RBCs, also known as red blood cells, are biconcave and flexible cells that lack a nucleus. Their main function is to carry oxygen and carbon dioxide throughout the body. RBCs have an average lifespan of 120 days. They contain hemoglobin, which is made up of protein chains that bind to oxygen and carbon dioxide. When RBCs reach the end of their lifespan, they are broken down by macrophages and the heme portion is recycled to form new RBCs, while the globin portion joins the protein pool.

1. RBC’s
Definition:
RBC’s is a flexibile, biconcave,
non-nucleated cell that have an
average life span of about 120
days

2. Flexible
Biconcave

3. RBC’s
• Circular
• Biconcave
7.2 µ m in diameter
2.2 µ m in thickness
RBC’s is not true cell
as it lack nucleus,
ribosomes and
mitochondria
• Main content of
RBC’s is Hb.
• Main function is to
carry O2 and CO2

4. RBC’s
Biconcave
Biconcave
shape
increase the Biconcave shape is caused by
surface area ankyrin and spectrin proteins
of the RBC’s
“Absent in spherocytosis”
up to 140 µ
2
Biconcave shape results in minimal tension
on the RBC’s membrane when the volume
increases
Water shift

5. Erythrocytic count
(Average)
5.4 mill / mm3
4.8 mill / mm3
increase due
to relative
intrauterine
hypoxia
decrease
decrease
Increase due to
relative hypoxia
Increase due
to decrease O2
tension

6. RBC’s
Is flexible and not stretchable
‫الفرق بين الستك و‬
‫ البلستيك‬into almost
RBC’s can be deformed
any shape and passes through
narrow channels

7. Hemoglobin:
Red O2 carrying respiratory pigment
O2
carriage
CO2
carriage
α chains 2
2 β chains

8. Types of hemoglobin
Type Chains
A
α 2 β 2 96 – 98 % of Hb in adult
F
Fetal Hb changed to Hb A, a process
α 2 γ 2 that is completed by the age of 4
months
Hb F has more affinity to O2 allowing more
extraction of O2 from the mother

9. Chemical reactions of hemoglobin
O2
carriage
O2 “ Oxygenation”
CO2
carriage
CO2 carriage
Affinity of O2 to Hb is decreased By:
H+ ion concentration
Temperature
2,3 DPG

10. Hemoglobin content
14 – 18 gm/dl
may reach 19
gm/dl due to
relative
intrauterine
hypoxia
12 – 16 gm/dl
10.5 – 12
gm/dl

11. Functions of RBC’s
1- Blood viscosity.
2- O2 and CO2 carriage.
3- Buffering function.
4- RBC’s membrane keep Hb inside
RBC’s protecting the renal tubules
from the hazardous effects of Hb.

12. .Blood viscosity- 1
F ib
rino
gen
RBC’s
Viscosity is important in the production of the
peripheral resistance and maintenance of diastolic
blood pressure.

13. 2- O2 and CO2 carriage
.
O2
carriage
CO2
carriage
α chains 2
2 β chains

14. .Buffering function- 3
H2O
+
CO2 + H2O
.C.A
-HCO3
HCO3- + H
Hb
-
CL
HbO2
CL-
H.Hb
HHbO2
• C.A. increases the reaction thousands times
• C.A. present inside RBC’s and not outside it

15. Why Hb buffering power is six
times more than plasma proteins
• The concentration of Hb is about 16 gm/dl
while that of plasma proteins is 7.3 gm/dl.
• Each Hb molecule contains 38 histidine
residues, which have the imidazole groups
responsible for the buffering power of Hb.

16. 4- RBC’s membrane
keep
Hb
RBC’s
the
inside
protecting
renal
tubules
from the hazardous
effects of Hb.

17. Life span of RBC’s
:After about 120 days
• The activity of the glycolytic pathway in
the RBC’s decreases as soon as the
RBC’s gets older
• The RBC’s membrane becomes fragile and
they rupture as they passes through tight
spots especially splenic sinsoids.
• The released Hb is picked up by
macrophages where it is broken into heme
and globin.

18. HB
Heme
++
B.M
Fe
Globin
Protoporphyrin
Stored in the
liver and
Formation
spleen as
of new
ferritin
RBC’s
Bilirubin
Secreted by
the liver in
bile
Protein pool