this presentation gives you a brief description of CVS. It also helps reader to know the basic of cardiology.

1. Introduction to the
CARDIOVASCULAR
SYSTEM
Presenter Name: Dr. Kashif Hussain Alvi Awan

2. INTRODUCTION
 The Cardiovascular system consist of Heart and
blood vessels. It is a closed circulatory system that
transport blood, oxygen and nutrient to all part to
the cells of the body and removes CO2 and
metabolic waste products from the body.
 The Heart is a 4 chambered pumping organ that
consist of 2 atrium and 2 ventricles. The force to
move blood around the body is provided by the
Heart and blood pressure. The Heart is enclosed
by a double wall sac called the pericardium.

4. PERICARDIUM
The pericardium is the fibrous sac that surrounds the Heart. It can be divided into
three layers,
1. The Fibrous Pericardium,
2. The Parietal Pericardium,
3. The Visceral Pericardium.
The parietal and visceral pericardia together form the SEROUS
PERICARDIUM. The two layers of the serous pericardium are continuous with
each other. The FIBROUS PERICARDIUM is a layer of connective tissue that
provides support and protects the Heart. It has a number of attachments to the
diaphragm, the sternum (via the sterno-pericardial ligaments), and the vertebral
column and holds the Heart in place.

5. The inner surface of the fibrous pericardium is lined by the outer (parietal)
layer of serous pericardium. The inner (visceral) layer of the serous
pericardium lines the outer surface of the Heart itself.
Between the two layers of the serous pericardium is the pericardial cavity,
which contains pericardial fluid. It is this fluid that provides lubrication
between the two layers, and allows the Heart to expand and contract.

7. • Pericarditis is an inflammation of the serous pericardium of
the Heart. It results in an accumulation of fluid in the pericardial
cavity, which effects the pattern of beating in the Heart.
• A massively increased amount of fluid in the pericardial cavity
will result in the Heart not being able to fill properly, meaning it
will be unable to propel blood around the body in its normal
manner. This condition is called cardiac tamponade, and will
often require the fibrous pericardium to be surgically opened in
order to remove the excess fluid.

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11. VALVES AND CHAMBERS
The Heart consists of four chambers i.e.
• 2 Atria (upper chambers).
• 2 Ventricles (lower chambers).
There is also a valve present through which blood passes before leaving each
chamber of the Heart. The valves prevents the backward flow of blood. Valves are the
actual flaps that are located on each end of the two ventricles (lower chambers of the
Heart). They act as one-way inlets of blood on one side of a ventricle and one-way
outlets of blood on the other side of a ventricle. Normal valves have three flaps,
except the mitral valve, which has two flaps.
The four Heart valves include the following:
•Tricuspid valve: located between the right atrium and the right ventricle
•Pulmonary valve: located between the right ventricle and the pulmonary artery
•Mitral valve: located between the left atrium and the left ventricle
•Aortic valve: located between the left ventricle

13. LAYERS OF HEART
The Heart is a muscular organ found in the middle mediastinum that pumps blood
throughout the body. It lies in the pericardial sac which protects it and assists with its
mechanics.
It consists of 3 layers:
1. Epicardium
2. Myocardium
3. Endocardium
• Epicardium: The epicardium is the outermost layer of the Heart.
It is actually the visceral layer of the serous pericardium which
adheres to the myocardium of the Heart. Nerves and blood vessels
that supply the Heart are found in the epicardium. At the roots of
great vessels, the epicardium reflects back and continues as the
parietal pericardium, forming an enclosed pericardial sac. The sac is
filled with serous pericardial fluid that prevents friction during Heart

14. • Myocardium: The myocardium is functionally the main
constituent of the Heart and is the thickest layer of all three Heart
layers. It is a muscle layer that enables Heart contractions.
• Endocardium: The endocardium is the innermost layer of the
Heart. It lines the inner surfaces of the Heart chambers, including
the Heart valve. The endocardium has two layers. The inner layer
lines the Heart chambers and is made of endothelial cells.
Superiorly, is the second layer: a subendocardial connective tissue
which is continuous with the connective tissue of the myocardium.
Branches of the Heart’s conduction system are immersed into the
subendocardial layer.

17. BLOOD VESSELS
The Blood vessels are the channels or conduits through which
blood is distributed to the body tissues. The vessels makes up
two closed systems of tubes that begin and end at the Heart.
Based on their structure and function, blood vessels are
classified as:
• Arteries
• Capillaries
• Vein

18. ARTERIES are the vessels that carries blood away from the Heart. The
wall of an artery consists of 3 layers
The Innermost Layer, the tunica intima (also called tunica interna), is
simple squamous epithelium surrounded by a connective tissue
basement membrane with elastic fibres.
The Middle Layer, the tunica media, is primarily smooth muscle and is
usually the thickest layer. It not only provides support for the vessel but
also changes vessel diameter to regulate blood flow and blood pressure.
The outermost layer, the tunica externa which attaches the vessel to the
surrounding tissue, is the tunica externa or tunica adventitia. This layer is
connective tissue with varying amounts of elastic and collagenous fibres.
Note: Pulmonary arteries transport blood that has a low oxygen content
from the right ventricle to the lungs. Systemic arteries transport
oxygenated blood from the left ventricle to the body tissues.

19. VEINS are the vessels that carries blood toward the Heart. The
walls of veins have the same three layers as the arteries. Although
all the layers are present, there is less smooth muscle and
connective tissue.
After blood passes through the capillaries, it enters the smallest
veins, called Venules. From the venules, it flows into progressively
larger and larger veins until it reaches the Heart. In the pulmonary
circuit, the pulmonary veins transport blood from the lungs to the
left atrium of the Heart. This makes the walls of veins thinner than
those of arteries, which is related to the fact that blood in the veins
has less pressure than in the arteries.
Venous valves are especially important in the arms and legs, where
they prevent the backflow of blood in response to the pull of

20. CAPILLARIES are the smallest and most numerous of the blood
vessels, form the connection between the vessels that carry blood away
from the Heart (arteries) and the vessels that return blood to the Heart
(veins).
The average diameter of capillaries is 5-8um.The primary function of
capillaries is the exchange of materials between the blood and tissue cells.
Capillary distribution varies with the metabolic activity of body tissues.
Tissues such as skeletal muscles, liver, and kidneys have extensive
capillary networks because they are metabolically active and require an
abundant supply of oxygen and nutrients.
About 5 percent of the total blood volume is in the systemic capillaries at
any given time. Another 10 percent is in the lungs.

21. CONTINUOUS CAPILLARIES are continuous endothelial
lining. They have tight junctions between their endothelial cells
along with intercellular clefts through which small molecules, like
ions, can pass.
Continuous capillaries are generally found in the nervous system,
as well as in fat and muscle tissue. Within nervous tissue, the
continuous endothelial cells form a blood brain barrier, limiting the
movement of cells

22. FENESTRATED CAPILLARIES have small openings in their
endothelium known as fenestrae or fenestra, which are 80 to 100 nm in
diameter. They are found in tissues where a large amount of molecular
exchange occurs, such as the kidneys, endocrine glands, and small intestine.
They are particularly important in the glomeruli of the kidneys, as they are
involved in filtration of the blood during the formation of urine.
SINUSOIDAL CAPILLARIES have endothelial linings with multiple
fenestrations (openings), that are around 30 to 40 nm in diameter. Sinusoidal
capillaries are mainly found in the liver, between epithelial cells
and hepatocytes. They can also be found in the sinusoids of the
spleen where they are involved in the filtration of blood to remove antigens,
defective red blood cells, and microorganisms.

26. Thank you
from the desk of:
hussainkashifhussain