Chapter 6 Flashcards
(26 cards)
What is an autograft?
A graft of tissue from one point to another of the same individual’s body
What is an isograft?
Tissue transplanted between genetically identical twins
What is an allograft?
Tissue transplanted between individuals that are unrelated of the same species
What is a xenograft?
Tissue transplanted between individuals of different species
HLA
(Human Leukocyte Antigen) Membrane molecules are found on the membrane of the cells and are unique to each individual they represent a biological identity card and are a major self-marker
MHC
Major histocompatibility complex genes that code for two classes of membrane glycoproteins that differ by their structure distribution and role
HLA molecules of class one
Coded by Loci A, B, and C and are expressed by all the nucleated cells
HLA molecules of class two
Coded by Loci DP, DQ, and DR and I expressed by some cells of the immune system
Are the genes that code for HLA molecules polymorphic?
yes baby
Explain the origin of the alleles of the genes of an individual
One of paternal origin and one of maternal origin
How is the expression of the MHC alleles?
They are codominant so each individual expresses on his cell membranes the proteins corresponding to both alleles of each gene
What are the cells of the immune system that can recognize all sorts of non-self molecules that enter the body?
Antigens
What are the two different types of leucocytes and where can they be found?
tissue leucocytes and circulating leucocytes this issue leucocytes can be found in body organs and the circulating leucocytes can be found in the blood
What are the leucocytes that derive from the myeloid stem cell?
Granulocytes monocytes and mast cells
What are the leucocytes that drive from the lymphoid stem cells?
B lymphocytes and T lymphocytes
Give examples of granulocytes
Neutrophils, eosinophils, basophils
State four facts about granulocytes
Granulocytes represent 67 of all leucocyte populations.
they live for 2 to 3 days
have small granules
medium in size
State five facts about monocytes
-Monocytes have a horseshoe-shaped nucleus
-constantly migrates into the tissue
-they become macrophages
-they are large
-they live for several days or even several years
State six facts about mast cells
-They have a rounded nucleus
-the cytoplasm rich in granules
-the granules are filled with histamine
-they possess receptors of certain antibodies
-found in the connective tissues and mucosa
-they vary in size
Compare B lymphocytes and T lymphocytes
They are both smooth and have a large nucleus and makeup 25% of the leucocyte population
B lymphocytes are characterized by membrane receptors called antibodies
T lymphocytes are characterized by a specific type of receptor for antigens called TCR (T cell receptors)
What happens to B lymphocytes upon activation
Upon activation B lymphocytes differentiate into plasma cells that secrete antibodies. these antibodies circulate in plasma
What are the different types of T lymphocytes?
Helper T lymphocytes: help other types of cells involved in immunity. They express a molecule called CD4 on their surface and are therefore called T4 lymphocytes.
Cytotoxic T lymphocytes: kill body cells infected by a microorganism. They express and a molecule called CD8 on their surface and are therefore called T8 lymphocytes
Suppressor T lymphocytes
What is phagocytosis
The engulfing of foreign bodies
What is diapedesis
The squeezing between capillary walls
