defences, in protecting the body.
Our nonspecific immune system which is our first and second line of defence includes
cellular, physical, and chemical defences which help to protect us against pathogens the
purpose of the innate immune response is to automatically prevent the movement and
spread of the foreign pathogens throughout our body.(the innate vs Adaptive immune
response Author unknown, 2021)
We also have physical and chemical barriers that protect the body when being invaded
Physical barriers include:
1. vomiting and defecation which help to expel micro-organisms
2. mucous membranes which produce mucus that traps bacteria or microbes
3. cilia lines the upper respiratory tract this then locks and propels inhaled debris to the
throat
4. urine this flushes all the microbes out of the urethra
5. hair located within the nose and stops air containing pollutants and dust
6. lastly the skin which has thick layers of dead cells in the epidermis this provides a
physical barrier
(Immune System, Author unknown 2021)
Chemical barriers include:
1. Saliva reduces the number of micro-organisms and washes mouth and teeth
2. Acidity this helps to inhibit bacterial growth on the skin
, 3. Gastric juice which is located in the stomach destroys bacteria and some toxins
because of its high acidic Ph which varies from 2-3
4. Hyaluronic acid this slows the spread of noxious agents
5. Sebum which provides protection on the skin and stops growth
(Immune System, Author unknown 2021)
The cellular barriers which include natural killer cells and phagocytic cells phagocytes like
dendritic, macrophages, and neutrophils cells are all present in the blood. Tissues or fluids
of the body add up to the front line of internal defence of the host which catches and
engulfs foreign particles by a process called phagocytosis however natural killer cells are the
first line of surveillance providing protection against virus infected cells and tumour cells.
(Author Aryal.S nonspecific immune response, 2021)
Phagocytosis is when a white blood cell engulfs or destroys a pathogen by using the plasma
membrane it’s given this also helps to engulf larger particles as well the type of cell that
performs phagocytosis are also known as a phagocyte.(Phagocytosis | British Society for
Immunology Author unknown, 2021)
Complements which are also known as a group of non-specific serum proteins that add up
to the functions of the immune system, they play a very important role in providing
resistance against infection they do this by activating a sequential cascade of active proteins
that are lyse foreign cells and are the principal mediators of inflammatory response. (Author
Aryal.S nonspecific immune response, 2021)
Inflammatory response also has a crucial role in immunity when it comes to tissues being
damaged the inflammatory response is initiated which makes the immune system mobilized
the immune cells of the innate immune system like eosinophils and neutrophils are the first
to be recruited to where the tissue is damaged or in other ways such as the lymphatic
system, or blood vessels these are then followed on by macrophages. (Healio Innate and
Adaptive immune response Author unknown, 2021)