Anatomy & Physiology The Circulatory System The Heart Muscular pump Pumps 5 liters of blood every minute Size of closed fist Less than a pound Central location between lungs Apex pointed end Base is opposite apex 2 Coverings & layers of the Heart Pericardium: sac that encloses/covers the heart. Layers 1.Epicardium-inner part of pericardium but outermost layer 2.Myocardium-thick, middle layer (Muscular). 3.Endocardium- smooth, inner lining Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 3 4 Pericardium Epicardium Myocardium Endocardium Pericardial Space Inside of the Heart Coronary Vessels Fatty Connective Tissue Outside of the Heart The Septum Partition between two sides Thick muscular wall Completely separates right side of heart from left side of heart 5 4 Heart Chambers 6 Upper heart chambers Right atrium Left atrium The receiving chambers 4 Heart Chambers Lower Heart Chambers Left ventricle Right ventricle The pumping chambers 7 The Right Side Right Atrium Thin walled cavity Receives deoxygenated blood from the Superior & Inferior Vena Cava Superior returns blood from the head and upper body Inferior returns blood from the lower body Right Ventricle Receives deoxygenated blood from Right Atrium Pumps blood to the lungs through the pulmonary artery 8 The Left Side Left Atrium Thin walled cavity Receives oxygenated blood from lungs Left Ventricle Receives oxygenated blood from L atrium Primary function to pump blood into general circulation Blood leaves L Ventricle thru aorta (largest artery in body) Has thicker muscle than R Ventricle 9 Structure of the Heart 10 The Heart Valves Keep the blood flowing in a forward direction. Prevent backflow of blood Heart sounds are produced by closure of the heart valves. Creates a lubb dubb sound Located at the entrance and exit of the ventricles. https://www.youtube.c om/watch?v=dDg7GDp R1RE https://www.youtube.c om/watch?v=dDg7GDp R1RE 11 Heart Valves There are 4 heart valves 2 valves located at the entry of the ventricles are called atrioventricular valves (AV) 2 valves located at the exit of the ventricles are called semilunar valves (SL) Atrioventricular Tricuspid Bicuspid (Mitral) Semilunar Aortic Pulmonary 12 Tricuspid & Bicuspid Valve Atrioventricular (AV) valves Tricuspid valve: between right atrium and right ventricle. Has three cusps Bicuspid (mitral) valve: between left atrium and left ventricle. Has two cusps 13 Valves of the Heart Semilunar (SL) valves Pulmonary SL valve: located at the exit of the right ventricle Aortic SL valve: located at the exit of the left ventricle Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 14 Structure of the Heart 15 https://www.youtube.com/watch?v=oHMmtqKgs50 Both atria contract at the same time Both ventricles contract at the same time Heart functions as two pumps: Pulmonary circulation: pump on the right side Pumps blood to lungs Systemic circulation: pump on the left side Pumps blood to rest of body Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 16 Pathway of Blood through the Heart Blood enters right atrium through superior vena cava and inferior vena cava Flows through tricuspid valve into right ventricle Passes through pulmonary SL valve Flows into pulmonary trunk and into pulmonary arteries Blood carried to lungs Carbon dioxide is released and oxygen is picked up Pulmonary veins carry blood to left atrium Blood flows through bicuspid valve into left ventricle Flows through aortic SL valve into aorta Distributed to all parts of the body through the systemic circulation Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 17 Pathway of Blood through the Heart Functions of the Heart Pump blood to the lungs through the pulmonary circulation Pump blood to the rest of the body through the systemic circulation Accomplished by contraction and relaxation of the cardiac muscle in the myocardium Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 18 19 20y/circulatory/heart/heart_dissection.ht ml Trace the blood through the heart https://www.youtube.com/watch ?v=KSbbDnbSEyM Heart dissection video: https://www.youtube.co m/watch?v=LWfA1lV92 E0 https://www.youtube.co m/watch?v=LWfA1lV92 E0 What makes the heart beat? Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 22 The heart has an electrical conduction system Starts at the SA (sinoatrial) Node LOCATED: RIGHT ATRIUM FREQUENTLY CALLED THE PACEMAKER Fires an electrical signal times per minute This electrical signal causes the atria to contract Conduction System of the Heart AV/ ATRIOVENTRICULAR NODE BUNDLE OF HIS/PURKINJE FIBERS The electrical signal travels rapidly down the BUNDLE OF HIS and out to the PURKINJE FIBERS. This electrical signal causes the ventricles to contract Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 23 HOLDS the electrical signal FOR 1/10 of a second The slower conduction allows the ventricles time to fill-up 24 https://www.youtube.com/watch ?v=fZT9vlbL2uAv/health/health- topics/topics/hhw/elect rical.htmln.com/sites/ /st udent_view0/chapter22/ani mation__the_cardiac_cycle __quiz_2_.html Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 25 Conduction System of the Heart The Cardiac Cycle 1. Consists of one complete heartbeat a.Two atria contract at same time b.Then relax while two ventricles contract c.If the heart beats 75 times per minute it takes about 0.8 seconds to complete one cardiac cycle. Systole-the contraction phase of the chambers Diastole-the relaxation phase of the chambers Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 26 27 The Cardiac Cycle-Atrial Systole Both atria contract at the same time AV valves are open Ventricles are in diastole (relaxed) Blood is forced into ventricles Takes about 0.1 second 28 The Cardiac Cycle-Ventricular Systole Both ventricles are contracting Blood is forced from ventricles into pulmonary & aortic (SL) valves and then to lungs/aorta Atria are in diastole and are filling with blood returned through vena cava Lasts 0.3 second 29 The Cardiac Cycle-Diastole All chambers are in simultaneous diastole 70% of ventricular filling occurs during this period Lasts 0.4 second 30 Heart Sounds Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc First heart sound: lubb a.Caused by closure of AV valves 2.Second heart sound: dupp a.Caused by closure of SL valves 3.Pause between dupp of the first beat and lubb of second beat a.Entire heart is resting 4.Abnormal heart sounds: murmurs a.Caused by faulty valves Arteries 1.Carry blood away from heart 2.Pulmonary arteries: transport blood from right ventricle to lungs 3.Systemic arteries: transport oxygenated blood from left ventricle to body tissues 4.The aorta is the largest artery 5.All other arteries branch from the aorta 6.It forms an arch as emerges from upper part of heart Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 32 Myocardium: needs a continuous supply of oxygen and nutrients The first branch from the aorta a.Right coronary artery b.Left coronary arteries Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 33 Blood Supply to the Myocardium Locate your carotid, radial, brachial, femoral, posterior tibial and dorsalis pedis pulses. Capillaries Smallest and most numerous of the blood vessels Connection between artery and vein Thin wall where exchange takes place So small erythrocytes must pass through in single file Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 35 Veins Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 36 Carry deoxygenated blood back to the heart Carry blood high in CO2 Smallest veins are called venules Walls are thinner than arteries Venous blood is a dark burgundy color Valves are needed to help transport blood back to the heart remember, blood is going up -- - valves prevent back flow! All veins empty into the Superior or Inferior Vena Cava 37 Superior Vena Cava Inferior Vena Cava You will not feel a pulsation when feeling veins. Circulatory Pathways The blood vessels of the body are functionally divided into two distinct circuits: Pulmonary circuit Systemic circuit Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 39 Circulatory Pathways, cont. Transports blood from right side of the heart to lungs Then returns it to left side of heart Contains oxygen-poor blood (increased levels of carbon dioxide) Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 40 Pulmonary Circuit Circulatory Pathways, cont. Provides blood supply to all body tissues Carries oxygen and nutrients to cells Picks up carbon dioxide and waste products Carries oxygenated blood from left ventricle through the arteries to the capillaries in the tissues From tissue capillaries: deoxygenated blood returns through a system of veins to right atrium Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 41 Systemic Circuit Circulatory Pathways, cont. Elsevier items and derived items 2009 by Saunders, an imprint of Elsevier Inc. 42 CORONARY ARTERIES NARROWING OF A CORONARY ARTERY Diseases of the Heart Coronary Heart Disease narrowing of the arteries that supply blood to the heart Caused by: Atherosclerosis (buildup of plaque) Or Arteriosclerosis (loss of elasticity and thickening of the wall) Angina Nitroglycerin dilates the coronary arteries May take up to 3 (5 minutes apart) then call 911 NTG may cause severe headache and hypotension Myocardial Infarction Heart attack or MI Lack of blood supply to myocardium Crushing chest pain Pain in left arm, jaw, shoulder Nausea Perspiration SOA Pale or gray color Heart Failure Ventricles fail to pump adequately Right side Failure edema or ascites Left side Failure SOA, cough, congestion Congestive Heart failure edema in lower extremiteis, SOA, Abnormal lung sounds Rheumatic Heart Disease Having frequent strep infections as a child Lead to Rheumatic fever Antibodies that help protect next time will then also attack lining of the heart Important to take full course of antibiotics EKG Holter Monitor Stress Test Echocardiogram 54 Cardiac Catheterization ANGIOPLASTY OFTEN REFERRED TO AS BALLOON SURGERY. Pacemaker 57 Implanted Defibrillator 58 Ventricular Assist Device 59 Coronary Artery Bypass Graft-CABG Heart Transplant Heart Transplant last resort, high risk of rejection.