The circulatory system transports nutrients, gases, and wastes throughout the body via blood and blood vessels. It consists of the heart, blood, and a network of arteries, veins, and capillaries. The heart pumps blood through this closed system of vessels. Arteries carry oxygenated blood away from the heart while veins return deoxygenated blood back to the heart. Capillaries facilitate the exchange of materials between blood and body cells. Circulatory systems can be open or closed depending on how the blood and vessels are organized.

1. Organs in the Circulatory
System
Prepared by:
Maeg John P. Carreon, LPT
Science Instructor
Saint Peter Academy of Alegria Incorporated

2. Circulatory System
A circulatory
system is an
internal transport
system that
distributes
materials
throughout the
body
This Photo by Unknown Author is licensed under CC BY-NC

3. A circulatory system consists of at
least one heart, the fluids that the
heart pumps, and the cavities or
vessels through which the fluids are
pumped.
Blood is the transport medium
contained within the blood vessels
Hemolymph is a mixture of blood
and interstitial fluid.
The Interstitial Fluid fills between
spaces between cells and allow
exchange of substances between
cells
This Photo by Unknown Author is licensed under CC BY-SA-NC

4. Most living things require
gasses – either in a form of
oxygen and carbon dioxide to
survive. Aside from gases,
nutrients and metabolic wastes
are also transported into and
from cells, respectively
Not all organisms need a
Circulatory System, some organisms
like Paramecium can easily
transport materials from their cell
to their surroundings since every
part of the cell lies very close to
plasma membrane.
This Photo by Unknown Author is
licensed under CC BY-SA

5. Open and Closed Circulatory System
The type of Circulatory System
depends on the organization of the
heart and Vessels and on the kind of
circulating fluids.
Anthropods have an Open
Circulatory System. Their heart
pumps blood through large vessels
into tissue spaces, mixing with
interstitial fluid. The hemolymph
reenters the heart through openings
called ostia.
Annelids and All vertebrates have
closed circulatory system. Their
heart pumps blood through system
of blood vessels
This Photo by Unknown Author is licensed under CC BY-SA-NC

6. Cardiovascular System
The closed circulatory system of vertebrates is also known
as Cardiovascular System.
The term cardiovascular comes from the Greek Word
kardia for heart and Latin word vasculum or vessel.
The main parts of the Cardiovascular system are the
heart, blood and blood vessels

7. Heart
The heart is composed largely of
cardiac muscle tissue. It has two
to four chambers depending on
the type of vertebrae. The human
heart has 4 chambers separated
by an internal wall known as the
septum
The two chambers at the top half
the heart are the Atria – the right
and left atrium. They receive
blood returning to their heart.
Below each atrium are the right
and left ventricles. They pump
blood away from the heart

8. Blood
Blood is the fluid or
transport medium that
carries gasses, nutrients,
and metabolic wastes.
The blood is also consists
of a viscious liquid known
as plasma. This makes
the blood thicker and
makes it flow slower than
water.

9. Blood Vessels
The circulatory system includes three types of blood vessels – the arteries,
capillaries, and veins.
They serves as networks or paths for the transport of blood to all parts of the
body

10. Arteries
The arteries carry blood
away from the heart.
They have a thick wall
with three layers. They
are thicker than the veins
since blood exerts
pressure on the artery
walls as it is pumped out
of the heart. The Aorta is
the largest artery in the
body.

11. Capillaries
Arterioles branch into
thinner vessels know
ans capillaries. These
vessels allow
exchange of nutrients,
gases and wastes
between the blood
and body cells. They
act as the bridge
between the arteries
and cells.

12. Veins
Veins collect the blood from
the capillaries. Veins have
thinner walls compared to
arteries but larger in
diameter. As the blood
returns to the heart, less
force and pressure is
necessary to make the the
blood move.
Larger veins also have
valves to prevent the
backward flow of blood.

13. References:
Bajo, Z., Pineda, L., Ramirez, R. P., & Taduran, R. C. (2017).
Moving Ahead in Science and Technology 9. FNB Educational
Incorporated.
9 Artery vs vein structure diagram Images, Stock Photos & Vectors. (n.d.). Shutterstock.
Retrieved August 21, 2022, from https://www.shutterstock.com/search/artery-vs-vein-
structure-diagram