Week One, Lecture 1 Flashcards
What are the 8 immune structures?
Lymph nodes Lymph vessels spleen tonsils and adenoids appendix Peyer's patches thymus bone marrow
In gestation, when do the immune stem cells develop?
By the ninth week gestation, in the liver and spleen.
Which lymphocytes dominate in the newborn’s system?
Which lymphocytic system do adults utilize?
Newborns: T H 2
adults: T H 1
Name two factors that impair immune function
stress and depression
What happens to the immune system with age?
It degenerates and the likelihood of cancer and autoimmune disorders increases
What are the two branches of innate defenses?
Physical (surface) barriers and internal barriers
Which are the functional surface barriers of the innate immune system?
skin and mucosa
What are the internal defenses of the innate immune system? (5)
- phagocytes
- fever
- natural killer cells
- antimicrobial proteins
- inflammation
What are the two branches of the adaptive immune system?
Humoral and Cell mediated
Describe each of these cells’ role in the innate immune system:
- macrophage
- B-cell
- T-cell (Helper)
- Natural killer cell
- epithelial cells
- Cleans up debris of viral infections and calls for T-cells
- Clean up viruses and alert other B-cells
- Call for “back up”
- These destroy infected cells with cytotoxins
- Keep things out
What are the two “lines” of innate defense
First line: Physical barriers (skin and mucosa)
Second line: Antimicrobial proteins, phagocytes, other cells (the most important mechanism here is inflammation)
What are some examples of protective chemicals inhibiting or destroying invaders in the first line innate defenses?
- Skin pH
- lipids in sebum/ dermacidin in sweat
- HCl and proteases in stomach
- lysozymes in lacrimal glands and saliva
- mucus as a physical trap
Which cells are involved in inflammatory response?
macrophages, mast cells, WBC’s, NK cells, inflammatory chems
What are two antimicrobial proteins in the innate immune system?
interferon and complement proteins
Describe macrophages
These develop from monocytes to become the main phagocytic cells. They remain as monocytes in the blood.
They can be either free or fixed.
Examples of free macrophages: alveolar, sinus, spleen and lymph macrophages
Examples of fixed macrophages: Kupffer.
When are neutrophils phagocytic
When they encounter infectious materials in the tissues
Explain the process of phagocytosis
- Phagocyte must adhere to pathogen or debris
- Pseudopod formation/this becomes a phagosome
- Phagosome fuses with lysosome forming phagolysosome.
- hydrolytic enzymes from the lysosome destroy pathogen
- exocytosis of vesicle
What is leukocytosis
This is the mobilization of leukocytes from the bone marrow in response to leukocytosis inducing factors from injured cells
What are natural killer cells?
Large granular lymphocytes that target cells that lack self antigen as well as tumor cells and virally infected cells (they induce apoptosis in those self cells)
Which cells have toll like receptors (in the boundary tissues)?
What happens when these receptors are bound and activated?
- Macrophages and epithelial cells
2. Activated TLR’s trigger the release of cytokines
What are three kinds of inflammatory mediators
- histamines (released from mast cells)
- Blood proteins
- kinins, prostaglandins, leukotrienes, complement proteins (released by mast cells, phagocytes, injured tissue, lymphocytes, basophils)
What do inflammatory chemicals do?
Cause dilation of arterioles resulting in hyperemia. Also increase capillary permeability locally inducing edema and release of exudate
What is in exudate?
What is the benefit in the surge of exudate?
Proteins, clotting factors and antibodies
Surge of exudate directs foreign material into lymphatic system and delivers clotting proteins which provide a scaffold for tissue repair and wall of the area
How does IF work?
Virus enters the cell
IF genes are turned on
Cells produce IF molecules and release them
These stimulate neighboring cells to produce antiviral protein.
These proteins block viral reproduction within the cells that produce them.
Additionally, they can activate macrophages and mobilize NK cells and oddly can reduce inflammation.