Circulatory system in Human
Circulatory system in human is the life-support system that provides our body cells with food and oxygen. It takes away waste product from the body cells.
Circulatory system in human is a system of vessels which connect all the cells, tissues and organs of the body together.
Parts of the circulatory system
There are three main parts of the circulatory system,i.e., blood, blood vessel and heart.
Blood is a red coloured viscous fluid stop it flows in the blood vessels.
Functions of blood
- Blood supplies food from intestine to every cell of the body.
- It carries oxygen from lungs to the body cell.
- It removes waste from the body cells.
- It helps in regulating body temperature.
- It protects body against infection.
The blood has two component,i.e.,Plasma and blood cells or corpuscles.
What is Plasma?
Plasma is the non living, liquid part of the blood. It is yellowish fluid. It removes carbon dioxide from cells and transports it to lungs. It also carries urea from the blood cells to the Kidneys.
Blood cells or corpuscles are of three kinds:-
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| blood composition |
Red blood corpuscles (RBCs):
White blood corpuscles(WBCs):
They defend the body against infection. The fight against germs and also provide immunity against infection. The white blood corpuscles are called soldiers of the body.
Blood platelets:
They are very minute cells present in the blood. They help to stop bleeding by clotting the blood.What are Blood vessels
Blood flows through a system of tubes called blood vessels. Blood vessels are of three kinds,i.e, arteries, veins, capillaries.
Arteries
Arteries have thick and muscular wall. They carry oxygenated blood from the heart to body organs.
But, pulmonary arteries carry deoxygenated blood from right auricle to lungs. The force of heart pumping keep the blood flowing through arteries.
But, pulmonary arteries carry deoxygenated blood from right auricle to lungs. The force of heart pumping keep the blood flowing through arteries.
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| Arteries and veins |
The blood in arteries is bright-red in colour because it contains a lot of oxygen (oxyhaemoglobin is bright red in colour). In arteries, blood flows with jerks and under grate force. We can feel the blood flow in radial artery on the inner side of the wrist.
Pulse is throbbing movement in the redial artery. it is caused due to the flow of blood under pressure due to the pumping of heart.
Pulse rate represent the number of heart beats per minute.
Pulse rate in a healthy person at rest range between 72 to 80 times per minute.
Veins bring blood from body organs to the heart. They have thin wall.They present inside the veins make the blood flow only towards the heart.(Circulatory system)
The flow of blood in veins is not jerky and the blood is oxygenated.But pulmonary veins carry oxygenated blood from lungs to left auricle of the heart.
Veins begin as capillaries.They join and rejoin to form large veins that open into the right auricle of the heart.(Circulatory system)
Capillary are the finest blood vessel.They connect arteries with veins.The capillary have very thin walls(only one cell thick).
The capillaries where they join the arteries, supply food and oxygen to the cells. The capillaries at the end, where these join with the veins, collect carbon dioxide and waste products from the cells and carry the blood to veins .
Heart is of the size of fist and is somewhat cone shaped.It has thick walls formed of cardiac muscles.These muscles contract and relax throughout the life and never get tired. Therefore, heart beats continuously and pump blood into the whole body.(Circulatory system)
Our heart is four chambered.It has two auricles atria and to ventricles. The heart is divided into two halves by thick muscular septum.
Each half has an each half has an auricles above and a ventricle below. The right half of the heart has deoxygenated blood while the left half has pure or oxygenated blood.
The septum prevents mixing of oxygenated and deoxygenated blood present in the right and left half of the heart.(Circulatory system in human)
The left ventricle is the largest heart chamber and has the thickest walls. It receives oxygenated blood from the left auricle and pumps it to the whole body.
There are valves in the heart. These valves prevent the backflow of blood in the heart and the blood vessels. They open and close about 100000 times a day.
When both atria and ventricles are relaxed, both the Atria get filled with blood.
The right Atrium receives deoxygenated blood from various part of the body and the left Atrium receives oxygenated blood from lungs by pulmonary veins.(Circulatory system)
Now, both Atria contract simultaneously and their cuspid valves open up.Blood from left Atrium comes in the left ventricle and from right Atrium in the right ventricle.
Both,the atria relax and ventricles contract. The cuspid walls between the auricles and ventricles are Slam shut and semilunar valves between left ventricle and aorta open up.,(Circulatory system)
Oxygenated blood from left ventricle is pumped into aorta and is distributed to all body parts by arteries.
The oxygenated blood from right ventricle is pumped into the pulmonary aorta and is transported to lungs by the pulmonary arteries for oxygenation.(Circulatory system)
Types of blood groups
There are four types of blood groups namely A, B, AB and O.
Blood of all human beings belong to one of four groups. Persons with blood group O can donate blood to all, so O group is called Universal Donor persons with AB group can receive blood from all and so AB group called Universal recipient.(circulatory system)
What is pulse rate?
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| Pulse rate |
Pulse rate in a healthy person at rest range between 72 to 80 times per minute.
Veins
Veins bring blood from body organs to the heart. They have thin wall.They present inside the veins make the blood flow only towards the heart.(Circulatory system)
The flow of blood in veins is not jerky and the blood is oxygenated.But pulmonary veins carry oxygenated blood from lungs to left auricle of the heart.
Veins begin as capillaries.They join and rejoin to form large veins that open into the right auricle of the heart.(Circulatory system)
Capillaries
Capillary are the finest blood vessel.They connect arteries with veins.The capillary have very thin walls(only one cell thick).
The capillaries where they join the arteries, supply food and oxygen to the cells. The capillaries at the end, where these join with the veins, collect carbon dioxide and waste products from the cells and carry the blood to veins .
(Circulatory system in human)
Heart
heart is a muscular organs.It is located in the thoracic or chest cavity between the lungs. It is tilted slightly towards the left. |
| Internal structure of hear showing path of blood flow |
Heart is of the size of fist and is somewhat cone shaped.It has thick walls formed of cardiac muscles.These muscles contract and relax throughout the life and never get tired. Therefore, heart beats continuously and pump blood into the whole body.(Circulatory system)
Our heart is four chambered.It has two auricles atria and to ventricles. The heart is divided into two halves by thick muscular septum.
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| External heart |
Each half has an each half has an auricles above and a ventricle below. The right half of the heart has deoxygenated blood while the left half has pure or oxygenated blood.
The septum prevents mixing of oxygenated and deoxygenated blood present in the right and left half of the heart.(Circulatory system in human)
Auricles or atria
Auricles are the receiving chamber of the heart. There walls are thinner than those of ventricles.The right auricle receives deoxygenated blood from the whole body while the left auricle receive oxygenated blood from lungs.Ventricles
Ventricles are distributed chambers of the heart. Their walls are thick . The right ventricle receives deoxygenated blood from the right auricle and pumps it to the lungs for oxygenation.The left ventricle is the largest heart chamber and has the thickest walls. It receives oxygenated blood from the left auricle and pumps it to the whole body.
There are valves in the heart. These valves prevent the backflow of blood in the heart and the blood vessels. They open and close about 100000 times a day.
Working of the heart and circulation of blood
When both atria and ventricles are relaxed, both the Atria get filled with blood.
The right Atrium receives deoxygenated blood from various part of the body and the left Atrium receives oxygenated blood from lungs by pulmonary veins.(Circulatory system)
Now, both Atria contract simultaneously and their cuspid valves open up.Blood from left Atrium comes in the left ventricle and from right Atrium in the right ventricle.
Both,the atria relax and ventricles contract. The cuspid walls between the auricles and ventricles are Slam shut and semilunar valves between left ventricle and aorta open up.,(Circulatory system)
Oxygenated blood from left ventricle is pumped into aorta and is distributed to all body parts by arteries.
The oxygenated blood from right ventricle is pumped into the pulmonary aorta and is transported to lungs by the pulmonary arteries for oxygenation.(Circulatory system)
Types of blood groups
There are four types of blood groups namely A, B, AB and O.
Blood of all human beings belong to one of four groups. Persons with blood group O can donate blood to all, so O group is called Universal Donor persons with AB group can receive blood from all and so AB group called Universal recipient.(circulatory system)
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