Al-noor University Anatomy Lecture Notes PDF

Al-noor University Dept :- Anesthesiology Subject :- Theory Applied Physiology Second stage 2024-2025 Dr :- Zuhair S Alhayali Lectuer -5 Systemic circulation part 1 And...

Al-noor University Dept :- Anesthesiology Subject :- Theory Applied Physiology Second stage 2024-2025 Dr :- Zuhair S Alhayali Lectuer -5 Systemic circulation part 1 And Coronary circulation The cardiovascular system (sometimes called the circulatory system) consists of the heart, blood vessels, and lymphatics. This network brings life-sustaining oxygen and nutrients to the body’s cells, removes metabolic waste products, and carries hormones from one part of the body to.another The heart is actually two separate pumps: The right side pumps the blood to the lungs to receive oxygen, and the left side pumps the oxygenated.blood to the rest of the body About the size of a closed fist, the heart lies beneath the sternum in the mediastinum (the cavity between the lungs) between the second and.sixth ribs In most people, the heart rests obliquely, with its right side below and almost in front of the left. Because of its oblique angle, the heart’s broad part or top is at its upper right, and its pointed end (apex) is at its lower left. The apex is the point of maximal impulse, where the heart sounds are the.loudest Heart structure Surrounded by a sac called the pericardium, the heart has a wall made up of three layers: the myocardium, endocardium, and epicardium. Within the heart lie four chambers (two atria and two ventricles) and four valves (two atrioventricular [AV] and two semilunar valves). (See Inside the heart.) Pericardium The pericardium is a fibro serous sac that surrounds the heart and the roots of the great vessels (those vessels that enter and leave the heart). It consists of the fibrous pericardium The fibrous pericardium, composed of tough, white fibrous tissue, fits loosely around the heart, protecting it and the The serous pericardium :the thin smooth inner portion, has two layers The parietal layer lines the inside of the fibrous-1.pericardium The visceral layer adheres to the surface of the-2.heart.serous pericardium Between the fibrous and serous pericardium is the pericardial space. This space contains pericardial fluid that lubricates the surfaces of the space and allows the heart to.move easily during contraction The wall :The wall of the heart consists of three layers The epicardium, the outer layer (and the visceral layer of-1 the serous pericardium), is made up of squamous epithelial.cells overlying connective tissue The myocardium, the middle layer, forms most of the -2 heart wall. It has striated muscle fibers that cause the heart.to contract The endocardium, the heart’s inner layer, consists of -3 endothelial tissue with small blood vessels and bundles of.smooth muscle -:Inside the heart Within the heart lie four chambers (two atria and two ventricles) and four valves (two.atrioventricular and two semilunar valves) A system of blood vessels carries.blood to and from the heart The chambers :The heart contains four hollow chambers.two atria (singular: atrium) and two ventricles The atria, the upper chambers, are separated by the interatrial septum. They receive blood returning to the heart and supply blood to the.ventricles The right atrium receives blood from the superior and inferior venae cavae. The left atrium, which is smaller but has thicker walls than the right atrium, forms the uppermost part of the heart’s left border. It receives blood from the two pulmonary.veins The right and left ventricles, separated by the interventricular septum, make up the two lower chambers. The ventricles receive blood from the atria. Composed of highly developed musculature, the ventricles are.larger and have thicker walls than the atria The right ventricle pumps blood to the lungs. ,The left ventricle which is larger than the right, pumps blood.through all other vessels of the body The valves ,The heart contains four valves.two AV valves and two semilunar valves The valves allow forward flow of blood through the heart response and prevent backward flow. They open and close in to pressure changes caused by ventricular contraction and blood.ejection The two AV valves separate the atria from the ventricles. The right AV valve, called the tricuspid valve, prevents backflow from the right ventricle into the right atrium. The left AV valve, called the mitral valve, prevents backflow from the left.ventricle into the left atrium One of the two semilunar valves is the pulmonic valve, which prevents backflow from the pulmonary artery into the right ventricle. The other semilunar valve is the aortic valve, which prevents.backflow from the aorta into the left ventricle The tricuspid valve has three triangular cusps, or leaflets. The mitral valve, also called the bicuspid valve, contains two cusps, a large anterior and a smaller posterior. Chordae tendineae attach the cusps of the AV valves to papillary muscles in the.ventricles The semilunar valves have three cusps that are shaped like half moons Conduction system Contraction of the heart, occurring as a result of its conduction system, causes blood to move.throughout the body The conduction system of the heart contains ,pacemaker cells :which have three unique characteristics automaticity, the ability to generate /1 an electrical impulse automatically conductivity, the ability to pass the /11 impulse to the next cell contractility, the ability to shorten the /111 fibers in the heart when receiving the.impulse The sinoatrial (SA) node, located on the endocardial surface of the right atrium, near the -superior vena cava, is the normal pace maker of the heart, generating an impulse between 60 and 100 times per minute. The firing of the SA node spreads an impulse throughout the right and left atria, resulting in.atrial contraction The AV node, situated low in the septal wall of the right atrium, slows impulse conduction between the atria and ventricles. This resistor” node allows time for the contracting“ atria to fill the ventricles with blood before the.lower chambers contract  From the AV node, the impulse travels to the bundle of His (modified muscle fibers), branching off to the right and travels left bundles. Finally, the impulse to the Purkinje fibers, the distal portions of the left and right bundle branches. These fibers fan across the surface of the ventricles from the endocardium to the myocardium. As the impulse spreads, it brings “the word” to the blood-filled ventricles to contract The conduction system has two built-in safety mechanisms. If the SA node fails to fire, the AV node will generate an impulse between 40 and 60 times per ,minute. If the SA node and AV node fail the ventricles can generate their own impulse between 20 and 40 times per.minute Understanding preload, contractility, and afterload f you think of the heart as a balloon, it will help you.understand stroke volume Coronary circulation The heart relies on the coronary arteries and their branches for its upply of oxygenated blood and depends on the cardiac veins to.remove oxygen-depleted blood During systole, blood is ejected into the aorta from the left ventricle. During diastole, blood flows out of the heart and then through the coronary arteries to.nourish the heart muscle The right coronary artery supplies blood to the ,right atrium, part of the left atrium, most of the right ventricle and the inferior part of the left ventricl The left coronary artery, which splits into the anterior descending artery and circumflex artery, supplies blood to ,the left atrium, most of the left ventricle.and most of the interventricular septume Vessels that supply the heart Coronary circulation involves the arterial system of blood vessels that supply oxygenated blood to the heart and the venous system that removes oxygen-depleted blood.from it Thank you for listening