Lymphatic System Introduction Components Lymph fluid Lymphatic vessels

Lymphatic System

Introduction – Components: • Lymph fluid • Lymphatic vessels • Lymph nodes and organs – Functions: • Drains excess interstitial fluid – return this fluid to the blood stream • Transport fats from the digestive tract to the bloodstream • Immune responses

The Lymphatic System

Lymphatics – Originate as lymph capillaries • Allow fluid to enter but not exit through one way valves – Capillaries unite to form larger vessels • Resemble veins in structure • Connect to lymph nodes at various intervals – Lymphatics ultimately deliver lymph into 2 main channels • Right lymphatic duct – Drains right side of head & neck, right arm, right thorax – Empties into the right subclavian vein • Thoracic duct – Drains the rest of the body – Empties into the left subclavian vein

Lymph Capillaries

Lymphatic Vessels

Main Channels of Lymphatics

Lymph Nodes – Oval structures located along lymphatics – Enclosed by a fibrous capsule – Lymph enters nodes through afferent lymphatics, flows through sinuses, exits through efferent lymphatic – Contain high concentrations of immune system cells (white blood cells) • Memory immune cells detect foreign molecules and are activated

Lymph Node

Immune responses • Upon encountering a foreign molecules memory cells are activated and create an immune response – The immune response involves cells not bound to the lymph nodes which then replicate and move throughout the body via the lymphatic/cardiovascular systems.

Tonsils – Multiple groups of large lymphatic nodules – Location – mucous membrane of the oral and pharyngeal cavities – Palatine tonsils • Posterior-lateral walls of the oropharynx – Pharyngeal tonsil • Posterior wall of nasopharynx – Lingual tonsils • Base of tongue

Tonsils

Spleen – Largest lymphatic organ • Many of the same functions as lymph nodes – Located between the stomach & diaphragm – Additional functions • Removes worn out/defective/ruptured blood cells (RBC) • Storage of platelets • Production of new RBC

Spleen

Thymus Gland – Located behind the sternum – The capsule divides it into 2 lobes – Function • Differentiation and maturation of one type of lymphocytes (type of white blood cells)

Thymus Gland

Autoimmune diseases • Autoimmune – self immunity – Immune cells start to recognize your own cells as being foreign molecules. – Can result in a number of different diseases depending on what is now considered to be foreign

Autoimmune diseases • Type I diabetes (juvenile diabetes) – Beta cells which produce insulin are targeted as foreign and destroyed by the immune system. – Little to no insulin is produced – This prevents uptake of glucose (sugar) by tissues – Glucose is our main source of energy.

Rheumatoid Arthritis • Pain swelling and stiffness in the joints – Typically in the fingers and wrists – Can affect other parts of the body such as eyes and lungs • Exact cause is unknown

Sarcoidosis • Commonly referred to in the TV show House, not sure why. • Inflammation of the lungs, skin or lymph nodes

Narcolepsy • Recent studies suggest this may be an autoimmune disease – Uncontrolled sleep cycles • May last a few seconds to several minutes long.