Erythrocytes and Erythrocyte Indices

Question 1

what are erythrocytes for?

Answer 1

oxygen and carbon dioxide transport

Question 2

what are leucocytes for?

Answer 2

defence mechanisms

Question 3

what are platelets for?

Answer 3

platelet plug (bleeding)

Question 4

what does haematocrit mean?

Answer 4

packed cell volume

Question 5

what is the normal mean corpuscular volume?

Answer 5

80-95 fl

Question 6

what does fl stand for?

Answer 6

femtolitre

Question 7

what is the mean corpuscular volume?

Answer 7

average volume of one red blood cell

Question 8

how do you calculate the mean corpuscular volume?

Answer 8

volume of large number of RBC’s / number of RBC’s or MCV = PCV or Hct / RBC

Question 9

what is the mean corpuscular haemoglobin?

Answer 9

average amount of haemoglobin in 1 RBC

Question 10

how do you calculate the mean corpuscular haemoglobin?

Answer 10

amount of Hb in a large number of RBC’s / number of RBC’s or MCH = Hb / RBC

Question 11

what is MCV measured in?

Answer 11

femtolitres fl

Question 12

what is MCH measured in?

Answer 12

picograms pg

Question 13

what is mean corpuscular haemoglobin concentration?

Answer 13

average concentration of haemoglobin in one red cell

Question 14

how do you calculate MCHC?

Answer 14

amount of Hb in one red cell / volume of one red cell or MCHC = MCH / MCV

Question 15

what is MCHC measured in?

Answer 15

grams per litre g/L

Question 16

what is another way to calculate MCHC?

Answer 16

amount of haemoglobin in a large number of RBC’s / volume of these RBC’s or MCHC = Hb / PCV or Hct

Question 17

what is normal?

Answer 17

range 95% of population have values between these limits (mean +/- standard deviations)

Question 18

what are the normal ranges of haemoglobin?

Answer 18

m - 130-170 g/L

f - 115-160 g/L

Question 19

what are the normal ranges of red cell count?

Answer 19

m - 4.3-5.7 x10^12 / l

f - 3.9-5.1 x10^12 / l

Question 20

what are the normal ranges of haematocrit or packed cell volume?

Answer 20

m - 0.39-0.50 l/l

f - 0.34-0.47 l/l

Question 21

what are these normal ranges dependent on?

Answer 21

sea level an altitude

Question 22

what would happen to the normal levels of a person at higher altitudes?

Answer 22

PCV increased and more Hb and RBC’s to compensate for reduced O2

Question 23

what is haemolysis?

Answer 23

the rupture or destruction of RBC’s

Question 24

what can induce haemolysis?

Answer 24

drugs

Question 25

describe iron metabolism... (6)

Answer 25

intake, absorbed, bound to plasma membrane, bone marrow, haemoglobin in RBC's, storage and breakdown

Question 26

what are the 2 reasons for anaemia?

Answer 26

reduction in Hb or RBC concentration in blood or reduced supply of O2 to the tissues

Question 27

what are clinical symptoms? (2)

Answer 27

things a patient complains about and changes caused by the disease process eg breathlessness, fatigue

Question 28

what is a clinical sign?

Answer 28

changes observed by the clinician eg pallor, glossitis

Question 29

what are the 2 reasons for the change in the number of RBC's or Hb?

Answer 29

the cells are not being manufactured or the cells are being lost

Question 30

what are the 3 reasons for the RBC's not being manufactured?

Answer 30

a defect in the process, lack of building materials, not manufactured correctly eg genetic defect

Question 31

what are 2 ways in which the RBC's could be lost?

Answer 31

bleeding, change in the lifespan of the cells

Question 32

what could cause a change in the lifespan of the cells? (2)

Answer 32

destroyed prematurely, defective cells that don't function correctly

Question 33

what are platelets involved in?

Answer 33

clot formation

Question 34

how big is a platelet?

Answer 34

2-3 microns

Question 35

what is the lifespan of a platelet?

Answer 35

5-9 days

Question 36

how many platelets are made daily?

Answer 36

10 ^11

Question 37

what are platelets derived from?

Answer 37

megakaryocytes

Question 38

how many platelets does each megakaryocyte make?

Answer 38

5,000-10,000

Question 39

how are old platelets destroyed and in what cells?

Answer 39

phagocytosis in spleen and Kupffer cells in the liver

Question 40

how does a megakaryocyte divide

Answer 40

it grows forming branches until platelets bud off from it

Question 41

what is haemostasis?

Answer 41

the stopping of blood flow

Question 42

how is vascular injury arrested? (2)

Answer 42

vasoconstriction and coagulation cascade ***

Question 43

what is a thrombosis?

Answer 43

local coagulation or clotting of the blood in the circulatory system

Question 44

describe what happens when a thrombus occurs? (3)

Answer 44

thrombus forms, mass formed in blood vessels, aggregation of platelets

Question 45

what happens during a venous thrombus? (2)

Answer 45

breaks off (embolus), trapped in lung (pulmonary embolus)

Question 46

how many cases of pulmonary emboli as a results of venous thrombus are there in the USA per year?

Answer 46

600,000

Question 47

how many fatalities are there from pulmonary emboli?

Answer 47

20,000-50,000