The document summarizes key aspects of the cardiovascular system, including: - The cardiovascular system includes the heart and blood vessels, with the heart pumping blood through the vessels to circulate nutrients and oxygen throughout the body. - The heart has four chambers - two upper atria and two lower ventricles. The right side receives deoxygenated blood and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the body. - The sinoatrial node, located in the right atrium, acts as the natural pacemaker of the heart by producing rhythmic electrical impulses that cause the heart to contract and pump blood through the circulatory system

1. Cardiovascular System
Dr. Maria Idrees; PT

2. Introduction
• Cardiovascular system includes heart and
blood vessels.
• Heart pumps blood into the blood vessels.
Blood vessels circulate the blood throughout
the body.
• Blood transports nutrients and oxygen to the
tissues and removes

3. HEART
• Heart is a muscular organ that pumps blood
throughout the circulatory system.
• It is situated in between two lungs in the
mediastinum.
• It is made up of four chambers, two atria and
two ventricles. The musculature of ventricles
is thicker than that of atria.
• Force of contraction of heart depends upon
the muscles.

4. RIGHT SIDE OF THE HEART
• Right side of the heart has two chambers,
right atrium and right ventricle.
• Right atrium is a thin walled and low pressure
chamber.
• It has got the pacemaker known as sinoatrial
node that produces cardiac impulses and
atrioventricular node that conducts the
impulses to the ventricles.

5. • Right atrium receives venous (deoxygenated)
blood via two large veins:
1. Superior vena cava that returns venous blood
from the head, neck and upper limbs
2. Inferior vena cava that returns venous blood
from lower parts of the body
• Right atrium communicates with right ventricle
through tricuspid valve. Wall of right ventricle is
thick. Venous blood from the right atrium enters
the right ventricle through this valve.
• From the right ventricle, pulmonary artery
arises. It carries the venous blood from right
ventricle to lungs. In the lungs, the
deoxygenated blood is oxygenated.

6. LEFT SIDE OF THE HEART
• Left side of the heart has two chambers, left
atrium and left ventricle. Left atrium is a thin
walled and low pressure chamber.
• It receives oxygenated blood from the lungs
through pulmonary veins.
• This is the only exception in the body, where
an artery carries venous blood and vein carries
the arterial blood.

7. • Blood from left atrium enters the left ventricle
through mitral valve (bicuspid valve).
• Wall of the left ventricle is very thick. Left
ventricle pumps the arterial blood to different
parts of the body through systemic aorta.

8. SEPTA OF THE HEART
• Right and left atria are separated from one
another by a fibrous septum called interatrial
septum.
• Right and left ventricles are separated from
one another by interventricular septum.

10. CARDIAC PACEMAKER
• Pacemaker is the structure of heart from
which the impulses for heartbeat are
produced.
• It is formed by the pacemaker cells called P
cells. In mammalian heart, the pacemaker is
sinoatrial node (SA node)

11. Sinoatrial Node
• Sinoatrial (SA) node is a small strip of modified
cardiac muscle, situated in the superior part of
lateral wall of right atrium, just below the
opening of superior vena cava.
• Other parts of heart such as atrioventricular (AV)
node, atria and ventricle also can produce the
impulses and function as pacemakers.
• Still, SA node is called the pacemaker because the
rate of production of impulse (rhythmicity) is
more in SA node than in other parts

12. Spread of Impulses from SA Node