Lymphoid I Flashcards Preview

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Flashcards in Lymphoid I Deck (31):
1

Exterior Defenses

- Tears- lysozyme in tears
- commensals- In respiratory tract and GI tract
- Skin- physical barrier, fatty acids
- Low pH in gut
- Bronchi- mucus and cilia
- Nasal cavity- cilia
- Flushing of the urinary tract

2

Innate (non-specific) Immunity

- Neutrophils, macrophages, monocytes, etc phagocyitize and remove the pathogen

3

Natural Killer Cells (NK cells)

- Lymphocytes
- Surgical stress reduces NK cell numbers and function
- Post op loss is greatest after 3 days and recovers by one month
- increased risk

4

Acquired (specific) Immunity

- Antigen presenting to T and B lymphocytes
- Bacteria comes into contact with macrophage, ingested, presented with MHC to lympocyte
- T cell will create more T cells
- B cells will initiate humoral immunity (antibodies)

5

Antigen Recognition

- Must distinguish self vs non self

6

Function of the Lymphoid System

- Protection and Immunity
- Antigen Recognition
- Antigen Inactivation/ Elimination in response to Foreign material, micoorganisms, cancer cells, and organ transplants

7

Humoral Immunity

- B cell Lymphocytes
- Antigen reacts with antibodies present on the surface of the B cell, activating them
- Then they proliferate and differentiate into memory b cells and plasma cells
- Plasma cells secrete antibodies

8

Cell Mediated

- T cell Lymphocytes
- Cytotoxic T cells are activated by contact with an infected cell that presents antigen with MHC-I on its surface.
- Activation results in the productions of cytotoxic memory T cells and T cytotoxic cells that produce perforin

9

Central Lymphoid Tissues

- Bone Marrow
- Thymus

10

Fetal Liver

- B lymphocytes are produced here
- in adults, if the bone marrow is damaged, the liver can be reactivated in order to help produce B cells

11

Plasma Cells

- Antibody Factories
- Eccentric nucleus
- Abundance of Rough ER to make Immunoglobulins
- Terminally differentiated
- Produce and secrete Abs

12

Structure of Immunoglobulin (Ig)

- 2 heavy chains- connected by disulfide bonds
- 2 light chains- each held to a heavy chain by disulfide bond
- Has a constant portion
- Variable portion- Sequence of amino acids that are compliment to foreign pathogens

13

Somatic Recombination

- Random event of shuffling and if one is found to be compliment to a pathogen, then it initiates clonal expansion
- Combination of variable (V), diversity (D) and joining (J) segments during maturation of B and T cells

14

IgG

- Most common
- in blood and lymph, intestinal lumen
- activates phagocytosis
- neutralizes antigens
- protects newborns

15

IgM

- Pentamere
- first antibodies to be produced in an initial immune response

16

IgA

- Dimer with secretory component
- Produced in B cells of the lamina propria and presents as dimers in secretions
- Protects the surface of mucosas for it resists proteolysis

17

IgD

- Present only on surface of B cells (receptor)
- triggers B cell activation

18

IgE

- Bond to mast cells and basophils
- Participates in allergy and lyses parasitic worms

19

Antibody Response

- 1st exposure
- Lag time
- Primary response fairly low
- IgM>IgG
- 2nd exposure
- Shorter to no lag
- Greater Secondary Response- more antibody
- IgG>IgM

20

Agglutination

- Antibodies bind to antigens, forming aggregates and reducing the amount of free antigens

21

Opsonization

- Binding of antibodies to microorganism stimulates phagocytosis

22

Neutralization

- binding of antibody to microorganism blocks their adhesion to cells and inactivates toxins

23

Cytotoxicity

- Involves antibodies adhering to the surfaces of worms activating cells of the immune system (eosinophils and macrophages) and inducing them to liberate chemical agents that attack the surface of the animal

24

Complement Activation

- binding of antibodies to the initial protein of the complement system triggers a cascade which in turn eventually produces the membrane attack complex and causes cell lysis

25

PD-1

- Cell surface receptor expressed on T cells
- It, along with its ligands, down regulates the immune system by preventing the activation of T cells
- Pd-1 inhibitors activate the immune sytem to attack tumors and are therefore used to treat cancer
- These inhibitors "inhibit the brake"

26

T cell Origin and development

- Originate as stem cell in bone marrow
- Travel to thymus where they mature
- Differentiate into Cytotoxic T cells, Helper T cells, Suppressor T cells and memory T cells
- Antigen Presenting Cell with antigen presented via MHC activates T cell

27

MHC-I

- Major Histocompatability Complex I
- Present on all cell types
- Interacts with CD8+ cytotoxic T cells

28

MHC-II

- Major Histocompatability Complex II
- Present on Antigen presenting cells
- Interact with CD4+ helper T cells
- Pass thorugh endosome-lysosome vesicles (eg. phagocytosis)

29

Helper T cell

- CD4+
- Activated by interaction with antigen on APC
- Produces interleukins that induce activation, proliferation and differentiation of B cells
- Result is production of memory B lymphocytes and antibody producing plasma cells

30

Cytotoxic T cell

- CD8+
- Produces Perforins- create pores in target cell
- Contains the Fas Ligand- When activated, it will induce apoptosis in virus infected cell

31

Human Immunodeficiency Virus (HIV)

- CD4+ helper T cells are destroyed by the AIDS virus
- Over time the helper T cell number crashes
- The number of helper T cells are so low that they are no longer mounting a response against the virus
- Opportunistic viruses take advantage and lead to death