Lymphatic and immune system

Question 1

explain the direction of lymph (vessels)?

Answer 1

starts as lymphatic capillaries then goes to larger lymph vessels which then merge to lymph ducts. All of the ducts merge into the thoracic duct which drains into a neck vein

Question 2

what are lacteals?

Answer 2

special lymph vessels which carry lipids from the intestine in the form of chylomicrons.

Question 3

explain how the blood pressure and the lymphatic system work?

Answer 3

when blood goes through capillaries, pressure decreases dramatically. nutrients, neutrophils, macrophages, and wastes pass through the intercellular clefts of the endothelial cells.

when this occurs a lot of water is also lost. Lost water and protein are taken up by the lymph system and brought back into circulation.

oncotic pressure tries to retain water (albumin) while hydrostatic pressure and tissue osmolarity encourage it to leave the blood.

Question 4

what are the 5 components of innate immunity?

Answer 4

1. skin = protective barrier
2. lysozyme’s in tears and saliva. (they attack bacterial peptidoglycan walls)
3. monocyte macrophage’s and granulocyte neutrophils which non-specifically perform phagocytosis
4. stomach acidity
5. complement system of proteins (these proteins non-specifically bind the surface of foreign material)

Question 5

what is humoral immunity

Answer 5

antigen-antibody system which is specific for specific pathogens

Question 6

explain the general structure of an antibody.

Answer 6

composed of a 2 light chains and 2 heavy chains connected by disulphide bonds. additionally each light chain- heavy chain pair has a variable region and a constant region (variable on the light chain side)

Question 7

what is an epitope

Answer 7

the binding site on the antigen that an antibody binds too

Question 8

what is another name for antibody?

Answer 8

immunoglobulin

Question 9

what are the 5 classes of antibodies based on their constant regions?

Answer 9

Ig prefixes all of them…

M A D E G

Question 10

what is the most common plasma antibody

Answer 10

IgG

Question 11

explain antibody Ig M

location and function

Answer 11

location: blood + B cell surface
function: initial immune response

Question 12

explain antibody Ig A

location and function

Answer 12

location: secretions i.e. saliva
function: helps protect newborns and GI

Question 13

explain antibody Ig D

location and function

Answer 13

location: B cells
function: acts as antigen receptor like IgM

Question 14

explain antibody Ig E

location and function

Answer 14

location: blood
function: allergic reactions

Question 15

explain antibody Ig G

location and function

Answer 15

location: blood
function: ongoing immune response. This can cross the placental barrier

Question 16

explain the production of mature B cells (5 steps)

Answer 16

1. immature B cells are derived from bone marrow stem cells
2. the genes that encode the antibody proteins to be produced are recombined giving rise to many variable regions.
3. Once recombination occurs, the immature B cell expresses antibody molecules on it’s surface
4. the antibody presenting B cell then comes into contact with an antigen which stimulates it to proliferate
5. A. The immature B cell becomes a plasma cell which actively secretes the antibody
6. B. The “” becomes a memory cell ( dormant B cell waiting for recurrent infection)

Question 17

what is primary and secondary immune responses?

Answer 17

primary immune response –> upon first infection, immature B cells bind the antigen and proliferate which takes time therefore we experience symptoms.

Secondary immune response –> due to the presence of memory B cells, up second infection we amount an immune so fast symptoms don’t show (person is said to be immune)

this is how vaccines work.

Question 18

what are lymphokines and interleukins?

Answer 18

these are hormones released by T helper cells (CD4 cells) which help in communication with all other cells

Question 19

what are the two types of T cells? what do they do?

Answer 19

T helper (aka CD4 cell): activate B cells, help other T cells

T killer cells (cytotoxic cells or CD8 cells): they kill

Question 20

explain how a helper T cell can be specific to an antigen but not produce antibodies for it?

Answer 20

helper T cells recognize an antigen and then activate a killer T cell or B cell to deal with it.

Question 21

where do T cells mature?

Answer 21

thymus

Question 22

what is the MHC 1 complex? whats its involvement in cell-mediated immunity?

Answer 22

MHC 1 complex is a protein that is expressed on all nucleated cells (RBC’s aren’t nucleated). The job of these proteins is to randomly take peptide pieces in the cell and present them on the cell surface for T cells to check over. If the cell is infected, it may randomly present foreign material and therefore be recognized by T killer cells as an infected cell.

Question 23

explain MHC 2 complex?

Answer 23

The MCH 2 complex is only presented on cells called Antigen Presenting Cells (APC’s). These include B cells and macrophages. these phagocytosis particles or cells and display fragments of them on their surface via the MHC 2 proteins. T-helper cells recognize this and activate B cells and T killer cells

Question 24

true or false, Helper T cells can become activated when they encounter a foreign pathogenic particle in the blood.

Answer 24

false!! HELPER T CELLS CAN ONLY RECOGNIZE ANTIGEN PRESENTING CELLS.

Question 25

what monitors MHC 1 and 2 receptors?

Answer 25

MHC 1 –> killer T cells

MHC 2 –> helper T cells

Question 26

explain CD8 and CD4 cells and what they recognize.

Answer 26

CD4 cells are the same thing as helper T cells. These recognize MHC2 receptors on APC’s

CD8 is the same thing as cytotoxic T cells which recognize MH1 receptors

both 8 x 1 and 4 x 2 = 8 easy to remember

Question 27

what does bone marrow do?

Answer 27

produces all types of blood cells

Question 28

what does the spleen do?

Answer 28

filters blood, it a site for blood immune cell interaction. the spleen also kills aged erythrocytes

Question 29

What do the tonsils and appendix do?

Answer 29

they are both large regions of lymphatic tissue which are supposed to catch pathogens and present them to areas of immune cells.

tonsils –> back of throat
appendix –> beginning of intestine

Question 30

explain what occurs to B cells who recognize surface proteins of normal cells? What occurs to B cells who recognize normal soluble proteins like hemoglobin

Answer 30

B cells who bind normal cell surface proteins are induced to die via apoptosis

B cells who bind normal soluble proteins are inactivated and become ANERGIC (unresponsive)

both occur in bone marrow or lymph nodes

Question 31

where does T cell check up occur?

Answer 31

in the thymus or lymph nodes ( b cells was in bone marrow) T cells become anergic