The Lymphatic System

What Is the Lymphatic System? A system of thin tubes that run through the body called lymph vessels The liquid that is inside these vessels is called lymph It comes from plasma that fills empty spaces between blood vessels, which is called interstitial fluid, and is collected by the lymph vessels to make lymph

Lymph Nodes (or Glands) Small round structures found along the larger lymph vessels Found in 4 areas: Groin Neck Abdomen Armpits They make white blood cells

Organs That are Part of the Lymphatic System: Spleen (abdomen) Tonsils (throat) Thymus (chest) Adenoids (back of nose) All these organs are filled with white blood cells that filter blood and collect harmful bacteria and viruses

What Does the Lymphatic System Do? Drains fluid back to the bloodstream from the tissues Filters lymph Filters the blood Fights infections

Draining Fluid Back to the Blood Plasma leaks out of capillaries into the tissues to give food to the cells The leaked plasma is called interstitial fluid This fluid gets into the lymph vessels where it is eventually returned to the blood It carries with it waste from the cells

Filtering Lymph The lymph is filtered by the lymph nodes In the lymph nodes are filled with white blood cells that attack bacteria and viruses Cancer cells often end up here

Filtering Blood The spleen filters the blood It destroys old worn out red blood cells It has white blood cells that attack viruses and bacteria

Non-specific immunity This is the body’s ability to protect itself against a wide range of antigens without using antibodies: White blood cells are made in lymph nodes Your lymph nodes or glands become swollen when you are sick because they are working to make cells to fight infections White blood cells move out of capillaries by diapedesis and enter the lymphatic system to reach the site of infection Once they reach the pathogen they surround and destroy it through phagocytosis

Diapedesis Phagocytosis

When the Lymphatic System Goes Wrong Elephantiasis -Happens when the lymphatic vessels are blocked due to a parasite

When the Lymphatic System Goes Wrong Lymphedema -Happens when the lymphatic vessels are blocked -This may be caused by an injury to the lymph vessels or it may be inherited

Specific immunity The body’s ability to protect itself against a particular antigen using specific antibodies You can become specifically immune naturally (by being exposed to an infection like chicken pox or whooping cough) or artificially, by being given a vaccine **Vaccines do not cure you of diseases – you need to be vaccinated BEFORE getting sick!

Vaccines Were investigated by Edward Jenner in the 1700s. Later, Pasteur conducted a few experiments on fowl cholera 0ver 100 years later

Vaccine Manufacturing Attenuated vaccines are prepared from living bacteria or viruses. Manufacturers select strains that have lost their power to cause disease to make these Inactivated vaccines are prepared from bacteria or viruses that have been inactivated or killed by chemicals, heat or UV rays Vaccines can also be prepared through genetic manipulation, where scientists replace or remove genes in viruses and bacteria that cause disease Different vaccines can sometimes have different side effects

The Difference between Antibiotics and Vaccines Antibiotics cure disease by killing or injuring bacteria Antibiotics only treat bacterial infections. Antibiotics are useless against viral infections (for example, the common cold) and fungal infections (such as ringworm) There are broad-spectrum and narrow spectrum antibiotics

Class Assignment – Answer the following questions on loose leaf (due at the end of the class) Describe the lymphatic system in a paragraph. What are lymph nodes? What organs are part of the lymph system? Why do your glands get swollen when you are sick? What are the functions of the lymphatic system. Describe fully in paragraph form.