immune system 1

Question 1

what is immunology

Answer 1

study of physiological mechanisms that humans and animals use to defend their bodies from invasion by all sorts of organisms. to provide immunity, the immuno-system has to be the forst battle of defense

Question 2

what is an immunogen

Answer 2

a molecule that stimulates the immune system to produce a response

Question 3

what is an antigen

Answer 3

part of the immunogen that reacts is identified as foreign and triggers an immune response

Question 4

what is an epitope

Answer 4

part of the antigen that reacts with immune effector cells or soluble antibodies

Question 5

what are the 4 main types of pathoegns

Answer 5

bacteria
virus
fungi
parasite

Question 6

myeloid cells classification (granulocytes)

Answer 6

neutrophils
eosinophil
basophil

Question 7

myeloid cell classification (antigen presenting cell)

Answer 7

monocyte
macrophage
dendric cell

Question 8

whatare the 3 myeloid cell classifications

Answer 8

antigen-presenting cells
mast cells
granulocytes

Question 9

lymphoid cell classifcations

Answer 9

1)small lymphocytes
b cells
t cells

2) large lymphocytes
NK cells

Question 10

what are the primary lymphoid tissues

Answer 10

bone marrow: soft and spongy tissue that fills cavity bones
B and T cells originate in it
B cells mature whereas T cells leave immature

thymus: located above the heart
immature T cells from bone marrow migrate here, as they differentiate they progress from cortex to medulla

Question 11

what are the secondary lymphoid tissues

Answer 11

sites where mature lymphocytes are activated to respond to invading pathogen

Lymphatic vessels originate in the connective tissues throughout the body where they collect the plasma fluid that continually leaks out from blood vessels
* Lymph nodes lie at the junctions of a network of lymphatic vessels
* This fluid, called lymph, is returned to the blood vessels via the thoracic duct
* Circulating lymphocytes can move from blood capillaries to lymph nodes where they can eventually meet a pathogen

Question 12

what occurs at the lymph nodes in the secondary lymphoid tissues

Answer 12

• Arriving lymphocytes segregate in different areas of the lymph node
• During an infection pathogens are drained in lymph nodes from the afferent lymphatic vessels where they are trapped by dendritic cells and macrophages
• B and T cells “meet” the pathogen and are activated, undergo clonal expansion and differentiation
• As the lymphocytes grow in number, the lymph node increases in size (swollen glands)

Question 13

what are the two types of immunity

Answer 13

adaptive immunity and innate immunity

Question 14

differenced between adaptive and innate immunity

Answer 14

innate is rapid and takes a few hours and does not leave memory cells, whereas adaptive immunity takes a few days and creates memory cells

innate immunity is fixed whereas adaptive varies

innate immunity has limited specificity whereas adaptive immunity is highly specific

Question 15

what are the immediate innate immunity responses

Answer 15

barriers
antimicrobial peptides
complement system

Question 16

what is the complement system

Answer 16

group of 30 proteins that work in an orderly system
they have an inital action and a highly regulated enzymatic cascade

Question 17

what are the 4 roles of the compliment system

Answer 17

1) Some activated proteins bind covalently to bacteria (opsonin). Bacteria are then phagocytosed by cells with complement receptors
2) Some small fragments (C3a and C5a) of complement recruit phagocytes to the site and regulate the inflammatory response
3) Some products activate B cells
4) Terminal component of system generates Membrane Attack Complex
(MAC), which causes the Lysis of pathogen

Question 18

what are the two pathways in the complement system

Answer 18

classical pathway
alterative pathway

Question 19

what are main phagocytosis cells

Answer 19

1) neutrophils
short-lived cells
multilobed nucleus
abundant sites of acute inflammation

2) mononuclear phagocytoses (monocytes and macrophages)
blood monocytes
longer lived
also antigen presenting cells

Question 20

what is the process of phagocytosis

Answer 20

opsonization: makes a pathogen more susceptible to be engulfed
the pathogen is then engulfed and killed using lysosomal enzyme

Question 21

cytokines production

Answer 21

• Low molecular weight proteins - (5-25kDa) secreted by cells that stimulate or inhibit the activity, proliferation or differentiations of other cells
• Around 20 Cytokines - include sub groups interferons, lymphokines, interleukins, chemokines
  1. Mediators and regulators of innate immunity
  – Produced mainly by mononuclear phagocytes (neutrophils and macrophages) in response to infectious agent
  2. Mediators and regulators of adaptive immunity
  – Produced mainly by T lymphocytes in response to specific recognition of foreign antigens
  3. Stimulators of hematopoiesis – Produced by bone marrow stromal cells, leukocytes and other cells and stimulate the growth and differentiation of immature leukocytes