cells and organs of the immune system

Question 1

what is immune system

Answer 1

are cells and tissues in our body that recognize and attach foreign substances/pathogens in our body

Question 2

how are we infected

Answer 2

1. when pathogen bridge our first line of defence (are barriers which our body has build against the outside. example: skin, nose or epithelial cells lining our gut)
   so, body use both epithelial and mucosal surfaces lining all contact area from outside to protect us.

Question 3

what are mucosal or mucosal membrane

Answer 3

are membrane that line body cavity and surfaces of the internal organs.
they are consist of one or more epithelial cells on the surface.
mucosal membrane in our body they can secrete mucus for example in our nose to keep us health

Question 4

what happens at the site of entry

Answer 4

• first microorganism have to get close to us
• phagocyte (can eat up the pathogens) and local immune response will become active and try to hear the wound, preventing us from infection.
• so if they can not hear/ take care of infection, local immune response will induce second phase called inflammantion
• in inflammation they will be macrophage recruited and activated and we dendritic cells that move to close lymphonode and initiate adaptive immunity.
  -adaptive immunity have ability to target structure that are specific to the pathogen that is infecting us
• adaptive immunity will protect us from re-infection bt creating memory immunity. it is accomplished by specific antibody to the pathogen
• specific T cells can make macrophage more efficient
• cytotoxic T cells can kill and affect cells where virus is duplicated.

Question 5

what is inflammation

Answer 5

means they are more cells and immune molecule recruited to the site of infection.
ex: cytokine ,chemokines, complements, NK cells, phagocytes

Question 6

what is cytokines and chemokines

Answer 6

cytokines are proteins made up of cells that affect behaviour of other cells. often immune cells
chemokines are proteins that stimulate migration and activation of other cells. they guide cells to different place in our body

Question 7

what do we call cytokines made of lymphocytes

Answer 7

are called interleukines

Question 8

what are the cells of immune system

Answer 8

we main focus on white blood cells/ leukocytes
they are neutrophils, eosinophil, basophils, lymphocytes and monocytes, T and B cells

Question 9

where does all immune cells arise from

Answer 9

bone marrow or hematopoietic stem cells

Question 10

what is red blood cells and platelets

Answer 10

red blood cell they transport oxygen
platelets they help to close up wound/ clotting

Question 11

what are lymphoid progenetor

Answer 11

B and T cells (has antigen presenting receptors), NK cells, dendritic cells and ILC

Question 12

what are cells in granulocytes

Answer 12

neutrophils, eosinophils, monocytes, basophil and lymphocytes

Question 13

what is monocyte

Answer 13

they circulate in the blood and migrate into tissues and then they differentiate and become macrophages.

Question 14

what is macrophage

Answer 14

-macrophage in tissues they are long lived , they engolf and kill pathogens
- they induce inflammation
- they secrete signal in proteins that activate other immune cells to form immune response

Question 15

what is mast cells

Answer 15

• they found in tissues while other granulocytes are found in blood
• role in allergy responses
  -they have granule structure which secrete the activation

Question 16

where does cells in lymph node found

Answer 16

in blood and tissues

Question 17

when does lymph node cells become effector cells

Answer 17

example: when T and B cells encounter antigen they differentiate into effector cells.

Question 18

what are innate and adaptive immune response

Answer 18

• innate immune system is our first line of defence. and is based on pattern recognition receptor ( they are same always) that can detect common features of pathogens. so when it fails then
• adaptive immune system kick in. here we have antigen binding receptor (they can change and become better) involve and have high variability

Question 19

what are cells that belongs to innate immune system

Answer 19

-NK cells
-granulocytes
-dendritic cells
- ILC

Question 20

what are cells that belongs to adaptive immune system

Answer 20

B and T cells

Question 21

what are task of different cells in innate immune system upon activation

Answer 21

• macrophage (present antigen to T cells) and neutrophils: responsible for phagocytosis, induce inflammantion and activation of bactericidal mechanism (kill bacteria).
• dendritic cells: antigen uptake in peripheral cites and presenting antigen in lymph nodes. they also link two systems. they activate adaptive immune response.
• eosinophil: kill antibody-coated parasite
  -basophils; play role in allergy response
  -mast cells: they release granules that contain histamine and other active agent. they play role in allergy
  -NK cells: release lytic granules that kill virus-infected cells.

Question 22

what are task of different cells in adaptive immune system upon activation

Answer 22

-dendritic cells: form a bridge btn innate and adaptive immune system. recognize pathogen receptor and they can be activated and stimulated early in infection. they ingest pathogen. they associate with antigen surface in the way they can be recognized by T cells. and they will find T cells that fit on their surfaces then they deliver 3 different signals

• T cells: need 3 signals to be activated. they stimulate B cells. then they differentiate and become plasma cells that can produce antibodies that help to fight the infection

-B. cells : need 2 signals to be activated to make antibodies.

Question 23

how many signal do T and B cells need to be activated

Answer 23

T cells need 3 signals
B cells need 2 signals

Question 24

what can activated T cells do

Answer 24

• they can activate B cells
• they can differentiate and become plasma cells that help to produce many antibodies.

Question 25

what is the ability of antigen specific lymphocytes (t and b)

Answer 25

is self-tolerant: they have ability to differentiate non-self and self. means they can target parts on antigen and pathogen but not on our own tissues.

Question 26

what are two process that contribute to self-tolerance of adaptive immune cells

Answer 26

are clonal deletion and clonal selection

-clonal deletion is process where self-reactive T cells dies as result of apoptosis (get rid of unwanted or abnormal cells)
-clonal selection: b cells this is important for creating effective clones to fight infection

Question 27

what is autoimmunity

Answer 27

process where t and B cells fight against our own tissues

Question 28

where does two process help in self-tolerance occurs

Answer 28

T cells is in thymus
B cells in bone marrow

Question 29

what are organs that associate with immune system

Answer 29

lymph node
bone marrow
tensol

Question 30

what are two type of lymphoid organs

Answer 30

-primary/ central lymphoid organ is place where immune cells are produces and matured.

-secondary/ peripheral lymphoid organs: plays role in trapping and concentrating antigen to initiate adaptive immune response

Question 31

what are primary/ central lymphoid organ

Answer 31

• bone marrow: place of origin of all immune cells. B cells maturity
  -thymus: maturation of T cells

Question 32

what are secondary/ peripheral lymphoid organs

Answer 32

• spleen: filtrate blood
• lymph node: filtrate lymph draining tissues
  -mucosa-associate lymphoid tissue (tonsil): drain all mucosal tissues

Question 33

what is lymphatic system

Answer 33

• consist of open lymphatic vessels and create one direction of flow from the fluid to the heart.
• it keeps keeps body fluid on balance and defend our body during infection
• Lymphatic vessels, tissues, organs, and glands work together to drain a watery fluid called lymph from throughout the body.

Question 34

what is lymph node

Answer 34

-is kidney shaped small structure that help i our immune system by filtrating all tissues, foreign particles for example cancer cells

Question 35

what cause lymph node to enlarge

Answer 35

can be due to infection or cancer

Question 36

how is lymph node constructed

Answer 36

• consist of outer part called cortex
  cortex is consist of two part: outer cortex (which contain B cells which organize them into lymphoid follicles) and inner cortex ( paracortical area contain T cells, dendritic cells and sometimes is called T cell zone )
• inner part called medulla we have medullary cords which contains macrophages and plasma cells
• germinal centre : contain yellow B cells follicles and is place where mature B cells are activated, proliferate, differentiate and mutate their antibody gene through their somatic hypermutation to generate high-affinity antibodies.

-HEV is where T and B cells enter to node

• cells are guided by chemokines to the lymph node

Question 37

when does somatic hypermutation occurs

Answer 37

it occurs when B cells respond to the antigen along with signal from T cells activation

Question 38

mechanism on what happens in the lymph node

Answer 38

• we first have lymph draining from the tissues
• then lymph get into lymph node
• dendritic cells will be carrying along the antigen/ they can also be free antigen entering that way and macrophages
  -and they will travel along the sinus

Question 39

what is spleen

Answer 39

-collect antigen from blood
- lymphocyte leave and enter spleen by blood vessel
-it contains two part : red pulp (where red blood cells disposal take place) and white pulp (we have lymph tissue )
- PALS (many T cells and is place where dendritic cells meet T cells )
- lymphoid follicle containing B cells
- marginal zone: contain few T cells, many macrophages and B cells (produce antibody that can provide protection before real immune response)

Question 40

what is tensil

Answer 40

-pathogen can enter our body through mucosal region
- it contain many lymphocytes than rest of our body
- they have crypt epithelium inorder to increase the surface and collect a lot of antigen from food and air

Question 41

transport of immune cells

Answer 41

overview: when we have infection example on the foot, and there is lymph node behind knee, then antigen carried by dendritic cells and free antigen will travel to lymph node via lymphatic vessels.
antigen will be presented to the specific lymphocytes and if there will be some they will be activated.
activated lymphocytes they will undergo differentiation and proliferation and then they will leave through HEV to the cite of infection

Question 42

what is thoracic duct

Answer 42

is a vessel is largest part of lymphatic vessels that drains all the lymph to the blood circulation

Question 43

how does cell get to lymph node

Answer 43

• afferent lymphatic vessels: antigen and dendritic cells entrance to lymph node
• HEV where lymphocytes enters the blood vessels
  -efferent lymphatic vessels: exit of immune cells

Question 44

important of inflammation

Answer 44

• increase transport of immune cells to the lymphoid organs (bone marrow, spleen, tonsil)
  -by increasing flow of afferent lymph
• increase lymphocytes migration
• increase in the number of HEV

Question 45

where in our body do cells mediate their function

Answer 45

• cells are activated by antigen in secondary lymphoid organ and they will be transported to the infection site by blood.
  -kinetics: first innate and then adaptive immune system will follow like that to fight against infection

Question 46

question to answer before exam

Answer 46

1.What happens in primary versus secondary organs?
-Primary: where cells ate produced and matured
- secondary: where cells are activated by ntigen

2.What is the main purpose of the lymph node and its highly ordered structure with dedicated zones for different cells? Similarly, what is the purpose of the spleen?
-lymph node : filtrate all tissues/ antigen
- spleen: degrade white and red blood cells
- tensol: collect antigen from food and air

3.Name cells belonging to the innate (1) and cells belonging to the adaptive immune system (2). Explain how cells of the innate and cells of the adaptive immune system recognize pathogens (hint: which receptors do they use?).