1. LYMPHATIC SYSTEM
HLTAP301A

2. Lymphatic System
Closely connected to the circulatory system as it is mainly a network of capillaries and vessels
Plays an important role in defending the body against disease

3. Lymphatic System Components Lymphatic capillaries Lymphatic vessels
Lymphatic nodes
Lymphatic ducts
Lymph

4. Lymphatic system Body parts also containing lymphatic tissue Tonsils
Thymus gland
Peyer’s patches
spleen

5. Lymphatic System Functions Defence Removal of damaged body tissues
Destruction of cancerous cells

6. Lymphatic System Defence First line of defence
Skin – injury allows bacteria to enter the body
Mucous membrane – vaginal mucosa produces an acidic bacteria which prevents micro-organisms from entering the body
Normal body flora – digestive system contains bacteria in mouth and large bowel
Some body secretions – prevents entry of foreign invaders by liquid flow

7. Lymphatic System Second line of defence
Phagocytic cells – their job is to engulf and destroy invaders
Inflammatory response
Natural killer cells – type of WBC, T cells
Protective proteins – antibodies, B cells

8. How do they work?
B cell tags invaders with antibodies so other immune system cells will know to destroy them
Killer cell devours invaders or release toxic chemicals that kill invaders
Cytotoxic T cell destroys infected body cells before the virus has a chance to multiply
Macrophage devours invaders and launches the immune system attack
Memory cell makes immune responses faster next time the invader returns
Helper T cell coordinates the immune system attack by recruiting and activating other immune cells

9. White Blood Cells Neutrophils Make up about 70% of WBC
Produced in bone marrow then released into the bloodstream
Lifespan 6-8 hours
They engulf and destroy foreign invaders
During infectious illness their numbers increase-called neutrophila

10. White Blood cells 2. Lymphocytes About 20% of WBC Two types are
Type B which produce antibodies
Type T which destroy body cells affected by viruses

11. Lymphatic system Antibodies
The first time the body is exposed to a specific invader an immunologic memory is triggered
If the invader returns it does not cause disease because it is met with large amounts of the specific antibody
Active immunisation occurs when dead or weakened virus is injected into the body. This tricks the immune system into making antibodies
Passive immunisation is the injection of preformed antibodies into the body

12. Organs of the immune system
Lymphatic tissue
Made of a variety of cells belonging to the immune system
An example is the tonsils that guard the entrance to the digestive tract
Lymph nodes
Structures found lying along lymphatic vessels
They act as filters and trap foreign substances
Lymphocytes within these nodes produce antibodies

13. Organs Of the Immune system
Spleen
Found in the upper left abdomen against upper left side of stomach
Largest mass of lymphatic tissue in the body
Contains various types of WBC which trap and destroy invaders
Also produces antibodies
Rich blood supply and is the main filtering unit of immune system
Acts as a graveyard for worn out RBC

14. Organs of the Immune System
Thymus
Found in upper anterior chest cavity between sternum and pericardium
Plays important role in development and maturation of immune system
Once immune system is mature it no longer has a function

15. Lymph Flow
Body cells are surrounded by tissue fluid that comes from the bloodstream
Much of this fluid diffuses back into blood vessels and the excess filters into lymphatic capillaries and is called lymph
Lymph is similar to plasma but is 95% water
Lymphatic capillaries become larger until they empty into either the right lymphatic duct or the thoracic duct
These ducts then empty into the large veins of the upper body

16. Lymphatic System

18. Disorders
Allergic responses – for example asthma, dermatitis and anaphylaxis
Autoimmune – person’s immune system produces antibodies against it’s own cells. Includes rheumatoid arthritis, diabetes mellitus
Immunodeficiency diseases – compromised immune system. Example is AIDS