1. The Lymphatic System and Body Defenses12
The Lymphatic System and Body Defenses

2. The Lymphatic System and Body Defenses
I. Introduction– Functions
Transports:
White Blood Cells: Body Defences
II. Parts
Lymph Fluid
Lymphatic Vessels
Lymph Nodes
Lymphoid Organs
Have WBC

3. III. Physiology– Body Defences
A. Introduction-- 2 Systems or Processes
Innate, nonspecific
General Defense:
1st and 2nd lines of Defense involve non-specific processes:
Adaptive, specific
Specific Defence:
Immunity =
3rd Line of Defense involves lymphocytes

4. Figure 12.6

5. B. Innate (Nonspecific) Body Defences 1. FIRST LINE OF DEFENCE. a
B. Innate (Nonspecific) Body Defences 1. FIRST LINE OF DEFENCE a. Surface Membrane Barriers
i) Skin and mucous membranes
Physical barrier
Tissues
Protective secretions
pH of the skin:
Sebum:
Vaginal secretions:

6. b. Internal Membranes (Serous)
i) Stomach mucosa
ii) Saliva and lacrimal fluid:
iii) Digestive & Respiratory System Mucus:

7. 2. SECOND LINE OF DEFENCE: Cells & ChemicalsNK
Natural killer (NK) cells
- Not specific
Lyse Cancer
ii) Virus-infected cells
iii) Release perforin:
Bacteria

8. b. Phagocytes
Neutrophils and Monocytes
Phagocytosis:
Lysosomes:

9. Figure 12.9a

10. Second Line of Defense …
c. Inflammatory response
i) Injured cells:
ii) Four indicators:
Redness
Heat
Swelling
Pain

11. iii) Process:
Neutrophils migrate:
Diapedesis:
Phagocytosis:
Blood Vessels Leaky-- Fibrinogen
Basophils

12. iv) Functions:
Prevents spread of damaging agents
Disposes of cell debris and pathogens

13. iv) Functions:
Prevents spread of damaging agents
Disposes of cell debris and pathogens
d. Fever
= Abnormally high body temperature
Cause: Pyrogens secreted by WBC
Function: (1) Inhibit the release of iron and zinc needed by bacteria
(2)Increases the speed of tissue repair

14. C. THIRD LINE OF DEFENCE = Adaptive/Specific Defence System
1. INTRODUCTION
a. Produced by cells and chemicals
b. Immune response is the immune system’s response to:
c. Immunity occurs after:
d. Antibodies: 14

15. e. Cells of the adaptive defence system
Lymphocytes respond to specific antigens
B lymphocytes (B cells)
T lymphocytes (T cells)
Macrophages help lymphocytes 15

16. 2. Role of T cells
Coordinate Immune Responses

17. 3. Antibody-Mediated Immune Response Role of B Cells
Antigen
a. Primary Response
Body finds the specific B lymphocytes with the correct antibodies that bind to a specific antigen
B lymphocytes are cloned
Antibodies released to destroy antigen
Activity lasts for 4 or 5 days
Primary Response
(initial encounter
with antigen)
Receptor
1-2 weeks
Proliferation to
form a clone
Activated B
cells 17

18. Some B cells become long-lived memory cells
b. Secondary responses: when same pathogen encountered for 2nd time
Memory cells become active
Rapid response: hours to 1or 2 days
Stronger and longer lasting
Secondary Response
(can be years later)
Subsequent
challenge
by same
antigen results
in more rapid
response
Clone of cells
identical to
ancestral cells
Plasma
cells
Memory
B cells
Secreted antibody molecules 18

19. 4. Result of Secondary Response Is Active Immunity
a. Naturally acquired during 1st response to specific bacteria and viruses
b. Vaccines: Artificially acquired
Vaccine exposes immune system to pathogen parts with the antigens
First Humoral response is initiated
Memory B cells are saved
If pathogen ever encountered do 2nd response 19

20. Secreted antibody molecules Figure 12.12
Vaccine
Primary Response
(initial encounter
with antigen)
Vaccine binding
to a receptor on a
specific B cell
(B cells with
Proliferation to
form a clone
Activated B
cells
Plasma
cells
Memory
B cell
Secreted
antibody
molecules
Secondary Response
(can be years later)
Subsequent
challenge
by the real
pathogen
results
in more rapid
response
Clone of cells
identical to
ancestral cells
Plasma
cells
Secreted
antibody
molecules
Memory
B cells
Secreted antibody molecules
Figure 12.12 20

21. END