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What is meant by the term immunity? Outline briefly the role of B lymphocytes in the human immune system - Leaving Cert Biology - Question c - 2007
Question c
What is meant by the term immunity? Outline briefly the role of B lymphocytes in the human immune system. Distinguish between active and passive immunity. "Vaccin... show full transcript
Worked Solution & Example Answer:What is meant by the term immunity? Outline briefly the role of B lymphocytes in the human immune system - Leaving Cert Biology - Question c - 2007
Step 1
What is meant by the term immunity?
Answer
Immunity refers to the ability of the body to resist infections or diseases caused by pathogens, such as bacteria, viruses, and other foreign invaders. It involves the recognition and response to these antigens, enabling the body to protect itself from harmful effects.
Step 2
Outline briefly the role of B lymphocytes in the human immune system.
Answer
B lymphocytes, or B cells, play a crucial role in the immune system by recognizing specific antigens. Upon activation, they produce antibodies that neutralize or mark these antigens for destruction. Additionally, some B cells differentiate into memory cells, which provide long-lasting immunity against previously encountered pathogens.
Step 3
Distinguish between active and passive immunity.
Answer
Active immunity occurs when the body generates its own antibodies in response to an antigen, typically through infection or vaccination. In contrast, passive immunity is when antibodies are introduced into the body from an external source, providing immediate but temporary protection.
Step 4
"Vaccination gives rise to active immunity". Explain this statement.
Answer
Vaccination introduces a harmless form of an antigen into the body, stimulating the immune system to produce its own antibodies. This process not only enables the body to mount a defense against the real pathogen but also results in the formation of memory cells, which ensure long-term protection.
Step 5
In certain situations a person is given a specific antibody rather than being vaccinated.
Answer
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This is an example of passive immunity.
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Antibodies may be administered in situations where there is a risk of serious infection, such as after exposure to a disease, when the individual is immunocompromised, or when a vaccine is unavailable or too expensive.
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The duration of immunity following the administration of antibodies is generally short-lived, as the body does not produce memory cells for the introduced antibodies, leading to a decline in protection over time.