Unit 1 Task 3 The Structure and Function of the Cardiovascular System

Unit 1 Task 3

The Structure and Function of the Cardiovascular System


The Heart (www.google.co.uk/images/heart)


This is a diagram of the heart 

The heart is the organ that supplies blood and oxygen to all parts of the body. It is the pump to make the blood move around the body and makes up the cardiovascular system

The heart is divided by a partition or septum into two halves. The halves are in turn divided into chambers. The upper two chambers of the heart are called atria and the lower two chambers are called ventricles.

The heart is split up into Atriums such as the Right Atrium and the Left atrium. The Right is larger than the Left Atrium but has thinner walls, because carbon dioxide will be able to leave quicker. The Right Atrium has two major veins that move blood to the heart from all parts of the body. .The Superior Vena Cava returns the deoxygenated blood from the upper part of the body and the Inferior Vena Cava returns the deoxygenated blood from the lower part of the body. The Right Atrium receives blood back from the heart muscle itself. After the blood is collected in the Right Atrium it is pumped into the Right Ventricle through the Valve. The left atrium receives blood from four Pulmonary Veins. The blood received from the lungs has been oxygenated. The oxygenated blood that is collected in Left Atrium is then pumped into the Left Ventricle through the Bicuspid Valve.


The other parts of the heart are;
• Atria – “The upper chambers of the heart, they receive blood returning to our heart from either the body or the lungs” BTEC Sport 2008
• Ventricles – This is the pumping chambers of the heart, which have thicker walls than the atria. “The right ventricle pumps blood o the pulmonary circulation for the lungs and the left ventricle pumps blood to the systematic circulation for the body” BTEC Sport 2008
• Biscuspid Valve - The bicuspid valve, also known as the mitral valve, is a structure in the left side of the heart that controls the flow of oxygenated blood.
• Tricuspid Valve - Valves are flap-like structures that allow blood to flow in one direction. The tricuspid valve is located between the right atrium and the right ventricle.
• Aortic Valve – This is the valve situated between the right atrium and aorta, preventing backflow from the aorta into the ventricle
• Superior Vena Cava. This is a vein that receives deoxygenated blood from the upper body, “the importance of the Superior Vena Cava is to return blood back to the Right Atrium from the upper part of the body. It is one of the largest veins in the body.” www.brianmac.co.uk/heartandfunctions
• Inferior Vena Cava – This is a vein that receives blood from the lower parts of the body, “the importance of this is for carrying the blood back to the Right Atrium from the lower part of the body.” www.brianmac.co.uk/heartandfunctions
• Pulmonary Arteries: This is what carries oxygenated blood from the lungs to the left atrium. There the blood is oxygenated and sent to the Left Atrium in the heart.
• Pulmonary Veins- This is what carries deoxygenated blood from the heart back to the lungs

Blood Vessels!


There are four types of of blood vessels;
Types of Blood Vessels
Arteries
Arteries are elastic vessels that transport blood away from the heart.
Veins
Veins are elastic vessels that transport blood to the heart.
Capillaries
Capillaries are extremely small vessels located within the tissues of the body that transport blood from the arteries to the veins.

“Blood vessels carry blood from the heart to all areas of the body. The blood travels from the heart via arteries to smaller arterioles, then to capillaries or sinusoids, to venules, to veins and back to the heart.” www.biology.co.uk/bodysystemfunctions


Artery.



An artery is an elastic textured blood vessel which function is too transport blood away from the heart. There are two main types of arteries:
• Pulmonary arteries

• Systemic arteries.

“Pulmonary arteries carry blood from the heart to the lungs where the blood picks up oxygen. The oxygen rich blood is then returned to the heart via the pulmonary veins.” www.sportscience.com
“Systemic arteries deliver blood to the rest of the body. The aorta is the main systemic artery and the largest artery of the body. It originates from the heart and branches out into smaller arteries which supply blood to the head region (brachiocephalic artery), the heart itself (coronary arteries), and the lower regions of the body.” www.biology.about.com
Arterioles

Arterioles share many of the properties of arteries – they are strong, have a relatively thick wall for their size, and contain a high percentage of smooth muscle.Just like arteries, arterioles carry blood away from the heart and out to the tissues of the body. In addition to this "supply train" function, arterioles are very important in blood pressure regulation. www.highbloodpressure.co.uk/arterioles
These have thin walls, thinner than arteries. They are responsible for controlling blood flow to the capillaries.






Capillaries
“Unlike the arteries and veins, capillaries are very thin and fragile. The capillaries are actually only one epithelial cell thick. They are so thin that blood cells can only pass through them in single file. The exchange of oxygen and carbon dioxide takes place through the thin capillary wall. The red blood cells inside the capillary release their oxygen which passes through the wall and into the surrounding tissue. The tissue releases its waste products, like carbon dioxide, which passes through the wall and into the red blood cells.” Www.flu.edu.com


Capillaries are also involved in the body's release of heat. During exercise, your body and blood temperature rises. To help release this heat, the blood delivers the heat to the capillaries which then rapidly release it to the tissue. The result is that your skin takes on a flushed, red appearance. If you hold your hand, under hot water, your hand will quickly turn red for the same reason. Your arm, however, is not likely to change colour because it is not actually feeling an increase in temperature.



Veins

“Veins are similar to arteries but, because they transport blood at a lower pressure, they are not as strong as arteries. Like arteries, veins have three layers: an outer layer of tissue, muscle in the middle, and a smooth inner layer of epithelial cells. However, the layers are thinner, containing less tissue.” www.flu.edu.com
Veins facilitate the venous return, the return of deoxygenated blood to the heart. Which have thinner walls than arteries and a relatively large diameter. When the blood flows round the body they are passed by veins, which are smaller less pressured than arteries.





Bibliography
WWW.BRIANMAC.CO.UK
WWW.FLU.ED.COM
WWW.BIOLOGY.ABOUT.COM
WWW.HIGHBLOODPRESSURE.CO.UK
WWW.SPORTSSCIENCE.COM
Btec Sport 2008 Adams Et al