Blood and Blood Vessels.pdf

Blood and Blood Vessels 18/10/23, 2:53 PM Blood and Blood Vessels Blood • Can be separated by spinning in a centrifuge • Components: erythrocytes ~45%, buffy coat (leukocytes and platelets) <1%, plasma ~55% ◦ Plasma has clotting factors ◦ Clotting factors removed → serum Erythrocytes (RBCs) • Bico...

Blood and Blood Vessels 18/10/23, 2:53 PM Blood and Blood Vessels Blood • Can be separated by spinning in a centrifuge • Components: erythrocytes ~45%, buffy coat (leukocytes and platelets) <1%, plasma ~55% ◦ Plasma has clotting factors ◦ Clotting factors removed → serum Erythrocytes (RBCs) • Biconcave discs around 7µm in diameter • No nucleus or organelles (when mature) • Network of flexible cytoskeletal elements White blood cells Granulocytes Neutrophils • • • 40-75% of WBCs Phagocytes (when activated) Single, multi-lobed nucleus Eosinophils • • • 5% of WBCs Acidic granules that stain red, and a bi-lobed nucleus Granules contain hydrolytic enzymes - inflammation Basophils • • • 5% of WBCs Basic granules that stain purple/blue, and a bi-lobed nucleus Effector cells in allergic reactions Agranulocytes Monocytes • • • 1-5% of WBCs Precursors of tissue macrophages (phagocytes) Large, kidney bean-shaped nucleus Lymphocytes • 20-50% of WBCs https://galvanized-borogovia-4fa.notion.site/Blood-and-Blood-Vessels-4a3f3a69a6b348cba5b7228080f29aaf Page 1 of 3 Blood and Blood Vessels 18/10/23, 2:53 PM • • • Small spherical nucleus and basophilic (blue) cytoplasm B cells: give rise to antibody secreting plasma cells T cells: differentiate in thymus, many defensive functions Platelets • Cell fragments that have a key role in haemostasis Blood vessels Structure of arteries • Tunica intima: single layer of squamous epithelial cells (endothelium) supported by a basal lamina and a thin layer of connective tissue • • Tunica media: predominantly made up of smooth muscle Tunica adventitia: made up of supporting connective tissue Arteriole • 1 or 2 layers of smooth muscle in tunica media, almost no adventitia Capillaries • • Endothelial cells and a basal lamina 3 types: ◦ ◦ ◦ Continuous: no pores Fenestrated: small pores Discontinuous: large gaps Venules • Postcapillary venules: endothelium and thin layer of connective tissue https://galvanized-borogovia-4fa.notion.site/Blood-and-Blood-Vessels-4a3f3a69a6b348cba5b7228080f29aaf Page 2 of 3 Blood and Blood Vessels 18/10/23, 2:53 PM • Venules: intermittent smooth muscle in tunica media Veins • Tunica intima, a thin, continuous tunica media and a tunica adventitia https://galvanized-borogovia-4fa.notion.site/Blood-and-Blood-Vessels-4a3f3a69a6b348cba5b7228080f29aaf Page 3 of 3