The Defence System Flashcards
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.
B-cells
-divides to give a rise to a large number of identical cells
T-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
