The Lymphatic SystemThe Lymphatic System

What Is the Lymphatic System?What Is the Lymphatic System? A system of thin tubes that A system of thin tubes that

run through the body called run through the body called lymph vesselslymph vessels

The liquid that is inside The liquid that is inside these vessels is called these vessels is called lymphlymph

It comes from plasma that It comes from plasma that fills empty spaces between fills empty spaces between blood vessels, which is blood vessels, which is called interstitial fluid, and called interstitial fluid, and is collected by the lymphis collected by the lymph vessels to make lymphvessels to make lymph

Lymph Nodes (or Glands)Lymph Nodes (or Glands) Small round Small round

structures found structures found along the larger along the larger lymph vesselslymph vessels

Found in 4 areas:Found in 4 areas:– GroinGroin– NeckNeck– AbdomenAbdomen– ArmpitsArmpits

They make white They make white blood cellsblood cells

Organs That are Part of the Organs That are Part of the Lymphatic System:Lymphatic System:

Spleen (abdomen)Spleen (abdomen) Tonsils (throat)Tonsils (throat) Thymus (chest)Thymus (chest) Adenoids (back of Adenoids (back of

nose)nose)All these organs are All these organs are

filled with white filled with white blood cells that blood cells that filter bloodfilter blood and and collect harmful collect harmful bacteria and bacteria and virusesviruses

What Does the Lymphatic System What Does the Lymphatic System Do?Do?

1.1. Drains fluid back to the Drains fluid back to the bloodstream from the tissuesbloodstream from the tissues

2.2. Filters lymphFilters lymph

3.3. Filters the bloodFilters the blood

4.4. Fights infectionsFights infections

Draining Fluid Back to the BloodDraining Fluid Back to the Blood

Plasma leaks out of Plasma leaks out of capillaries into the capillaries into the tissues to give food to tissues to give food to the cellsthe cells

The leaked plasma is The leaked plasma is called interstitial fluidcalled interstitial fluid

This fluid gets into This fluid gets into the lymph vessels the lymph vessels where it is eventually where it is eventually returned to the bloodreturned to the blood

It carries with it waste It carries with it waste from the cells from the cells

Filtering LymphFiltering Lymph

The lymph is filtered by the lymph The lymph is filtered by the lymph nodesnodes

In the lymph nodes are filled with In the lymph nodes are filled with white blood cells that attack bacteria white blood cells that attack bacteria and virusesand viruses

Cancer cells often end up hereCancer cells often end up here

Filtering BloodFiltering Blood

The spleen filters the bloodThe spleen filters the blood– It destroys old worn out red blood cellsIt destroys old worn out red blood cells– It has white blood cells that attack viruses and It has white blood cells that attack viruses and

bacteriabacteria

Non-specific immunityNon-specific immunityThis is the body’s ability to protect itself against This is the body’s ability to protect itself against

a wide range of antigens without using a wide range of antigens without using antibodies:antibodies:

White blood cells are made in lymph nodesWhite blood cells are made in lymph nodes Your lymph nodes or glands become swollen Your lymph nodes or glands become swollen

when you are sick because they are working when you are sick because they are working to make cells to fight infectionsto make cells to fight infections

White blood cells move out of capillaries by White blood cells move out of capillaries by diapedesis and enter the lymphatic system to diapedesis and enter the lymphatic system to reach the site of infectionreach the site of infection

Once they reach the pathogen they surround Once they reach the pathogen they surround and destroy it through phagocytosisand destroy it through phagocytosis

Diapedesis

Phagocytosis

When the Lymphatic System Goes When the Lymphatic System Goes WrongWrong

ElephantiasisElephantiasis

-Happens when the -Happens when the lymphatic vessels lymphatic vessels are blocked due to are blocked due to a parasitea parasite

When the Lymphatic System Goes When the Lymphatic System Goes WrongWrong

LymphedemaLymphedema

-Happens when the -Happens when the lymphatic vessels lymphatic vessels are blockedare blocked

-This may be caused -This may be caused by an injury to the by an injury to the lymph vessels or it lymph vessels or it may be inheritedmay 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 Class Assignment – Answer the following questions on loose leaf following questions on loose leaf

(due at the end of the class)(due at the end of the class)1.1. Describe the lymphatic system in a Describe the lymphatic system in a

paragraph.paragraph.2.2. What are lymph nodes? What are lymph nodes? 3.3. What organs are part of the lymph What organs are part of the lymph

system?system?4.4. Why do your glands get swollen when Why do your glands get swollen when

you are sick?you are sick?5.5. What are the functions of the lymphatic What are the functions of the lymphatic

system. Describe fully in paragraph system. Describe fully in paragraph form.form.