Chapter 22 Lymphatic Bio 211 lab

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Lymphocyte Circulation – Fluid from blood enters interstitial fluid through capillaries – (Excess interstitial) fluid returned to venous blood through lymphatic vessels Lymph = interstitial fluid that has entered a lymphatic vessel Often contains ___________, lymphocytes and ____________.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Lymphatic Vessels – Are vessels that carry lymph – Lymphoid system begins with smallest vessels Lymphatic capillaries (terminal lymphatics)

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Lymphatic Capillaries – Differ from blood capillaries in 4 ways 1.Start as pockets rather than tubes 2.Have larger diameters 3.Have thinner walls 4.Flat or irregular in section

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Figure 22–2a Lymphoid Capillaries.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Lymphatic Capillaries – Endothelial cells loosely bound together with overlap – Overlap acts as one-way ________ Allows fluids, solutes, lymphocytes, viruses, and bacteria to enter Prevents return to intercellular space

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Lymph Flow – From lymphatic capillaries to larger lymphatic vessels containing valves – Lymphatic vessels travel beside ___________ Lacteals – Are special lymphatic capillaries in small intestine – Transport __________ from digestive tract

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Figure 22–3 Lymphatic Vessels and Valves.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Figure 22–4 The Relationship between the Lymphatic Ducts and the Venous System.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Structures of Body Defenses Lymphedema – Blockage of lymph drainage from a body limb – Causes severe swelling – Interferes with immune system function Lymphocytes – Make up 20–30% of circulating leukocytes – Most are stored, not circulating

Refer to Collection of Anatomy Images for additional lymphatic structures (pp , 71).