The Circulatory System and its Components

What is the job of the circulatory system?
As a living organism our body requires energy to work and stay alive. For some animals, substances like oxygen can be transported in and out of the body through the process of diffusion - the process that uses liquid or gases, to reach equilibrium, from a high concentration to a lower concentration. This process also occurs in our body however it is not enough to get the oxygen to all the cells in our body, especially the cells in the center of the body. Therefore we have a circulatory system. The circulatory system is in charge of:

-Get the nutrition to the cell (glucose and oxygen)
-Get the bad stuffs out of your body (Carbon dioxide and waste)

So, it is important that we have a circulatory system because if we didnt then we would not be able to survive since our organs would not receive the oxygen and nutrients.

Definition #2:The circulatory system is made up of vessels and muscles that help control the flow of blood around the body - this is called circulation. The main parts of the system are the arteries, capillaries, heart and veins. As the blood begins to circulate, it leaves the heart from the left ventricle and it passes to the aorta. The aorta is the largest artery in the body. The blood the leaves the aorta is full of oxygen. It is important for the cells in the brain and body to do their work. On its way back to the heart, blood travels through a system of veins, as it reaches the lungs, carbon dioxide is removed from the blood and replaced by the oxygen that we have inhaled through our lungs.
The body circulation systems and the components:
In our body we have the blood vascular system which is an example of a mass flow system. This system helped to carry oxygen and glucose around your body and supplies your organs to keep it alive. A system like this consisted of 4 parts:

  1. A medium – the fluid that flows in the system and carry the substances to the organs, in this case for the human body
  2. A system of tubes – this helps to carry the fluid around the body from place to place. In this case it is the arteries and veins
  3. A pump – this supplies the system with pressure to keep the fluid moving in the tubes. In this case it’s the heart
  4. Site of exchanges – this allow the materials deliver by the blood to enter the organs that needed it. In this case it’s capillaries.

In the body, there are blood vessels arranged in a network that connects all eventually connects to the heart. There are two main types of blood vessels: the vessels with blood flowing away from the heart, and the vessels with blood flowing towards the heart. The former type of vessels is called the arteries, while the latter is called veins. Capillaries are very fine blood vessels that join the arteries and the veins.

The arrangement of the human circulation system is called human double circulation because the blood passes through the heart two times with each complete circuit of the body. During this process, there is oxygenated blood and deoxygenated blood. In the image above, the movement pathways of the oxygenated blood is depicted in pink while that of the deoxygenated blood is in blue. Oxygenated blood has a lot of oxygen content, while deoxygenated has instead a lot of carbon dioxide.
Our circulatory system consists of:

1. Heart: the heart has 2 sides, the right and the left. On each side we have the right and the left atrium and ventricles. The reason for this is because the heart wants to separate the deoxygenated blood and oxygenated blood. Basically the blood after going around your body enters the right atrium and passes through the right ventricle. Then the blood travels to the lungs to get more oxygen, then to the left atrium and to the left ventricle to the body.
Here is a video that in more detail explains the heart's functin in the body:

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2. Blood vessels: blood vessels are connected to the heart; these vessels are all around in our body. These vessels help us transporting blood to different organs and provide them with needed nutrients. There are 5 different types of blood vessels: Aorta, Arteries, Capillary, Venule, Veins.
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3. Arteries: the arteries is directly connected to the heart, it is responsible for carrying oxygenated blood from the heart to the other organs of the body
4. Arterioles: the arterioles are basically the arteries but further away from the heart, and as further they are from the heart the smaller they get. Therefore these small arteries are called arterioles. They share many similar features with the arteries, like thick walls for their size, strong and high percentage of smooth muscle.

5. Veins: the veins are elastic blood vessels that transport blood from various regions back to the heart.
6. Venules: blood vessels that carry deoxygenated blood from the capillaries back to the vein
7. Capillaries: The capillaries are extremely small blood vessel; they are so small that red blood can only travel through them in single file. The capillaries are located within the tissue of the body, it transports blood from arteries to vein.

This video below here will show how the circulation system work clearly step by step and how different part contributes to the system itself:

The Blood:
The blood is very important in our body; it has a very important role in the circulatory system because blood acts as carriers that deliver oxygen and nutrient to the
organs. Average adults have about 5 dm3 of blood in our body; however there are many different types of blood cell in the medium of the circulatory system. One the table below I will be showing what the different type of blood cell are:

Appearance (shape & size)
Main Function
How their structure helps their function (job)
Plasma carries cells, gases, and dissolved nutrients around the whole body.
- It’s thin liquid helps their function by making cells, gases, and dissolved nutrients flow through tubes easily
Red blood cells
Capture231.PNG(From: Pickering, W. R. Complete Biology. Oxford [u.a.: Oxford UP, 2006. Print.)
Red blood cells transport oxygen and carbon dioxide between lungs and tissues so that our body can use the it to function.
- Its surfaces are covered by iron containing: hemoglobin (picks up and lets go of oxygen) and pigment.- Red blood cells don’t have nucleus and that creates more space for hemoglobin- Red blood cells are small and flexible, so they fit into capillaries more easily
White blood cells
sada.PNG(From: Pickering, W. R. Complete Biology. Oxford [u.a.: Oxford UP, 2006. Print.)
White blood cells (lymphocytes) Produce antibodies that help defense against diseases and viruses.
- White blood cells have large nucleus which can produce lots of copies of genes to make antibodies
White blood cells
das.PNG(From: Pickering, W. R. Complete Biology. Oxford [u.a.: Oxford UP, 2006. Print.)
White blood cells eat invading micro-organisms (e.g. viruses, bacteria etc) by the proces off phagocytosis to protect the cell.
- White blood cells are flexible so they can grow around invaders- White blood cells have cytoplasm that have enzymes to digest microorganisms/invaders- White blood cells detect microorganisms with their sensitive cell surface membrane
Capture12.PNG(From: Pickering, W. R. Complete Biology. Oxford [u.a.: Oxford UP, 2006. Print.)
Platelets are cell fragments which are involved in blood clotting. Blood clotting is a process by which the blood coagulates to form solid masses, or clots to form 'plugs' in blood vessel opening.
- Platelets are able to release blood clotting enzymes

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