1. The Lymphatic and Immune System
Jeffrey Zhao, Cindy Lee & Simona Dossi

2. The Lymphatic System Lymph vessels Organs
Large vessels & Lymph capillaries (scattered throughout body)
Skeletal muscle contracts  moves lymph fluid through valves
One-way system: capillary  large vessel
Lymph: clear watery fluid  formed from interstitial fluid
Organs
Bone marrow
Lymph Nodes
Spleen
Thymus
Associated with Circulatory System

3. The Lymphatic System

4. The Lymphatic System Bone Marrow: Lymph Nodes: Spleen: Thymus:
Tissue produces lymphocytes
B-Lymphocytes  bone marrow
T-lymphocytes  thymus gland
Blood cells: monocytes & leukocytes
Lymph Nodes:
Area of concentrated Lymphocyctes & macrophages
Along lymphatic veins
A mass of tissue
Spleen:
A larger Lymph Node filled with blood
Reserves blood  Filters/Purifies blood & lymph fluid
Thymus:
Secretes hormone Thymosin  causes pre-T-cells to mature

5. The Lymphatic System Functions: Lymphocytes:
Absorption of excess fluid
Collects, Filters & Returns fluid to blood stream
Absorption of fat
Immunity: Fights infections with lymphocytes
Lymphocytes:
Invades pathogens (bacteria & virus)
Respond to mutated cells (ex: cancer) and foreign proteins (ex: toxins)
Multiply quickly when they meet an antigen

6. The Innate Immune Defenses
Innate immunity mechanisms are fully functional without previous exposure to specific invaders
No recognition of indtruders
Innate defenses activate immediately after infection

7. Innate Defense: Physical & Chemical Barriers
The skin
Outside layer of dead skin and skin cells prevent entry
Oil glands secret oil to trap invaders
The Mucus
Mucus lines respiratory track and digestive track
Ensnares microbes
Bacteria
Certain bacteria in the intestine block binding sites that are potentially exploited by pathogens
Saliva, tears, milk, and mucus all contain lysozyme
Enzyme that kills bacteria
Gastric juice
Kills many bacteria and pathogens in stomach

9. THIS IS THE SLIDE BETWEEN THE FIRST LINE OF DEFENSE AND THE SECOND LINE OF DEFENSE. THE ONES THAT COME UNDER THESE ARE SECOND LINE OF DEFENSE. I THINK WE SHOULD CLARIFY THAT BUT IDK HOW

10. Innate Defense: Inflammatory Response
Capillary changes→ Redness, heat, swelling, pain
Histamine released by damaged cells→ capillaries dilate and become more permeable
White blood cells migrate from bloodstream to damaged cells
Monocytes turn into macrophages and dendritic cells
Phagocytizes pathogens and release cytokines
Chronic inflammation can be harmful
Inflammatory chemicals in blood may cause fever
Some bacteria or viruses may not survive the temp
Blood clotting

12. Innate Defense: Phagocytes and Natural Killer Cells
Phagocytes engulf and digest viruses and bacteria
Neutrophils leave capillary and phagocytize
Pus – white blood cells, dead cells, dead bacteria
Macrophage and dendritic cells
Engulf and stimulate T cells (adaptive immunity)
Natural Killer Cells – Kills virus-infected cells and cancer ells by contact
Also produces cytokines→ Promote adaptive immunity

14. Innate Defense: Protective Proteins
These proteins in plasma are created by the liver
Enhances inflammatory response
Increased phagocytosis
May bind to surface of pathogens and help white blood cells recognize it
Membrane Attack Complexes
Produces holes on bacteria

15. Adaptive Immune Defenses
Third Line of Defense
T Lymphocytes – T Cells
B Lymphocytes
Regulator T Cells and Self-Tolerance
Major Histocompatibility Complex (MHC) Molecules
APCs: Antigen-Presenting Cells
Clonal Selection
Antibodies

16. arise from stem cells in bone marrow
THIRD LINE OF DEFENSE
The adaptive third line of defense relies on: B lymphocytes T lymphocytes Once mature, both cell types circulate in the blood, lymph, and lymphatic tissue. Both cell types recognize different antigens and epitopes.
arise from stem cells in bone marrow

17. Antigens – substance that stimulate an immune response from B cells or T cells.
Epitopes – accessible piece of an antigen that provokes an immune response from a B or T cell

18. THREE PHASES RECOGNITION: ACTIVATION PHASE
antigen receptors on B and T lymphocytes recognize specific antigens or epitopes by binding to them.
ACTIVATION PHASE
the binding of an antigen receptor activates B and T cells, which triggers rapid cell division and soon form populations of effector cells and memory cells
EFFECTOR PHASE
after activation, B cells produce antibodies and T cells engage in a cell-mediated response.

19. T LYMPHOCYTES – T CELLS
Form in the bone marrow and mature in the thymus gland (where they got their name)
Fight pathogens in the cell-mediated immune response
Activation process begins when T cell antigen receptors bind with on the surface of antigen-presenting cells (APCs) by a molecule called major histocompatibility complex (MHC)
Examples of APCs:
Macrophages, dendritic cells, and sometimes B cells
Once activated, T cells replicate to form effector cells and memory cells.
Memory cells are responsible for immunological memory.

20. TWO MAIN TYPES OF T CELLS
Activated by interaction with APC
“announce” the intrusion to the immune system
Activate other cells by releasing cytokines, interleukin-1 (Il-1), and interleukin-2(Il-2)
CD4 accessory protein on the surface
Activated by helper cells
Kill infected cells by releasing perforin and granzymes
CD8 accessory protein on the surface

21. B LYMPHOCYTES B cells mature in bone marrow (^their name)
Typical B lymphocytes  100,000 identical antigen receptors on surface
Antigen receptors

22. B LYMPHOCYTES
Provide adaptive immunity through humoral immune response (means they produce antibodies, or immunoglobins)
Activated when an APC presents an antigen/epitope using a class II MHC molecule which then activates a helper T cell that recognized this epitope-MHC molecule complex
Once activated, B cells produce thousands of clones.
Some clones become effector cells, some plasma cells, and some memory cells.

23. MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) MOLECULES
Also known as HLA (human leukocyte anitgens)
Collection of cell surface markers that identify the cells as self
TWO MAIN CLASSES
CLASS I MHC MOLECULES
CLASS II MHC MOLECULES
Surfaces of every nucleated body cell
Specialized cells, including macrophages, B cells, dendritic cells, and activated T cells.

24. ANTIGEN-PRESENTING CELLS
APCs
ANTIGEN-PRESENTING CELLS
Job:
Taking in antigens and literally presenting them to our immune system.
Examples:
macrophage, dendritic cell, or B cell

25. ANTIBODIES (immunoglobins)
Y-shaped molecule 
four polypeptide chains: two identical heavy chains, two identical light chains
Four constant regions (C) and four variable regions (V)

26. TYPES OF IMMUNITY TYPES OF IMMUNITY Passive Immunity Active Immunity
Temporary
Antibodies are transferred to an individual from someone else.
Examples: maternal antibodies that pass through the placenta to the developing fetus or through breast milk to the baby
Permanent
The individual makes his or her own antibodies after being ill and recovering or after being given an immunization or vaccine.