13: natural protection vi immune system

Question 1

what is the immune system?

Answer 1

a complex system of cellular and molecular processes that identify self and non-self to protect body against foreign organisms and materials

Question 2

what are two cellular parts of the immune system?

Answer 2

lymphocytes and monocytes

Question 3

what are lymphocytes?

Answer 3

a type of immune cell that is made in the bone marrow and is found in the blood and in lymph tissue

Question 4

what are monocytes?

Answer 4

a type of white blood cell (leukocyte) in blood and tissues

Question 5

what are two molecular parts of the immune system?

Answer 5

antigens and lymphokines

Question 6

what are antigens?

Answer 6

• any substance that causes body to make an immune response against that substance
• include toxins, chemicals, bacteria, viruses, or other substances that come from outside the body

Question 7

what is non-specific immunity?

Answer 7

• physical + biochemical barriers to entry, eg skin, hair, body secretions
• cellular components, eg granulocytes, mediator cells, mononuclear cells
• humoral components, eg natural antibodies

Question 8

how do the immune responses of non-specific (NS) and specific (S) immune systems differ?

Answer 8

• NS is antigen independent, S is antigen dependent
• NS has an immediate maximal response, while S has a lag time between exposure + maximal response
• in S, exposure results in immunological memory, while NS does not
• S is antigen specific, NS is not

Question 8

what is specific immunity?

Answer 8

• attacks pathogens or antigens
• enhanced response when same organism/antigen is received subsequently
• mediated by humoral and cellular response

Question 9

what are other names for non-specific immunity?

Answer 9

innate or native

Question 10

what is another name for specific immunity?

Answer 10

adaptive

Question 11

explain the two types of adaptive immunity

Answer 11

humoral immunity: b lymphocytes secrete antibodies that prevent infection and eliminate extracellular microbes
cell-mediated immunity: t lymphocytes either activate macrophages to kill phagocytosed microbes or cytolytic t lymphocytes directly destroy infected cells

Question 12

what are the 5 phases of adaptive immune response and what happens in them?

Answer 12

recognition phase: antigen is recognised
activation phase: lymphocytes are activated
effector phase: antigen is eliminated
decline: antigen stimulated lymphocytes die by apoptosis
memory: surviving antigen specific cells responsible for memory

Question 13

what is the function of a b lymphocyte?

Answer 13

neutralisation of a microbe, phagocytosis, complement activation

Question 14

what are the functions of helper t cells

Answer 14

• activation of macrophages
• inflammation
• activation (proliferation n differentiation) of t and b lymphocytes

Question 15

what are the functions of cytolytic t lymphocytes and natural killer cells?

Answer 15

killing of infected cells