Immune System
Non-Specific Response
First line of defence Second line of defence
Active immunity is activated if pathogens do get into
Positive Immunity
the body
Chemical & Physical barriers Phagocytosis-
This is the body’s natural barrier which includes • Phagocytes take in and breakdown foreign
particles when detected. They are a type of
Skin – protect the body from physical
WBC (white blood cell).
damage, microbe infections, dehydration.
• When the phagocyte detects an external
Microbes have a hard time trying to
item, it moves towards it.
penetrate the dead dry outer layer of the
• The membrane of the phagocyte then
skin, the sebum produced by the skin also
ventures out and surrounds the foreign
helps kill any microbes that try to infect
object in a vacuole.
the body though the skin.
• The lysosomes inside the phagocyte combine
with and release enzymes into the vacuole.
• The enzymes then breakdown the external
object and the products are either absorbed
Stomach acid- the stomach contains into the cell or released.
hydrochloric acid which destroys micro-
organisms that are swallowed alongside
food and drinks. It helps defend the body
from food poisoning caused by salmonella
and other bacteria.
https://www.britannica.com/science/phagocytosis
Tears, saliva and mucus- carry enzymes
called lysozyme which destroys Inflammation
microorganisms.
Nasal hair, mucus, cilia- Nasal hair traps Most often occurs when the body has an
and dust and large micro-organisms and injury and infection is localised at one site.
prevents them entering the body. When tissue is damaged the mast cells and
Mucus- it is sticky, it also traps dust and damaged white blood cells release histamine
microbes, they then are taken away by Dilation and increased leakiness of local
cilia, these are small hairs on the cells blood vessels; migration of phagocytes to the
which line the gaseous exchange tract. area
Sweat glands- Secrete combination of Phagocytes consume the bacteria and cell
water, sodium chloride and metabolic debris and then the tissue begins to heal
https://www.google.com/url?sa=i&url=https%3A%2F
waste products which hinder the growth of %2Fwww.pinterest.com%2Fpin
non- normal microflora. %2F349451252311955735%2F&psig=AOvVaw2Q1q_nIUYRgpV
P1HzN5ZHd&ust=1585158173739000&source=images&cd=vfe
&ved=0CAkQjhxqFwoTCMjNiMXUs-gCFQAAAAAdAAAAABAM
Non-Specific Response
First line of defence Second line of defence
Active immunity is activated if pathogens do get into
Positive Immunity
the body
Chemical & Physical barriers Phagocytosis-
This is the body’s natural barrier which includes • Phagocytes take in and breakdown foreign
particles when detected. They are a type of
Skin – protect the body from physical
WBC (white blood cell).
damage, microbe infections, dehydration.
• When the phagocyte detects an external
Microbes have a hard time trying to
item, it moves towards it.
penetrate the dead dry outer layer of the
• The membrane of the phagocyte then
skin, the sebum produced by the skin also
ventures out and surrounds the foreign
helps kill any microbes that try to infect
object in a vacuole.
the body though the skin.
• The lysosomes inside the phagocyte combine
with and release enzymes into the vacuole.
• The enzymes then breakdown the external
object and the products are either absorbed
Stomach acid- the stomach contains into the cell or released.
hydrochloric acid which destroys micro-
organisms that are swallowed alongside
food and drinks. It helps defend the body
from food poisoning caused by salmonella
and other bacteria.
https://www.britannica.com/science/phagocytosis
Tears, saliva and mucus- carry enzymes
called lysozyme which destroys Inflammation
microorganisms.
Nasal hair, mucus, cilia- Nasal hair traps Most often occurs when the body has an
and dust and large micro-organisms and injury and infection is localised at one site.
prevents them entering the body. When tissue is damaged the mast cells and
Mucus- it is sticky, it also traps dust and damaged white blood cells release histamine
microbes, they then are taken away by Dilation and increased leakiness of local
cilia, these are small hairs on the cells blood vessels; migration of phagocytes to the
which line the gaseous exchange tract. area
Sweat glands- Secrete combination of Phagocytes consume the bacteria and cell
water, sodium chloride and metabolic debris and then the tissue begins to heal
https://www.google.com/url?sa=i&url=https%3A%2F
waste products which hinder the growth of %2Fwww.pinterest.com%2Fpin
non- normal microflora. %2F349451252311955735%2F&psig=AOvVaw2Q1q_nIUYRgpV
P1HzN5ZHd&ust=1585158173739000&source=images&cd=vfe
&ved=0CAkQjhxqFwoTCMjNiMXUs-gCFQAAAAAdAAAAABAM
