Cardiovascular System Cardiovascular System Includes the heart, blood vessels and blood. (add blood to your notes) Vital for survival, without circulation the tissues lack oxygen and nutrients and waste will accumulate. Heart Average Heart 13 centimeters long and 9 cm wide. As a kid, the size of your fist. As an adult…closer to twice the size of your fist. Vary along with body size. Heart A hollow, cone-shaped, muscular pump located within the mediastinum of the thorax and resting upon the diaphragm. The heart is bordered by the lung, posteriorly by the spinal cord, and anteriorly by the sternum. Heart Put your hand on your heart. Did you place your hand on the left side of your chest? Many people do, but the heart is actually located almost in the center of the chest, between the lungs. It's tipped slightly so that a part of it sticks out and taps against the left side of the chest, which is what makes it seem as though it is located there. Layers of the Heart Pericardium- Covering that encloses the heart and the proximal ends of the large blood vessels to which it attaches. The outer fibrous pericardium is a tough, protective sac largely composed of dense connective tissue. Wall of the Heart (3 distinct layers) Epicardium- corresponds with the visceral pericardium. It is protective serous membrane that consists of connective tissue covered by epithelium, and it includes blood capillaries Myocardium- thick and largely consists of the cardiac muscle tissue that pumps blood out of the heart chambers. Endocardium- Inner most layer that consists of epithelium and connective tissues that contains many elastic and collagenous fibers. Also contains blood vessels and some specialized cardiac muscle fibers. Structure of the Heart Major Parts of the Heart The heart is divided into four hollow champers, two on the left and two on the right. Atria- (Atrium)These are the upper chambers of the heart which have thin walls and receive blood returning to the heart. Ventricles- The lower chambers which force blood out of the heart into the arteries. Blood flow will go like this…right atrium, right ventricle, other stuff…left atrium to the left ventricle. Major Parts of the Heart Superior These Vena Cava and Inferior Vena Cava- are two large veins that enter the right atrium. They are carrying blood that is low in oxygen from tissue in the body. Major Parts of the Heart Throughout the heart circulation you will be responsible for 4 valves… Tricuspid, Bicuspid, Pulmonary and Aortic Valves Regardless of location… all valves in the heart have essentially the same purpose which is to allow blood to flow in the correct order and preventing blood from flowing backwards as the heart contracts and relaxes. Major Parts of the Heart Tricuspid Valve- guards the atrioventricular orifice between the right atrium and right ventricle. Valve permits the blood to move from the right atrium to the right ventricle. (may need to be fixed on guided reading notes) Bicuspid Valve (aka mitral valve)- blood goes from the left atrium into the left ventricle through this atrioventricular orifice. Major Parts of the Heart Pulmonary Valve- the flaps between the right ventricle and the pulmonary artery. When the ventricle relaxes, the valves closes, preventing the back flow of blood from the pulmonary artery to the right atrium. Aortic valve- This is the valve that the blood will flow through as it moves from the left ventricle to the aorta. This prevents blood from moving or back flowing from aorta back into the left ventricle during ventricular relaxation. The crazy things they do! Throughout the body’s circulation system the following holds true.. Veins always carry oxygen poor blood to the heart! Arteries always carry oxygen rich blood to the heart or throughout the body! EXCEPT IN THE PULMONARY CIRCULATION SYSTEM!! The pulmonary circulation system is the flow of blood from the heart to the lungs and then back again! Just the opposite holds true here!! Major Parts of the Heart Pulmonary Arteries- the blood vessel that carries oxygen-poor blood from the right ventricle of the heart to the lungs. Pulmonary Veins- the blood vessel that carries oxygen-rich blood from the lungs to the left atrium of the heart. COLORING!! The coloring “concept” will remain constant throughout. Always color oxygen poor veins or arteries BLUE Always color oxygen rich veins or arteries RED! Major Parts of the Heart The oxygen poor blood leaves the heart through the pulmonary value and the pulmonary artery to the lungs. You have 2 pulmonary valves. (right and left) Left atrium receives the blood from the lungs through four pulmonary veins (2 from the right lung 2 from the left lung) Major Parts of the Heart Aorta- is the largest diameter artery in the body. ( It is almost the diameter of a garden hose.) It extends upward from the left ventricle, arches over the heart to the left and descends just anterior and to the left of the vertebral column. You have an ascending and a descending aorta. It takes blood away from the heart. Major Parts of the Heart Septum- The muscular wall that separates the left and right sides of the heart. Basic Structure of the Heart The human heart is primarily a shell. There are four cavities, or open spaces, inside the heart that fill with blood. Two of these cavities are called atria (atrium). The other two are called ventricles. The two atria form the curved top of the heart. The ventricles meet at the bottom of the heart to form a pointed base which points toward the left side of your chest. The left ventricle contracts most forcefully, so you can best feel your heart pumping on the left side of your chest. Main Arteries of the Heart The top of the heart connects to a few large blood vessels. The largest of these is the aorta, or main artery, which carries nutrient-rich blood away from the heart. Another important vessel is the pulmonary artery which connects the heart with the lungs as part of the pulmonary circulation system. The two largest veins that carry blood into the heart are the superior vena cava and the inferior vena cava. They are called "vena cava" because they are the "heart's veins." The superior is located near the top of the heart. The inferior is located beneath the superior. How Blood Flows Through the Heart Day and night, the muscles of your heart contract and relax to pump blood throughout your body. When blood returns to the heart, it follows a complicated pathway. If you were in the bloodstream, you would follow these steps one by one. You will need to write this down these steps and include as part of your notes…Not in the guided reading This is a vital part of this chapter! How Blood Flows Through the Heart 1. Oxygen-poor blood flows from the body into the superior and inferior Vena Cava 2. The Vena Cava’s dump the blood into the right atrium. 3. Blood flows through the right atrium into the right ventricle by way of the Tricuspid Valve. 4. The right ventricle pumps the blood to the Pulmonary Trunk through the Pulmonary Valve. 5. The oxygen poor blood will the go through the 2 Pulmonary Arteries (right and left) to the lungs. How Blood Flows Through the Heart 6. Once the lungs have saturated the blood with oxygen it then will travel back to the heart through the 4 Pulmonary Veins (right and left) 7. The newly oxygen-rich blood enters the left atrium. 8. From the left atrium it will go to the left ventricle by way of the bicuspid valve. 9. From the left ventricle the blood will then go the aorta via the aortic valve. 10.The aorta will then pump the oxygen-rich blood to all parts of the body. Circulation Circulation Blood Vessels The blood vessels are organs of the cardiovascular system and they form a closed circuit of tubes that carries blood from the heart to cells and back again. These vessels include arteries, arterioles, capillaries, venules, and veins. Arteries and Arterioles Arteries are strong, elastic vessels that are adapted for carrying the blood away from the heart under high pressure. These vessels subdivide into progressively thinner tube and eventually give rise to the finer branched arterioles. Capillaries Capillaries are the smallest diameter blood vessels. (Capillaries are so small that it takes ten of them to equal the thickness of a human hair.) They connect the smallest arterioles and the smallest venules. They are extensions of the inner linings of arterioles in that their walls are endothelium ( a single layer of epithelial cells) Venules and Veins Venules are the microscopic vessels that continue from the capillaries and merge to form veins. The veins which carry blood back to the atria, follow pathways that roughly parallel those of the arteries. Paths of Circulations Pulmonary Circuitconsists of vessels that carry blood from the heart to the lungs and back to the heart. Systemic Circuit- Carries blood from the heart to all body parts, except the lungs, and back again. Pulse Rate Feel your pulse by placing two fingers at pulse points on your neck or wrists. The pulse you feel is blood stopping and starting as it moves through your arteries. As a kid, your resting pulse might range from 90 to 120 beats per minute. As an adult, your pulse rate slows to an average of 72 beats per minute. Blood Pressure Blood Pressure is the pressure of the blood against the walls of the arteries. It results from two forces. One by the force created as the heart pumps blood into the arteries. The other is the force of the arteries as they resist the blood flow Blood Pressure Normal: 120/80 Pre-Hypertension: 120-139/80-89 Elevated: 140/90 Cool Facts Your body has about 5.6 liters (6 quarts) of blood. This 5.6 liters of blood circulates through the body three times every minute. In one day, the blood travels a total of 19,000 km (12,000 miles)—that's four times the distance across the U.S. from coast to coast. The heart pumps about 1 million barrels of blood during an average lifetime—that's enough to fill more than 3 super tankers. Cool Facts Your heart beats about 100,000 times in one day and about 35 million times in a year. During an average lifetime, the human heart will beat more than 2.5 billion times. lub-DUB, lub-DUB, lubDUB. Sound familiar? If you listen to your heart beat, you'll hear two sounds. These "lub" and "DUB" sounds are made by the heart valves as they open and close.