Red blood cells carry oxygen to tissues via the bloodstream. They lack a nucleus and organelles to maximize oxygen carrying capacity. White blood cells defend against pathogens through phagocytosis or antibody production. Platelets contain clotting factors and promote clot formation at sites of injury. Plasma is mostly water carrying nutrients, waste, hormones, and antibodies. It maintains electrolyte balance and protects against infection.

1. BLOOD
Composition and functions
Francisco Vázquez Ávila
Juan Pablo Carreira

2. COMPOSITION OF BLOOD
Plasma is a pale yellow sticky liquid. It makes up
55% of the blood’s volume. The components of
plasma are water 92%, dissolved protein 8%,
glucose, amino acids, vitamins, minerals, urea,
uric acid, CO2, hormones, antibodies. Plasma
carries dissolved materials such as glucose,
amino acids, minerals, vitamins, salts, carbon
dioxide, urea, and hormones. It also carries heat
energy.
Red Blood Cells are tiny biconcave disc-shaped cells. They
do not have a nucleus or mitochondria and are the most
common type of blood cell. It’s the vertebrate organism's
principal mean of delivering oxygen (O2) to the body
tissues via the blood flow through the circulatory
system. They take up oxygen in the lungs or gills and
release it while squeezing through the body's capillaries.
These cells' cytoplasm is rich in haemoglobin, an iron-
containing biomolecule that can bind oxygen and is
responsible for the blood's red color.

3. COMPOSITION OF BLOOD
White Blood Cells (leucocytes) are colorless cells and possess a
nucleus that are part of the immune system involved in
defending the body against both infectious disease and foreign
materials. Some ‘feed’ on pathogens by phagocytosis. These
white blood cells are called phagocytes. Others,
the lymphocytes produce antibodies, the specific defense
proteins. They are made by the bone marrow and lymphatic
tissue. Five different and diverse types of white blood cells
exist, but they are all produced and derived from
a multipotent cell in the bone marrow known as
a hematopoietic stem cell. They live for about three to four
days in the average human body.
Platelets, also called thrombocytes, are tiny fragments
of large bone marrow cells. They carry specialized blood
clotting chemicals. The clotting chemicals are released
where blood and lymph vessels are injured. A nucleus is
not present in platelets.

4. RED BLOOD CELLS
Red blood cells tissues via Red blood cells lack
are the most the blood flow a cell nucleus and
common type through most organelles to
of blood cell. It’s the circulatory accommodate
the vertebrate system. In maximum space for
organism's humans, mature haemoglobin.
red blood cells
principal mean of Approximately a
delivering oxygen are oval and
quarter of the cells in
(O2) to the body flexible
biconcave disks. the human body are
red blood cells.
There are 2.4 million new erythrocytes
produced per second. The cells
develop in the bone marrow and
circulate for about 100–120 days in the
body before their components are
recycled by macrophages. Each
circulation takes about 20 seconds.

5. WHITE BLOOD CELLS
The name "white blood cell" derives from the fact that after centrifugation of a blood sample, these
cells are found in a thin white layer of nucleated cells. There are several different types of white
blood cells. They all have many things in common, but are all distinct in form and function.
TYPE MAIN TARGETS LIFETIME
NEUTROPHIL • bacteria 6 hours
• fungi
EOSINOPHIL • larger parasites 8-12 days
• modulate allergic inflammatory responses
BASOPHIL • release histamine for inflammatory few hours to
responses
few days
LYMPHOCYTE • releases antibodies and assists activation of T cells from weeks to
• returns the functioning of the immune system to normal
operation after infection; prevents autoimmunity
years
• virus-infected and tumor cells.
MONOCYTE • it migrates from the bloodstream to other tissues and from hours to
differentiate into tissue resident macrophages in the liver.
days
MACROPHAGE • Is a monocyte derivative. from months to
years
DENDRITIC CELLS • can be myeloid or lymphoid derived. from months to
• main function is as an antigen-presenting cell that activates
lymphocytes
years

6. BLOOD PLASMA
Blood plasma is the straw-colored/pale-yellow liquid component • Blood serum is
of blood that normally holds the blood cells in whole blood in blood plasma
suspension. It makes up about 55% of total blood volume. It is without fibrinogen
or the other
the intravascular fluid part of extracellular fluid (all body fluid
clotting factors (for
outside of cells). It is mostly water and contains example, whole
dissolved proteins glucose, clotting factors, mineral blood minus both
ions, hormones and carbon dioxide. Plasma also serves as the the cells and the
protein reserve of the human body. It plays a vital role in clotting factors).
intravascular osmotic effect that keeps electrolyte in balance form
and protects the body from infection and other blood disorders • Plasmapheres
is is a medical
Normal concentration therapy that
Ion
range (mmol.l−1) involves blood
plasma
Sodium 135-145 extraction,
treatment,
Potassium 3.7-5.1 and
reintegration.
Chloride 95-105
Calcium 2.1-3.7

7. PLATELETS
• Platelets, or thrombocytes, are small,
irregularly shaped clear cell fragments which
are derived from fragmentation of
megakaryocytes.
• The average lifespan of a platelet is normally
just 5 to 9 days.
• Platelets are a natural source of growth factors.
• They circulate in the blood of mammals and
are involved in hemostasis, leading to the
formation of blood clots.
• If the number of platelets is too low,
excessive bleeding can occur. However, if
the number of platelets is too high, blood
clots can form thrombosis, which may
obstruct blood vessels and result in such
events as a stroke, myocardial
infarction, pulmonary embolism or the • Platelets release a multitude of growth factors
blockage of blood vessels to other parts of including platelet-derived growth factor, a
the body. potent chemotactic agent, and TGF beta, which
stimulates the deposition of extracellular
• There are disorders that reduce the number of matrix. Both of these growth factors have been
platelets, such as heparin-induced shown to play a significant role in the repair and
thrombocytopenia or thrombotic thrombocytopenic regeneration of connective tissues
purpura that typically cause thrombosis, or clots,
instead of bleeding.