Arteries,veins,and capillaries!!! Ashley Bacon Period 5 Jasmine Jennings April 30,2012 Katesha Nobles Mrs. Howard Kayonia Vance and Glenna
Introduction: • Our cardiovascular system consists of the heart and a closed system of vessel known as the: • Arteries • Veins • Capillaries • Today we will be taking a closer look at these vessels and find out how they work together.
Arteries (conclusion): • Arteries deliver blood to capillaries where the actual exchange of oxygen and carbon dioxide occurs.
Artery: • Arteries are blood vessels that carry blood away from the heart. • Consist of 3 walls of layers: • Tunic intima- the interior layer is made of epithelial cells, and is very smooth which allows blood to flow through easily. • Tunic media- the muscular middle, this bulky coat help to pump blood. • Tunica external- the most outer layer, made of connective tissue, helps support and protect the vessels, and attaches to vessel surrounding tissue.
Veins: • Veins are the blood vessels which carry deoxygenated(very low levels of oxygen) blood back to the hear. The pulmonary vein carries oxygenated blood from the lungs, back to the heart ready to be pumped around the rest of the body. • The structure of veins is similar to that of arteries, consisting of the three layers: • Tunica Adventitia- this is the strong outer covering of arteries and veins which consists of connective tissues, collagen and elastic fibers. • Tunica Media- this is the middle layer and consists of smooth muscle and elastic fibers this layer is thinner in veins. • Tunica Intima- this is the thinner layer, which has direct contact with blood flowing through the vein.
Vein Facts: • The walls of veins are more narrow than arteries. (Thinner walls) • Veins are far away from the heart. • Venules are very small veins.
Capillary: • Capillaries are the smallest of all blood vessels and form the connections between veins and arteries. While arteries branch and divide into arterioles and continue to reduce in size as they reach the muscle they become capillaries. Unlike veins and arteries their main function is not transporting blood they are designed to allow movement of substances.
Capillary example: • FOR AN EXAMPLE OF HOW THE CAPILLARY FUNCTION : • WHEN YOU GET COLD AND COME INSIDE YOU BECOME HOT BECAUSE YOUR CAPILLARIES ARE CONSTRICTING DUE TO THE OVERWHELMING CHANGE IN EXTERNAL TEMPERATURE. • THE WALLS ARE SO THIN THAT MOLECULES SUCH AS OXYGEN WATER AND LIPIDS CAN PASS THROUGH THEM BY DIFFUSION AND ENTER THE TISSUES. WASTE PRODUCTS SUCH AS CARBON DIOXIDE AND UREA CAN DIFFUSE BACK INTO THE BLOOD TO BE CARRIED AWAY FOR THE REMOVAL OF THE BODY.
Questions: • What type of blood do veins carry? • Which vein is the exception to this rule? • What are very small veins called? • How is the structure of capillaries related to their function? • Which vessels carries blood away from the heart?
Answers: • Deoxygenated • Pulmonary vein • Venules • Capillaries are sites for gas exchange, they have a large surface area. The walls are very thin making it easy for oxygen and carbon dioxide to diffuse through them. • Artery
Conclusion: • Arteries, veins, and capillaries work together by the arteries taking blood from the heart to the cells of the body. Capillaries take the blood to the individual cells to give them food and oxygen. They then take Carbon Dioxide and waste away from the cells. Veins then take blood from the capillaries back to the heart. The Heart then sends blood through another artery to the lungs. It goes through different capillaries to get rid of Carbon Dioxide and pick up Oxygen. Then it goes through another vein back to the heart. From the heart, it goes back to the starting point. • During the process, some of the blood going to the cells of the body goes through the kidneys to get rid of wastes. Some goes through the liver to get rid of different wastes and to pick up food from the intestines. Some goes to muscles. Some goes to the brain. Some feeds the heart so it can pump blood.
References: • Google.com • Answers.com • Textbook