General Physiology - Lymphatic System PDF

UNIVERSITY OF THE VISAYAS - GULLAS “GENERAL PHYSIOLOGY LECTURE” Prepared by: Mr. Rommeljun Solijon Datiles  Defending-Test “GENERAL PHYSIOLOGY MYSTERY” Guess me? You are CORRECT! Spleen Guess me? You are CORRECT! Lymph Nodes Guess me?  You are CORRECT! Lymphe...

UNIVERSITY OF THE VISAYAS - GULLAS “GENERAL PHYSIOLOGY LECTURE” Prepared by: Mr. Rommeljun Solijon Datiles  Defending-Test “GENERAL PHYSIOLOGY MYSTERY” Guess me? You are CORRECT! Spleen Guess me? You are CORRECT! Lymph Nodes Guess me?  You are CORRECT! Lymphedema (Filariasis) - Wuchereria Bancrofti Guess me? You are CORRECT! Lymphoma Guess me? You are CORRECT! Tonsilitis Guess me? You are CORRECT! HIV/AIDS Guess me? You are CORRECT! Macrophage Guess me?  You are CORRECT! White Blood Cells (Leukocytes) Guess me? You are CORRECT! Thymus Guess me? You are CORRECT! Immune System LEARNING OBJECTIVES At the end of the lesson, the student should be able to: 1. explain the immune and lymphatic systems functions and its parts; 2. describe the different functions of the lymph organs; and 3. appreciate the significant role of immune system in humans healthy lifestyle IMMUNE AND LYMPHATIC SYSTEM “The eye attempts to limit local immune and inflammatory responses to preserve vision. This phenomenon, known as ocular immune privilege, is mediated by a combination of local and systemic mechanisms. While immune privilege is believed to protect the eye from day-to-day inflammatory insults, it is not absolute and its mechanisms are still incompletely understood.”  To bathe the cells of the body and provide nutrients, nearly 20 liters of blood plasma is filtered through capillaries every day. A large proportion of this tissue fluid moves directly to the veins, and back to the heart. However, the lymphatic system processes nearly 20% of this fluid, which escapes from capillaries and cells.  The lymphatic system consists of open-ended vessels, lymph nodes, and organs such as the tonsils, spleen, and thymus. Unlike the blood vascular system, lymphatic circulation is not a closed loop. It creates a one-directional flow of lymph towards the heart. Lymph reenters the cardiovascular system at subclavian veins situated near the neck. What is Lymphatic System? Immune system: The lymphatic system is a part of the immune system. The immune system’s role is to protect the body from disease and other harmful substances. It is continually working to build up a defense against germs. As a part of the immune system, the lymphatic system plays an important role. As it moves lymph throughout your body, it identifies, filters out, and reacts to foreign substances by creating antibodies. How does Lymphatic System work? The lymphatic system includes tissues, vessels, and organs that move fluid throughout the body and fight infection. When excess plasma (the liquid portion of blood) collects in your body’s tissues, the lymphatic system collects it and moves it back into your bloodstream. How does Lymphatic System work? q Fighting Infection Starts With Lymph Lymph is made up of more than plasma. The excess fluid that drains from your cells and tissues is made of many substances, including: Damaged cells Cancer cells Bacteria Viruses Protein Fats Minerals Nutrients How does Lymphatic System work? There are two major functions of the lymphatic system. The first is to drain interstitial fluid and maintain the fluid balance between blood and tissue fluid. The second is to fight infection and mediate immunity. How does Lymphatic System work? Fluid Homeostasis Lymphatic circulation is necessary for homeostasis since it maintains the fluid balance between tissues and blood vessels. This role becomes apparent when there is an injury to a lymph node. Water retention, also known as lymphedema, in a limb is one of the side effects of a blockage within a lymphatic vessel or node. This is particularly true after cancer treatment since surgery, radiation therapy, and chemotherapy can injure this intricate network. Lymphedema can be mild or severe, sometimes even leading to the thickening of the skin and compromised immunity. How does Lymphatic System work? Immunity Lymphocytes are a group of white blood cells that are found in the nodes and organs of the lymphatic system. They include B-cells, T-cells, and natural killer cells. Lymphatic vessels non-specifically collect the fluid surrounding tissues. This means that the lymphatic system often carries pathogens from different parts of the body towards lymph nodes. How does Lymphatic System work? 1- Lymph and Tissue Fluid Tissue fluid is a fluid surrounding the cells of a tissue. It is leaked plasma - Plasma from the blood capillaries move to the tissue through gaps in the walls and become tissue fluid. Tissue fluid play an important role in substance exchange between blood and cells. It supplies cells with O2 and nutrients and takes away waste products including CO2. 1- Lymph and Tissue Fluid At the end of the capillary bed, the tissue fluid leaks back into the blood, and becomes plasma again, but not all of it. A little of it is absorbed by the lymphatic vessel and becomes lymph. 1- Lymph and Tissue Fluid The lymphatic vessel takes the lymph to the blood stream by secreting them in a vein near Subclavian vein the heart, called subclavian vein. Subclavian artery 1- Lymph and Tissue Fluid The lymph in the lymphatic vessels are moved along by the squeeze of muscles against the vessel, just like some veins. 1- Lymph and Tissue Fluid The return of tissue fluid to the blood in the form of lymph fluid prevents fluid built up in the tissue. 2- Production of Lymphocytes The lymphatic system is an important component of the immune system, which fights infection. One group of white blood cells, the lymphocytes, are made in lymph glands such as the tonsils, adenoids and spleen. The glands become more active during an infection because they are producing and releasing large numbers of lymphocytes. 2- Production of Lymphocytes The lymphocytes can live and multiply in the lymphatic system, where they attack and destroy foreign organisms. Lymphoid tissue scattered throughout the body filters out pathogens, other foreign matter and cellular debris in body fluids. 3- The absorption of fatty acids and glycerol from the small intestine Following the chemical and mechanical breakdown of food in the digestive tract, most nutrients are absorbed into the blood through intestinal capillaries. Many digested fats, however, are too large to enter the blood capillaries and are instead absorbed into lymphatic capillaries by intestinal lacteals. Fats are added to the blood when lymph joins the bloodstream. From Your Tissues to Your Lymph Nodes Lymphatic vessels are tiny blood vessels and tubes that move lymph from tissues to lymph nodes, which filter out damaged and cancer-causing cells. In addition, the lymph nodes create immune cells to fight infection and other harmful substances it detects in the fluid Through Lymphatic Vessels to Collecting Ducts Once the lymph passes through the lymph nodes, it continues through the lymphatic vessels until it reaches the collecting ducts. There, it empties before returning the filtered lymph to your bloodstream.4 Lymphatic System Organs In addition to lymph, lymphatic vessels, lymph nodes, and collecting ducts, many organs are involved in the lymphatic system. Primary lymphatic organs produce immune cells called lymphocytes, while secondary lymphatic organs fight off germs and harmful substances. Primary lymphatic organs include: o Bone marrow: This sponge-like tissue is located inside your bones. Here, immune cells grow and multiply. Primary lymphatic organs include: o Thymus: This gland is located behind the breastbone. Immune cells, called T-cells, mature in the thymus. T-cell maturation is facilitated by the epithelial cells of the thymus when they present antigens to these evolving lymphocytes. Secondary lymphatic organs include: o Spleen: This organ sits in the left upper corner of the abdomen. The spleen stores immune cells and platelets and break down red blood cells. -Plays a role in the lymphatic system, clearing bacteria and other pathogens that have been coated with antibodies. Secondary lymphatic organs include: o Tonsils: These are located in the throat. They stop germs from entering the body through the mouth and nose. They also use white blood cells to fight infection. -The makes the tonsils the first line of defense against ingested and inhaled pathogens. Secondary lymphatic organs include: o Lymph Nodes: These bean-shaped glands are located throughout the body, including the armpits, groin, and neck. They filter lymph and create antibodies. -An infection causes the lymph nodes to enlarge. Secondary lymphatic organs include: o Lymph Vessels: Lymph vessels have very thin walls. They have an inner layer of endothelial cells and a layer of smooth muscles and valves that prevent the backward flow of fluid. Lymph vessels are attached to surrounding tissue through connective tissues called adventitia. Secondary lymphatic organs include: o Mucous membranes: These are located through your respiratory and digestive systems. The membranes in your bowel wall, appendix, respiratory and urinary tracts, and vagina fight off foreign substances and infections. Lymphatic Diseases When the lymphatic system malfunctions, some diseases or disorders can occur. These complications can range from infections to blockages to cancer. Blockage o A blockage in the lymphatic system often leads to fluid buildup. o In addition, blockages can result from scar tissue from surgery, injury, or infection. Examples of disorders associated with blockage include: Blockage o Lymphedema: This is an accumulation of lymph fluid in the body. It most commonly occurs in the arms and legs. It ranges from mild to very painful. It is common in people who have received cancer treatment. Blockage o Lymphatic Filariasis: Also called elephantiasis, this infection is caused by a parasite that infects the body through a mosquito bite. The worms invade the lymphatic system, resulting in a blocked lymphatic system and swelling, pain, and disfigurement. Inflammation and Infection o Lymphadenopathy This is the medical term for swollen lymph nodes. Lymph nodes, themselves, can become infected, but swollen lymph nodes also indicate an infection within the body. Some infections that commonly result in enlarged lymph nodes include mononucleosis, strep throat, HIV, and skin infections. Lymphoma (cancer of the lymph nodes) and leukemia may also be associated with lymphadenopathy. Inflammation and Infection o Lymphadenitis This term refers to an infection of the lymph node(s). This infection often occurs due to germs that spread through the lymphatic system from one part of the body to the lymph nodes. Inflammation and Infection o Lymphangitis Inflammation of the lymph vessels, which may result from some bacterial infections. Inflammation and Infection o Lymphocytosis This condition is a higher than normal amount of lymphocytes, often a result of your body dealing with infection or inflammation. Inflammation and Infection o Castleman Disease This condition is an overgrowth of cells in the lymphatic system. An infection causes it. It may result in a full feeling in the abdomen, lumps in the armpits, groin, neck, and weight loss. Congenital or Genetic Conditions o Intestinal Lymphangiectasia This occurs when there is a loss of lymph tissue in the intestines. Most often, children are diagnosed before age 3. Congenital or Genetic Conditions o Lymphangioma This is a malformation in the vascular lymphatic system, includes cystic hygroma. Congenital or Genetic Conditions o Lymphangioleiomyomatosis This is a rare lung disease where cells grow out of control in the lymph nodes, lungs, and kidneys. Congenital or Genetic Conditions o Autoimmune Lymphoproliferative This genetic disorder of the lymph nodes, liver, and spleen results in high lymphocytes. Cancer o Cancer of the lymphatic system is called lymphoma. o It occurs when lymphocytes multiply in the body uncontrollably. There are two categories of lymphoma: Hodgkin lymphoma and non- Hodgkin lymphoma. Caring for Your Lymphatic System o Your exposure to certain things can impact the lymphatic system. Therefore, there are some ways that you can support a healthy lymphatic system, including: