Immune system Marisol Gomez Period 1

Purpose of Line of defense:

1st: The external membrane, skin and mucous. The surface barrier but physical barrier to most microorganisms. Kills many microorganisms

2nd line: protein, phagocytes, and other cells. Have pattern recognition receptors that recognize and bind.

3rd line of defense: attack a particular foreign substance.

Innate and adaptive:

The innate immune system is skin and mucous membrane. It's internal defenses are phagocytes, natural killer cells, inflammation, antimicrobial proteins, and fever.

Adaptive immune system: Contains Humoral immunity (B cells) that contain antibodies produced by lymphocytes and circulate freely in body fluids. They bind temporarily to target cell. Also, cellular immunity (T cells). Where the lymphocytes act against target cells. They directly kill infected cells and indirectly release chemicals that enhance inflammatory response.

Antigens V Antibodies:

Antigens: mobilize adaptive defenses and provoke immune response. Can be complete or incomplete antigen. Can be self-antigen (non-antigenic to self but can be to others). Non self, not normally found in the body.

Antibodies: Proteins secreted by plasma cells. Can bind with antigen detected by B cells. Grouped into 1/5 Ig classes , .

3 APCs:

Dendritic cells: In connective tissues. Link between innate and adaptive.

Macrophages: connective tissue and lymphoid organs. Present antigens to T cells. trigger inflammatory responses and recruit defenses.

B lymphocytes: Don't activate naive T cells. Present to helper T cells to assist own activation.

IgM: Activates complement. Secreted by plasma cells during primary response.

IgA: found in body secretions Stops pathogens from attaching to epithelial tissue.

IgD: Found in B cell, antigen for B cell receptor.

IgG: Protects against antibody of secondary and late primary.

IgE: Stem and bind to mast cells or basiphils. Secreted by plasms cells in skin.

Major functions:

Immune system: to provide resistance to diseases

Lymphatic system: transport lymph. Also maintains fluid, absorbs fat, and nutrients

lymph organs functions:

Lymph modes: cleanse lymph, Site for lymphocyte activation and proliferation

spleen: cleanse blood, remove aged defective red cells. Site for activation and proliferation. Store platelets

Malt: prevent pathogens from peetration mucous membrance. Site for lymph activation and proliferation

Thymus: site of T cell maturation

Passive v Active immunity:

Active immunity: B cell encounter antigen and produce specific antigen

Passive immunity: readymade antibodies introduced to body.

  • B cells not challenged by antigens
  • Protection ends when antibodies degrade

Naturally v Artificial acquired:

In Active humoral:

Naturally: formed in response to bacterial or viral infectio

Artificial: formed in response to vaccine of dead.

In passive humoral:

Naturally: antibodies delivered to fetus by the placenta

Artificial: injection of serum, gamma globulin

Disorders Associated:

Hodgkins's disease: immunodeficiency cause cancer B cells depress lymph node cells.

Autoimmune disease: immune system loses the ability to distinguish self-form from foreign

Immunodeficiency: Congenital conditions that impair function and production

Hypersensitivities: Immune response to perceived threats

HIV: cripple immune system. Interfere with helper t cell

SCID: genetic defect with marked deficit of B and T cell

Cells Involved:

Helper T cells: activate humoral and cellular arms

CD8 cells: become cytotoxic. can destroy cells and also become memory cells

CD4 cells: become helper T cells. Activate B cells

Naive T cells: termed cd4 and cd8

dendritic cell: in connective tissue and epidermis, Mobilize sentinels of tissue.

cytotoxic cells: directly attack and kill other cells

Regulatory T cells: prevent autoimmune reactions

macrophages: distributed in the CT. activate T cell

B cell: prevent antigen to help T cell