Download - Blood
Blood
Blood• Blood is a fluid connective tissue that
circulate through the cardiovascular system
• Conveying nutrients and oxygen to cells
• Carrying wastes and carbon dioxide away from cells
• Carrying hormones and other regulatory agents to and from the cells
• Having a major homeostatic role
BLOOD CONSISTS OF:FORMED PLASMA, 55%
ELEMENTS, 45%
which include: which include:
Red blood cells Water
White blood cells Proteins
Blood plateles albumin globulins
fibrinogen
Other solutes
Cells and platelets in circulating blood
Red blood cells (erythrocytes)
• Red blood cells constitute the largest number of cells in the blood
(4,5-5,5 mln/mm cub)
• Red blood cells do not have a nucleus
• Red blood cells are specialized for the transport of oxygen and carbon dioxide by means of hemoglobin
White blood cells
White blood cells are motile cells: they leave the circulation and migrate to their site of activity in the connective tissue
Include:
GRANULOCYTES AGRANULOCYTES
Neutrophils Lymphocytes
Eosinophils Monocytes
Basophils
Blood platelets
• Plateles are membrane-bounded, enucleate cytoplasmic fragments of the resident cells of the red bone marrow - megacaryocytes
• Plateles function is blood clotting, clot retraction, and clot dissolution
Hemopoiesis
Origin of connective tissue & blood cells
Prenatal hemopoiesis
• Mesoblastic phase (2-6 weeks of gestation) – within the wall of the yolk sack (umbilical vesicle)
• Hepatic phase (6-38 weeks of gestation) – within the liver of embryo & fetus)
• Splenic phase (12-38 weeks of gestation) – within the spleen of embryo and fetus
• Myeloid phase (from 24 week of gestation through the rest of lifespan) – in the red bone marrow
Postnatal hemopoiesis (myeloid & lymphoid cell lines)
• Stem cells– Pluripotential hemopoietic stem cells (PHSC)– Multipotential hemopoietic stem cells (MHSC)
(colony-forming units: CFU-GEMM + CFU-Ly)
• Progenitor cells – Unipotential cell lines
(colony-forming units: CFU-E, CFU-Meg, CFU-Eo, CFU-Ba, CFU-GMo, CFU-LyT, CFU-LyB)
• Precursor cells
Precursor cells in the formation of erythrocytes and granulocytes