Waste Disposal and Immunity The Lymphatic System Waste Disposal and Immunity

What is the lymphatic system? The lymphatic system is a network similar to the circulatory system, consisting of vessels, nodes, ducts and organs.

Vocabulary you need to understand Antibody – a specialised protein that is made to destroy a specific pathogen Antigen – any substance that the body recognises as foreign Lymphocyte – a type of white blood cell involved in immunity Macrophage – a scavenger cell that engulfs and destroys microbes

Vocabulary you need to understand Microbe (micro-organism) – an organism that is too small to be seen by the naked eye Pathogen – a disease caused by a microorganism Phagocyte – a cell that is able to engulf and digest microbes

What is the lymphatic system? The lymphatic system contains immune cells called lymphocytes, which protect the body against antigens (viruses, bacteria, etc.) that invade the body.

Functions of the Lymphatic system to collect and return interstitial fluid, including plasma protein to the blood and thus help maintain fluid balance to defend the body against disease by producing lymphocytes to absorb lipids from the intestine and transport them to the blood 
Source jdaross.mcmail.net

Lymph Organs Include the bone marrow, lymph nodes, spleen, and thymus. Precursor cells in the bone marrow produce lymphocytes. B-lymphocytes (B-cells) mature in the bone marrow. T-lymphocytes (T-cells) mature in the thymus gland. Besides providing a home for lymphocytes (B-cells and T-cells), the ducts of the lymphatic system provide transportation for proteins, fats, and other substances in a medium called lymph.

Lymph nodes Human lymph nodes are bean-shaped and range in size from a few millimeters to about 1-2 cm in their normal state.

 White blood cells are located within honeycomb structures of the lymph nodes. Lymph nodes are enlarged when the body is infected due to enhanced production of some cells and division of activated T and B cells.
 They may become enlarged due to a tumor or infection

Lymph fluid Lymph means clear water and it is basically the fluid and protein that has been squeezed out of the blood (i.e. blood plasma). The lymph is drained from the tissue in microscopic blind-ended vessels called lymph capillaries.

Lymph Vessels Are made up of lymph vessels and lymph capillaries. These lymph capillaries are very permeable, and because they are not pressurized the lymph fluid can drain easily from the tissue into the lymph capillaries. As with the blood network the lymph vessels form a network throughout the body, unlike the blood the lymph system is a one-way street draining lymph from the tissue and returning it to the blood.

Task Using your notes from the lesson on anatomical positioning try to work out the names of the lymph nodes in the following areas; Underarm Groin Behind the knee Back of the head In front of the ear In the neck

Task answers Underarm – Auxillary Groin – Inguinal Behind the knee – Popliteal Back of the head – Occipital In front of the ear – Pre Auricular In the neck – Sub Mandibular