1. NOTES: The Lymphatic / Immune System (UNIT 10 part 1)

2. The lymphatic system is closely associated with the cardiovascular system.

3. Functions of the Lymphatic System:
● transports excess fluid to the bloodstream
● absorbs fats
(lacteal inside villi)
● helps defend the body against disease-causing agents (pathogens)

4. LYMPHATIC PATHWAYS Lymphatic capillaries ● microscopic, closed-end
tubes that extend
into intercellular spaces
● receive LYMPH through
their thin walls
(LYMPH = the fluid of the lymphatic system; contains water and dissolves substances that leaked out of blood capillaries.)
● lymphatic capillary networks parallel blood capillary networks

6. Lymphatic vessels: ● have walls similar to those
of veins, but thinner, and have
valves to prevent backflow of
lymph
● become larger as vessels merge; lead to LYMPH NODES and then merge, merge, merge before returning to circulatory system.

7. Organs of the Lymphatic System
Lymphatic vessels: transport lymph
Lymph nodes: “hang out spot” for immune system cells
Spleen: filters blood (immune cells detect germs)
Thymus: mature T cells (1 type of immune system cell)
Tonsils: lymphoid tissue that “samples” bacteria & viruses as you swallow

8. Lymphatic System Condition:
Lymphedema: swelling (edema) due to accumulated lymph
Causes:
Surgical removal of lymph nodes (i.e. cancer treatment)
Some medicines
Damage to lymph nodes

9. NOTES: The Immune System (UNIT 10 part 2)

10. • PATHOGEN: a disease-causing agent; causes infection
-pathogens include:
viruses fungi
bacteria protozoans

11. Background Pathogen Info: Bacteria vs.Virus
*Alive (1 celled organism)  take ANTIBIOTICS to slow their growth
*Not alive, therefore no antibiotics
*Viruses “hijack” cells & use the cells’ machinery in order to reproduce (use cells’ ribosomes. ATP, amino acids, etc.)
* 2 types: 1. hijacker (cold)
2. hijacker & infiltrator (HIV)
*VACCINES prepare your immune system in case you are exposed to that virus later (can be difficult to develop due to high # of virus mutations)

12. Examples of bacteria that cause infection:
E. coli
Salmonella
Staphylococcus
Examples of viruses that cause infection :
Papovavirus – papilloma (warts)
Adenovirus – respiratory diseases
Herpes virus – herpes
Poxvirus – smallpox
Parvovirus – roseola
Picornavirus – polio
Rhinovirus – common cold

13. The body has nonspecific and specific defenses against infection.
Why don’t YOU have mold on your skin???

14. Nonspecific Defenses:
• general defense
• provide protection against many different pathogens
• involve physical and chemical barriers, fever, inflammation, phagocytosis

15. Specific Defenses: • very precise • target certain pathogens
• also known as ACQUIRED IMMUNITY
• involve specialized lymphocytes (T cells and B cells) that recognize and respond to specific pathogens
**nonspecific defenses are quick to respond; specific defenses are slower to respond

16. NONSPECIFIC DEFENSES 1) Species Resistance
• each species is resistant to certain
diseases that may affect other species
• examples: measles, mumps,
gonorrhea, and syphilis infect
humans but not other animal species
• one species may be resistant to a disease that affects another species because its tissues somehow fail to provide a suitable environment for the pathogen (temperature, chemical environment, etc.)

17. 2) Mechanical Barriers = FIRST LINE OF DEFENSE (keep out!)
● mechanical barriers / physical barriers include:
-skin (and associated hairs)
-mucous membranes
-fluid (sweat and mucus)
● as long as they remain intact, they can keep out many pathogens

19. **all other “nonspecific defenses” are considered the SECOND LINE OF DEFENSE (pathogen inside…. destroy!)

20. 3) Phagocytosis – removes foreign particles from the lymph and blood
• the most active phagocytes in blood are NEUTROPHILS and MONOCYTES
• Monocytes give rise to MACROPHAGES

21. • MACROPHAGES are found in the linings of blood vessels in the:
-bone marrow
-liver
-spleen
-lungs
-lymph nodes

22. 4) Chemical Barriers
• gastric juice: contains hydrochloric acid (HCl) and enzymes (e.g. pepsin) that are lethal to pathogens
• tears: contain the enzyme LYSOZYME
(which has antibacterial action)
• the salt in perspiration accumulates on the skin and kills bacteria on the skin

23. 4) Chemical Barriers (cont.)
• INTERFERONS: chemicals released by virus-infected cells; they bind to receptors on uninfected cells; block virus replication

24. 5) Fever
• higher body temperature increases the rate of phagocytic cells
• also lowers iron levels in the blood (bacteria and fungi require iron, so this slows their growth)

25. 6) Inflammation • a tissue response to injury or infection
• histamine & other chemicals released by damaged tissues attract WBCs to the site
• histamine dilates capillaries & other chemicals make capillaries more permeable so WBC’s can slip out
• produces: localized redness, swelling, heat and pain
 the mass of WBCs, bacterial cells, and damaged tissue forms a thick fluid called PUS

28. CLICKER QUESTION:
Which of the following is NOT a nonspecific defense? A) Gastric juice B) Lysozyme found in tears C) fever D) Macrophages (phagocytic cell) E) Skin F) All of nonspecific defenses

29. CLICKER QUESTION:
Which of the following is NOT part of the 1st line of nonspecific defense?
Gastric juice
Skin
Sweat
Mucus membranes

30. CLICKER QUESTION:
TRUE or FALSE: Interferons are a chemical defense (part of 2nd line of defense) and they are released by virus- infected cells.

31. CLICKER QUESTION: How do antibiotics work?
By interfering with a bacteria’s ability to divide or survive.
By interfering with a virus’ ability to divide or survive.
By increasing the number of “good cells” in your body.
A and B
All of the above

32. CLICKER QUESTION: What causes inflammation? A tissue injury
Broken/damaged lymph capillaries
Infection
A and C
All of the above