U3: 22- Specific Cellular Defences Against Pathogens Flashcards
Is the 3rd line of defence described as specific or non-specific?
Specific
Which group of cells in the immune system bring about a specific immune response?
B-Lymphocytes and T-Lymphocytes
All lymphocytes originate in the bone marrow. If they pass to the thymus to mature what do they become?
T-Lymphocytes
If lymphocytes complete their maturation in the bone marrow what do they become?
B-Lymphocytes
What name is given to any foreign molecule that is able to elicit a specific immune response from a lymphocyte?
Antigen
Give some examples of antigens.
Bacteria, viruses, cancer cells, molecules on the surface of transplanted cells
There are a number of different lymphocytes. What is found on the surface of every lymphocyte that makes each lymphocyte different?
A different antigen receptor
What are the antigen receptors on the surface of lymphocytes specific to?
One type of antigen
Whenever an antigen attaches to the specific antigen receptors on a lymphocyte the lymphocyte is activated and responds by dividing repeatedly to form identical lymphocytes. What is this called?
A clonal population
Whenever an antigen enters the body the B-Lymphocytes respond by producing what?
Antibodies
What shape is an antibody?
Y-shaped
What is found at the end of each arm of the Y-shaped antibody?
A receptor specific to a particular antigen
When a B-Lymphocyte becomes activated by the presence of an antigen it responds by making a clone of B-Lymphocytes which all make antibodies. What other cells are made to produce the same antibodies if they are needed in the future?
Memory B-Lymphocytes
What name is given to the combination formed when the antibody binds to the antigen?
Antigen-antibody complex
The formation of the antigen-antibody complex makes the pathogen more susceptible to…?
Inactivation of it or the toxin it produces and phagocytosis
What happens when B-Lymphocytes respond to a harmless substance such as pollen, dust or feathers?
An allergic reaction occurs
In hay fever, which is an allergic reaction, B-Lymphocytes produce antibodies which then attach to which cells in the connective tissue?
Mast cells
During an allergic reaction mast cells over produce a substance which causes nasal congestion and constricted airways. What is this substance?
Histamine
During anaphylactic shock lots of histamine is released so the blood vessels undergo extreme vasodilation. What does this do to blood pressure that can potentially result in death?
Blood pressure drops suddenly
Whenever a phagocyte captures a pathogen it normally presents some of the pathogen’s antigen on the phagocyte surface. What name is given to the phagocyte in this state?
Antigen-presenting cell
What recognises and binds with these antigens on the surface of an antigen presenting cell?
A T-Lymphocyte that has the specific antigen receptor that recognises that particular antigen
When an antigen-presenting cell becomes attached to a T-Lymphocyte what two things happen?
A clonal population of T-Lymphocytes are made as well as memory T-Lymphocytes
The T-Lymphocytes destroy the infected body cells by which process?
Apoptosis (programmed cell death)
Apoptosis by T-Lymphocytes destroy the majority of the infected cell, however, the cell membrane of the infected cell is not destroyed. What process follows apoptosis to remove the remaining parts of the dead cell?
Phagocytosis
What name is given to cells that the body recognises as part of that person and unique to them?
Self cells
Normally T-Lymphocytes do not attack self cells and only attack non-self cells. If they do attack self cells what is this called?
Autoimmunity
What autoimmune disease is characterised by the T-Lymphocytes attacking the insulin producing cells in the pancreas?
Type 1 diabetes
Name an autoimmune disease where the joints become inflamed.
Rheumatoid arthritis
What name is given to the first time the body produces antibodies to a disease?
Primary response
If a person survives an earlier exposure to a certain pathogen and then becomes exposed again later what response kicks in?
Secondary response
In which 3 ways is the secondary immune response better than the primary immune response in preventing a disease the second time round?
Antibody production is more rapid, produced at a higher level and lasts for a longer time
Which cells ensure that the secondary immune response is made possible?
Memory cells
Which lymphocytes are attacked by HIV (Human Immunodeficiency Virus)?
T-Lymphocytes
Which disease follows HIV where the person is susceptible to opportunistic infections such as pneumonia and rare forms of cancer because their immune system is so weak?
AIDS (Acquired Immune Deficiency Syndrome)
