CARDIOVASCULAR SYSTEM FUNCTION - Info Dear
CARDIOVASCULAR SYSTEM FUNCTION
Heart Anatomy (The Pumping Organ)
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| CARDIOVASCULAR SYSTEM FUNCTION - Info Dear |
The Heart:-
The heart is a muscular pumping organ which pumps the blood toward the whole body parts and received the blood from the body. The human heart is surrounding by a membrane called pericardium. Pericardial fluid is present in between the heart and the pericardium membrane which reduce the friction between them. The pericardium membrane also prevents the heart from overextension.
Heart Location:-
The human heart is located on the left side in the chest cavity under the ribs. The size of the human heart is as same as the size of the hand fist of the same person
Heart Structure:-
The wall of the human heart is consists of the three layers which are
- Epicardium
- Myocardium
- Endocardium
Epicardium Function:-
It is the outer layer of the heart. It is a transparent and thin layer of the heart. Epicardium is made up of breakable or very week connective tissue.
Myocardium Function:-
It is the middle and most important layer of the heart. It is made up of special types of muscles called cardiac muscles. It is the major layer of the heart and the muscles of the myocardium control the contraction and the relaxation of the heart.
Cardiac Muscles Cells Function:-
The cardiac muscles are composed of chains of a single cell. Each cell has its own nucleus. The chains of cells are arranged into fibers and these fibers are connected with each other. These muscles are striated which means that these muscles show some visible stripes under the microscope. The Cardiac muscles are involuntary muscles which mean that we cannot control the movement of the cardiac muscles. The cardiac muscles contract automatically under the control of the Autonomic Nervous System of the body.
Endocardium Function:-
It is the inner layer of the heart. It is a very thin membrane which makes the surface of the valves of the heart.
The parts or the chambers of the human heart:-
The human heart consists of four chambers two upper chambers called Atria or Auricles which are named as the Right Atrium and the Left Atrium and two lower chambers which are called the ventricles which are Right Ventricle and Left Ventricle.
THE BLOOD AND THE BLOOD VESSELS
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THE BLOOD AND THE BLOOD VESSELS |
The composition of Blood:-
The blood is the medium in which dissolved nutrients, gases, hormones and wastes are transported through the body. The blood is considered a specialized form of tissue which consists of a liquid called blood plasma and blood cells which are freely suspended in the plasma. In a normal healthy person, plasma constitutes about 55% by volume of the blood and cells or cell-like bodies about 45% by volume of the blood. So, the blood has two major components
Blood Plasma:-
The blood plasma is composed of approximately 90% water and the other 10% composed the dissolved substances like Inorganic salts, plasma proteins, organic nutrients, Hormones, Nitrogenous waste products, Dissolved gases etc.
Blood Cells:-
The human blood contains many cells that are different from the other body cells because the blood cells circulate throughout the body. The Blood contains the following cells
(i) Red Blood Cells:-
The red color of the blood is due to the presence of the red blood cells. These cells are produced in the red bone marrow of short bones like sternum, ribs, and vertebrate. The average life span of the red blood cell is about four months (120 days) after which it breaks down and disintegrated in the liver and spleen by phagocytes.
(ii) White Blood Cells:-
White blood cells are also called Leukocytes. These cells are colorless because they do not contain pigments. They are not confined to the bloodstream, as they also migrate out into the tissue fluid. These cells are responsible for the protection of the body from the germs. For example, when any germ entered in the human body, the white blood cells start to kill that germ. The white blood cells die in the process of killing the germs and they accumulate to form the pus.
(iii) Platelets:-
These are not cells but are the particles of large cells called Megakaryocytes. They do not contain nucleus and pigments. Each microliter of blood contains 150000 to 300000 platelets. The platelets in the blood are totally replaced once every 10 days.
Platelets Function:-
Platelets are stable in the blood but when they encounter a wound they set in motion a complex series of events. One of these events is the conversion of fibrinogen, (a solid plasma protein) into an insoluble form, fibrin. The fibrin threads enmesh red blood cells and other platelets in the area of damaged tissue, ultimately start the blood clotting process and serve a temporary seal to prevent bleeding until the damaged tissue can be repaired.
Functions of the blood:-
Human blood performs the following functions
Transportation of material:-
Blood transport the material like nutrients, water, salts, and waste products to the different parts of the body like the endocrine tissue secretes the hormones which travel with the blood and perform the action at the target sites.
Transportation of gases:-
The essential gases like the respiratory gases (Oxygen & Carbon dioxide) are also transported by blood.
Maintenance of ph:-
Blood is also responsible for the maintenance of acid-base concentration in the body which means the blood control the concentration of hydrogen and hydroxyl ion in the body to the constant level.
Maintenance of Homeostasis:-
The blood also controls or maintain the number of chemicals in the body and make them balanced so, we can say that the blood also maintains the homeostasis.
Exchange of materials:-
Blood helps in the exchange of materials between blood and body tissue through blood capillaries.
Protection from Microbes:-
Blood contains many proteins like interferon (produced by the liver) and antitoxins (produced by blood cells). These proteins protect the body from nucleic acid and toxins of invading organisms.
Blood Vessels:-
There are three basic types of blood vessels present in the human body which differ from each other on the basis of their characteristics.
Arteries:-
Arteries are the blood vessels that carry blood from the heart to the various body parts. Arteries have thick, muscular and elastic walls. Arteries are further divided into arterioles. All the arteries supply oxygenated blood except the pulmonary artery.
Capillaries:-
These are microscopic blood vessels, which are only one cell thick and consist of a single layer of endothelial cells. Arteries lead to the capillaries, which are abundant in the metabolically active sites. The diameter of the capillary is approximately 7 microns. The walls of the capillaries are permeable so that they provide the region of exchange of oxygen, carbon dioxide, dissolved food, and excretory products with the tissue around the capillaries. Capillaries make a very dense network around the tissue for Osmosis (movement of anything from its higher concentration to the lower concentration through a permeable membrane is called Osmosis)
Vein:-
Veins are blood vessels that carry blood from capillaries back to the heart. Except for the pulmonary veins, all the veins carry deoxygenated blood. Blood flows from the capillaries into small veins, and from these into the larger veins that carry blood to the heart. Veins consist of very thin layers and less elastic than the arteries.
The function of the Cardiovascular System:-
When the deoxygenated blood comes from the body and enters in the right Atrium by a very large vein called Vena Cava. As the blood enter, the right atrium contract and the blood enter in the right Ventricle through a valve called tricuspid (have three flaps) by the contraction pressure of the right atrium. Then the right ventricle contracts and the blood is forced to move towards the lungs for purification process through an artery called Pulmonary artery through the pulmonary valve.
In the lungs, the carbon dioxide present in the blood is replaced with the oxygen from the fresh air through very tiny capillaries the oxygen move from fresh air and mixed with the blood and now this blood is called oxygenated blood (oxygen-rich blood). Similarly, the carbon dioxide moves from blood to the air by the simple process of Osmosis (the movement of anything from its higher concentration to its lower concentration through a permeable membrane).
After that, the oxygenated blood is pulled by the left atrium relaxation and the blood enters into the left atrium through a vein called Pulmonary Vein. Then the left Atrium contracts and the oxygenated blood enters into the left ventricle through a valve called Bicuspid valve (have two flaps). Then a big artery called Aorta carries oxygenated blood from left ventricle to all over the body. Similarly, after the consumption of oxygen, the deoxygenated blood again enter in the Right Atrium and make a blood circulation cycle.
The overall human cardiovascular System is controlled by the Parasympathetic Autonomic Nervous System. The Parasympathetic Autonomic Nervous System controls the simple involuntary responses by influencing organs, glands, and smooth muscles. The Parasympathetic Autonomic nervous System also controls the contracts of the pupils of eyes, digestion process of food, heartbeat etc.
