RBCs

Question 1

life span of RBCs ……

Answer 1

120 days

Question 2

count of RBCs

Answer 2

on average 5 million / mm3
4.5-5.5 in men
3.8 -4.8 in women
less in children than in adult but high in newly born infants

Question 3

RBCS constituents

Answer 3

-Hb 34% ( the most important )
-water 60%
-6% stroma , inorganic and other organic substances
-the chief cation in RBCs is K+ (Na+, Mg++ present in small amounts )
- the anion include Cl-, HCo3 -, phosphate and Hb

Question 4

red pigment appears red when combined with …….and bluish when combined when ………

Answer 4

O2
deoxygenated

Question 5

the average normal Hb content of blood is …..

Answer 5

13 - 17 in men
12- 15 in women
in the body of 70 kg man they are about 900 g of Hb and 0.3 g of Hb destroyed and 0.3 g is synthesized every hour

Question 6

the Hb molecule consists of two parts …….

Answer 6

globin portion and heme moiety

Question 7

illustrate the functions of RBCs

Answer 7

1. blood viscosity
2. functions of membrane :
   - biconcave shape provides a maximum surface area for gas exchange and diffusion
   - it’s a lipoprotein semipermeable membrane to allow anions to pass freely but not cations thus K+ is kept inside and Na+ outside
   - contain agglutinogen that determine the blood groups
   -keep Hb inside and prevent its loss in urine
   - it’s plastic and flexible in nature to allow changes in shape and size of cell, so RBCs with diameter 8 can squeeze through the 3 diameter capillary without rupture
   3.function of Hb :
   - Hb is important buffer in blood
   - help in carriage of Co2 from the tissue to the lungs ( in the form of carbamino compounds)
   - carriage of O2 from the lungs to the tissue

Question 8

what is the result of present Hb in plasma ?

Answer 8

it would :
1. increase the viscosity of the blood which may increase the work of the heart
2. exert an osmotic pressure which would interfere with filtration at capillaries

Question 9

illustrate oxygen carrying capacity of the blood

Answer 9

• O2 is poorly soluble in the plasma , 98% of O2 bound to Hb .
• each of the four iron atoms ( ferrous ) bind reversibly to one molecule of O2 , so each Hb bind with 4 O2 molecule
• each gram Hb unite with 1.33 ml O2
• an average of15 gm Hb in 100 ml of blood ,so each 100 ml blood can carry 19.95 ml O2