Engineering the Heart: Heart Valves - Lesson. Summary. Students learn how healthy human heart valves function and the different diseases that can affect heart valves. They also learn about devices and procedures that biomedical engineers have designed to help people with damaged or diseased heart valves. Students learn about the pros and cons of different materials and how doctors choose which engineered artificial heart valves are appropriate for certain people. Heart valve diseases, including valve stenosis, valvulitis and valve prolapse, can be fatal if the valve is not replaced. Engineers and physicians work together to design valves made of materials that the human body accepts and function for as long as possible, and that require the least invasive procedures for implantation. If one or more of your heart valves becomes damaged or diseased, it can affect the flow of blood through your heart. A diseased or damaged valve can affect the flow of blood in two ways: If the valve does not open fully. Two valves instead of one? He was sent home because he was not symptomatic and will be given a heart monitor on the 31st. It is on the left side of the heart and has two cusps. Heart valves (preview) - Human Anatomy The heart valves can be broken down into two types: atrioventricular and semilunar valves. Regurgitation happens when a valve doesn't close properly and blood leaks backward instead of moving in the. How is valve disease. A normal heart has valves. 3 Low Blood Pressure; 4 All About Heart Rate.Heart bicuspid aortic valve anatomy. In anatomy, the heart valves are valves in the heart that maintain the unidirectional flow of blood by opening and closing depending on the difference in pressure on each side. Werner responded: Doubtful. If your father survived into adulthood and procreated, i suspect he has 4 =' See the Assessment section for details. Be ready to show the attached Power. Point presentation, which includes two short video animations.)The heart is arguably the most important muscle in our bodies. What is the heart responsible for doing? It is important that blood always flows in a certain direction, otherwise cells would not get oxygen or be able to release carbon dioxide when needed. To make sure blood always flows in one direction, the heart has four one- way valves. Many different types of valves exist, but all are devices that control or direct the flow of fluids. What are examples of valves in your home? Washing machines and dishwashers have valves also. The valves in your heart are similar to the valves in your home, except they control the flow of blood instead of water. Our heart valves allow blood to flow through them in one direction only. The four valves are the aortic valve, the mitral valve, the pulmonary valve and the tricuspid valve. Every time the muscles in the heart contract to pump blood, certain valves open and others close to make sure the blood is only pumped in the correct direction. All of the valves have leaflets or flaps that are the moving pieces of the valve. When a valve opens, its leaflets separate to allow blood flow, and when the valve closes, its leaflets come together to block the blood flow. When a person is unwell, diseases can affect the heart valves so they do not work as well as they should. We will learn about these different diseases, which can all be fatal if the damaged valve is not replaced. We will also discuss pros and cons of different types of replacement valves that are designed by biomedical engineers. In theory, the best artificial valve would not require open heart surgery, be made of materials that do not cause blood to clot and last for a person's lifetime. All things we are about to learn!(Next, show students the seven- slide Heart Valves Presentation while covering the next material. The Power. Point file also includes useful photos and videos. See the Lesson Background section for a slide- by- slide guide to the presentation.)What diseases can affect the heart valves and endanger a person's health? Three such diseases are valve prolapse, valve stenosis and valvulitis. Valve prolapse is a condition in which the leaflets become floppy or stretched out, allowing blood to regurgitate, or flow back in the wrong direction. Regurgitation can result in the heart increasing its workload, meaning pumping harder, to keep enough blood flowing through the body. Valve stenosis is calcium build- up in the valve leaflets, causing them to stiffen and fail to open completely. When the heart beats, blood flow is slowed down causing pressure to build in certain heart chambers. Over time, this can thicken the heart wall, as well as enlarge and weaken the heart. Valvulitis is the inflammation or swelling of a valve. This is most commonly caused by another disease called rheumatic fever, and less frequently by bacterial endocarditis and syphilis. Eventually, an inflamed valve can degenerate or its leaflets become stiff and calcified, leading to valve stenosis. Biomedical engineers have developed a few different types of artificial valves and each type has pros and cons. Purely mechanical artificial valves are made with metal, wire and plastics that are foreign to cells in the human body. Blood cells do not like the presence of foreign materials, and their presence often leads to increased chances of fatal blood clots. As a result, patients who receive these types of artificial valves must take blood thinning medications and lower their levels of physical activity. On the other hand, these artificial valves do not degrade, meaning they will work for the rest of patients' lives without needing to be replaced. Other types of artificial valves are made with real animal tissue; these biological types are more accepted by the human body and do not lead to blood clotting. Because of this, people with these implants can maintain normal lifestyles and be active. The downside is that these artificial valves degrade and only last about 1. Replacing the original heart valve or an artificial heart valve is a traumatic experience, requiring open heart surgery. Biomedical engineers are currently working on designing artificial heart valves that could be placed in the body similar to how stents are implanted (as we will see in a short video clip), avoiding open heart surgery. Example artificial heart valves (left to right): a biological valve (using human or porcine tissue), a mechanical valve, and recently FDA- approved tri- leaflet valve using bovine tissue. The far right valve is made of cow tissue attached to a stainless steel mesh frame with a polyester wrap and is inserted into the body through a small opening made in a leg artery. Copyright . What do you think would be important factors? Or, play the videos directly from You. Tube using the URLs provided in the notes section the two slides, or in the Slide 4 and Slide 7 paragraphs, below.)Slide 1: Title slide: Heart Valves. Slide 2: (Review, as necessary, the path of blood flow in the human heart.) The blood enters the heart from the body through the superior vena cava and the inferior vena cava. Then the blood enters the right atrium chamber of the heart. The blood then moves through the tricuspid valve (shown as two white flaps) into the right ventricle chamber of the heart. Then the blood moves through the pulmonary valve (shown as two white flaps) into the pulmonary artery (one on each side of the heart). The blood re- enters the heart through the pulmonary veins (two on each side of the heart), and travels into the left atrium. The blood then passes through the mitral valve (shown as two white flaps) and into the left ventricle chamber of the heart. The blood then moves through the aortic valve (shown as two white flaps) and into the aorta. Slide 3: In this cross- section drawing, we can see the four heart valves that are present in mammalian hearts. The four valves in your heart are the tricuspid valve, the pulmonary valve, the mitral valve and the aortic valve. The tricuspid valve is located between the right atrium and the right ventricle; the pulmonary valve is located between the right ventricle and the pulmonary arteries; the mitral valve is located between the left atrium and the left ventricle; and the aortic valve is located between the left ventricle and the aorta. The mitral and tricuspid valves are atrioventricular (AV) valves located between the atria and the ventricles. Two semilunar (crescent- shaped, like a half- moon) valves, the aortic and pulmonary valves, are located in the arteries leaving the heart. The mitral valve is the only bicuspid valve in the human heart. The valves open and close with the movements of the heart. When the ventricles contract, the pulmonary valve and the aortic valve open so the blood can be pushed out in the correct direction, while the tricuspid valve and the mitral valve close, so the blood cannot slip back into the atria. Slide 4: (Play the embedded Heart Valve Surgery . It also shows surgery to replace a damaged mitral valve, with options for a mechanical or biological valve. The stringy- looking material attached to the tricuspid and mitral valves are tendons attached to the ventricle walls; they assist in opening and closing these valves at the appropriate times. Open heart surgery to replace a mitral valve. Copyright . The following three primary conditions can be caused by disease or be inherited and can affect the heart valves and endanger a person's life: valve prolapse, valve stenosis and valvulitis. Valve prolapse is a condition in which the valve leaflets become floppy or stretched out, allowing blood to regurgitate (flow back in the wrong direction). Regurgitation can result in the heart increasing its workload (meaning pumping harder) to keep up the cardiac output (to keep enough blood flowing through the body). This condition is caused by many factors, but two main factors include magnesium deficiency and degraded hyaluronic acid (also called hyaluronan). Valve stenosis is calcium build- up in the valve leaflets, causing them to stiffen and fail to open completely. When the heart beats, blood flowing out of the left ventricle is impeded, causing pressure to build in the chamber. Over time, this can thicken the heart wall, and enlarge and weaken the heart. It can be caused by congenital heart defects at birth, such as a bicuspid aortic valves (instead of three leaflets), calcium build- up on the valve from calcium in your blood depositing on the valve, or rheumatic fever, which is a complication of strep throat that can result in scar tissue forming on the aortic valve. Sometimes calcium deposits collect on the rough surface of the scar tissue. Valvulitis is the inflammation of a valve. Inflammatory changes in the aortic, mitral and tricuspid heart valves are caused most commonly by rheumatic fever and less frequently by bacterial endocarditis and syphilis. Infected valves degenerate, or their cusps become stiff and calcified, resulting in valve stenosis and obstructed blood flow. Human Heart – Diagram and Anatomy of the Heart. The left atrium is one of the four hollow chambers of the heart. It plays the vital role of receiving blood from the lungs via the pulmonary veins and pumping it to the left ventricle. The left atrium is a small, hollow structure on the superior left side of the heart. It is separated from the right atrium by the interatrial septum and from the left ventricle by the bicuspid (mitral) valve. A thin, irregular pouch of cardiac tissue known as the left auricle extends from the left atrium along its anterior surface. The heart wall of the left atrium is much thinner and weaker than that of the left ventricle. It is made of three distinct layers: the epicardium, myocardium, and endocardium. The epicardium is a thin layer of simple squamous epithelium that protects the heart wall by giving it smooth surface and by secreting pericardial fluid to lubricate the pericardial space. Deep to the epicardium is the.. Often confused with the left atrium, it is one of the most prominent structural features of the left atrium and plays an important role in the pumping of blood within the heart. The name auricle comes from the Latin word auricula, which means “ear” and refers to the floppy dog- ear shape of the auricle. Anatomy. The left auricle is a thin pouch of the heart wall located on the anterior surface of the left atrium. Its walls are only about one sixteenth of an inch (1 mm) in thickness and less than 1 inch (2. The interior size of the left auricle changes considerably during each heartbeat, filling with blood and expanding before contracting to pump blood. At its superior end, the left auricle merges with the walls of the left atrium. From this point, it descends inferiorly just anterior to the.. Together with the right ventricle, it forces blood out of the heart into the arteries to be carried back to the various sites throughout the body. The left ventricle has a much thicker wall than the right ventricle. It must force blood to all other parts of the body against a great flow of resistance, so the walls are stronger than that of the right ventricle. Two cusps form this valve. Its cusps are attached to papillary muscles by way of the chordae tendinae and it allows blood to enter the left ventricle from the left atrium. The chordae tendineae spring form the papillary muscles. It located at the base of the pulmonary trunk. This valve opens when the right ventricle contracts. When the right ventricular muscles relax, blood starts back up the pulmonary trunk, causing the valve to close to prevent the flow from returning into the ventricular chamber. These myocardial fibers can be found in the heart's inner ventricular walls. They conduct electrical impulses which permit the heart to contract in a coordinated way. It is located in the upper right corner of the heart superior to the right ventricle. Deoxygenated blood entering the heart through veins from the tissues of the body first enters the heart through the right atrium before being pumped into the right ventricle. The right atrium is one of the two atria of the heart, which function as receiving chambers for blood entering the heart. It is located to the right of the left atrium and superior to the much larger and more muscular right ventricle. Between the right atrium and right ventricle is a one- way valve known as the tricuspid valve. The muscular walls of the right atrium are much thinner than those of the ventricles and feature a wrinkled flap shaped like a floppy dog ear, known as the auricle. The auricle is hollow and extends outward from the anterior surface to increase the internal volume of the right atrium. Deoxygenated.. It's a small, cone- shaped pouch which comes out from the upper and front part of the atrium and overlaps the root of the aorta. The RAA is very muscular, and is lined with small muscles on its surface. It collects deoxygenated blood from the bloodstream and moves it into the heart's right ventricle. Together with the left ventricle, it forces blood out of the heart into the arteries to be carried back to the various sites throughout the body. The right ventricle has a much thinner wall than the left ventricle. This chamber pumps blood a fairly short distance to the lungs. This valve is composed of three leaflets, or cusps. This valve permits blood to move from the right atrium into the right ventricle and prevents it from moving back the other way. The cusps fold out of the way when the blood pressure is greater on the atrium side, and they close when the pressure is greater on the ventricular side. At the base of this trunk is a pulmonary semilunar valve that is made up of three leaflets or cusps. This valve opens when the right ventricle contracts. When the right ventricular muscles relax, blood starts back up the pulmonary trunk, causing the valve to close to prevent the flow from returning into the ventricular chamber. It supplies blood to the left lung; it runs down to the root of that lung and from there it branches out into two separate arteries. These smaller arteries each transport blood to one of the lung's left lobes. It is a thicker artery, and a longer one, compared to the left pulmonary artery. The right pulmonary artery provides the right lung's blood supply; it runs down to the root of the right lung and from there it branches out into two separate arteries. These smaller arteries each transport blood to one of the lung's right lobes. All of the blood delivered from the heart to the systemic tissues of the body passes through the aorta, making it the largest artery in the human body. As the aorta extends from the heart, it begins as the ascending aorta before turning 1. From the arch the aorta passes posterior to the heart and descends through the thorax and abdomen as the descending aorta. Three major arteries branch off from the superior arterial wall of the aortic arch to supply blood to the tissues of the superior regions of the body: the brachiocephalic trunk, left common carotid artery, and left subclavian artery. The brachiocephalic trunk is the first artery to arise from the aortic arch, carrying blood to the right arm and the right side of the head and neck. Next to branch from the aorta.. The portion of the descending aorta above the diaphragm is called the thoracic aorta, and gives off branches into the thoracic wall. These branches, the bronchial, pericardial, and esophageal arteries, supply blood to the organs for which they were named. Below the diaphragm, the descending aorta becomes the abdominal aorta and stems off into branches that reach the abdominal wall and various tissues and organs of the abdomen. The brachiocephalic artery supplies blood to the tissues of the brain and the head. It is the first branch of the aortic arch and rises up to a point near the junction of the sternum (breast bone) and the right clavicle (collarbone). At this point, it divides, giving rise to the common carotid artery, which carries blood to the right side of the neck and head, and the right subclavian artery, which leads to the right arm. It collects blood from veins serving the tissues inferior to the heart and returns this blood to the right atrium of the heart. Although the vena cava is very large in diameter, its walls are incredibly thin due to the low pressure exerted by venous blood. The inferior vena cava forms at the superior end of the pelvic cavity when the common iliac veins unite to form a larger vein. From the pelvis, the inferior vena cava ascends through the posterior abdominal body wall just to the right of the vertebral column. Along its way through the abdomen, blood from the internal organs joins the inferior vena cava through a series of large veins, including the gonadal, renal, suprarenal and inferior phrenic veins. The hepatic vein provides blood from the digestive organs of the abdomen after it has passed through the hepatic portal system in the liver. Blood from the tissues of the lower back, including the.. Within the neck, the left common carotid artery extends out into the left external carotid artery and the left internal carotid artery. The external jugular vein passes over the sternocleidomastoid. It starts in the parotid gland. Where the retromandibular vein divides posteriorly and the posterior auricular vein connects with it, it forms the external jugular vein. This vein gets the majority of the blood from the cranium’s exterior and the face’s deeper portions. It can be found at the lowest section of the small depression known as the hilum of the lung, and often feeds directly into the left atrium of the heart. This is the smaller of the two internal jugular veins. The internal jugular veins return deoxygenated blood from the head to the heart. The left internal jugular vein curves forward and joins the subclavian vein, and then crosses over the left common carotid artery at the neck’s root. It begins at the height of the fourth thoracic vertebra and runs along the superior mediastinal cavity to the base of the neck before arching across the body to the edge of the Scalenus anterior. Demand pacemakers sense when the heart is sending its own impulses, and work only when the heart fails to beat, or on demand. Fixed- rate pacemakers send impulses to the heart and bring about a continuous steady rate. The electrical impulses generate from the pacemaker and will cause rhythmic contraction of the heart. The electrical impulses generate from the pacemaker and will cause rhythmic contraction of the heart. The electrical impulses generate from the pacemaker through this electrode tip and will cause rhythmic contraction of the heart. Within the neck, the right common carotid artery branches out into the right external carotid artery and the right internal carotid artery. The parotid gland is where the external jugular vein starts. It’s formed where the posterior auricular vein and the retromandibular vein’s posterior separation meet. This vein gets the majority of the blood from the cranium’s exterior and the face’s deeper portions.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
September 2017
Categories |