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IMMUNITY VALENTINA RE AND BIANCA IERACI - Coggle Diagram
IMMUNITY
VALENTINA RE AND BIANCA IERACI
INMUNE SYSTEM
Is one of the most important systems in our body as it is made up of cells that protect you from the constant threat of pathogens.
PATHOGEN = viruses, bacteria,
fungi, protists, parasitic worms, etc.
1st line of defence (non specific): we have external protection against the pathogens, for example, our skin or mucous membranes
2nd line of defence (non especific): this would be the inflamatory responses. When bacteria get inside your body, cells will react realising subtances (macrophages)
3rd line of defence (specific): includes B and T cells (white blood cells). This line of defence is going to be an adaptive response.
adaptive response
: specific response to an antigen, it is to say, something your body recognizes as non-self.
2 adaptive responses
cell-mediated
involves cytotoxic T cells that have the ability to destroy cells that have been infected by the pathogen, by releasing perforin. This causes the infected cell to perform apoptosis.
by this, it can kill the pathogen or prevent it from replicating inside the infected cell.
for it to work, you have to activate the cytotoxic T cells
humoral
involves B cells: white blood cells that have the ability to make antibodies.
antibodies
: proteins that have an antigen binding area that allows them to bind to a specific antigen
can be found in blood, mucus, saliva, breast milk, etc.
Different types of antibodies such as IgE
they can deactivate the pathogen by affecting the ability of this one to move, reproduce and cause harm.
they both include "memory cells" that will launch an effective attack if the pathogen is ever encountered again.
A person is immune to a disease if the pathogen that causes the disease is unable to reproduce in the body and cause illness.
Active immunity:
occurs when the person´s own lymphocytes make the antibody.
Natural
: as a result of the person having previously had the disease and forming B or T memory cells.
Artificial
: as a result of vaccination. By introducing weakened pathogens into the body.
Passive immunity:
occurs when antibodies from elsewhere are introduced into the body
Natural
: this happens in young babies. As a baby acquires antibodies from its mother in breast milk.
Artificial:
as a result of an injection of antibodies obtained from another animal.
Immune system
The human immune system is made up of the organs and tissues involved in destroying pathogens inside the body.
Phagocytes
: are produced in the bone marrow by the mitotic division of precursor cells. This produces cells that develop into monocytes or neutrophils.
Monocytes:
are inactive cells which circulate in blood, They leave blood (macrophages) as the result of encoutering chemical signals indicating that bacteria or viruses are present. Monocytes / macrophages can live for several months.
Neutrophils:
they travel in blood, and then leave it in large numbers at sites of infection and engulf and digest bacteria in a similar way to macrophages. A neutrophil lives for only a few days.
Lymphocytes:
regognise specific pathogens through interaction with receptors in their cell surface membranes, and respond in one of several ways.
B-lymphocytes:
places some of its specific receptor molecules in its cell surface membrane. If it encourages an antigen that binds with this receptor, the B-lymphocyte is actived. It divides repeatedly by mitosis to produce a clone of genetically identical pasma cells. Some of the clone cells become memory cells. These remain in the blood form many years. more antibody is secreted more rapidly, and the pathogens will be destroyed before they have a chance to reproduce. Therefore, the person has become immune to thid psthogen.
T-lymphocytes:
include T helper cells and T killer cells. Both cells place their specific receptors in their cell surface membranes. On encountering the relevant antigen, they are activated and divide by mitosis to form a clone. Activated T helper cells secrete chemicals called cytokines, these stimulate monocytes and macrophages to attack and destroy pathogens. Activated T killer cells attach to body cells that display the antigen matching their receptor. T killere cell destroys thr infected body cell.
