Dr. Saima’s
Cardiovascular System
Cardiovascular system is made up of heart & blood vessels i.e. arteries, veins, capillaries. These blood
vessels distribute blood throughout the body. The capillaries are the thinnest and exchange of O2 and
CO2 at tissue levels occurs in the capillaries.
The heart is located in the chest between the lungs behind the sternum and above the diaphragm. At
the 3rd week of Gestation, the heart starts its work. So the heart is the first organ developed in human
body.
Functioning Of Heart:
The heart consists of two sides i.e. Left side and Right side. Similarly, there are four chambers in the
heart: Right Atrium, Right Ventricle, Left Atrium and Left Ventricle.
Right Atrium:
Right Atrium has a Sinoatrial Node between the superior and inferior Vena Cava. The SA Node is
responsible for initiating impulse. Right Left
Receives deoxygenated blood from superior vena cava and inferior Atrium Atrium
vena cava.
Drains blood to Right Ventricle through AV (Artioventricular) valve /Tricuspid valve.
Right Ventricle: Right Left
From Right Ventricle blood goes to Pulmonary Artery to lungs to Ventricle Ventricle
pulmonary veins and then to Left Atrium. All Arteries contain oxygenated blood expect
Pulmonary arteries.
Left Atrium:
Receives oxygenated blood from Pulmonary Veins.
Drains blood to Left Ventricle through Mitral Valve/Bicuspid Valve.
Left Ventricle:
Through left Ventricle, oxygenated blood comes out through Aorta/Systemic Artery.
Septa:
There are 2 septa in the heart that do the work of separation. Right Left
Atrium Atrium
The septum between the two Atria is called
Interatrial Septum.
The Septum between the two Ventricles is called Right Left
Intraventricular Septum. Ventricle Ventricle
, Valves:
There are four Valves in the heart.
Tricuspid and Bicuspid Valves are responsible between the two chambers.
Semilunar Valves:
Right Left
Pulmonary Valve (Right Side)
Atrium Atrium
Aortic Valve (Left Side)
These valves prevent the back flow of blood.
Layers: Right Left
The heart has three layers: Ventricle Ventricle
The outermost layer is called Pericardium.
The middle layer is called Myocardium.
The inner layer is called Endocardium.
Pericardium: The pericardium consists of two layers. The outer layer is Parietal/Epicardium layer &
the inner layer is Visceral layer. Between the two layers there exists a space filled with pericardial
fluid.
Myocardium: (Myo=Muscles) Myocardium is made up of muscles. These muscles contribute to the
following
Contraction 90%
Pacemaker: Initiates impulses.
Conducting system: A Conducts impulse i.e. transmits impulses from one part to another.
Endocardium: Endocardium is made up of endothelial cells, the same cells that make up the blood
vessels. Endocardium is also continuous with the blood vessels.
Actions of the heart:
Chronotropic Effect: The beating of the heart is called the chronotropic effect. The normal heartbeat is
72beats/min. It can be both positive and negative. In positive chronotropic effect, the heartbeat
increases and is termed as Tachycardia (more than 100beats/min). If the effect is negative, the
heartbeat decreases and is termed as Bradycardia (less than 50beats/min).
Inotropic Effect: The effect of contraction is called inotropic effect. It can be positive and negative.
Dromotropic Effect: The speed of conduction is called dromotropic effect. It can also be negative and
positive. Dromotropic Effect is produced by Sympathetic and Parasympathetic Nervous System
(Autonomic Nervous System).
Circulation:
There are two types of circulation in the blood i.e. Systemic Circulation & Pulmonary circulation.
Cardiovascular System
Cardiovascular system is made up of heart & blood vessels i.e. arteries, veins, capillaries. These blood
vessels distribute blood throughout the body. The capillaries are the thinnest and exchange of O2 and
CO2 at tissue levels occurs in the capillaries.
The heart is located in the chest between the lungs behind the sternum and above the diaphragm. At
the 3rd week of Gestation, the heart starts its work. So the heart is the first organ developed in human
body.
Functioning Of Heart:
The heart consists of two sides i.e. Left side and Right side. Similarly, there are four chambers in the
heart: Right Atrium, Right Ventricle, Left Atrium and Left Ventricle.
Right Atrium:
Right Atrium has a Sinoatrial Node between the superior and inferior Vena Cava. The SA Node is
responsible for initiating impulse. Right Left
Receives deoxygenated blood from superior vena cava and inferior Atrium Atrium
vena cava.
Drains blood to Right Ventricle through AV (Artioventricular) valve /Tricuspid valve.
Right Ventricle: Right Left
From Right Ventricle blood goes to Pulmonary Artery to lungs to Ventricle Ventricle
pulmonary veins and then to Left Atrium. All Arteries contain oxygenated blood expect
Pulmonary arteries.
Left Atrium:
Receives oxygenated blood from Pulmonary Veins.
Drains blood to Left Ventricle through Mitral Valve/Bicuspid Valve.
Left Ventricle:
Through left Ventricle, oxygenated blood comes out through Aorta/Systemic Artery.
Septa:
There are 2 septa in the heart that do the work of separation. Right Left
Atrium Atrium
The septum between the two Atria is called
Interatrial Septum.
The Septum between the two Ventricles is called Right Left
Intraventricular Septum. Ventricle Ventricle
, Valves:
There are four Valves in the heart.
Tricuspid and Bicuspid Valves are responsible between the two chambers.
Semilunar Valves:
Right Left
Pulmonary Valve (Right Side)
Atrium Atrium
Aortic Valve (Left Side)
These valves prevent the back flow of blood.
Layers: Right Left
The heart has three layers: Ventricle Ventricle
The outermost layer is called Pericardium.
The middle layer is called Myocardium.
The inner layer is called Endocardium.
Pericardium: The pericardium consists of two layers. The outer layer is Parietal/Epicardium layer &
the inner layer is Visceral layer. Between the two layers there exists a space filled with pericardial
fluid.
Myocardium: (Myo=Muscles) Myocardium is made up of muscles. These muscles contribute to the
following
Contraction 90%
Pacemaker: Initiates impulses.
Conducting system: A Conducts impulse i.e. transmits impulses from one part to another.
Endocardium: Endocardium is made up of endothelial cells, the same cells that make up the blood
vessels. Endocardium is also continuous with the blood vessels.
Actions of the heart:
Chronotropic Effect: The beating of the heart is called the chronotropic effect. The normal heartbeat is
72beats/min. It can be both positive and negative. In positive chronotropic effect, the heartbeat
increases and is termed as Tachycardia (more than 100beats/min). If the effect is negative, the
heartbeat decreases and is termed as Bradycardia (less than 50beats/min).
Inotropic Effect: The effect of contraction is called inotropic effect. It can be positive and negative.
Dromotropic Effect: The speed of conduction is called dromotropic effect. It can also be negative and
positive. Dromotropic Effect is produced by Sympathetic and Parasympathetic Nervous System
(Autonomic Nervous System).
Circulation:
There are two types of circulation in the blood i.e. Systemic Circulation & Pulmonary circulation.
