Chapter 22 Lymphatic System and Circulation Lecture 4 PDF
Document Details
Uploaded by ClearerProtactinium
Tags
Summary
This document provides lecture notes on the lymphatic system's anatomy, organization, and lymph circulation. It discusses the components of the lymphatic system, including lymph, lymphatic vessels, white blood cells, and lymph tissues/organs. It also covers the functions of the lymphatic system, including preventing and fighting infections, producing lymphocytes, and returning fluids and solutes to the blood.
Full Transcript
1 Part Only – An Overview of the Lymphatic System’s Anatomy, Organization, & Lymph Circulation. We have all those immune cells, now what? Why was this series “Immunity AND Lymphatics”? What are lymphatic vessels and how does this differ from the “circulatory system?” Cells, tissues, + organs t...
1 Part Only – An Overview of the Lymphatic System’s Anatomy, Organization, & Lymph Circulation. We have all those immune cells, now what? Why was this series “Immunity AND Lymphatics”? What are lymphatic vessels and how does this differ from the “circulatory system?” Cells, tissues, + organs that defend against pathogens (disease), and respond to wastes and toxins. 4 Main Components: 1) Lymph – fluid in vessels; ◦ similar to plasma but no plasma proteins. 2) Lymphatic vessels (lymphatics) – carry lymph from tissue to veins. 3) Specialized WBCs: ◦ lympho- + phagocytes, etc. 4) Lymph tissues + organs ◦ Ex: Lymph nodes, spleen + thymus 1) Prevents & fights infections to maintain health. 2) Produce, maintain, and distribute lymphocytes. ◦ T-cells, B-cells, and NK-cells; produced? ◦ Red bone marrow, mature at organs (bone + thymus), and reside in lymphoid tissues (spleen + tonsils). 3) Return fluids + solutes from interstitial fluid (IF) to blood ◦ “Indirect filtration of blood” 4) Distribute hormones, nutrients, and waste products into general circulation. ◦ An alternative route if unable to enter circulation directly. Fluids and lymphocytes leave plasma, enter IF, enter lymph, and drain into venous system ◦ Via subclavian veins – 1 way flow! Fluid from IF first enter via smallest lymph vessels? ◦ Lymphatic capillaries; ◦ once in lymph, no movement back to IF. Tissue fluid Tissue cell Blood Lymphatic capillaries capillaries (a) Relationship between a capillary bed of the blood vascular system and lymphatic capillaries. The IF to indirectly filter blood. Lymph. Cap. differences to blood caps:(22.2) ◦ 1) Start as pockets (blind ends) w/in tissues rather than continuous tubes. ◦ 2) Have larger diameters. ◦ 3) Have thinner walls, very permeable endothelium w/incomplete/absent basement membrane. Cell overlap forming minivalves. Capillaries of small intestine special for transporting lipids from digestive tract ◦ Lacteals. larger Collecting vessels. ◦ Similar to veins, thinner walled, more internal valves due to low pressure Collecting vessels converge and form lymphatic trunks – large collecting sites. (22.4) Drain “purified” lymph into subclavian veins. ◦ Where trunks empty. 1) Right lymphatic duct collects lymph from right side of body superior to diaphragm. 2) Thoracic duct collect lymph inferior of diaphragm and left side superior to diaphragm. Lymphoid nodules = areas of densely packed, unencapsulated lymphocytes w/in areolar CT. ◦ No clear line of separation from surrounding tissue (although easy to see). Each nodule contains a germinal center which lymphocyte division occurs. We will explore the MALT or Mucosa-associated lymphoid tissues. ◦ Ex: tonsils, Peyer patchs, and appendix. Lymphatic Organs – Lymph nodes, spleen, and thymus – are encapsulated organs that rely on blood supplies to enter and exit the organ. We will compare and contrast both next lecture!
