Cardiovascular System: Heart Anatomy and Circulation PDF

Official (Closed) - Non Sensitive Cardiovascular system HBS1_School of Health Sciences Official (Closed) - Non Sensitive Introduction to cardiovascular system HBS1_School of Health Sciences Official (Closed) - Non Se...

Official (Closed) - Non Sensitive Cardiovascular system HBS1_School of Health Sciences Official (Closed) - Non Sensitive Introduction to cardiovascular system HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1a Objectives To understand the anatomy of the heart including chambers, heart valves, major blood vessels, pericardium and coronary circulation. To understand the structure of the conducting system of the heart To interpret the electrical events recorded in electrocardiogram To understand cardiac output and the factors that influence heart rate and stroke volume and Blood pressure HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1a The Cardiovascular System A closed system of the heart and blood vessels The heart pumps blood Blood vessels allow blood to circulate to all parts of the body Arteries: Carry blood away from heart Arterioles: Are the smallest branches of arteries Veins: Return blood to heart Venules: Collect blood from capillaries Capillaries: Small, thin-walled vessels between smallest arteries and veins Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill, HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1a Functions of the cardiovascular system: Transport: Deliver oxygen and nutrients to cells and tissues Remove carbon dioxide and other waste products from cells and tissues Protection: carries the cells and chemicals of immune system Regulation – Homeostasis Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill, HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1b The Heart Location Thorax, behind the sternum, between the lungs in the inferior mediastinum Orientation Pointed apex directed toward left hip Base points toward right shoulder About the size of a human fist ©2016, WebMD, LLC HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1b Mid-sternal line 2nd rib Sternum Diaphragm HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1b Coverings and Walls of the Heart Pericardium—a double-walled sac Serous membrane that surrounds the heart and lines the pericardial cavity 1. Parietal pericardium: outside layer that lines the inner surface of the fibrous pericardium 2. Visceral pericardium: next to heart; also known as the epicardium Serous fluid fills the space between the layers of pericardium HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1b Walls of the Heart Three layers of the heart wall: 1. Epicardium Outside layer made up of connective tissue This layer is the visceral pericardium 2. Myocardium Middle layer Mostly contains cardiac muscle 3. Endocardium Inner layer known as endothelium Source: https://d2jmvrsizmvf4x.cloudfront.net/0cf1L3slSkuAz2WXFsCe_untitled1361983671892.png HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1c Internal anatomy of the heart HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1c Internal Anatomy of the heart Right ventricle Left ventricle Four chambers: Thinner Very thick Left Atrium, Right Atrium myocardium / myocardium / Left Ventricle, Right Ventricle wall wall Interventricular septum Lower Produces 4–6 Separates the two ventricles times as much pressure pressure than Interatrial septum system right Separates the two atria Pumps blood only Pumps blood to to lungs aorta and then to the whole body HBS1_School of Health Sciences (Marieb and Keller, 2018)  Gross anatomy of the heart Official (Closed) - Non Sensitive CVS_1c Left atrium Right atrium Right ventricle Left ventricle Interventricular septum HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1c External anatomy of the heart HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1c Heart Valves - Allow blood to flow in only one direction  prevent backflow Four valves Atrioventricular (AV) valves— between atria and ventricles Bicuspid (mitral) valve (left side of heart) Tricuspid valve (right side of heart) Anchored in place by chordae tendineae (“heart strings”) Open during heart relaxation and closed during ventricular contraction HBS1_School of Health Sciences (Marieb and Keller, 2018) Official (Closed) - Non Sensitive CVS_1c Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1c Heart Valves - Allow blood to flow in only one direction  prevent backflow Semilunar valves— between ventricle and artery Pulmonary semilunar valve Aortic semilunar valve Closed during heart relaxation but open during ventricular contraction HBS1_School of Health Sciences (Marieb and Keller, 2018) Official (Closed) - Non Sensitive CVS_1c Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1c Heart Sounds Stethoscopes are used to listen for four heart sounds First heart sound ("lubb") due to AV valves closing Second heart sound ("dupp") due to semilunar valves closing Third and fourth heart sounds Are faint Due to atrial contraction and blood flow into ventricles HBS1_School of Health Sciences (Marieb and Keller, 2018) Official (Closed) - Non Sensitive CVS_1c Superior vena cava Aorta Left pulmonary artery Right pulmonary artery Left atrium Right atrium Left pulmonary veins Right pulmonary veins Pulmonary semilunar valve Left atrioventricular Fossa ovalis valve (bicuspid valve) Aortic semilunar valve Right atrioventricular valve (tricuspid valve) Left ventricle Right ventricle Chordae tendineae Interventricular septum Inferior vena cava Myocardium Visceral pericardium (epicardium) HBS1_School of Health Sciences Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill, Official (Closed) - Non Sensitive CVS_1d Circulation Pulmonary circulation Systemic circulation HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1d The heart is a double pump, each side supplying its own circuit. Pulmonary circulation: Blood flows from the right side of the heart to the lungs and back to the left side of the heart HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1d Pulmonary circulation From the right ventricle, blood leaves Blood leaves right ventricle the heart as it passes through the pulmonary semilunar valve into the Pulmonary valve (pulmonary semilunar valve) pulmonary trunk Pulmonary trunk splits into right and Pulmonary trunk left pulmonary arteries, which carry blood to the lungs In the lungs, blood picks up oxygen Right and left pulmonary arteries and drops off carbon dioxide Oxygen-rich blood returns to the Respiratory capillaries (where gas exchange occurs) heart through the four pulmonary veins Right and left pulmonary veins Flows into left atrium HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1d Systemic circulation: Blood flows from the left side of the heart to body tissues, and back to the right side of the heart HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1d Systemic circulation Blood leaves left ventricle, flows through: Oxygen-rich blood returns to the heart through the four pulmonary veins Aortic valve (aortic semilunar valve) Blood enters the left atrium and travels through the bicuspid valve into the left Ascending aorta and aortic arch ventricle From the left ventricle, blood leaves the heart arteries via the aortic semilunar valve and aorta Reach the tissues were Substances move to Numerous branches to capillary beds in the tissues and from the blood and tissue cells through capillary walls Systemic veins Deoxygenated blood will travel via superior and inferior venae cavae reach the right Inferior and superior venae cavae, coronary sinus atrium Flows into right atrium HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1d HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1d Capillary beds of lungs where gas exchange occurs Pulmonary Circuit Pulmonary arteries Pulmonary veins Aorta and branches Venae cavae Left atrium Right Left atrium ventricle Right Heart ventricle Systemic Circuit Capillary beds KEY: of all body tissues Oxygen-rich, CO2-poor blood where gas exchange occurs Oxygen-poor, CO2-rich blood Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill, HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1e Coronary circulation HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1e Coronary Circulation Blood in the heart chambers does not nourish the myocardium The heart has its own nourishing circulatory system consisting of: Coronary arteries—branch from the aorta to supply the heart muscle with oxygenated blood Cardiac veins—drain the myocardium of blood Coronary sinus—a large vein on the posterior of the heart, receives blood from cardiac veins Blood empties into the right atrium via the coronary sinus HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1e Left and right coronary arteries originate at base of aorta. Right branches: Into marginal and posterior interventricular arteries Left branches: Circumflex and anterior interventricular arteries Anastomoses: Interconnections formed between arteries Provide alternate pathways for blood supply to cardiac muscle HBS1_School of Health Sciences Official (Closed) - Non Sensitive Aorta CVS_1e Pulmonary Superior trunk vena cava Left atrium Anastomosis (junction of vessels) Left coronary Right artery atrium Circumflex artery Right coronary artery Left ventricle Right ventricle Anterior Right interventricular marginal artery artery Posterior (a) The major coronary arteries. interventricular HBS1_School of Health Sciences artery Official (Closed) - Non Sensitive HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1e Superior vena cava Great Anterior cardiac cardiac vein veins Coronary sinus Small Middle cardiac cardiac vein vein (b) The major cardiac veins. HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1e (Marieb and Keller, 2018) HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1f The working heart -1 The conducting system HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1f The role of cardiac muscles….. Two types of cardiac muscle cells Na+, K+, Ca++ and Cl- move in and involved out of the cells in a specific manner, ​Contractile cells creating electrical charges on both sides of the cell membrane. ​Conducting system Changes in the electrical charges across the cell membrane  Cardiac muscle activity is initiated depolarization  Action potential and controlled by movements ions Cardiac muscle can initiate its own across the cell membrane. contraction in a regular way, but its rate is influenced by both intrinsic and extrinsic factors HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1f Cardiac conduction system: network of specialized cardiac muscle cells that initiate/distribute a stimulus to contract Sinoatrial (SA) node is the heart’s pacemaker Once SA node starts the heartbeat Impulse spreads to the AV node Then the atria contract At the AV node, the impulse passes through the AV bundle, bundle branches, and Purkinje fibers Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill, Blood is ejected from the ventricles to the aorta and pulmonary trunk as the ventricles contract HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1f HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1f Electrocardiogram (ECG or EKG) Recording of heart’s electrical activities from body surface by placing electrodes / leads at various designated positions To assess performance of nodal, conducting, and contractile components If part of heart is damaged by heart attack, may see (Marieb and Keller, 2018) abnormal ECG pattern HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1f HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1f (Marieb and Keller, 2018) HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1g The working heart Cardiac contraction HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1g Heart Contractions Contraction of atria and ventricles Cardiac cycle  period between occurs in a coordinated manner start of one heartbeat and the next; Atrial cells first heart rate  number of beats per Followed by ventricular cells minute Two atria contract first to fill ventricles; two ventricles then contract to pump blood into Systole = contraction pulmonary Diastole = relaxation and systemic circuits HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1g Sequence of contractions 1. Atria contract together first: atrial systole Push blood into the ventricles Ventricles are relaxed (diastole) and filling 2. Ventricles contract together next: ventricular systole Push blood into the pulmonary and systemic circuits Atria are relaxed (diastole) and filling Typical cardiac cycle lasts 800 msec HBS1_School of Health Sciences (Marieb and Keller, 2018) Official (Closed) - Non Sensitive CVS_1g Cardiac Output Cardiac output (CO) Stroke volume (SV) Amount of blood pumped by each Volume of blood pumped by side (ventricle) of the heart in one each ventricle in one minute contraction (each heartbeat) CO = HR × SV About 70 ml of blood is pumped CO = HR (75 beats/min) × SV (70 out of the left ventricle with ml/beat) each heartbeat CO = 5250 ml/min = 5.25 L/min Heart rate (HR) Typically 75 beats per minute Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill, HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1g The picture can't be displayed. Factors Affecting Factors Affecting Heart Rate (HR) Stroke Volume (SV) Autonomic End-diastolic End-systolic innervation Hormones volume (EDV) volume (ESV) HEART RATE (HR) STROKE VOLUME (SV) = EDV — ESV CARDIAC OUTPUT (CO) = HR x SV Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill, HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1h Clinical monitoring of circulatory efficiency Pulse Alternate expansion and recoil of a blood vessel wall (the pressure wave) that occurs as the heart beats Monitored at “pressure points” in superficial arteries where pulse is easily palpated Pulse averages 70 to 76 beats per minute at rest, in a healthy person HBS1_School of Health Sciences (Marieb and Keller, 2018) Official (Closed) - Non Sensitive CVS_1h Systemic Blood Pressure Pumping action of heart Measuring blood pressure generates blood flow Systemic arterial BP is Pressure results when flow is measured indirectly by opposed by resistance in the auscultatory methods using blood vessels a sphygmomanometer and listening for sounds of Systemic pressure is highest in Korotkoff with a stethoscope aorta and declines throughout pathway HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1h Regulation of Blood Pressure Maintaining blood pressure requires cooperation of heart, blood vessels, and kidneys All supervised by brain Three main factors regulating blood pressure Cardiac output (CO) Peripheral resistance (PR) Blood volume Blood pressure varies directly with CO, PR, and blood volume HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1i Regulation of cardiovascular functions HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1i Homeostatic mechanisms Ensure adequate tissue perfusion (blood flow through tissues) Blood flow must match changes in demand for oxygen and nutrients Two regulatory pathways 1. Autoregulation Occurs at local level 2. Central regulation Neural and endocrine control Activated if autoregulation is ineffective Official (Closed) - Non Sensitive CVS_1i Official (Closed) - Non Sensitive CVS_1i Regulation at the tissue level Autoregulation Involves local changes in blood flow within capillary beds Regulated by precapillary sphincters in response to chemical changes in interstitial fluid Vasodilators: Local chemicals that increase blood flow © 2018 Pearson Education, Ltd. Official (Closed) - Non Sensitive CVS_1i Central regulation Involves both neural and endocrine mechanisms Neural Medulla oblongata has integration centers for cardiac reflexes Activation of cardiovascular center Can increase cardiac output and alter the blood flow to nonessential or inactive tissues Endocrine Release of hormones, producing short and long-term increases in blood pressure © 2018 Pearson Education, Ltd. Official (Closed) - Non Sensitive CVS_1i Neural controls Baroreceptor Reflexes Chemoreceptor Reflexes Receptors monitor degree of Receptors sensitive to changes in stretch elicited by blood pressure. carbon dioxide, oxygen, and pH in ( Baro = Presssure) blood and CSF and activates the cardiovascular regulatory center in Receptors are located at medulla oblongata Aortic sinuses Located in carotid and aortic Carotid sinuses bodies and medulla oblongata Very sensitive to ensure adequate flow to, and perfusion of, brain HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1i Hormonal Control of Cardiovascular Performance Short-term Epinephrine and Norepinephrine ( E and NE) cause rapid increase of cardiac output and vasoconstriction Long-term Antidiuretic hormone (ADH), angiotensin II, EPO Raise BP when too low HBS1_School of Health Sciences