Immune System Flashcards
What is the second line of defense?
The second line of defense consists of white blood cells, phagocytes and inflammatory response.
WBC’s would act if pathogens/invaders actually get within your body. They normally circulate throughout the blood but will enter the body’s tissues if invaders are detected.
Phagocytes are also a WBC, but they are responsible for eating foreign particles. Once they’re engulfed, it breaks them apart in organelles called Lysosomes.
The inflammatory response is triggered when the injured body cells release chemicals called histamine. This causes capillaries to dilate, pain receptors to activate, pyrogen to be released and sent to the hypothalamus which causes temperature to rise, swelling, redness and WBCs to flock to the infected area.
What is the third line of defense?
Once the pathogen has entered the tissues, the third line of defense activates which is an attack from lymphocytes. There are two types of lymphocytes: B-lymphocyte and T-lymphocyte.
B-lymphocyte make bullets like antibodies to kill pathogens. They mature and are produced in bone marrow.
T-lymphocytes have two types of cells: The Helper T-Cell and the Killer T-Cell. The Helper T-Cell activates other cells, keeps them going and alerts about the invader; a dobber cell. The Killer T-Cell kills the pathogen. T-lymphocytes are produced in bone marrow but mature in the Thymus.
What are the two divisions of the third line of defense called?
The two divisions of the third line of defense are:
Antibody-mediated immunity which it is controlled by antibodies. This works in the fluids of the body and is produced by B-lymphocytes.
The other division is the cell-mediated immunity which involved Killer T-Cells and Helper T-Cells.
Cellular Immunity vs Antibody/Humoral Immunity.
Cellular immunity is carried out by T-Cells and infected cells are killed by Cytotoxic T-Cells. The Antibody/Humoral immunity is carried out by B-lymphocytes where antibodies are produced and dumped into the bloodstream where it binds to antigens and deactivates them.
The Pathway of Specific Immune Response
- Pathogens eaten by macrophage
- Displays portion of pathogen on surface
- Helper T-Cell recognises pathogen
- Activated Helper T-Cell goes into bloodstream and activates Cytotoxic/Killer T-Cells and B-lymphocytes
- B-lymphocytes create antibodies and B-memory cells
- Antibodies will kill the pathogens, memory cell will remember it for next time
- Activated T-Cells will also make T-memory cells and kill infected cells
What is immunity?
A resistance to a disease-causing organism or substance. There are two types of immunities: Passive and Active.
What is Active immunity?
Active immunity is that you produce the antibodies and that your body has been exposed to the antigen naturally.
Artificial active immunity is that your body responds to an injected bacteria which is in a form of an injection.
What is Passive immunity?
Passive immunity is that you don’t produce the antibodies, but that its already produced; e.g breast milk. Artificial passive immunity is antibiotics.
What are some immune disorders?
Some immune disorders are:
- AIDS (Acquired Immune Deficiency Syndrome) HIV (Human Immunodeficiency Virus): Lowers the immune system response
- Allergies: Immune system mistakenly recognises harmless foreign particles as serious threats which launches inflammatory response (sneezing, coughing, runny and watery eyes). Anti-histamine needs to be used to block the effect of the response and bring relief to the sufferers.
What is the first line of defense?
The first line of defense consists of the majority of the body’s exterior such as the skin, eyes, respiratory tracts, vagina, urethra and anus. The skin is a impervious barrier against bacteria (unless it is cut) and the eyes produce chemicals that prevent the growth of bacteria and cleanses, whilst the respiratory tracts (mouth, nose ears etc) have wax to trap the pathogens, saliva to clean the mouth and hairs and mucus to trap pathogens. The vagina secretes acid that prevents the growth of bacteria and the urethra (urine) prevents bacterial growth and the anus has a mucus membrane to trap pathogens.
There is also the hydrochloric acid in the stomach which kills the pathogen if it manages to enter through the throat.
