Composition and functions of blood
Composition
of blood
Blood is a complex fluid composed of several
components, each with its own specific functions. The main components of blood
are:
Plasma:
Plasma is the liquid portion of blood and makes up about 55% of the total blood
volume. It is a pale yellow fluid consisting of water, electrolytes (such as
sodium, potassium, calcium), proteins, hormones, waste products, and nutrients.
Some of the major proteins found in plasma include albumin, globulins, and
fibrinogen.
Red Blood Cells
(Erythrocytes): Red blood cells are the most numerous
cells in the blood and make up about 40-45% of the total blood volume. They are
disc-shaped cells containing haemoglobin, a protein that binds to oxygen and
carbon dioxide. The main function of red blood cells is to transport oxygen from
the lungs to body tissues and carry carbon dioxide back to the lungs for
exhalation.
White Blood Cells
(Leukocytes): White blood cells are a crucial part of the immune
system and make up a small percentage of the blood (around 1%). There are
different types of white blood cells, including neutrophils, lymphocytes,
monocytes, eosinophils, and basophils. Their primary function is to protect the
body against infections, foreign invaders, and abnormal cells.
Platelets
(Thrombocytes): Platelets are tiny cell fragments that
make up a small fraction of blood (less than 1%). They play a vital role in
blood clotting or coagulation. When a blood vessel is damaged, platelets gather
at the site to form a clot and prevent excessive bleeding.
These blood components work together to perform
various essential functions in the body, including:
1. Transporting
oxygen, nutrients, and hormones to body tissues.
2. Removing
waste products and carbon dioxide from tissues.
3. Maintaining
proper pH and electrolyte balance in the body.
4. Regulating
body temperature.
5. Forming
clots to stop bleeding and promote wound healing.
6. Supporting
the immune system in defending against infections and diseases.
Blood composition can vary slightly depending on
factors like age, sex, and overall health. Maintaining the proper balance and
functioning of these blood components is crucial for overall health and
wellbeing.
Functions
of blood
Transportation:
Blood serves as a transportation system, carrying various substances to
different parts of the body. Some of the key elements transported by blood
include:
Oxygen:
Blood carries oxygen from the lungs to tissues and organs, supporting cellular
respiration and energy production.
Nutrients:
It transports nutrients obtained from the digestive system, such as glucose,
amino acids, and fatty acids, to cells throughout the body.
Waste Products:
Blood carries waste products, like carbon dioxide and metabolic waste, away
from tissues to be eliminated through the lungs (exhalation) and kidneys
(urine).
Hormones:
Blood transports hormones produced by endocrine glands, helping to regulate
various physiological processes.
Regulation of
Body Temperature: Blood helps regulate body temperature
by distributing heat throughout the body. When the body temperature rises,
blood vessels dilate, allowing more blood to flow closer to the skin's surface,
promoting heat dissipation. In contrast, when the body is cold, blood vessels
constrict to reduce heat loss, conserving warmth for vital organs.
Maintenance of pH
and Electrolyte Balance: Blood helps maintain the body's
acid-base balance (pH) and electrolyte levels. It contains buffering systems
that prevent drastic changes in pH, ensuring stable physiological conditions.
Electrolytes like sodium, potassium, calcium, and others are essential for
proper nerve function, muscle contraction, and maintaining cellular osmotic
balance.
Immune Response:
Blood contains white blood cells (leukocytes) that play a critical role in the
body's immune system. These cells defend against infections, bacteria, viruses,
and other foreign substances by identifying and destroying pathogens and
producing antibodies to neutralize them.
Blood Clotting
(Coagulation): When blood vessels are damaged, platelets in the
blood come together to form a clot, preventing excessive bleeding. This
process, known as coagulation or hemostasis, is crucial for wound healing and
preventing blood loss.
Hormone and
Enzyme Regulation: Blood helps in distributing hormones
and enzymes produced by various organs and glands. These chemical messengers
play essential roles in coordinating and regulating various physiological
processes throughout the body.
Tissue Repair and
Healing:
Blood contains growth factors and other components that aid in tissue repair
and healing. Platelets release growth factors at the site of injury, promoting
cell proliferation and tissue regeneration.
Overall, blood plays a central role in maintaining
the body's equilibrium, supporting various bodily functions, and protecting
against diseases and infections. Its continuous circulation ensures that
essential substances reach the cells, and waste products are efficiently
removed from the body.
