Chapter 17: The Human Immune System (ABO Blood types (ABO antibodies…
Chapter 17: The Human Immune System
Pathogens: Organisms that cause disease.
Germs are spread through physical contact, airborne contact (e.g. coughing), contaminated water/food, and infected animals.
Our body's immune system can fight in a
(attacking anything foreign) or
(identifying invading cells) way.
First line of defence
Barrier that prevents pathogens from entering the body.
: Release mucous, trapping microbes.
: In respiratory system. Sweeps out mucous containing microbes.
: Kills germs that enter through nose + mouth.
Second line of defence
Limits the spread of invaders
before specific lines of defence kick in.
Characterised by swelling, redness, soreness, and increased warmth.
(enlargement of blood vessels).
Increases blood supply
to infected areas (bringing more nutrients and cells like phagocytes to fight invaders).
Also responsible for symptoms for the
(e.g. sneezing, redness of the eyes).
increased body temperature
--> faster immune system --> microbes find it harder to function.
Engulf invading microbes.
(a type of white blood cell that extends
) can engulf large no. of microbes for a long period of time.
Chemicals released to block
Specific defence - Third line of defence
in the blood, lymph, lymphatic tissue: Spleen, nodes, tonsils, and adenoids.
Originate in bone marrow.
2 types of lymphocytes.
(anything that triggers an immune response).
against a specific antigen.
Remember: B for boost
Fight pathogens in
. Does not produce antibodies.
Remember: T for take on.
Each antibody can only bind to
one specific antigen
and nothing else.
to them -->
--> to be engulfed by phagocyte.
Fundamental mechanism in the development of immunity.
Antigens bind to
T/ B lymphocytes
, which become
(clones itself) and differentiate into
plasma and memory cells
Fight antigens immediately (primary immune response).
Don't live long.
Also fight antigens.
in blood in small no. for a lifetime.
: Capacity of the immune system to generate a secondary immune response.
Mechanism that prevents you from getting a specific viral infection more than once.
Types of immunity
and don't survive long.
E.g. Maternal antibodies given to baby through placenta or breastmilk.
a baby gets from its mother. Contains
You make antibodies yourself after
recovering from an illness/ after vaccine.
dead/ alive viruses
to stimulate immune response.
ABO Blood types
ABO antibodies circulate the blood plasma and bind with ABO antigens in an improper transfusion.
It's dangerous for a recipient to have antibodies for the antigens of the donor.
is done to prevent this. (Where the two individuals blood samples are mixed in a lab to see if they match).
: Universal donor because it contains no antigens that would trigger any other blood type to make antibodies.
: Universal recipient because even if it's triggered by A and B antigens, it will not produce any antibodies.
Blood is inherited and unchangeable.
4 blood types: A, B, O, AB.
Antigens are on the surface of red blood cells
and can trigger the body to make antibodies to fight against it if foreign.
Meaning of the table: Antigens are present, antibodies are not until triggered to be produced by another non-matching antigen. The table shows the antibodies produced if triggered.
Acquired immune deficiency syndrome.
HIV (human immunodeficiency virus)
attacks helper T cells
(which is a type of T lymphocyte that helped B lymphocyte make antibodies).
(viral RNA uses
enzyme to make DNA and
(make part of) its own genome, like a reverse transcription.
Dangerous as it weakens the immune system, so the patient is vulnerable to diseases like cancer and infections.
Allergies, antibiotics, vaccines, and autoimmune diseases.
Hypersensitive immune responses to
Response: Lots of
Sometimes an acute allergic response leads to
, which can result in death.
Kill bacteria/ fungi.
the disease after a person is ill.
Prevent viral infections
There are no cures for viral infections.
E.g. Human papilloma virus vaccine to prevent cervical cancer.
When the immune system cannot properly tell apart itself and foreign things.
Perceives certain structures in the body as foreign and attacks them.
E.g. Multiple sclerosis, juvenile diabetes.
Treatment: Reduce symptoms by
suppressing the immune system
while also maintaining the body's ability to fight disease.