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Flashcards in The Defence System Deck (15)
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Distinguish between active and passive immunity.

ACTIVE-antibodies are produced by person in response to invading antigens
PASSIVE- antibodies produced in another individual are given to person


Why is a person more likely to pick up an infection in hospital than at home?

-poor hygiene
-more pathogens in hospital


State two ways, other than colour, in which red blood cells differ from white blood cells.

RED - no nucleus/ no vacuole/ contain haemoglobin
WHITE- nucleus/vacuole/ bigger than red blood cell


Name a group of white blood cells other than lymphocytes.

Monocytes/ phagocytes


What is the role of antibodies in the body.

-produced by white blood cells in response to antigen
-antibodies bind to an antigen, which may kill the pathogen,destroy its activity or prevent it from entering the host cell


Name types of T-cells.

Helper T-cells
Killer T-cells
Suppressor T-cells
Memory T-cells


State role of Helper T-cells.

Formed in response to white blood cells engulfing pathogens
- help B cells make antibodies


State role of Killer T-cells

Attack and destroy abnormal body cells , eg. Virus infected cells & cancer cells


State role of Suppressor T-cells

Decrease activity of B-cells and T-cells
Turn of immune system when antigen is no longer present.


Write note of lymphocytes-role.

-white blood cells responsible for immunity
-originate in red bone marrow but mature in different places
1) lymphocytes maturing in bone marrow are called B-cells
2) lymphocytes maturing in thymus are called T-cells


What is meant by the term immunity?

Immunity is the ability to resist disease caused by a specific pathogen.


Outline the role of B- lymphocytes in human immune system

Produce memory cells
Recognise a particular antigen& produce antibodies


What is an ANTIGEN ?

A foreign substance that triggers production of a specific antibody by lymphocytes


Name two types of lymphocytes and state a role of each when viruses enter blood or other microorganisms.

-divides to give a rise to a large number of identical cells
-Killer T-cells attack and destroy abnormal body cells


Distinguish clearly between antibodies and antibiotics.

ANTIBODIES: protein molecule made by a lymphocyte in response to an antigen
ANTIBIOTIC: chemicals made by microorganisms that kill harmful microorganisms