Chapter 14

 Describe 3 layers of heart wall  Describe structure of pericardium and it’s functions  Compare right and left heart  Name 4 chambers of heart and compare functions  Name the valves at the entrance and exit of ventricles and cite functions  Describe blood circulation through the myocardium  Describe the cardiac cycle  Name and locate components of heart’s conduction system  Explain effects of the autonomic nervous system on heart rate  List and define several terms that describe variations in heart rates  Explain what produces the two main heart sounds  Describe several common types of heart disease  List 5 actions that can be taken to minimize the risk of heart disease  Describe 4 methods for studying the heart  List several approaches to the treatment of heart disease  WORD ANATOMY!!!

 3 LAYERS : - Endocardium (thin smooth lining of interior) - Myocardium (thick, muscular middle layer) - Epicardium (serous membrane on outside)

 Cells are striated (actin and myosin)  Has single nucleus  Involuntarily controlled  Intercalated disks (allow for rapid electrical impulse transfer)  Branching fibers (enables coordinated contraction)  Thick muscle that pumps blood through the blood vessels and through body

Pericardium Consists of fibrous outermost layer that anchors the heart to supporting structures. Divided into parietal and visceral layers. There is a potential space between the two layers.

 Right Heart Functions to pump blood low in oxygen to the lungs. This is called the Pulmonary Circuit. Consists of right atrium, right ventricle and valves  Left Heart Functions to pump blood high in oxygen to the entire body. This is called the Systemic Circuit. Consists of left atrium, left ventricle and valves.

Atria and Ventricles

Right Atrium Receives blood that is returning from the body tissues. Pumps blood low in oxygen to right ventricle. Superior and Inferior Vena Cava are the large vessels entering. Coronary Sinus also enters right atrium with blood drained from heart itself.

Right Ventricle Receives blood from the right atrium. Pumps venous blood to the lungs via the pulmonary trunk. Pulmonary trunk divides into right and left pulmonary arteries.

Left Atrium Receives oxygen rich blood from the lungs. Blood enters through the pulmonary veins. Pumps blood into the left ventricle.

Left Ventricle Receives blood from the left atrium. Has the thickest walls. Pumps oxygen rich blood to the all parts of the body. Blood leaves through the aorta. Apex is formed by the LV.

 Valves are one way valves that direct blood flow through the heart.  Valves that are between atria and ventricles are the atrioventricular valves.  Valves that are between ventricles and vessels are the semilunar valves. - Right AV - Left AV - Pulmonic Valve - Aortic Valve

 Systemic Circuit blood enters Right Atrium through Superior and Inferior Vena Cava  Blood goes through the Tricuspid (AV) valve into Right Ventricle.  Right Ventricle pumps blood through the Pulmonic (semilunar) valve into the pulmonary trunk.  Blood leaves divisions of pulmonary trunk to enter the lungs. (Pulmonary Circuit)  Blood returns from the lungs through the pulmonary veins to the Left Atrium.  Blood goes through the Mitral (AV) valve into the Left Ventricle.  Left Ventricle pumps blood through the Aortic (semilunar) valve to the body and back into the Systemic Circuit.

 SVC/IVC  RA  Tricuspid  RV  Pulmonic  Lungs  Pulmonary veins  LA  Mitral  LV  Aortic  Body

Coronary Circulation Supplies the heart muscle with own blood supply Right and Left Coronary arteries are the main ones. Encircle the heart. Receive blood when heart relaxes. Drains back into the RA. Vessels affected with Heart Attacks.

 Although we refer to Right and Left Heart, the heart contracts and works together.  Active phase, when contraction occurs, is called Systole.  Resting phase, when chambers are filling, is called Diastole.  One complete sequence of contraction and relaxation is called the Cardiac Cycle.  Each cardiac cycle is a single heartbeat.

 CO = HR x SV  The volume of blood pumped out by the ventricles in 1 minute is called cardiac output (CO)  The volume of blood ejected from ventricles with each heartbeat is called stroke volume (SV)  The number of times the heart beats within 1 minute is called the heart rate (HR)

 Heart is stimulated to contract by specialized tissue within the heart. The action potential is initiated here and spreads through the structure of the heart.  SA node ( Pacemaker of the hear t)  AV node  Atrioventricular bundle (bundle of His)  Purkinje fibers

 SA node (sinoatrial node) is located in the Right Atrium and is commonly called the Pacemaker of the Heart because it sets the rate of heart contraction  AV node (atrioventricular node) is located in the interatrial septum in Right Atrium  AV bundle (bundle of His) is located in the interventricular septum.  Purkinje fibers are located throughout the myocardium.

Control of Heart Rate Heart rate can be affected by the nervous system, hormones and internal influences: ANS plays a major role. Hormones, ions, and drugs. Exercise affects the heart rate by increasing amount of blood ejected with each heart beat. There are different kinds, or variations, of heart rate.  Bradycardia – slow heart rate, usually less than 60 bpm  Tachycardia – a fast heart rate, more than 100 bpm  Sinus Arrhythmia – variation due to changes in rate and depth of breathing  Premature beat – a heart beat that comes before the normal beat

 “Lub – Dub”  “lub” is caused by the closing of AV valves  “dub” is caused by the closing of the semilunar valves  MURMURS : - an abnormal sound usually caused by a faulty valve - can be caused by many things - organic and functional murmurs

The most common cause of death in the country !

 Anatomical - Endocarditis : inflammation of the heart lining - Myocarditis : inflammation of heart muscle - Pericarditis : inflammation of the serous membrane on surface of heart  Causative Factors - Congenital : present at birth - Rheumatic heart disease : caused by rheumatic fever - Coronary Heart Disease (CAD) : involves the vessels supplying the heart muscle - Heart Failure : deterioration of the heart tissues

Congenital Heart Disease Foramen Ovale (Atrial Septal Defect) Ductus Arteriosus (Patent Ductus Arteriosus) Coarctation of the Aorta tetralogy of Fallot  Ventricular Septal Defect – *** the most common SINGLE congenital heart defect  tetralogy of Fallot The most common congenital heart defect. - It occurs as a combination of four defects. - Includes: Pulmonary Artery Stenosis, Interventricular Septal Defects, Aortic Displacement to the Right and Right Ventricular Hypertrophy

Rheumatic Heart Disease Caused by a Streptoccal infection (same one that causes strep throat) The antibodies formed to combat the disease, attack the heart valves Most frequently the mitral valve The incidence of rheumatic fever has decreased with the use of antibiotics

Coronary Heart Disease Lumen may narrow because of artherosclerosis Vessel narrowing leads to ischemia Ischemia causes Myocardial Infarction Angina Pectoris Arrhythmia (Flutter/Fibrillation) Defibrillators, AED, Thrombolytics

 Angioplasty is a procedure used to open an occluded coronary vessel to restore blood flow to the heart.  Stents can be placed in vessel to keep it open.  Can be the only treatment for MI or pt may require CABG.

Heart Failure Condition where heart is unable to pump correctly and give enough oxygen to tissues. Results in enlarged chambers, ventricles are not able to contract properly, blood backs up, and blood pressure increases. CHF : Retention of fluid from heart failure. Managed with diet, drugs and managed lifestyle.

 Heredity plays a major role  Environmental factors  Disease  Personal Habits  Age alone contributes to: heart decreasing in size, valves become less flexible, decrease strength of contraction & conduction system failure

FACTORS THAT CAN NOT BE MODIFIED… FACTORS THAT CAN BE MODIFIED  Age  Gender  Heredity  Body type  Smoking  Physical activity  Weight control  Diet  HTN  DM and gout

Heart Studies Stethoscope tells you a lot of information EKG/ECG Cardiac Catheterization Fluoroscopy US / Echo

 Drugs (Digoxin, NTG, Beta-blockers, Antiarrhythmics, Anticoagulants)  Pacemakers  Cardioversion (Chemical or Electric)  Angioplasty  Heart Surgery (CABG, Valve Replacement, Transplant)

Know the following: Structure/Layers of Heart Heart Divisions and Valves Heart Blood Supply Flow of blood through heart Function of heart and Cardiac Output Conduction/Control of heart rate (What is this controlled by?) Heart Disease Prevention of Heart Disease Heart Studies Treatment of Heart Disease