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PATHOGENS - Coggle Diagram
PATHOGENS
First line: Non-specific external barriers
nose
produces mucus so any particle trying to enter the body for the nose gest stuck to the mucus and never escape
has internal hair that traps any kind of particles trying to come inside the body
Trachea and bronchi
runs from the nose towards the lungs
cells that line the trachea also have hairs called cilia, move mucus and pathogens upwards towards the throat where it is swallowed into the stomach.
produce mucus
Skin:
Prevents pathogens from gaining entry into the body
If cut or grazed, it immediately begins to heal itself, often by forming a scab, which prevents infection as the skin acts as a physical barrier.
Eyes
tears containing enzymes like lysozyme, and tears come out in the form of reflex tears and our eyes are forsed to blink
because of the water on the eyes and the eyes itself blinking the particle which was trying to come in then has to jump out because of this situation
Stomach
produces hydochloric acid
in such corrosive solutions no thing can survive and so the pathogen get killed
Third line: Specific immune cells
Mechanism of third line of defence
Attack the pathogen
Remember the pathogen by the antigens present on it
Recognize the pathogen
main characters
Antigen
Antibody
Lymphocytes
Main Function
Attack the pathogen not destroyed by 1st and 2nd line of immunity
Develop immunity by developing memory of the infection
Antigen
It is a carbohydrate or protein on the surface of the pathogen. It can provoke the immune system of the host.
Antibody
These are proteins produces by the lymphocytes. It has the ability to recognize, bind to and destroy the pathogen. It is always Y-shaped.
the antibody will then go and stick to the antigen and try to kill the pathogen by itself or calls the Macrophage for help for killing the pathogen
second line of defence: Non specific immune cells
phagocytosis
Follow process of phagocytosis
It is a process wherein a cell binds to the item it wants to engulf on the cell surface and draws the item inward while engulfing around it. The process of phagocytosis often happens when the cell is trying to destroy something.
There are three main groups of phagocytes: macrophages, neutrophils (type of granulocyte) and dendritic cells
Inflammation
When tissue damage occurs, macrophages release a chemical called cytokines
Cytokines causes local vasodilation (widening of blood vessels) and increases capillary permeability (ability of solids and liquids to pass through) to improve the recruitment of leukocytes (white blood cells) to the region
Damaged cells also release chemotactic factors (chemicals that attract other molecules/cells) which attract leukocytes to the site of infection. Phagocytosis takes place.
While inflammation is necessary to allow immune cells access to damaged tissue, there are unavoidable side effects
immune cells and there function
Granulocytes
Type of white blood cell
Contains granules (small particles) with enzymes that are released during infections, allergic reactions, and asthma
enzymes in the granules damage or digest pathogens and release inflammatory mediators into the bloodstream
Dendritic cells
present on sites that can contact external environments
act as bridge between the innate immune system and the adaptive immune system
derived from monocytes
Mast cells
Reach first at the site of injury
Causes inflammation (swelling) at the injury site by releasing proteins called as histamines to bring in other cells of the immune system
Natural Killer cells
these cells do not kill pathogens
Destroy infected host cells in order to stop the spread of an infection
Neutrophils
Usually arrive first at the site of infection
Contain granules toxic to bacteria and fungi
Macrophages
that can leave the circulatory system by moving across the walls of capillary vessels
Release special proteins called as cytokines in order to signal and recruit other cells to an area with pathogens
derived from monocytes
Main functions of second line of defence
Inflammation (swelling
Degranulation
Phagocytosis