1. The Lymphatic / Immune System
Honors Biology
Unit 8
Powerpoint #7

2. Lymphatic System: Purpose:
Transports a watery fluid called lymph.
This fluid distributes immune cells, and other factors throughout the body.
It also interacts with the circulatory system to drain fluid from cells and tissues

3. Lymphatic System: Functions:
Collect and return fluids, including blood plasma, to the blood, maintaining fluid homeostasis.
Defends the body against disease by producing lymphocytes.
Absorbs lipids from the intestine, and transports them to the blood.

4. Absorbs lipids from small intstine

5. Why do we need the Lymphatic System?
Every 24 hours the circulatory system slowly leaks 3 liters of blood.

6. Lymphatic System: Structures:
white blood cells (lymphocytes)
Bone marrow
Thymus
Spleen
Tonsils
lymph nodes
lymph vessels

7. Lymph / Lymph Vessels
Lymph: fluid and protein that has been squeezed out of the blood (blood plasma).
Vessels: A network of permeable capillaries and vessels that lymph drains into.

8. Lymph Vessels
The lymph system is one- way, draining lymph from tissue, back to the blood.
Lymph movement depends on smooth muscle action, and skeletal system movement.

9. Lymph Nodes: Filters Lymph as is travels in the lymph vessels.
White blood cells are located within the lymph nodes.
Bean-shaped, size ranges from 3mm to 2cm.
Can become enlarged due to infection.
A combination burglar alarm and West Point. They guard against intruders, but also train the ‘military’ to fight.

10. Lymph Nodes

11. White Blood Cells Bone marrow produces lymphocytes
Normally in blood, but can be found at any location.
Re-enter blood circulation through lymph vessels.
Fight foreign invaders (microorganisms)
Some last 2-5 days, others last for years.

12. Lymphocytes attacking cancer cell

13. Thymus:
Location of the development of T-cell lymphocytes.

14. Spleen:
Fist-sized mass of lymphatic tissue that destroys old or damaged red blood cells and platelets.

16. Elephantitis

17. Immune System & Disease
Disease- any change that disrupts normal body functions (other than injury)
Causes-
Bacteria
viruses
fungi
environmental factors (smoke, lead, pesticides)
genetically inherited (hemophilia, Down's Syndrome)

18. Infectious diseases are caused by microorganisms
Germ Theory of Disease
Proposed by Louis Pasteur & Robert Koch
Infectious diseases are caused by microorganisms

19. Agents of Disease
Virus- tiny particles that invade & replicate within living cells
Is not alive, only a piece of DNA or RNA bound in a protective coat

20. Agents of Disease Bacteria- single celled organisms (prokaryotic)
Most don’t cause disease
Those that cause disease attack cells directly or produce toxins that harm cells

21. Agents of Disease
Protists- tiny single celled organisms that spread via insects, blood, food, or water
Examples: Malaria, Sleeping sickness, traveler’s diarrhea

22. Agents of Disease
Worms-- flatworms & roundworm eggs that grow inside other organisms
Examples: Schistosoma
Ascaris
tapeworm

23. Agents of Disease Fungi– most are harmless Tinea attacks the skin
causes athlete’s foot &
ringworm

24. Spread of Disease
Coughing, sneezing, or physical contact
Contaminated food & water
Animals

25. Fighting Infectious Disease
1. Antibiotics– compounds that kill bacteria without harming host cells
Many are produced naturally by organisms (like mold creates penicillin) discovered by Alexander Fleming
2. Antiviral drugs– inhibit their ability to invade cells
3. Rest & fluids so your own immune system can work well!

26. The Immune System
Immunity- fighting off disease before it actually makes you ill
2 categories:
Specific- targeted for 1 disease
Nonspecific- general line of defense against anything

27. Non-specific Defense 1st line of defense – Physical -Skin -Mucus
-Sweat
-Tears
The sweat & tears contain lysozymes (enzyme that breaks down bacteria cell walls)

28. Non-specific Defense 2nd Line of defense Inflammatory response–
Phagocytes (white blood cells)
go to site of injury to engulf foreign agents
2. Fever can slow down growth or stop growth of some pathogens (also ‘s heart rate to get WBC’s to site faster)
3. Interferon proteins help cells resist viruses by slowing down their replication in cells

29. Specific Defense T cells B cells Attacks antigens within cells
Immune response is triggered by antigens (any foreign agent)
Creates B & T Lymphocytes
T cells
Attacks antigens within cells
B cells
Attacks antigens in body fluids

30. Antibodies Proteins created by B cells
Bind to antigens to stop them from moving into cells & signals proteins (produced by liver) to destroy the antigen
B memory cells store info to create antibodies quickly against another antigen attack

31. Antibodies Y shaped with 2 identical binding sites
Shape of binding site is specific to an antigen with a complementary shape
Most healthy adults can produce 100 million different types of antibodies

32. Cell Mediated Immunity
Important in fighting infections caused by fungi & protists & viruses
T-cells divide into killer, helper, suppressor, & memory cells
Killer T-cells destroy the agents
Helper T-cells produce memory T cells
Suppressor T-cells releases substances that shut down the killer T-cells

33. HIV & T-cells
HIV replicates inside T- cells, and then destroys them as they burst open to release more viruses
When Immune cells are destroyed, other diseases & infections can weaken & kill AIDS patients

34. Acquired Immunity
Edward Jenner created the 1st vaccine against smallpox using attenuated (heated so it won’t cause the disease) cowpox
Active Immunity is the injection of a mild form of the pathogen to stimulate our immune systems to create antibodies

35. Passive Immunity
Lasts only a short time because they are not created by the body’s own immune system
Examples:
1) Mother passing antibodies through placenta or breast milk to baby
2) Vaccines with antibodies against diseases like malaria, yellow fever, rabies

36. Immune System Disorders
Allergies- overreactions of immune system to antigens
Mast cells are specialized cells that initiate the inflammatory response
Histamines- chemicals released by mast cells that increase blood flow & fluids to the area
This causes sneezing, watery eyes, & runny nose

37. Autoimmune Diseases Body attacks the body’s own cells
Examples: Type I diabetes, rheumatoid arthritis, myasthenia gravis, & multiple sclerosis (MS), Lupus