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Chapter 11 Immunity in Humans - Coggle Diagram
Chapter 11
Immunity in Humans
11.3 Types of Immunity
Two types of immunity:
Active Immunity :
• Antibodies produced
naturally
by lymphocytes
• Remains for a
long
period of time
a)
Natural active immunity
• Acquired after an individual recover from an injection
• When someone is
infected
by pathogens.
Lymphocytes
will produce
antibodies
as a response to these antigens.
• When an individual
recovers
from an infection, that individual will gain a
permanent
immunity against the disease.
• When the individual is attacked again by the same pathogen, the lymphocytes that stored memories of the pathogen, that is, memory cells will rapidly produce antibodies to react immediately against the antigens.
b)
Artificial active immunity
• Acquired when an individual is given vaccine
• To protect oneself from being infected by a highly infectious disease, an individual can be immunised against the disease.
• When individual
recovers
from an infection, that individual will gain
permanent
immunity against the disease
• When the individual is attacked again by the same pathogen, the lymphocytes that stored memories of the pathogen, that is, memory cells will
rapidly
produce antibodies to react
immediately
against the antigens.
Passive Immunity :
• The body does not produce its own antibodies.
• Antibodies are obtained from an external source.
• Passive immunity does not persist and can only give immediate,short-term and temporary protection
a)
Natural passive immunity
• Acquired through breastfeeding and from the mother to the foetus during pregnancy
• Acquired by a foetus when the
mother's antibodies
diffuse through the placenta into the blood flow of the foetus
• Antibodies also protect the baby for the first few months after birth through antibodies that are found in the mother's milk or colostrum when breastfeeding.
b)
Artificial passive immunity
• Acquired through an antiserum injection
• This immunity is acquired through an
antiserum injection
or
serum
that contains specific antibodies to fight specific antigens
• The antiserum injection gives immediate protection but only for a short period of time.
Examples:
antiserum for poisonous snakes
anti-rabies serum
11.2 ACTIONS OF ANTIBODIES
Agglutination
Antibodies coagulate the pathogens
Make them an easy target to be trapped
Destroy by phagocytes
Lysis
Antibodies combine with antigens
Causing bacteria to be broken down and decomposed
Neutralisation
Produced by bacteria
Neutralise the toxin
Antibodies bind with toxins
Precipitation
Antibodies react with dissolved antigens to
form an insoluble complex
Easily destroy by phagocytes
Opsonisation
Acts as a marker for phagocytes
To recognise the antigens and destroy them
Antibodies combine with antigens
11.1 BODY DEFENCE
ANTIGENS
-foreign particles that enter the body and subsequently stimulate immune response
Three lines of defence to fight
against diseases in our body
First Line of Defence
-Not specific
-prevent the entry of pathogens into the body via physical and chemical
Physical
Skin
-prevent the entry of pathogens = tough and difficult for microorganisms to penetrate
-continous shedding of dead cell layers on the skin surface = make it difficult for various type of microorganisms to grow
-Act as chemical shield
MUCOUS MEMBRANE
-Mucus membrane that lines the respiratory structure
-Secretes mucus
-Mucus contain lysozyme that destroy bacteria that found in the air
Chemical
Hydrochloric acid
-Acid in the stomach
-destroy bacteria present in food and drinks
LYSOZYME
-Antimicrobial protein that can dissolve and destroy some types of bacteria
-Example = secretion of tears, saliva and nasal mucus
https://bit.ly/3kG2kKf
Second line of defence
Non-specific defense mechanisms
Fever
Increases phagocytic activity
Fight against microorganisms
Phagocytosis
Types pf phagocytes
Neutrophils
Monocytes
Microorganisms (dead cells) are trapped and digested by phagocytes
Inflammation
Condition of the cells that swell due to infection by pathogens
Response
Damaged tissue released histamine
Histamine increases permeability of blood capillaries to phagocytes
Blood clotting mechanisms is triggered
Phagocytes carry out phagocytosis
Third Line of Defence
Involved immune response of lymphocytes
Lymphocyte T
attack the infected cells and produces chemical substances that trigger the lymphocyte B
Lymphocyte B
divides and forms the plasma cells and memory B cells
Antibodies produced are specific to kill specific pathogens.
Plasma cells produce antibodies that are compatible with the antigens
Memory B cells produced by the lymphocyte B function to store the information about the pathogens that infect the body
Plasma cells get activated to produce antibodies rapidly when the body is exposed to the same pathogens
Immunity
-the body ability to fight infections caused by pathogens or other foreign objects, through specific attacks on the pathogens
Pathogens
-microorganisms that cause disease
Example : bacteria, fungi and protozoa
ANTIBODIES
-Protein found on the lymphocytes surface or protein released by lymphocytes into the blood plasma
11.4 HEALTH ISSUES RELATED TO HUMANITY
Human Immunodeficiency Virus (HIV)
Attacks the human immunes system
Can cause AIDS
HIV spreads in the lymphocyte and destroys the lymphocytes
Does not show any symptoms for the first few years
Symptoms of disease
Chronic diarrhoea
Fungi infection
HIV transmission
Enters the body through the transfer of body fluid such as blood and semen or across the placenta
Individuals can be infected by HIV through unprotected sexual relations with an infected individual
Causes Acquired Immunodeficiency Syndromes (AIDS)
AIDS patient is easily infected by other diseases because of the progressive destruction of the individual's immune system
