1. The Lymphatic System

2. 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

3. 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

4. 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

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

6. 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

7. 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

8. 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

9. 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

10. Diapedesis
Phagocytosis

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

12. 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

13. 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!

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

15. 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

16. 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

17. 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.