blood

Question 1

what does blood consist of?

Answer 1

• formed elements: cells + platelets
• extracellular matrix: plasma
• water, dissolved ions, gases, plasma protein

Question 2

plasma vs serum in blood

Answer 2

plasma: liquid part of the blood
serum: doesn’t clot

Question 3

red blood cells

Answer 3

• diameter ~8µm
• able to squeeze through closed capilaries

Question 4

what is the function of sub-plasmamembrane cytoskeleton?

Answer 4

maintains RBC shape and flexibility and move through capillary beds

Question 5

characteristics of RBC

Answer 5

• few cytoplasmic organelles
• no nucleus in fully differentiated
• cytoplasm packed with hemoglobin that binds with o2 and co2
• cytoplasm contain enzyme carbonic anhydrase

Question 6

white blood cells

Answer 6

• travel in circulatory system
• function outside the circulatory system in CT/epithelia

Question 7

what are the 2 types of WBC?

Answer 7

granulocytes and agranulocytes

Question 8

granulocytes

Answer 8

most important in low specificity ‘innate immunity’

Question 9

neutrophils

Answer 9

• 1st responder for non-specific innate immune response
• most abundant WBC & short-lived
• multilobed nucleus
• granules -> contain anti-bacterial enzymes

Question 10

basophils

Answer 10

• long-lived + amplify innate immune response
• granules are highly basophilic with histamine and heparin

Question 11

eosinophils

Answer 11

• short-lived + mop-up in late stages of innate & adaptive immune responses
• granules contain major basic protein that permeabilizes the membranes of parasite and histaminase -> break down histamine -> homeostasis

Question 12

monocytes

Answer 12

• largest circulating blood cell
• exit circulation by diapedesis (migrate through blood vessel wall)
• differentiate into macrophage in CT
• kidney shaped nucleus

Question 13

granulocytes vs agranulocytes

Answer 13

granulocytes: have granules; include neutrophils, eosinophils, and basophils; immediate immune reponses
agranulocytes: lack granules; include lymphocytes and monocytes; long-term immune response and inflammation

Question 14

lymphocytes

Answer 14

• found nucleus
• involved in highly specific ‘adaptive’ immunity

Question 15

platelets

Answer 15

• membrane bound cell fragments no nucleus
• contain granules/secretory vesicles, integrins, cytoskeletal elements
• normally free floating in circulating blood

Question 16

hematopoiesis

Answer 16

blood cell production

Question 17

regulation of hematopoiesis

Answer 17

• by growth factors/cytokines (stem cell factor)
• by hormones from another organ then travel to the marrow (erythropoietin)

Question 17

hematopoietic stem cells

Answer 17

• cell cluster in bone marrow, normally quiescent
• multipotent, can proliferate and self-renew

Question 18

how does SCF binding activate intrinsic tyrosine kinase activity?

Answer 18

SCF binds to kit -> phosphorylate tyrosine -> activate kinases including Abl -> initiate blast/precursor cell proliferation

Question 19

what is produced when kidney detect reduced O2?

Answer 19

erythropoietin -> erythrocyte production by bone marrow

Question 20

EPO recepter signalling

Answer 20

• E{P binds to transmembrane cytokine receptor on cells of the erythroid lineage
• recuits intercellular/cytoplasmic kinase amplifier
• generates phosphorylated messengers which can directly affect transcription
• upregulation -> expand erythroblast