Sunday, February 10, 2008

Well, well, here it is--the missin' blogs: B CELLS (2/6) & T CELLS (2/8)

WOO HOO THE 3rd Line of Defense is Acquired Immunity B CELLS & T CELLS

Well first and formost i would like to appologize to my fellow class mates as i always do for not having the sherpa repost in on Time.... ma bad. Well the library is a quiet place to work so i guess this is where i'll be writtin from.


..... The 3rd line of defense in the immune system is Acquired Immunity which consists of specific defenses: lymphocytes (B cells and T cells) and antibodies(immunoglobulins).

This defense mechanism is activated in reponse to antigens on pathogens that are not recognized as self-cells or home-cells.

Antigens are proteins that serve as nametags for the t cells and b cells to recognize if a cell is a home cell or a foreigner.

B Cells mature in the bone marrow and belong to the humoral (body fluids) response system.
T cells mature in the thymus and belong to the cellular response system.

B Cells
There are two types of B cells: plasma cells and memory cells. The plasma cells produce anitbodies and make memory cells. The memory cells have a long term immunity to a specific antogen. They are the defense against attackers that are floating freely in the lymph and blood.

Antibodies: proteins that bind to specific antigens.
IgM: 1st immune response.
IgG: 2nd immune response: more antibodies in plasma
IgA: in external secretions
IgE: release of histamine, triggers allergic reactions

B cell immune response system.
T Cells

An immune response to infected cells(pathogens inside cells).
They are the defense against non-self cells.
The two types of T cells are Helper T Cells and Killer T Cells.
Helper T Cells alert the immune system of intruders.
Killer T Cells attack the infected body cells

T cells know that a cell is infected when there are antogens of a foreign invader on the outside of the cell. The infected cell digests the pathogen and the MHC carry the pieces to the surface kind of like a wanted poster.

The Helper T cell then releases interluekin 1 to produce more helper t cells to look for more infecter cells. It also releases interleukin 2 to alert the Killer T cells that there is an invader. This activates the Killer T Cells. The interleukin 2 also stimulates B cells to drop more anti bodies in case there are whole pathogens in the humoral system.

The killer t cells destroy the infected target cell by making holes in it (apoptosis). Since the membrane is now punctured the cell is no longer semi permeable it is wholy permeable and water rushes in from a hypotonic solution to a hypertonic solution and the cell pops.


PS If youre really feeling like a nerd play an immune system game:
Monday Nights Sherpa Will Be SAAD. =)

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