Blood I

Question 1

function of blood

Answer 1

• transport: O2, nutrients, CO2 and waste products

- immune response

Question 2

what is the composition of blood

Answer 2

plasma (55%)

cells (40-45%)

Question 3

when does haemopoisis begin
then 6 wks-6 months
6 months-birth
adult life

Answer 3

in yolk sac at 3rd week of gestation
6 wks–6 mo: liver, spleen (extramedullar)
6 mo–birth: bone marrow taking over (medullary)
In adult life: bone marrow

Question 4

how do mature cells form

Answer 4

pluripotent stem cells–> myeloid or lymphoid cells–> committed stem cells–> earliest recognisable precursors–> mature cells

Question 5

how is MCV mean cell volume calculated

Answer 5

PCV/RBC count

Question 6

how is mean cell Hb calculated

Answer 6

Hb (g/dl)/RBC count

Question 7

how is mean cell Hb conc calculated

Answer 7

Hb g/dl/ PCV

Question 8

what are the essential diatary constituents of blood

Answer 8

• iron
• vit B12
• folic acid

Question 9

what is anaemia

Answer 9

haemiglobin lower than ref level for age and gender
reduction in red cell mass
classified in terms of RED CELL INDICES (MCV)

Question 10

what are the 3 major types of anaemia

Answer 10

• hypochromic microcytic with low MCV
• normochromic normocytic with a normal MCV
• macrocytic with a high MCV

Question 11

what are the pathological consequences of anaemia

Answer 11

tissue hypoxia

Question 12

what are the clinical manifestations of anaemia

Answer 12

• can be asymptomatic
• fatugue
• headaches
• faintness
• pallor of conjuctiva

Question 13

what is anisocytosis in anaemia

Answer 13

variation in size

eg low VitB12

Question 14

what is poikilocytosis

Answer 14

variation in shape

eg sickle cell

Question 15

what is anisochromasia

Answer 15

variation in haemoglobinisation

eg low Fe

Question 16

what are the causes of anaemia

Answer 16

• dec production
  (suppressed proliferation, defective maturation)
• inc destruction/loss
  (haemorrhage, haemolysis)

Question 17

describe Fe deficiency

Answer 17

• causes microcytic and hypochromic anaemia
• most common cause of anaemia
• iron status controlled by absorption
• stored ferritin and haemosiderin

Question 18

what causes Fe deficiency

Answer 18

• inc demands
• chronic blood loss
• poor diet
• malabsorption

Question 19

how to treat Fe deficient anaemia

Answer 19

• find and treat underlying cause
• Fe to correct anaemia
• monitored by RETICULOCYTE count and Hb
• oral Fe

Question 20

what happens if Fe therapy doesn’t work

what could be the cause

Answer 20

• non-compliance
• incorrect diagnosis
• mixed deficiency eg thalassamia
• chronic inflammation eg TB, malaria INFECTIOUS, and rheumatoid arthiritis
• malignant disease eg carcinoma, sarcoma, lymphoma

Question 21

what is megaloblastic anaemia

Answer 21

• eg macrocytic, normo/hypochromic
• characterised by megaloblasts in bone marrow eg erythroblasts with delayed nucleus formation
• large oval RBCs
• hypersegmented neutrophils

Question 22

what are the causes of megaloblastic

Answer 22

• deficiency of VitB12 and folate
• abnormal metabolism of B12 and folate
• other defects of DNA synthesis

Question 23

dietary folate i sessential for what

Answer 23

DNA synthesis

as it provides methylation to form DNA

Question 24

where is B12

Answer 24

• meat
• fish
• dairy produce
• not in plants

Question 25

where is B12 absorbed

Answer 25

in terminal ileum, Intrinsic Factor req

Question 26

what is the function of B12

Answer 26

methylation for DNA synth

Question 27

what are the causes of B12 deficiency

Answer 27

• low dietary inate
• malabsoption: gastric (pernicious anaemia, congenital lack of IF, gastrectomy)
• intestinal: Crohn’s, blind loop syndrome, ileal resection

Question 28

folate is from where

Answer 28

• meat
• greens
  (present as polyglutamates)

Question 29

how is folate metabolised

Answer 29

converted to MONOGLUTAMATE during absorption

Question 30

what are the causes of folate deficiency

Answer 30

• nutritional (poor diet, overcooking food)
• malabsorption (tropical sprue, coeliac, Crohn’s)
• excess utilisation (pregnancy, lactation, malignancy, haemolytic anaemia)
• drugs (alcohol, anti-convulsants)