3. Definition of blood:
It is a red liquid that circulates in the arteries and
veins of the humans and other vertebrates.
It carries oxygen to and Carbon dioxide from the
tissues of the body.
4. 1. Amount: Blood constitutes about 7 to 9% of total body
weight or 79ml/kg body weight.( Male: 4-6 liters of
blood, Female 4-5 liters of blood)
2. Color: Red color of blood is due to oxygenated
hemoglobin, when oxygen is removed then blood
appears bluish and darker.
3. Viscosity: Viscosity of blood ranges between 3.5 to 5.5
as blood contains RBCs. It is thicker, heavier and
viscous than water. More RBCs and blood protein,
higher the viscosity and slower the flow of blood.
4. Specific gravity or density: of blood is in between
1.045 to 1.065
Characteristics of a Blood:
5. 5. pH: Blood is slightly alkaline. Its pH is between 7.35-
7.45. Arterial blood is more alkaline than venous
blood, because it has less carbon dioxide.
6. Temperature: of blood is about 38⁰C(100.4⁰F). Blood is
the part of circulatory system. It performs important
functions.
Cont…
6. Functions of Blood:
Transportation
It transports oxygen from lungs to
body tissues and carbon dioxide
from the cells to the lungs.
It transports nutrients from
alimentary tract to the tissues.
It transports hormones from
endocrine gland to their target
glands and to tissues.
It transports waste products of
cellular metabolism from body
tissues to excretory organ like
kidney.
It transports heat produced in
active tissues to other active
tissues.
Regulation
It regulates acid base balance or
pH through the distribution of
buffer.
It regulates the amount of H2O
and electrolyte in body fluid.
It regulates body temperature by
increasing or decreasing blood
flow to the skin and through the
heat absorbing or coolant
properties of its water content.
7. Cont…
Protection
Phagocytic WBC and
specialized plasma protein and
antibodies protect the body
against micro-organisms and
toxins.
Clotting mechanism protects
against blood loss.
