Module 3

Question 1

site of blood origin

Answer 1

-2 to 8 weeks in the yolk sac
-2 to 5 months in liver and spleen
-4th month bone starts producing RBC
-5th month the bone marrow is the primary site of hematopoiesis

Question 2

what is hematopoiesis

Answer 2

formation of red blood cells

Question 3

what are blood cells produced from

Answer 3

-multipotential hematopoietic stem cell > blast cell> rbc, wbcs, monocytes, macrophages, lymphs, plasma cells
-after more maturation specific WBC, PTL,

Question 4

what is the function of neutrophils

Answer 4

-known as granulocytes (have granules)
-polymorphonuclear leukocyte
-protection against bacterial and fungal infections
-main one associated with phago and a localized inflammatory response
-influences the adaptive immune response: shuttles pathogens,
-can move into peripheral tissues by diapedesis and phagocytize in tissue

Question 5

what are granzymes

Answer 5

granules that have antibacterial substances

Question 6

what are some signs and disorders of neutrophil function

Answer 6

-when O2 radicals and granule contents are released into tissue by phagocytes it can cause tissue damage like dust inhalation or nicotine

autoimmune diseases: too much phagocytosis when the body attacks self ie RA, MS

-this abnormal function can lead to : recurrent, unusual, persistant and severe infections

Question 7

what are eosinophils

Answer 7

-granulocytes
-homeostatic regulators to control inflammation
-defends against parasites
-it granules proteins can damage endothelial cells

Question 8

what are basophiles

Answer 8

-they are granulocytes
-heparin and histamine
-partake in hypersensitivity reactions by increasing vascular permeability, muscle spasm , and vasodilation
-anaphylactic shock
-degranulate when antigen like pollen bind to IgE that are on the surface of mast cells

Question 9

what are the steps in phagocytosis

Answer 9

chemotaxis- adherence - engulfment- phagosome formation- fusion - digestion and destruction

Question 10

what happens in chemotaxis

Answer 10

1st step in phagocytosis
-phagocytic cells are attracted to injury
-neutrophils and monocytes are first
-macrophages stay in the tissues
-neutrophils initiate complement pathway C5

-phagocytosis is made faster through opsonization you bind the Fc portion of AB or C3b to the pathogen
-by products C3B and C4B are created

Question 11

what is adherance

Answer 11

2nd step in phagocytosis
- cell surface receptors help leukocytes adhere

-IGG family - antigen specific receptors ie T cell receptor
-Selectin Family ie leukocyte adhesion molecule
-integrin family - works with the cell surface and extracellular matrix

Question 12

what is engulfment

Answer 12

3rd step in phagocytosis
- pathogen is destroyed when phagocytes engulfs it by active membrane invagination
-projections on the cell membrane called pseudopodia go around the pathogen like arms
-the pseudopodia meet and close up the bacterium
-like slime taking something over
-in order for phagocytosis to be effective the bacteria has to be more hydrophobic

Question 13

what is phagosome formation , fusion , digestion and destruction

Answer 13

4th 5th and 6th step of phagocytosis

• digestion needs energy anaerobic processes
  -granules from phagocyte + phagosome form a phagolysosome
  -there are three types of degrading enzymes:
  -primary or azurophilic -lysosome
  -2ndary/ specific containing - lactoferrin
  -3ary containing caspases

-the degranulation of neutrophils releases the lysosome, lactoferrin , defensin and enzymes to increase permeability

-monocytes are good as phagocytic cells because they have a lot of lipase which attacks bacteria with lipid capsule for example TB
-monocytes can destroys cells with receptors or complements

Question 14

what disease state involve leukocyte integrins

what are integrins

Answer 14

integrins help to aid adhesion

-LAD leukocyte adhesion deficiency occurs because of impaired leukocyte adhesion ; its genetic
-causing fatal bacterial and fungal infections
-caused by epinephrine and corticosteroids

Question 15

what is the phagocytic engulfment test?

Answer 15

-it is a screening test where a mix of bacteria and phagocytes are incubated and examined to see if there are engulfed bacteria
-get buffy coat and broth culture with smear and prep and read

if this test is abnormal then it means there is impaired neutrophilic function pair this test with signs and symptoms noted in patient

Question 16

what is phagocytosis increased by

Answer 16

complement proteins with ab
-signaled by chemicals
-increased through opsonization

Question 17

what are neutrophil extracellular traps - NETS

Answer 17

• formed by neutrophils which release nuclear components into extracellular space

-composed of chromatin, histones, antimicrobial proteins

-bacteria trapped in the nets will die

-this is part of the innate immune response

Question 18

where are monocytes and macrophages located

Answer 18

-monocytes migrate freely from blood to tissues like neutrophil diapedisis

-macrophages fixed or wandering (basically monocytes that have gone from blood to tissue) lining of lungs, lung, spleen

Question 19

what is the macrophage function

Answer 19

-a rest macrophage is converted into the activated macrophage by cytokines during infection
-or from T lymph specifically sensitized to the antigen - cell mediated immunity

Question 20

what is the primary function of monocytes and macrophage

Answer 20

1-phagocytosis
- activated macrophage ingest and kills microorganisms
-dispose of damaged or dying cells
-phagocytosis activity increases when there is injury

2-antigen presentation
-process the antigen and presents it to the lymphocyte to kick start the immune system

3-induction of immune system
- macrophage secretes interleukin 1 which activates the lymphocyte proliferation causing T cell B cell response to start

4-secretion of biologically active molecules
-mono/macro can make transferrin, interferon
interleukin 1 - supports b cell proliferation and ab production -
t lymph produce lymphokines
tissue necrosis factor alpha also makes interleukin 1 both induce fever and inflammatory response

Question 21

if mono/macro activity disturbed what happens

Answer 21

-monocytes dont migrate any more- more infections
-if there are is an issue in either than it can cause abscess formation
-these issues manifest as lipid storage disease with low resistance to infection

Question 22

what are the steps of leukocyte recruitment like during inflammatory reaction

Answer 22

• CAPTURE of free flowing wbc
  -ROLLING - wbcs move with the blood flow endothelial cells
  -SLOW ROLLINGintegrins promote adhesion of leukocyte to endothelial cell wall
  -FIRM ADHESION the cells will be rearranged for the WBC to geT out oF the vessel and into the tissue
  -TRANSMIGRATION

Question 23

what is inflammation manifested as

Answer 23

-redness
-heating
-swelling

-dilation of blood vessel
-microvascular changes to plasma protein to free from blood stream
-leukocyte transmigrates from endothelium and builds up at the site of injury

primary local to localize, repair and remove pathogen

Question 24

what is sepsis

Answer 24

-inflammation overwhelms the body
-tachycardia, fever, high resp rate
-TLR cause APC to product cytokines : tumor necrosis factor, interleukin 1 and 6

the liver is then stimulated to produce CRP - pro inflammatory markers
-this triggers a sever immune response - tissue damage, organ failure
cytokines activate PMNs polymorphs