2.  The circulatory system is an
organ system that passes
nutrients gases, hormones, blood
cells, etc. to and from cells in the
body to help fight diseases and
help stabilize body temperature.
 This system may be seen strictly
as a blood distribution network,
but some consider the circulatory
system as composed of the
cardiovascular system, which
distributes blood.

3. Heart
Blood
Blood Vessels

4.  The Heart is a muscular organ found in all
animals with a circulatory system, that is
responsible for pumping blood throughout the
blood vessels by repeated, rhythmic
contractions.
 The vertebrate heart is composed of cardiac
muscle. The average human heart, beating at
72 beats per minute, will beat approximately
2.5 billion times during an average 66 year
lifespan, and weighs approximately 250 to
300 grams in females and 300 to 350 grams
in males.

5. Structure of Heart
• The human heart has four
chambers, two superior atria and
two inferior ventricles. The atria
are the receiving chambers and
the ventricles are the discharging
chambers. The right ventricle
discharges into the lungs to
oxygenate the blood. The left
ventricle discharges its blood
toward the rest of the body via
the aorta.
• Blood flows through the heart in
one direction, from the atria to
the ventricles, and out of the
great arteries, or the aorta for
example. This is done by four
valves which are the tricuspid
valve, the mitral valve, the aortic
valve, and the pulmonary valve

6. Blood
 Blood is a specialized fluid that delivers
necessary substances to the body's cells such
as nutrients and oxygen and transports waste
products away from those same cells.
 Vertebrate blood is bright red when its
hemoglobin is oxygenated.
 Blood has 3 parts – a)RBCs
b)WBCs
c)Platelets

7. RBCs – Red Blood Cells
 Red blood cells (erythrocytes) are the most
common type of blood cell and the vertebrate
organism's principal means 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.

9.  White blood cells (leukocytes) are cells of the
immune system involved in defending the
body against both infectious disease and
foreign materials.Five different and diverse
types of leukocytes exist, but they are all
produced and derived from a multipotent cell
in the bone marrow known as a hematopoietic
stem cell. Leukocytes are found throughout the
body, including the blood and lymphatic
system.

11.  Platelets or thrombocytes are small,
regularly-shaped clear cell fragments (i.e.
cells that do not have a nucleus containing
DNA), which are derived from fragmentation
of precursor. The average lifespan of a
platelet is normally just 5 to 9 days. Platelets
play a fundamental role in hemostasis and
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.

12. Platelets

13. Blood Vessels
 The blood vessels are the part of the
circulatory system that transport blood
throughout the body.
 There are three major types of blood
vessels:
a)Arteries
b)Capillaries
c)Veins

14.  Arteries are blood vessels that carry
blood away from the heart. This blood is
normally oxygenated, exceptions made
for the pulmonary artery.
 The circulatory system is extremely
important for sustaining life. Its proper
functioning is responsible for the delivery
of oxygen and nutrients to all cells, as
well as the removal of carbon dioxide
and waste products.

15. ARTERIES

16. Capillaries
 Capillaries are the smallest of a body's blood
vessels and are parts of the microcirculation. They
are only 1 cell thick. These micro vessels, measuring
5-10 in diameter, connect arterioles and venules, and
enable the exchange of water, oxygen, carbon
dioxide, and many other nutrient and waste chemical
substances between blood and surrounding tissues.

18.  In the circulatory system, veins are blood
vessels that carry blood towards the
heart. Most veins carry deoxygenated
blood from the tissues back to the heart;
exceptions are the pulmonary and
umbilical veins, both of which carry
oxygenated blood to the heart.

19. Veins

20.  The heart beats around 3 billion times in the
average person's life.
 About 8 million blood cells die in the human
body every second, and the same number are
born each second.
 Within a tiny droplet of blood, there are
some 5 million red blood cells.