Superficial Temporal Artery Internal Carotid ArteryExternal Carotid Artery Common Carotid Arteries Subclavian Artery Superior Vena CavaPulmonary Arteries HeartInferior Vena Cava Common Iliac Artery Aorta Descending Aorta
Common Iliac Vein Subclavian VeinAxillary Vein Axillary ArteryBrachial Artery Ulnar Artery Radial Artery Basilic VeinInternal Iliac Artery External Iliac VeinExternal Iliac Artery Great Saphenous Vein Femoral Artery Femoral Vein
Tibial Arteries Small Saphenous Vein Tibial Veins
The Cardiovascular System
Cardiovascular System consists of following components.
1. Blood : Blood is a fluid material which is the main component of the Cardiovascular System. It consists of the Plasma Fluid and Blood Cells. It circulates throughout the Body and provides nutrients and essential substances to the Cells, and in exchanges takes away their waste products. Every Human has approximately 5 litres of Blood in his/her body.
2. Heart : It is the central organ required for pumping of Blood inside whole body. It consists of Cardiac Muscles that contract and relax rhythmically as Heart Beats. It has four Chambers. Two Atria and Two Ventricles, one on each side. Hence forming Right sided and Left sided Heart. Atria receive blood from the vessels called Veins and pump it into the Ventricles. Ventricles are more powerful and pump this blood out of the Heart through vessels (Arteries) to the designated locations.
3. Blood Vessels : Cardiovascular System has a network of vessels reaching almost every part of the body. They are narrow tubes spread throughout the body and help transferring the Blood through them. They are further divided as :
a. Arteries : These are the vessels carrying the Blood away from the Heart. They are Muscular and narrower. They branch along their way and keep becoming smaller and smaller.
b. Arterioles : These are narrowest part of the Arteries just before the beginning of the Capillaries. They have a muscular sphincter at their commencement which can contract and block blood flow.
c. Capillaries : Just after the Arteriole ends Capillaries arise. Each Capillary is a fine network of very thin walled (just one cell thick) vessels. It is here where exchange of substances between the Blood and Cells takes place.
d. Venules : Where capillaries end, few of them join together to form larger vessels called Venules.
e. Veins : 2 or 3 small Venules join to form larger vessels called Veins. Veins carry Blood towards the Heart. They are less muscular and wider in diameter than the Arteries. They coalesce together on their way to Heart to form larger vessels.
TYPES OF CIRCULATION :
Cardiovascular System involves three types of closed circulatory circuits. These circulations are :
- Coronary Circulation : This is the circuit that supplies blood to Heart itself meant for its nutrition and survival. Coronary Circulation involves Coronary Arteries arising directly from the Aorta. They divide and provide heart and its muscles with Blood carrying oxygen and nutrients. This Blood is then drained into the Coronary Veins which then pours into the Coronary Sinus and through there ultimately into the Right Atrium.
- Pulmonary Circulation : Pulmonary Circulation involves Lungs and Right Side of the Heart. Right Atrium receives blood through Vena Cavae and pumps it into the Right Ventricle. Right Ventricle pumps this Blood into the Pulmonary Arteries. Pulmonary Arteries reach Lungs and divide to form capillaries in junction with the Alveoli. At last Pulmonary Veins carry blood from capillaries to the Left Side of the Heart.
- Systemic Circulation : Systemic Circulation is the circulation which supplies rest of the body. It involves Left Atrium that receives Blood from the Pulmonary Veins, which is then pumped into the Left Ventricle. Left Ventricle then pumps the blood powerfully into the Aorta and then Systemic Arteries carry the blood to different organs. Blood is drained via the Systemic Veins into the Vena Cavae and again Right Atrium, and the cycle continues.
- Main function of the Cardiovascular System is to supply every cell of the body with the Oxygen and Nutrients (food, hormones, enzymes etc.). They are involved in vital cellular functions and their survival.
- Cardiovascular System is also involved in carrying away the Carbon Dioxide and waste of the Cells (Urea, Uric acid etc.) to be excreted out via respective Organs.
- Pulmonary Circulation is involved in Oxygenation of the Blood by absorption of the Oxygen through Alveoli and excretion of Carbon Dioxide into them.
- Coronary Circulation involves Oxygen and Nutrient supply to the Heart for its proper function. Heart pumps Blood 24 hours a day till death hence requires vigorous oxygen and nutrient supply. Waste is also carried away by these vessels.
- Lungs receive dual blood supply. Pulmonary Circulation is supplied for the Oxygenation of the Blood by Lungs, and Systemic Circulation provides Nutrients and clears waste for protection and survival of the Lungs themselves.
- Cardiovascular System also protects the body against diseases as it carries Blood Cells and other Hormonal Substances involved in Immunity and Protection against harmful foreign particles and diseases.
- Blood is involved in maintaining body Temperature, pH and Osmotic Pressure.
- Cardiovascular System also forms clots (Hemostasis) and heals injuries by replacing dead tissue with new one.
CLINICAL SIGNIFICANCE :
- Cardiovascular System forms one of the three parts of the Triad of Life, other two being Nervous and Respiratory System. Stoppage of its working means death.
- Cardiovascular System is frequently involved in many pathological conditions like diseases, inflammation, injury etc.
- Measure of Vital Signs from Cardiovascular System like Heart Rate, Blood Pressure etc provide important information to the clinician for proper medical investigation and treatment.