Flashcards in immune system Deck (56):
what is innate (non-specific) immune system?
-first line of defence
-responses are rapid but limited
use toll-like receptors
does the innate immune system involve the production of antibodies?
what cells does the innate immune response include?
-natural killer cells
what is the adaptive or specific immune system?
-specifically targets foreign material to which body has already been exposed
-takes time to prepare for attack
-formation of memory cells
what is the response of the adaptive immune system mediated by?
-response is mediated by B and T lymphocytes
what cells are in the adaptive immune system?
what are the chemical/internal innate barriers?
what are neutrophils
highly mobile phagocytes that engulf and destroy unwanted material
what are eosinophils
-secrete chemicals that fight parasites
-involved in allergic reactions
what are basophils
-release histamine and heparin
-involved in allergic reactions
what are monocytes
-transformed into macrophages
what are lymphocytes
1) B cells
-transformed into plasma cells that secrete antibodies
2) T cells
-responsible for cell-mediated immunity
-directly destroy and invade mutant cells
what is the complement system?
its a system that compliments the actions of antibodies to kill foreign cells by forming membrane attack complexes (MAC)
how does the compliment system work/ consist of?
consist of plasma proteins, when activated, the donut shaped protein complex embeds itself in the surface membrane of nearby microorganisms , creating a large channel through the membrane- the hole punching technique makes the membrane makes the membrane leaky, resulting in the victim cell swelling and bursting.
what does interferon act as?
a whistle blower
how does interferon work?
When a virus invades a cell, in response to being exposed to nucleic acid, the cell secretes interferon. Once released into the EFC, interferon binds with receptors on the plasma membrane of a healthy neighboring cell as a signal that they need to prepare for a viral attack Interferon is a whistle blower.
what does interferon trigger?
Interferon triggers the production of virus-blocking enzymes. Shen interferon binds with other cells, they synthesis enzymes that can break down RNA and inhibit protein synthesis
what other actions can interferon do?
-enhances macrophage activity and antibody production
-exerts anticancer (NK cells) and T cells
-slows cell division
enhances action of NK cells,
what is inflammation?
-non specific response to tissue injury with the help of a macrophages and neutrophils
are NK cells specific or non specific?
-they lyse and destroy virally infection host cells and cancerous cells
what is the sequence of inflammation
-defense of resident tissue macrophages
-increased capillary permeability
-walling off the inflamed area
-emigration of leukocytes
-marking of destruction of bacteria
-mediation of inflammatory response by phagocyte-secreting chemicals
-tissue healing and repair
what occurs In localized vasodilation
- bacteria invasion at injury
-release of histamine
-enhances dilation of blood vessles, so more blood flow can go to injured site
-brings more leucocytes and plasma proteins
what is localized oedema?
-the accumulation of plasma proteins in internstial fluid
-moves fluid out of capillary and accumulate in injured area
-pain from inflammation is causes by distention of swollen tissue and prostaglandins
what occurs in the walling off the inflamed area?
-leaked plasma proteins also brings thromboplastin- thrombin
-this converts fibrinogen into fibrin
-forms a clot around the bacterial invader and damaged tissue
walling off prevents spread of invaders
what are the 3 ways leukocytes emigrate to invaded tissue?
what do chemotaxis (secreted by macrophages) do?
-attract neutrophils and monocytes which squeeze out between cells of the blood vessles (diapedesis) and migrate of the infection site
what happens in the destruction of bacteria phase?
macrophages and neutrophils release hydrolytic enzymes (lysosomes) that break down bacteria and trap it, the trapped portion forms pus.
what does interleukin (IL-1) do?
increases proliferation and differentiation of B and T cells for antibody production and cell-mediated immunity
what are the two subgroups of specific immunity?
1) antibody-mediated or humoral immunity
2) cell-mediated immunity
what does antibody-mediated/ humoral immunity involve?
-production of B lymphocytes derived from plasma cells
what do B cells do
B cells: recognize free existing foreign invaders, such as bacteria and their toxins, a few viruses, secrete antibodies specific for invaders
what does cell-mediated immunity involve?
involves production of T cells
what do T cells do?
-directly attack unwanted cells
-specialize in recognition and destroying body cells gone awry, including virus- infected cells and cancer cells.
what is an antigen?
-a surface protein present on the microbes and tags a microbe as a foreigner
structure of antibody?
- made up of four interlinked polypeptide chains
-has two, long heavy chains, and two short light chains
where Is the antigen binding site?
fab, of the Y region
-determines what the antigen can bind to
what does the tail portion of the antibody do and what is it called?
-region determines the functional; properties of the antibody
what does IgM do?
serves as a B cell surface receptor for antigen attachment and secreted in the early stages of plasma cell response
what does IgG do?
most abundant in blood
-only produced when body is exposed to the same antigen
what is IgA found?
found in the secretion of the digestive, respiratory, and milk and tears
what does IgE do?
-helps protect against parasitic worms
-involved in common allergic responses
where is IgD present?
Is present on the surface of many B cells
what are the two possibilities that B cells do when binding to a presented antigen?
1) differentiate into active plasma cells
2) become dormant
what happens after B cells differentiate into plasma cells?
-they produce specific antibodies to neutralize specific antigen
what do plasma cells do?
-produce and secrete IgG antibodies
-marks antigen for destruction
what is the other thing that B cells can become?
memory cells (dormant)
what is active immunity?
-results from exposure to antigen
what is passive immunity?
-from mother to fetus
they don't secrete antibodies, the directly bind and destroy target cells
-carry out cell mediated immunity
what are the two types of T cells?
1) CD8 cells
2) CD4 cells
what are CD8 cells?
-cytotoxic or killer T cells
-destroy host cells of anything foreign
what do CD4 cells do?
secrete chemicals that amplify the activity of other immune cells
what are the three methods of antigen neutralization?
what is agglutination
when foreign cells or mis-matched transfused RBS bind together and clumps
what is precipitation
when antigen-antibody complexes involves toxins that become large and separate out from solution