Lecture 7 - Immune system Flashcards
What is the blood comprised of
Erythrocytes, Leukocytes and Platelets (thrombocytes)
What does plasma do
Plasma carries blood cells, proteins, nutrients, metabolic products and waste, and other
molecules being transported around the body.
What is Haematocrit
The percentage of blood volume
that is erythrocytes
Men - 45%
Women 42%
What is Bulk flow
Rapid flow of blood throughout the
body
What are some features of RBCs
Biconcave
Flexible membrane
Large SA
No mitochondira
No DNA
Where are RBCs produced
Bone Marrow
What are Reticulocytes
Young erythrocytes in bone marrow contain a few
ribosomes which produce a web-like appearance
(reticular) when stained
What is the breakdown product of haemoglobin
Bilirubin - Yellow colour
Why is there a decrease in ability of the blood to carry oxygen in Anemia
1) a decrease in the total number of RBCs
2) Low haemoglobin per RBC
3) a combination of both
How are RBCs replaced
erythropoietin (a hormone from the
kidneys) to stimulate erythropoiesis
What s Haemostasis
The stoppage of bleeding
What is the response to a severed blood vessel
Constriction - Slows blood flow to the area
Presses Endothelial surfaces together inducing a “stickiness”“gluing” them together
What is platelet activation
Platelets release ADP and serotonin that induce changes
in metabolism, shape and surface protein expression on platelets (as well as releasing actin and myosin to allow contraction)
What does EDTA do
A chemical
compound
that prevents
clotting by
“mopping up”
calcium
What does heparin do
prevents clotting by
activating a plasma
protein called
antithrombin III (found in endothelial cells)
What is the clinical testing significance for EDTA (Ethylene-diamine-tetra-acetic acid)
Use these tubes for
measuring biomarkers
in plasma (e.g., the
levels of inflammatory
cytokines, counting
cells SYSMEX)
What is the significance of Heparin in Clinical testing
Use these tubes
assessing cell function
(i.e., can an immune cell
produce inflammatory
cytokines or kill virus
infected cells).
Slides 9-12
What is an example of immunity
Blood donation/transfusion
What are 2 incompatibilities in blood donation/transfusion
he recipient’s anti-B antibodies cause the transfused cells to be attacked;
the anti-A antibodies in the transfused plasma cause the recipient’s cells to be attacked
What is the most abundant class of plasma antibodies
IgG
What do IgMs do
Class of antibodies that is produced first in all immune responses - providing bulk of specific humeral immunity against bacteria and viruses
What are Igs and what are the 5 major classes
Immunoglobulin (Igs) are proteins that function as B-Cell receptors and antibodies
IgA, IgD, IgE, IgG, IgM
What are Type 1 interferons
Group of cytokines that nonspecifically inhibit viral replication
What are Type 2 interferons
(Interferon-gamma) stimulate the killing ability of NK cells and macrophages
What does IL-1 do (interleukin 1)
Cytokine secreted by activated helper T cells that activates helper `T cells, exerts many inflammatory effects and mediates many of the systems acute phase responses, including fever
What does IL-2 do
Cytokine secreted by activated T helper cells that causes helper T cells, cytotoxic T cells and NK cells to proliferate and causes activation of macrophages
What does IL-6 do
Cytokine secreted by macrophages that exerts multiple effects on immune system cells, inflammation, fever, and acute phase response
What do Kinins do
Peptides that split from kininogens in inflamed areas and facilitate the vascular changes associated with inflammation; they also activate neuronal pain receptors
What is a MAC
Membrane Attack Complex - group of complement proteins that form channels in the surface of a microbe, making it leaky and killing it
What are natural antibodies
Antibodies to the erythrocyte antigens (A or B type)
What are opsonins
general name given to any chemical mediator that promotes phagocytosis
What is Perforin
Protein secreted by cytotoxic T cells and NK cells that form channels in the plasma membrane of the target cell, making it leaky and killing it, (similar to a MAC)
What is Tumor necrosis factor-alpha (TNF-alpha)
Cytokine secreted by macrophages that has the same actions as IL-1
What are activated macrophages
Macrophages whose killing ability has been enhanced by cytokines, particularly IL-2 and interferon-gamma
What is an APC
Cell that presents antigen, completed with MHC proteins on its surface to T cells
What are B-cells
Lymphocytes that, upon activation, proliferate and differentiate into antibody-secreting plasma cells; provide major defence against bacteria, virus-infected cells and cancer cells; and bind antigen associated with class 1 MHC proteins
What do cytotoxic T cells do
The class of T lymphocytes that, upon activation by specific antigen, directly attack the cells bearing that type of antigen; are major killer of virus-infected cells and cancer cells; and bind antigen associated with class 1 MHC proteins
What are dendritic cells
Cells that carry out phagocytosis and serve as APC
What is Eosinophils
Leukocytes involved in destruction of parasites and in immediate hypersensitivity
What are Helper T cells
The class of T cells that, via secreted cytokines, play a stimulatory role in the activation of B cells and cytotoxic T cells; also can activate NK cells and macrophages, and bind antigen associated with class II MHC proteins
What do lymphocytes do
The type of leukocyte responsible for adaptive immune response - B cells, cells NK cells
What are macrophages
Cell type that
1- functions as a phagocyte
2- processes and presents antigen to helper T cells
3 - secretes cytokines involved in inflammation, activation of lymphocytes and the systemic acute phase response to infection or injury
What are mast cells
Tissue cells that bind IgE and release inflammatory mediators in response to parasites and immediate hypersensitivity reactions
What do memory cells do
B cells and cytotoxic T cells that differentiate during an initial immune response and respond rapidly during a subsequent exposure to the same antigen
What are monocytes
A type of Leukocytes; leaves the bloodstream as a macrophage
What do NK cells do
Class of lymphocytes that bind to cell smearing foreign antigens without specific recognition and kill them directly; major targets are virus-infected cells and cancer cells; participate in antibody-dependant cellular cytotoxicity (ADCC)
What do neutrophils do
Leukocytes that function as phagocytes and also release chemicals involved in inflammation
What do Plasma cells do
Cells that differentiate from activated B lymphocytes and secrete antibodies
What are T cells
Lymphocytes derived from precursors that differentiated in the thymus
