Transcript ST120 Unit 2: The Heart
ST120 Unit 2: The Heart
Concorde Career College, Portland
The Heart
Objectives: Evaluate the anatomic development of the heart Describe the basic anatomy of the heart, including coverings, wall, chambers, and valves Trace the flow of blood into, through, and out of the heart Evaluate myocardial infarction Describe the conduction system of the heart Describe basic cardiac dysrhythmias and electrocardiogram elements
The Heart: Part of the Cardiovascular System
Cardiovascular (Circulatory) System
Blood
Heart
Arteries
Veins
Capillaries
Cardiovascular System
Cardiovascular
Pertaining to the heart and blood vessels.
Cardiovascular System
Heart
the pump
Peripheral vascular system
arteries – carry blood AWAY from the heart Veins – carry blood TOWARD the heart capillaries – tiny webs that connect the arteries and veins peripherally; gas exchange takes place called internal respirations The lymphatic system also part of the circulatory system
Function of the Blood Circulatory System Simply→
Transportation
Blood Transports Hormones Enzymes Oxygen Carbon dioxide Carries nutrients (from various organs) and oxygen to the body’s cells for use, which creates waste (from the lungs) The waste (includes carbon dioxide ) is carried from the cells to the excretory organs. Example-Lungs expires carbon dioxide
Cardiovascular System
The Heart
Cardiovascular System
General Information Located in the mediastinum Slightly bigger than a fist Contracts approximately 72 times per minute 2/3 of the heart is located toward the left of the thoracic cavity
Cardiovascular System
Function of the Heart Pump Systole (contraction) Diastole (relaxation)
Coverings of the Heart
Pericardium – loose fitting sac that covers the entire heart Serous pericardium – inside the pericardium; composed of two layers Parietal layer lines the inside of the pericardium Visceral layer thin layer that covers the heart Pericardial cavity – space located between the Parietal layer and the Visceral layer; contains pericardial fluid to reduce friction
Pericardium
Heart Anatomy Epicardium is the outer layer of the heart wall Each chamber is lined by a thin layer of tissue called the endocardium The wall of each chamber is composed of cardiac muscle tissue called the myocardium
Cardiovascular System
Chambers of the Heart Atria (receiving chambers) Ventricles (pumping chambers) Separated into right and left sides by the septum
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HEART CHAMBERS
UPPER CHAMBERS – RIGHT AND LEFT ATRIA which receives oxygen poor blood returning from lungs and body LOWER CHAMBERS – RIGHT AND LEFT VENTICLES moves oxygen rich blood into arteries
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Cardiovascular System
Heart Valves Tricuspid (right atrioventricular) Bicuspid (mitral or left atrioventricular) Pulmonary (semilunar) Aortic (semilunar)
HEART VALVES
why do we need heart valves?
To keep the blood flowing one direction
ventricle is called the?
TRICUSPID VALVE
ventricle is called the?
BICUSPID VALVE or MITRAL
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Heart Valves
SL or semilunar valves located between the two ventricles and the arteries that carry the blood away from the heart 1 7
Heart Valves
Pulmonary semilunar valve is located at the beginning of the pulmonary artery that allows blood to flow from the right ventricle to the lungs Aortic semilunar valve is located at the beginning of the aorta and allows blood to flow out of the left ventricle into the aorta 1 8
Cardiovascular System
Chordae Tendineae Stabilize valve flaps to promote one way blood flow
Cardiovascular System
Myocardial Blood Supply
Right coronary artery
Left coronary artery
Circumflex artery
Right marginal branch
Anterior and posterior interventricular arteries
Coronary arteries and Coronary veins .
Blood Flow through the Heart The right side of the heart receives oxygen-poor blood from the veins •Blood enters right atrium through the superior vena cava the inferior vena cava and 2 2
Blood Flow through the Heart
When the heart “beats”, first the atria contract simultaneously ( atrial systole ) 2 3
Blood Flow through the Heart
Then the ventricles fill with blood and they contract together When the ventricles contract, blood in the right ventricle is pumped through the pulmonary semilunar valve into the pulmonary artery and to the lungs, where it is oxygenated 2 4
Blood Flow Through the Heart
Oxygenated blood veins returns to the left atrium through 4 pulmonary It then passes through the left AV or bicuspid valve to the left ventricle 2 5
Blood Flow Through the Heart
From the left ventricle , the blood is pumped out through the aortic semilunar valve to the aorta From the aorta to the rest of the body!
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Conduction System
Electrical impulses that signal the heart to beat All cardiac muscle fibers in each region of the heart are electrically linked together !
Intercalated disks muscle fibers are electrical connectors that join the 2 7
Cardiovascular System
Conduction System Sinoatrial (SA) node Atrioventricular (AV) node Bundle of His Right and left bundle branches Purkinje fibers
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Cardiac Cycle Each complete heartbeat is called a cardiac cycle Consists of alternating
systole
(contraction) and
diastole
(relaxation) of atria and ventricles Stroke volume is the volume of blood ejected from the ventricles during each beat Cardiac output is the volume of blood ejected from the left ventricle into the aorta 3 0
Pathology
Coronary Atherosclerotic Heart Disease a condition in which fatty material collects along the walls of arteries. This fatty material thickens, hardens (forms calcium deposits), and may eventually block the arteries; endothelial cell dysfunction Myocardial Ischemia (reduced blood supply) of the heart muscle, usually due to the blockage caused by Coronary Atherosclerosis Angina pectoris – chest pain due to Myocardial Ischemia Myocardial Infarction (MI) – death of heart muscle tissue from Myocardial Ischemia, which leads to sudden cardiac death
Pathology
Ventricular fibrillation – pumped out of the heart major
dysrhythmia
of the ventricles. They flutter without coordination which results in lack of blood Heart block – a disease in the electrical system of the heart Asystole – cardiac arrest Myocardial rupture – blood escaping the ventricles and entering the pericardial sac; can result in
cardiac tamponade
Cardiac aneurysm – ballooning of the ventricular wall resulting in increases pressure in the ventricles
Coronary Atherosclerotic Heart Disease
Coronary Atherosclerotic Heart Disease
Coronary Atherosclerotic Heart Disease
Treatments
Preformed in the Cardiac Catheterization lab
(Cath Lab)
Percutaneous Transluminal Coronary Angioplasty (PTCA) Coronary Stent Intra-coronary Thrombolysis
Coronary Stent - A Treatment for Coronary Atherosclerotic Heart Disease
Percutaneous Transluminal Coronary Angioplasty (PTCA)
Treatments
Preformed in the Heart Room in the OR Suite Coronary Artery Bypass Grafting (CABG) Permanent pacemaker
Surgical Treatment : Coronary Artery Bypass Grafting (CABG)
Possible Grafts for CABG 1. Saphenous vein 2. Internal thoracic arteries (mammary) 3. Radial Artery
Saphenous Vein Harvesting
Postoperative Healing
Endoscopic Saphenous Harvesting
Mammary Artery Harvesting
Internal Mammary Artery
Radial Artery Harvesting
Cardiopulmonary Bypass
Identify the locations of the tube insertions into the circulatory system
Permanent Pacemaker
Dysrhythmias
Sinus Dysrhythmia – most common; related to vagal nerve impulses to the SA node; benign Sinus Tachycardia – minute heart rate of 100 beats or more per Sinus Bradycardia minute heart rate of 60 beats or less per
Atria Dysrhythmias
Dysrhythmias originating in the atria: Premature atrial beat – often associated with stress or consumption of caffeine or nicotine Atrial tachycardia – usually benign atrial rate of 150-250 beats per minute; Atrial flutter atrial rate of 250-350 beats per minute; can result in increased ventricular rate and decrease in oxygen Atrial fibrillation atrial rate of 350-600 beats per minute; results in increased ventricular rate and decrease in oxygen
Ventricular Dysrhythmias
Benign PVC’s – less than 5 per hour; absence of heart disease Complex PVC’s – greater than 10-30 per hour; with or without heart disease Malignant PVC’s – same as complex except with left ventricular dysfunction Ventricular tachycardia – 140-250 beats per minute Ventricular flutter – 250-350 per minute regular contractions but at a fast rate of
Electrocardiogram
ECG or EKG Electrical signals can be picked up form the body surface and transformed into visible tracings by an instrument called an electrocardiograph The electrocardiogram electrical activity is the graphic record of the heart’s
ECG
3 characteristic deflections or waves P wave – depolarization (triggers contraction) of atria QRS complex ventricles - depolarization (triggers contraction) of T wave - repolarization of ventricles
Cardiothoracic Procedures
Features of the ECG Paper
ECG Electrical Correlation
Electrocardiograph (Normal Sinus Rhythm)
Sinus Rhythm
Occasional (Incidental) PVC
Bigeminy (PVC Every Other Beat)
Ventricular Fibrillation (V Fib)
Premature Atrial Contraction (PAC)