Chapter 6 The Lymphatic and Immune Systems

The Lymphatic System Works closely with the immune system to protect and maintain the health of the body Functions (3 primary) 1.Absorbing fats and fat soluble vitamins from the small intestine 2.Removes waste from the tissues 3.Provides assistance to the immune system

Absorption of Fats and Fat-soluble Vitamins Food is digested in the small intestine where nutrients, fats and fat-soluble vitamins are absorbed The villi are small finger-like projections that line the small intestine, which contain blood vessels and lacteals

Blood vessels in the villi absorb most of the nutrients from the digested food directly into the bloodstream Fats and fat-soluble vitamins (Vitamins A,D,K, & E)that cannot be absorbed into the bloodstream are absorbed by the lacteals of the lymphatic system

Waste Removal from the Tissues The lymphatic system removes waste products and excess fluids created by the cells. It also destroys pathogens and takes away foreign substances that are present in the tissues

Cooperating with the Immune System The lymph nodes work closely with the immune system to protect the body against invading microorganisms and diseases.

Major Structures of the Lymphatic System Lymph Lymphatic vessels and ducts Lymph nodes

Lymphatic Circulation (the secondary circulatory system) Transports lymph from tissues throughout the body and eventually returns this fluid to the veins So…what is lymph? Are you otterly confused?

Lymph Clear, watery fluid that transports waste products and proteins out of the spaces between the cells of the body tissues (interstitial fluid) Also destroys bacteria or other pathogens that are present in the tissues

Interstitial Fluid and the Creation of Lymph… Plasma from arterial blood that flows out of the capillaries into the spaces between the cells. Transports nutrients, oxygen, and hormones to the cells 90% of this fluid is reabsorbed by the capillaries and returned to venous circulation The remaining 10% not reabsorbed becomes lymph, which is transported by the lymphatic vessels and is filtered by lymph nodes located along those vessels

Mary, Mary, quite contrary How does your lymph fluid flow? Lymph flows from the lymphatic capillaries into the progressively larger lymphatic vessels – Lymphatic vessels have valves to prevent the backflow of lymph just like veins These vessels eventually joint together to form 2 ducts Each duct is responsible for draining a specific region of the body

Right Lymphatic duct Collects lymph from the right side of the head and neck, and the upper right quadrant of the body and right arm empties into the right subclavian vein Thoracic duct The largest lymphatic vessel Collects lymph from the left side of the head and neck, the upper left quadrant of the trunk, the left arm, and the entire lower portion of the trunk and both legs Empties into the left subclavian vein Keep in mind…unlike the cardiovascular system, this is a closed circuit!

Lymph Nodes Small bean shaped structures that contain specialized cells called lymphocytes that are capable of destroying pathogens Unfiltered lymph flows into the nodes, where the lymphocytes destroy harmful substances such as bacteria, viruses, and malignant cells

lymph nodes are scattered throughout the entire body along the larger lymphatic vessels Approximately half of the nodes are in the abdomen 3 major groups of nodes: Cervical lymph nodes – located on the sides of the (?) Axillary lymph nodes – located in the (?) Inguinal lymph nodes – located in the (?) area

Additional lymphatic structures Tonsils Thymus Spleen Lacteals (where are these again? What are they for?) Peyer’s patches The Vermiform appendix (AKA…the appendix) Lymphocytes (Specialized white blood cells) While these structures are made up of lymphoid tissue, their primary roles are in conjunction with the immune system!

Tonsils... 3 masses of lymphoid tissue form a protective ring around the back of the nose and upper throat Play an important role in the immune system by preventing pathogens from entering the body (especially the lungs) from the nose and mouth Adenoids – located in the nasopharynx Palatine tonsils – locate on the right and left sides of the throat (these are the ones you typically see) Lingual tonsils- located at the base of the tongue

Thymus Located superior to the heart While made largely of lymphoid tissue, it is an endocrine gland that assists the immune system. Produces hormones that “mature” T lymphocytes (we will revisit the thymus in Chapter 13)

Peyer’s Patches & the Vermiform Appendix Consist of lymphoid tissue and work with the immune system to protect against the entry of pathogens through the digestive tract Peyer’s patches – located on the walls of the ileum (last section of the small intestine) generate lymphocytes to help protect from infection due to pathogens Vermiform appendix – hangs from the lower portion of the cecum (1 st section of the large intestine). Thought to be a vestigial organ and while once believed to be useless, recent research indicates it may play an important role in the immune system

Another use for the Appendix… The appendix can be detached from the cecum and surgically secured to the bladder. The free end is then brought to the surface of the skin to create an opening for catheterization. This Mitrofanoff procedure is often times used for patients with neurogenic bladder.

The Spleen Located in the (LUQ) of the abdomen, inferior to the diaphragm and posterior to the stomach Filters microorganisms and other foreign material from the blood Forms lymphocytes and monocytes Has hemolytic function of destroying worn-out RBC’s and releasing hemoglobin for reuse Also stores extra erythrocytes (?) and keeps the balance between these cells and the plasma of the blood “Lemme’ spleen..no, there is to much. Lemme’ sum up.”

The surgical removal of the spleen, also known as a (?) is most often performed to treat a ruptured spleen (?). Often caused by abdominal trauma, spleen injury can cause excessive bleeding from the spleen (?) This procedure may also be used to treat other conditions, including an enlarged spleen (?), which can be caused by injury, infectious diseases such as mononucleosis, or an abnormally functioning immune system. Pathology and Diagnostic Procedures of the Lymphatic System

Any disease process affecting a lymph node or lymph nodes is known as (?). Swollen glands are an inflammation of the lymph nodes, also known as (?) and is frequently an indication of the presence of an infection. A benign tumor formed by an abnormal collection of lymphatic vessels due to a congenital malformation of the lymphatic system is called a (?).

Primary lymphedema - a hereditary disorder due to a malformation of the lymphatic system which most commonly causes swelling in the feet and legs. Secondary lymphedema – caused by damage to the lymphatic system that most commonly causes swelling in the limb nearest to the damaged lymphatic vessels. Cancer treatments (surgery, chemo, and/or radiation) and trauma (burns, injury, and scarring) are the most frequent cause of this condition. Ex. Elephantitis, due to the parasitic filarial worms blocking the lymph vessels. Pathology and Diagnostic Procedures of the Lymphatic System This condition is swelling due to an abnormal accumulation of lymph fluid within the tissues and is known as (?) There are 2 classifications of this condition…