Class Notes (811,705)
Canada (494,883)
BIOC21H3 (35)
Lecture 9

Lecture 9-Lymphatics.docx

7 Pages
Unlock Document

Biological Sciences
Stefan Rusyniak

Lecture 9-Lymphatic Tissues - Dont have a pump so no cardiac muscle to pump blood through them - Increased osmotic pressure at end of bloodstream due to abundance of different proteins (e.g. albumin which causes them majority of water to return to tissue) - When you cut your finger = inflammation (5 cardinal signs of inflammation; swelling is due to extra water and fluid buildup in the tissue; this water is drained from tissue via lymphatic vessels and is a good thing because if you get a cut, easy access for pathogens to get into your body and thus want an inflammatory response (thus want neutrophils in place). You will have small fragments of bacteria and viral components floating around in this tissue and fluid and this gets drained by the lymphatic vessels. Lymphocytes will respond to pathogens and they are the only WBC that can recirculate after the lysis of a blood vessel. It will be able to get into the lymphatic vessel (not capillary-too small). - Anything thats a fragment of something is referred to as an antigen because it generates an antibody (an immune response) = fragments of viral and bacterial proteins are antigens. Neutrophils break down the pathogens = fragments of bacteria = antigens because they are non-self (body recognizes them as foreign substances thus creating an immune system) o Lymphatic vessels flows to lymph nodes (Problem: 5% of all lymphocytes are B-cells. Each B cell can only respond to 1 antigen and produce 1 antibody; billions of B-cells in your blood and each one can only respond to 1 thing and can only generate 1 antibody. What are the chances that a B-cell in your bloodstream will meet the viral antigen that it will respond to? = low) which is why the antigen is drained into multiple lymph nodes which increases the chances of the antigen meeting the specific B-lymphocyte in the lymph node o Lymphocytes are highly specialized (bring fluid containing the antigen to area where there is a lot of lymphocytes (like a filter = lymph nodes) in order to increase the chances of meeting the right B-lymphocytes that will be able to respond to the antigen) - Primary Lymph Organs o Where lymphocytes initially develop, initial education o Immunocompetent = cell capable of recognizing non-self particles and capable of responding to self particles o Thymus teaches lymphocytes to respond appropriately and distinguish b/w self and non-self (keeping cells that respond the right way) o Galt (not really an organ; associated with lymphatic tissue), thymus, and bone marrow help to educate lymphocytes - Secondary Lymph Organs o This is where lymphocytes become active (collected into larger clusters, antigen when passing through has to pass through millions of these cells so increases chance that antigen will meet the right B-lymphocyte and will be able to initiate an immune response) - Antigen Presenting Cells (APC) o An antigen is a fragment of any kind of protein; something that you can produce an antibody against (self-antigens and non-self antigens and the role of the immune system is to differentiate b/w these two) o Ref diag. A fibroblast (any cell in body will produce these proteins and any protein produced by the cell will be used in some way but some will be broken down via proteosome) Proteosome breaks down protein produced in cell into small fragments and gets presented on the surface within a protein complex called the MHC I complex MHC I complex is there on the surface to present any protein fragment (small peptide sticking out in the surface); if the peptide/fragment of protein isproduced within the body, it is a self-antigen (tells immune system that this cell belongs in your body) o If virus attacks cell, will hijack cells system and produces more viral proteins. Some viral proteins will be broken down by proteosome and some of these proteins will be presented on the surface = green peptide on MHC I = non-self antigen (antigen that is not produced by the body) so the immune system can tell if the body has been infected by a virus because the MHC I complex on its surface which normally holds only self- antigens is now holding a non-self antigen = allows T-cell to kill the cell o All cells in the body produces MHC I complexes and present self-antigens on the surface so immune system knows that the cell belongs in the body o Macrophages are phagocytes and when it finds a bacterial cell, engulfs it, lysosomes breaks it up into small pieces (into peptides = 6-10 amino acids in length). Peptides will be presented on the surface of MHC II complex. B/T cell will come along and binds to peptide and knows it will need to produce more antibodies to counteract the effects of the antigen MHC II complexes are on surfaces of cells that phagocytises foreign components and present those fragments on the surface. MHC I complex will only present what is produced inside of the cell. Macrophages will have MHC I complexes because its a cell in your body and can get infected. This shows that macrophages are a cell that belongs in your body so immune system recognizes this (prevents immune system from responding to proteins being produced in the body so it will not attack the cell) o Some vi
More Less

Related notes for BIOC21H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.