived neurotoxin (EDN); ----destruct parasites. histaminase, arylsulfatase, collagenase. ----attenuate allergic reactions. • Azurophilic granules: acid hydrolases. ----attenuate allergic reactions.
Basophils • 0~1% of the leukocyte count • Nucleus is divided into irregular lobes. • Specific granules are intensely basophilic and fill the cytoplasm. distributing unevenly. • Participate in anaphylaxis, anticoagulation.
Leukocytes-agranulocytes • Do not have specific granules, but contain azurophilic granules. • The nucleus is round or indented. • Includes lymphocytes and monocytes.
Lymphocytes • 20~40% of the leukocyte count • The spherical cell has a spherical densely stained nucleus with an indentation. • The cytoplasm is scanty, pale basophilic . • All related to immune reactions.
Lymphocytes • According different function, they can be classified B and T cells. They are indistinguishable in conventional blood smears. • According different size, they can be classified small, medium and large Lymphocytes .
Monocytes • 3~10% of the leukocyte count • The largest cells of the leukocytes(up to 20 μmin diameter) . • The nucleus is oval, eccentrically placed. • Precursors of the cells of the mononuclear phagocytotic system.
Platelets • Nonnucleated, cytoplasmic fragments derived from megakaryocytes. • Appearing in clumps in stained blood smears, purple-red colour • Promote blood clotting and help repair gaps in the walls of blood vessels.
Hemopoiesis • Hemopoiesis includes both erythropoiesis and leukopoiesis, as well as thrombopoiesis. • In the adult, erythrocytes,granulocytes, monocytes, and platelets are formed in the red bone marrow; lymphocytes are also formed in the red bone marrow and in the lymphatic tissues.
Monophyletic theory • Pluripotential stem cell (PPSC) differentiate into multipotential myeloid stem cell and multipotential lymphoid stem cell. • Multipotential myeloid stem cell only in bone marrow and give rise to all blood cells other than lymphocytes. • Multipotential lymphoid stem cell in bone marrow and in lymphoid tissues ,give rise to lymphocytes.
Bone Marrow • Red bone marrow lies entirely within the spaces of bone, in the medullary cavity of young long bones and the spaces of spongy bone. • Bone marrow not active in blood cell formation contains predominately adipose cells, giving it the appearance of adipose tissue.
Summary • What is plasma? • What do blood cells include? • What is the characteristics of each kind of blood cells?