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The Circulatory System

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❶The heart is roughly triangular in shape.

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Arteries carry blood away from the heart, and veins carry it toward the heart. Capillaries are tiny links between the arteries and the veins where oxygen and nutrients spread to body tissues. The inner layer of blood vessels is lined with cells that create a smooth passage for the transfer of blood. This inner layer is surrounded by connective tissue and smooth muscle that help the blood vessel to expand or contract.

Blood vessels expand during exercise to meet the increased demand for blood and to cool the body. Blood vessels contract after an injury to reduce bleeding and also to conserve body heat. Arteries have thicker walls than veins The basis of how the human heart functions is the focus of this paper. It beats almost miraculously to a certain rhythm throughout In five pages this paper examines the human circulatory system in a consideration of the heart's 4 chambers, the veins, and the ar Glycogen is a polypeptide which is also prod Weighing between 7 and 15 ounces, the human heart is generally about the same size as the indiv This paper considers the existing status of the universal or national health care system in Canada In nine pages information systems development is examined in a consideration of four methodologies including Information Systems w But what about th New to eCheat Create an Account!

The Circulatory System The Circulatory System Circulatory System is the combined function of the heart, blood, and blood vessels to transport oxygen and nutrients to organs and tissues throughout the body and carry away waste products.

Professionally written essays on this topic: Overview of the Circulation System for Humans In five pages this paper examines the human circulatory system in a consideration of the heart's 4 chambers, the veins, and the ar Overview of the Cardiovascular System a healthy body, are voluntary muscles and contract when the brain sends a signal telling them to react, making movement possible.

We can see from that the left side of heart is completely separated from the right side by a partition called septum. So, the two pumps in the heart work independently. The separation of left and right sides of the heart is necessary to prevent the mixing of the oxygenated blood on the left side with the deoxygenated blood on the right side.

Before we describe the circulation of blood in the human body with the help of a diagram, we should keep the following two points in mind: First that the blood circulates in our body in two forms: The blood carrying oxygen in it is called oxygenated blood. We get oxygenated blood in the lungs where the fresh oxygen of air passes into the blood.

The blood having no oxygen in it is called deoxygenated blood. The deoxygenated blood is formed in all the organs of the body except the lungs. This is because when the oxygenated blood passes through the organs of the body, the body cells use up its oxygen and make it deoxygenated. The deoxygenated blood, however, carries carbon dioxide in it which is produced during respiration in body cells. The second point to remember is that when blood circulates in the body, then it supplies oxygen, digested food and other chemicals like hormones to all the cells of the body.

It also carries back waste products like carbon dioxide, etc. The heart beats non-stop all the time. The heart beat is due to the rhythmic contraction and relaxation of the heart muscles which make up the atria and the ventricles. Please note that the two atria left atrium and right atrium contract together and relax together. Similarly, the two ventricles left ventricle and right ventricle contract together and relax together. The contraction of two atria is immediately followed by the contraction of the two ventricles.

The heart beats or beating of heart circulates the blood in the human body. We will now describe the circulation of blood in the human body with the help of a highly simplified diagram. When the muscles of all the four chambers of the heart are relaxed, the pulmonary vein brings the oxygenated blood oxygen-carrying blood from the lungs into the left atrium of the heart.

When the left atrium contracts, the oxygenated blood is pushed into the left ventricle through the valve V 1. When the left ventricle contracts, the oxygenated blood is forced into the main artery called 'aorta'.

This main artery then branches into smaller arteries which go into different body organs except the lungs. The smaller arteries called arterioles further branch into capillaries The smaller arteries and capillaries have not been shown in Figure 88 to keep the diagram simple. The main artery carries blood to all the organs or parts of the body like head, chest, arms, stomach, intestines, liver, kidney, trunk and legs except the lungs.

When the oxygenated blood passes through the capillaries of the body organs, then it gives oxygen to the body cells. Since the blood loses oxygen here, we say that the blood has been deoxygenated. The blood also gives the digested food and other dissolved materials to the body cells.

At the same time, carbon dioxide produced as a waste material during respiration enters into the blood. The deoxygenated blood carrying carbon dioxide from the body organs enters into the main vein called vena cava. The main vein carries the deoxygenated blood to the right atrium of the heart. When the right atrium contracts, deoxygenated blood is pushed into the right ventricle through the valve V 2.

And when the right ventricle contracts, the deoxygenated blood are pumped into the lungs through the pulmonary artery. In the lungs, deoxygenated blood releases its carbon dioxide and absorbs fresh oxygen from air. So, the blood becomes oxygenated again.

This oxygenated blood is again sent to the left atrium of heart by pulmonary vein for circulation in the body. This whole process is repeated continuously. In this way, the blood keeps on circulating in our body without stopping due to which all the body parts keep on getting oxygen, digested food and other materials all the time. The blood circulation also keeps on removing waste products formed in the cells of the body.

The blood circulatory system in human beings is an example of double circulation. This can be explained as follows: A circulatory system in which the blood travels twice through the heart in one complete cycle of the body is called double circulation. In the human circulatory system the pathway of blood from the heart to the lungs and back to the heart is called pulmonary circulation; and the pathway of blood from the heart to the rest of the body and back to the heart is called the systemic circulation.

These two types of circulation taken together make double circulation. The animals such as mammals including human beings , and birds have four-chambered heart which consists of two atria and two ventricles. In a four-chambered heart, the left side and right side of the heart are completely separated to prevent the oxygenated blood from mixing with deoxygenated blood Such a separation allows a highly efficient supply of oxygen to the body cells which is necessary for producing a lot of energy.

This energy is useful in warm-blooded animals like mammals and birds which have high energy needs because they constantly require energy to maintain their body temperature. All the animals having four-chambered hearts have double circulation in which the blood passes through the heart 'twice' in one complete cycle of the body. The animals such as amphibians and many reptiles are cold-blooded animals whose body temperature depends on the temperature in the environment.

They do not need energy to maintain their body temperature and hence their requirement of energy is less. The amphibians like frogs and reptiles like lizards have a three-chambered heart which consists of two atria and one ventricle.

Due to incomplete division within their heart, the oxygenated and deoxygenated bloods mix to some extent in amphibians and reptiles. This reduces the production of energy.

The amphibians and reptiles have, however, a double circulation that delivers blood to the lungs and the rest of the body, respectively. The fish has a two-chambered heart which consists of one atrium and one ventricle. The fish does not have lungs, it has gills to oxygenate blood.

In a fish, the heart pumps deoxygenated blood to the gills. Oxygenation of blood takes place in the gills. The oxygenated blood from the gills is supplied to the body parts of the fish where oxygen is utilised and carbon dioxide enters into it making it deoxygenated.

This deoxygenated blood returns to the heart to be pumped into gills again. The flow of blood in a fish is called single circulation because the blood passes through the heart of fish only once in one complete cycle of the body.

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So, the human circulatory system consists of the heart, arteries, veins, capillaries, and blood. In the circulatory system, the heart acts as a pump to push out blood. The arteries, veins and capillaries act as pipes (or tubes) through which the blood flows.

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- The Circulatory System The circulatory system in anatomy and physiology is the course taken by the blood through the arteries, capillaries, and veins and back to the heart. In humans and the higher vertebrates, the heart is made up of four chambers the right .

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The human circulatory is one of, if not the, most important systems in the body. It consist of such organs as the heart and lungs. However every organ and organ system in the body is nourished and kept alive through the use of the circulatory system. The main organ in the circulatory system is the /5(2). This essay has been submitted by a student. This is not an example of the work written by our professional essay writers. Circulatory System is the combined function of the heart, blood, and blood vessels to transport oxygen and nutrients to organs and tissues throughout the .

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Page 2 Circulatory system Essay. of the circulatory system that is able to drain this excess fluid and its accompanying waste products out the tissues. ere it can be taken by the blood to the various organs that remove It from the body. Free Essay: The Human Circulatory System The human circulatory is one of, if not the, most important system in the body. “It consists of such organs as the.