1. BLOOD
Prepared by: Basoz Hasan Omer
Supervisor : Dr.Shang
Salahaddin university
College of science
Biology Department
Histology
Group –D-
2. Introduction
Blood is a remarkable and complex fluid that serves
as a lifeline for all vertebrates, including humans.
Comprising roughly 7-8% of total body weight, blood
is a connective tissue that circulates through a
closed system of vessels, ensuring the transport of
essential substances and contributing to various
physiological processes.
3. Red blood cells
(Erythrocytes)
Erythrocytes are the most
abundant cells in the blood,
responsible for the transport of
oxygen from the lungs to tissues
and the return of carbon dioxide
to the lungs for exhalation. Their
biconcave shape increases
surface area, allowing for
efficient gas exchange, and they
contain hemoglobin, a protein
that binds with oxygen.
White blood cells
(Leukocytes)
Leukocytes play a crucial role in
the immune system, defending
the body against infections,
pathogens, and foreign
substances. There are different
types of white blood cells,
including neutrophils,
lymphocytes, monocytes,
eosinophils, and basophils, each
with specific functions in
immune response and
surveillance.
4. Platelets (Thrombocytes)
Platelets are cell fragments essential
for blood clotting (hemostasis).
When a blood vessel is injured,
platelets adhere to the site, releasing
chemicals that promote clot
formation. This process prevents
excessive bleeding and maintains
vascular integrity.
5. • The main function of the blood is to maintain
intracellular.
• Providing intercellular communication in the
body: carries hormones (secreted by endocrine
glands) to the target organs.
• Protection and defense: it allows cells and
immunological proteins to transport from place to
place where need them.
• Self repair mechanism: clotting cascade.
Functions of the Blood
6. Blood Types
The ABO blood group system classifies blood into
types A, B, AB, and O based on the presence or
absence of specific antigens on the surface of red
blood cells
The Rh factor further categorizes blood as Rh-positive
or Rh-negative. Understanding blood types is crucial
for blood transfusions and organ transplants.
7. Plasma
Plasma is the liquid component of blood, constituting
about 55% of total blood volume. It is a complex
solution containing water, electrolytes, proteins,
hormones, nutrients, and waste products. Plasma acts
as a medium for transporting these substances
throughout the body, contributing to homeostasis.
8. References
• 1.Wintrobe MM. In: Blood, Pure and Eloquent: A Story of Discovery, of People, and of Ideas. Wintrobe
MM, editor. New York: McGraw-Hill; 1980. p. 771.
• 2. Bauer J. Advances in cell separation: recent developments in counter-flow centrifugal elutriation and
continuous flow cell separation. J. Chromatogr. B. 1999;722(1-2):55-69.
