blood and immune system

Question 1

Innate immune system

Answer 1

Immune system you are born with
- first line of defence so is rapid
-non specific
-barriers to keep harmful materials from the body.

Question 2

Aquired immune system

Answer 2

-developed when your body is exposed to an antigen
-antigen specific
-capacity for memory
-rapid and specific response

Question 3

Physical barriers

Answer 3

-epithelial layers (outer surface of the body,organ and blood vessels e.g. skin )
-hair
-fluid
-mucus

Question 4

Respiratory epithelia

Answer 4

• cells are ciliated. Mucus traps the pathogen and Cilla beats it out of the lungs to be coughed up or swallowed

Question 5

Cellular barriers

Answer 5

-activates when there is a breach to the physical barriers
-white blood cells collect at the site of infection
-phagocytosis = engulf and degrade pathogens. Under gone by neutrophils (short lived), macrophages,mast cells,dendritic cells (long-lived)

Question 6

natural killer cells

Answer 6

• Kill virally infected cells
  -can detect and control cancer cells

Question 7

Humoral responses

Answer 7

Secreted macromolecules that protect you
- cytokines _ proteins that alter the behaviour of other cells
-chemokines- proteins that attract other cells

Question 8

Complement

Answer 8

• Blood plasma proteins that defend againstinfection
• contact with pathogen causes an activating protease cascade
• enhance the ability of antibodies and phagocytes Cells

Question 9

Interferons (IFN)

Answer 9

• innate response to viral infections
  -release IFN proteins which stimulates neighbouring uninflected cells to become antiviral

Question 10

Acquired immune defences

Answer 10

• Cellular = cytotoxic t- cells, T-helper cells and B lymohocytes
  -Acellular =antibodies and cytokines

Question 11

Roles of t and B lymphocytes

Answer 11

-T-cells directly attack infected or abnormal cells
-cytotoxic T cells recognise and kill virus-infected cells,cancer cells and cells that display abnormal antigens on their surface
- B cells = produce antibodies which neutralise pathogens

Question 12

cytokines

Answer 12

-signalling molecules
-aid cell-cell communication and stimulate the movement of cells to the site

Question 13

connectivity of the immune system

Answer 13

-once the pathogen enters the barriers the innate responses stimulate the adaptive immune system
-adaptive responses stimulate innate

Question 14

pathogen-associated molecular patterns (PAMPS)

Answer 14

• repeating molecules common in pathogens that are absent from human cells
  -Recognised by receptors called PAMP recognition receptors (PRRs)

Question 15

Toll-like receptors

Answer 15

-type of PRRs
-on the cell surface and binds to bacterial peptidoglycan
-som bind to DNA or RNA
-binding of peptidoglycan activates a cell cascade resulting in an immune response

Question 16

Damage associated molecular patterns (DAMPs)

Answer 16

-releases signals by stressed, injured, or dying cells.
-can a activate innate or adaptive immune cells to cause a response
-can activate inflammation

Question 17

four concepts in immune recognition

Answer 17

• Innate immune response:
• Can recognise generic features of pathogens (PAMPs)
• Can recognise danger signals from non-apoptotic cell death (DAMPs)
• Acquired immune response:
• Can learn to recognise specific pathogens (adaptive immunity)
• Can ignore human molecules (self-tolerance)

Question 18

inflammation causes

Answer 18

-injury
-autoimmune
-pathogen
-chemical/toxins

Question 19

mechanism of inflammation

Answer 19

-infection/wound triggers the host response
-host responses include immune cell recruitment, vascular changes(histamines), tissue remodelling

Question 20

example of mechanisms which causes symptoms of inflammation

Answer 20

-capillary widening=increased blood flow=heat
-increased permeability of cells-fluid releases into tissues-redness/swelling
-attraction of leukocytes(white blood cells
)= extravasation of white blood cells to the site of injury=tenderness
-systemic response= fever and proliferation of white blood cells=pain

Question 21

vascular changes

Answer 21

vasodilation= increases of oxugen passing through and waste product removal and a decrease in blood pressure

Question 22

stimuli for vasodilation

Answer 22

• Histamine – released by tissue
  resident mast cells or basophils
• Prostaglandins and leukotrienes –
  released by neutrophils and mast
  cells
• Nitric oxide as a result of clotting
  pathways
• Protein products of complement
  activation

Question 23

leukocyte migaration

Answer 23

• The passage of leukocytes in and out of blood vessels, lymphatic vessels
  and tissues. leukocytes travel through the blood. endothelium cells release signals to tell the leukocytes that there is a site of damage so leukocytes latch onto endothelium receptors. when they travel through small capillaries they begin rolling/crawling and then undergo paracellular and transcellular transmigration to pass through the cell and migrate into the tissue
  -migration is due to the chemotactic gradient

Question 24

immune deficiency

Answer 24

• More frequent infections
• More damage from each infection
• Damage from unbalanced immune
  response unrelated to infection
  (inflammation, allergy,
  autoimmunity)
• Increased risk of cancer

Question 25

example of disorder immune responses

Answer 25

-arthritis,lupus,aids,leukemia.asthma,allergys

Question 26

the hygiene hypothesis

Answer 26

-it explains the increasing prevalence of allergic and autoimmune diseases in industrialized countries. -suggests that the reduction in exposure to infectious agents and microorganisms in early life, due to improved hygiene practices and sanitation, leads to an inadequately primed immune system

Question 27

lymphoid tissue

Answer 27

-where the blood and the lymph meet

Question 28

B and T helper cells

Answer 28

-they have antigen receptors on the cell surface. each cell has one type of receptor and each receptor is specific for a single antigen

Question 29

lymphoid circulation

Answer 29

-non-lymphoid cells pass through in blood vessels -lymphoid cells move from blood to lymph node through high-endocytic venules -lymphatic cells are concentrated in the endocytic venules and exit through the lymphatic vessels

Question 30

cells in lymphoid follicles

Answer 30

-dendritic cells arrive in the lymph-loaded with antigens to present to B and T cells - B and T cells arrive from the blood, each with its receptors waiting to be activated by antigens on the dendric cells -B and T cells get activated -activated T cell interacts with activated B cell (cytokines) to stimulate it -B cells make antibodies

Question 31

germinal centre formation

Answer 31

-once the B cells are activated prior via dendric cells -Some of the activated B cells migrate to the follicles of lymphoid organs and form germinal centers. -Within germinal centers, B cells undergo rapid proliferation -B cells undergo mutuations which generates a diverse pool of B cells with slightly different antibody receptors -B cells with antibody receptors that bind more strongly to the antigen presented by follicular dendritic cells are more likely to survive and proliferate further - results in the production of antibodies with increased specificity and effectiveness against the antigen. - Some of the B cells differentiate into long-lived plasma cells, which produce large quantities of antibodies. Others become memory B cells, providing long-term immunity against future encounters with the same antigen.

Question 32

clonality

Answer 32

-lymphocytes that was activated proliferates to form clones with the same receptor specificity

Question 33

clonal selection

Answer 33

-Naive lymphocytes encounter specific antigens from pathogens. -When a lymphocyte's receptor matches the antigen, it becomes activated. -The activated lymphocyte undergoes rapid division, creating many copies of itself (clones). -Some of the cloned B cells differentiate into plasmacells which produce antibodies and some memory cells

Question 34

primary immune response

Answer 34

-the initial reaction of the immune system to a specific antigen, such as a pathogen or foreign substance, that the body encounters for the first time -starts within antigen recognition -Antigen-presenting cells present antigens to helper T cells -Activated helper T cells release cytokines that help regulate and coordinate the immune response. - Activated B cells then differentiate into plasma cells, which produce and release antibodies specific to the antigen. -developed memory cells

Question 35

antigen structure

Answer 35

-similar to an antibody structure with two identical heavy chain and two identical light chains -has a constant and variable region -variability in the proteins Complementarity determining regions controls how the protein folds

Question 36

how is the diversity of antigens made?

Answer 36

-combinational diversity= com

Question 37

why is a mechanism of self-tolerance needed?

Answer 37

-self-recognising cells could be harmful if it underwent clonal expansion -a mechanism to remove cell-recognising self-antigens from the repertoire before clonal expansion is established