1 / 16

Blood

Blood. 2007. Blood = specialized connective tissue. Cells = 45% of blood Erythrocytes (red blood cells, RBCs) Leukocytes (white blood cells, WBCs) Platelets Extracellular matrix of blood = Plasma; 55% of blood 5-6 Liters total blood volume in adult. Functions of Blood.

raheem
Télécharger la présentation

Blood

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Blood 2007

  2. Blood = specialized connective tissue • Cells = 45% of blood • Erythrocytes (red blood cells, RBCs) • Leukocytes (white blood cells, WBCs) • Platelets • Extracellular matrix of blood = Plasma; 55% of blood • 5-6 Liters total blood volume in adult

  3. Functions of Blood • Gaseous transport – RBCs carry oxygen and carbon dioxide • Transport of metabolites and regulatory molecules (hormones) • Homeostatic regulation of body temperature, osmotic balance • Transport of cells and antibodies for defense and immunity

  4. Erythrocytes • Most numerous blood cells • Transport O2 and CO2 via hemoglobin • Only cell in blood stream that remains in blood stream • Biconcave disk shape provides large surface area relative to volume, 8 mm in diameter • Shape maintained by bendable cytoskeleton • In mammals, no nucleus, mitochondria, ER, ribosomes in mature RBCs. All expelled during development. • 120-day life span; destroyed by macrophages in spleen and bone marrow.

  5. Erythrocytes

  6. Relative Size of Blood Cells

  7. Leukocytes = White Blood Cells • Granulocytes = neutrophils, eosinophils, basophils • Numerous secretory vesicles in cytoplasm • 2 or more lobes to nuclei • Typically short lived (a few days) • Die by apoptosis and scavenged by macrophages • Agranulocytes = lymphocytes and monocytes • Single lobed nuclei • Do NOT have abundant secretory vesicles • Circulate for a few days and then invade tissues and become macrophages • Rounded in shape when circulating, flattened and motile in tissues.

  8. Leukocyte Cell Types Agranulocytes Granulocytes Lymphocyte Basophil Monocyte Neutrophil Eosinophil Platelets

  9. Neutrophils – 60-70% of circulating leukocytes • Multi-lobed nuclei, 3-5 lobes • Main function: phagocytosis and destruction of bacteria • Motile: large numbers exit the blood stream early in response to acute bacterial infections. • Granules contain: lysozyme and other antimicrobial enzymes, collagenase plus others. • In females, the nucleus has a drumstick (Barr body), contains the condensed, inactivated second X chromosome.

  10. Eosinophils – 2-4% of circulating leukocytes • 2-lobed nucleus • Principal function: allergic and inflammatory reactions and parasitic infections • Often found at sites of chronic inflammation, commonly in respiratory or digestives tracts • Counteract the effects of basophils in allergic reaction: secrete histaminase which degrades the histamine secreted by basophils. • Prominent eosinophilic granules (red/pink)

  11. Basophils - <1% circulating leukocytes • Involved in allergic and inflammatory reactions • Bilobed nucleus • Basophilic granules (blue/black stained) obscure the view of the nucleus • Secrete histamine (vasodilation) and heparin (anti-coagulant)

  12. Blood Cells

  13. Lymphocytes – 20-25% circulating leukoctyes • Variable in size, 6-18 mm in diameter • Single, round, heterochromatic nucleus • Agranulocyte • Function in immunity • 2 classes, indistinguishable morphologically • B cells – humoral (antibody-mediated) immune response • T cells – mature in thymus, cell-mediated immune response

  14. Monocytes – 3-8% circulating leukocytes • Largest in size of circulating leukocytes • Large, acentric kidney-shaped nucleus • Agranulocyte • Stay in circulation a few days and then migrate into connective tissue and differentiate into macrophages • As macrophages: phagocytize and destroy dead cells

  15. Platelets (Thrombocytes) • Principal function: blood clotting • Produced by megakaryocytes in bone marrow –bud off cytoplasm to form platelets. • 2 mm in diameter (very small) and anucleate • 10-day life span

  16. Relative #s of Leukocytes Monocyte > Lymphocyte > Eosinophil > Basophil Neutrophil > Platelets

More Related