Introduction to the Human Cardiovascular System PDF

Introduction to the Human Cardiovascular System Dr : Hana faraj katich  INTRODUCTION  The cardiovascular system consists of the heart, blood vessels, and blood. Its primary function is to transport nutrients and oxygen-rich blood to all parts of the body and to carr...

Introduction to the Human Cardiovascular System Dr : Hana faraj katich  INTRODUCTION  The cardiovascular system consists of the heart, blood vessels, and blood. Its primary function is to transport nutrients and oxygen-rich blood to all parts of the body and to carry deoxygenated blood back to the lungs. Figure 1-2(f) COMPONENTS OF CARDIOVASCULAR SYSTEM BLOOD HEART BLOOD VESSELS  BLOOD The Blood: Blood cells & Plasma Blood cells 1- Erythrocytes - Red Blood Cells(RBCs) 2- Leucocytes- white blood cells(WBCs) 3- Thrombocytes-platelets. Plasma is fluid portion What is blood? Blood, by definition, is a fluid that moves through the vessels of a circulatory system. In humans, it includes plasma (the liquid portion), blood cells (which come in both red and white varieties), and cell fragments called platelets.  Plasma: is the main component of blood and consists mostly of water, with proteins, ions, nutrients, and wastes mixed in.  Red blood cells are responsible for carrying oxygen and carbon dioxide.  Platelets are responsible for blood clotting.  White blood cells are part of the immune system and function in immune response.  HEART Heart is a four chambered, hollow muscular organ approximately the size of your fist Location: – Superior surface of diaphragm – Left of the midline – Anterior to the vertebral column, posterior to the sternum Chapter 18, Cardiovascular System 8  HEART Figure 18.1 Chapter 18, Cardiovascular System 9  R & L atrium receive blood from vein Ventricle pump blood out of the heart R.A receives deoxygenated blood from vein. L.A receives oxygenated blood from pulmonary veins.  Valves of the Heart The heart has two types of valves that keep the blood flowing in the correct direction. The valves between the atria and ventricles are called atrioventricular valves, while those at the bases of the large vessels leaving the ventricles are called semilunar valves. The right atrioventricular valve is the tricuspid valve. The left atrioventricular valve is the bicuspid, or mitral, valve. The valve between the right ventricle and pulmonary trunk is the pulmonary semilunar valve. The valve between the left ventricle and the aorta is the aortic semilunar valve. Heart Valves  Heart valves ensure unidirectional blood flow through the heart  Atrioventricular (AV) valves lie between the atria and the ventricles  AV valves prevent backflow into the atria when ventricles contract Chapter 18, Cardiovascular System 13 Heart Valves  Semilunar valves prevent backflow of blood into the ventricles  Aortic semilunar valve lies between the left ventricle and the aorta  Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk Chapter 18, Cardiovascular System 14 Heart Valves Figure1518.8a, b Chapter 18, Cardiovascular System When the ventricles contract, atrioventricular valves close to prevent blood from flowing back into the atria. When the ventricles relax, semilunar valves close to prevent blood from flowing back into the ventricles. Pathway of blood through heart Both atria contract at the same time and both ventricle contract at the same time Heart work as two pump R & L Pathway of blood through heart include three circulation: 1. Pulmonary circulation 2. Systemic circulation 3. Coronary circulation  Pulmonary circulation The Pulmonary circulation is the portion of the cardiovascular system which Transports oxygen depleted blood away from the heart to the lungs and returns oxygenated blood back to the heart.  Or This circulatory system moves blood between the heart and lungs. It is where oxygen enters the blood and carbon dioxide leaves the blood.  Oxygen deprived blood from the vena cava enters the R A of the heart and flows through the the tricuspid valve into the right ventricle, from which it is pumped through the pulmonary semilunar valve into the pulmonary arteries which go to the lungs. Pulmonary veins return the oxygen-rich blood to the heart, where it enters the left atrium before flowing through the mitral valve into the left ventricle. Then, oxygen-rich blood from the left ventricle is pumped out via the aorta, and on to the rest of the body.  Systemic circulation Systemic circulation is the portion of the cardiovascular system which transports oxygenated blood away from the heart, to the rest of the body, and returns oxygen-depleted blood back to the heart. Systemic circulation is much longer than pulmonary circulation, transporting blood to every part of the body.  Coronary circulation Coronary circulation is the circulation of blood in the arteries and veins that supply the heart muscle Coronary circulation is the functional blood supply to the heart muscle itself Pathway of Blood Through the Heart and Lungs  Right atrium  tricuspid valve  right ventricle  Right ventricle  pulmonary semilunar valve  pulmonary arteries  lungs  Lungs  pulmonary veins  left atrium  Left atrium  bicuspid valve  left ventricle  Left ventricle  aortic semilunar valve  aorta  Aorta  systemic circulation Chapter 18, Cardiovascular System 22 Pathway of Blood Through the Heart and Lungs Figure 23 18.5 Chapter 18, Cardiovascular System  BLOOD VESSELS Blood Vessels -A closed network of tubes These includes:  Arteries  Capillaries  Veins  BLOOD VESSELS -Arteries(Distributing channel) Thick walled tubes Elastic Fibers Circular Smooth Muscle –Capillaries (microscopic vessels) One cell thick Serves the Respiratory System –Veins (draining channel)  BLOOD VESSELS General structure 1.Tunica intima 2.Tunica media 3.Tunica adventitia  ARTERIES  Blood vessels that carry blood away from the heart are called arteries.  They are the thickest blood vessels and they carry blood high in oxygen known as oxygenated blood (oxygen rich blood).  CAPILLARIES (5-8 micron) The smallest blood vessels are capillaries and they connect the arteries and veins. This is where the exchange of nutrients and gases occurs.  VEINS Blood vessels that carry blood back to the heart are called veins. They carry blood that is high in carbon dioxide known as deoxygenated blood (oxygen poor blood).  CIRCULATION –Coronary circulation – the circulation of blood within the heart. –Pulmonary circulation – the flow of blood between the heart and lungs. –Systemic circulation – the flow of blood between the heart and the cells of the body. SYSTEMIC AND PULMONARY CIRCULATION Figure 18.5 Chapter 18, Cardiovascular System 31