blood and immune

Question 1

CD34+ HSC give rise to:

Answer 1

two multipotent stem cells - myeloid or lymphoid progenitors

Question 2

Myeloid progenitor can give rise to:

Answer 2

erythrocyte, a platelet producing megakaryocyte, a mast
cell or a myeloblast

Question 3

Myeloblast further differentiates into:

Answer 3

either a neutrophil, basophil, eosinophil or monocyte

Question 4

Lymphoid progenitor differentiates into:

Answer 4

B lymphocyte or immature T lymphocyte

Question 5

Immature T lymphocyte differentiates into:

Answer 5

CD4 or CD8 in the thymus

Question 6

Steps of classical pathway:

Answer 6

1. Antibody (IgM or IgG) binds to the surface of microbe
2. C1q binds to Fc region of the bound antibodies activating C2, C4 and C3
3. These form a covalently bound C3 convertase on the microbe surface

Question 7

Steps of alternative pathway:

Answer 7

Complement C3 is activated just by being close to the surface

Question 8

Steps of lectin pathway:

Answer 8

Lectins (carbohydrate) bind to proteins that bind to unusual carbohydrates unique to the microbe

Question 9

Steps of end stage complement:

Answer 9

1. The surface-bound convertases activate complement C5
2. C5 forms a pore with C6, 7, 8 and 9
3. This pore inserts into some bacterial membranes to cause lysis 4. This is called MAC or membrane attack complex

Question 10

Anaphylotoxins are:

Answer 10

Powerful chemoattractants that recruit and activate phagocytes. The small polypeptides, C3a, C4a and C5a, are generated by cleavage of the larger proteins

Question 11

Complement receptors on phagocytic cells:

Answer 11

CR1, CR2 and CR3 that bind the surface convertases (engulfing the bacterium)

Question 12

Fc receptors (FcR):

Answer 12

are on all myeloid cells and bind Ig immune complexes formed on
the microbe surface

Question 13

Bacteria are distinguished by:

Answer 13

the Gram stain

Question 14

Gram positive bacteria:

Answer 14

have a thick peptidoglycan cells wall and are resistant to direct complement MAC lysis

Question 15

Gram negative bacteria:

Answer 15

have a thinner peptidoglycan layer and an outer membrane and are often more sensitive to direct MAC lysis

Question 16

CR1 receptor on myeloid cells binds to:

Answer 16

C3b on the complex on the pathogen’s surface, initiating phagocytosis

Question 17

Fc receptor:

Answer 17

is found on mast cells and binds to IgE

Question 18

5 steps in Fc receptor phagocytosis:

Answer 18

1. Ingestion - The bacterium, held on the surface by Fc receptors or complement receptors,
   invaginates into a phagosome.
2. Fusion – The phagosome and lysosome fuse to form the phagolysosome.
3. Acidification - the phagolysome acidifies H+ pumped in.
4. Digestion – Acidification activates protease and stimulates the production of superoxides such as
   H2O2 and HOCl (hyperchlorous acid) which are highly toxic to bacteria. Powerful proteases eat at
   the microbe.
5. Exocytosis – expulsion of the digested microbe

Question 19

LPS is:

Answer 19

found on all gram negative bacteria, and is recognised by TLR4 in and MD2 (LPS binding protein)

Question 20

B cells:

Answer 20

mature in secondary lymphatic organs such as the spleen and lymph nodes. They form the humoral arm of the adaptive response

Question 21

T cells:

Answer 21

home to the thymus where they mature into T cells and provide cellular adaptive immunity

Question 22

TCRs are associated with:

Answer 22

CD4 and CD8 that distinguish two functionally
different types of T lymphocytes

Question 23

Igm affinity vs avidity:

Answer 23

low affinity, high avidity

Question 24

The loop regions are called:

Answer 24

complementarity determining regions (CDR)

Question 25

MHC Class I picks up peptide antigens from:

Answer 25

inside the cell and presents them to CD8 cytotoxic T cells

Question 26

MHC Class II molecules pick up:

Answer 26

digested antigens from the phagolysosome (extracellular) and present them to CD4 T cells to drive help

Question 27

LPS is:

Answer 27

- a PAMP found on all Gram negative bacteria - recognised by TLR4 in conjunction with MD2 a serum protein sometimes called LPS binding protein

Question 29

Igm avidity binding is:

Answer 29

pentameric, 7x higher than individual affinity binding

Question 30

Avidity binding is stronger or weaker than affinity

Answer 30

Stronger

Question 31

Antigen binding site of TcR and Ig is formed by:

Answer 31

the 6 protein loops that connect the B strands in the Ig variable domain

Question 32

The loop regions are called

Answer 32

Complementarity determining regions

Question 33

What diversity do loop regions have

Answer 33

Amino acid

Question 34

What is loop region diversity caused by

Answer 34

imprecise joining of germline gene segments in the Ig and TcR locus

Question 35

Loop with most diversity

Answer 35

CD3

Question 36

MHC class I picks up peptide antigens from:

Answer 36

inside the cell

Question 37

MHC class II picks up peptide antigens from:

Answer 37

outside the cell (phagolysosome)

Question 38

MHC class I's pathogen:

Answer 38

virus

Question 39

MHC class II's pathogen:

Answer 39

bacteria

Question 40

hives is caused by:

Answer 40

the release of histamine into the tissue from mast cells in the skin

Question 41

oedema is caused by:

Answer 41

leakage of fluid into the spaces between cells. The swelling remains until the fluid has drained

Question 42

What is the FcεR receptor and where is it found?

Answer 42

found on mast cells and binds the Fc region of IgE antibodies

Question 43

Why is IgE binding to FcεR considered irreversible?

Answer 43

Why is IgE binding to FcεR considered irreversible

Question 44

What happens during the first exposure to an allergen?

Answer 44

The body inappropriately produces IgE in response to the allergen. IgE binds to mast cells, "sensitizing" them

Question 45

What happens during the second exposure to the same allergen?

Answer 45

The allergen cross-links IgE on mast cells, triggering degranulation

Question 46

What is cross-linking in mast cell activation?

Answer 46

When an allergen binds to multiple IgE antibodies on the mast cell surface simultaneously, causing activation

Question 47

avg human blood volume

Answer 47

5L

Question 48

blood loss of over _% can be fatal

Answer 48

20%

Question 49

high BP (hypertension) consequences

Answer 49

strokes

Question 50

low BP (hypotension) consequences

Answer 50

shortness of breath, fatigue, dizziness, fainting

Question 51

RBC make up about _% of the total blood volume

Answer 51

45%

Question 52

RBC dry weight is _% hemoglobin

Answer 52

96%

Question 53

Carbaminohaemoglobin is found in ____ blood

Answer 53

venous blood