Cardiology The medical specialty that studies the anatomy and physiology of the cardiovascular system and uses diagnostic tests, medical and surgical procedures, and drugs to treat cardiovascular diseases.

Figure 5-1 Cardiovascular system

The Cardiovascular System A continuous, circular body system that includes the heart and the vascular structures (blood vessels such as arteries, capillaries, and veins) Moves blood throughout the body and transports oxygen, carbon dioxide, nutrients, and wastes in the blood

Anatomy of the Cardiovascular System Heart – A muscular organ that contracts at least once every second to pump blood through the body – Has an extensive electrical system that initiates and coordinates its contractions

Figure 5-2 Surface of the heart

Anatomy of the Cardiovascular System (cont’d) Heart Chambers – The heart contains four chambers, two on the top and two on the bottom. – Each small upper chamber is an atrium. – Each large lower chamber is a ventricle. – The septum, a center wall, divides the heart into right and left halves. – The inferior tip of the heart is the apex.

Figure 5-3 Chambers and valves of the heart

Anatomy of the Cardiovascular System (cont’d) Four valves control the flow of blood through the heart: – Tricuspid – Pulmonary – Mitral / Bicuspid – Aortic

Figure 5-4 Aortic valve

Anatomy of the Cardiovascular System (cont’d) Heart Muscle – Myocardium — composed of cardiac muscle – Responds to electrical impulses generated by a node within the heart itself – Contracts in a coordinated way to pump blood – Thickest on the left side of the heart

Table 5-1 Layers and Membranes of the Heart

Figure 5-5 Layers and membranes of the heart

Anatomy of the Cardiovascular System (cont’d) Thoracic Cavity – Contains the lungs and the mediastinum, an irregularly shaped central area between the lungs

Anatomy of the Cardiovascular System (cont’d) Mediastinum – Contains the heart and parts of the great vessels (aorta, superior vena cava, inferior vena cava pulmonary arteries and veins), as well as the thymus, trachea, and the esophagus

Figure 5-6 Mediastinum

Anatomy of the Cardiovascular System (cont’d) Blood Vessels – Vascular channels through which blood circulates in the body – Have a central opening or lumen through which the blood flows – Lined with endothelium, a smooth inner layer that promotes the flow of blood

Anatomy of the Cardiovascular System (cont’d) There are three kinds of blood vessels in the body, each performing a different function: – Arteries – Capillaries – Veins

Anatomy of the Cardiovascular System (cont’d) Arteries – Large blood vessels – Smaller branches of an artery are arterioles

Anatomy of the Cardiovascular System (cont’d) All arteries share some important characteristics and functions: – They carry blood away from the heart to the body. – They carry bright red blood that has a high level of oxygen. Exception: pulmonary arteries – Most arteries lie deep beneath the skin. – All arteries have smooth muscle in their walls.

Figure 5-7 Vasoconstriction and vasodilation

Anatomy of the Cardiovascular System (cont’d) Capillaries – Smallest blood vessels in the body – The lumen of a capillary is so small that blood cells must pass through in single file.

Anatomy of the Cardiovascular System (cont’d) Veins – Capillaries combine to form small veins known as venules, which then combine to form the largest veins.

Anatomy of the Cardiovascular System (cont’d) All veins share some important characteristics and functions: – They carry blood from the body back to the heart. – They carry dark red-purple blood with a low level of oxygen. Exception: pulmonary veins

Anatomy of the Cardiovascular System (cont’d) All veins share some important characteristics and functions: – The largest veins have valves that keep the blood flowing in one direction―toward the heart. – Many veins are near the surface of the body and can be seen just under the skin as bluish, sometimes bulging lines.

Figure 5-8 Valves in a vein

Anatomy of the Cardiovascular System (cont’d) Aorta – Largest artery in the body – Receives blood from the left ventricle of the heart

Figure 5-9 Arteries and veins around the heart

Figure 5-10 Arteries in the body

Anatomy of the Cardiovascular System (cont’d) Arteries – Coronary artery – Carotid artery – Subclavian artery – Axillary artery (armpit) – Brachial artery (upper arm) – Radial artery (thumb side of the lower arm) – Ulnar artery (little finger side of the lower arm)

Anatomy of the Cardiovascular System (cont’d) Thoracic Aorta and Arterial Branches – The thoracic aorta travels inferiorly through the thoracic cavity. – It branches into arteries that bring blood to the esophagus, muscles between the ribs, diaphragm, upper spinal cord, and the back.

Anatomy of the Cardiovascular System (cont’d) Abdominal Aorta and Arterial Branches – Brings oxygenated blood to the stomach, liver, pancreas, spleen, gallbladder, small and large intestines, adrenal glands, kidneys, ovaries, testes, and the lower spinal cord – Abdominal aorta ends where right and left iliac arteries begin

Anatomy of the Cardiovascular System (cont’d) Abdominal Aorta and Arterial Branches – Iliac artery – Femoral artery (upper leg) – Popliteal artery (near the knee joint) – Tibial artery (front and back of the lower leg) – Peroneal artery (little toe side of the lower leg)

Anatomy of the Cardiovascular System (cont’d) Two major veins of the body – Superior vena cava – Inferior vena cava Other major veins – Jugular vein – Portal vein – Saphenous and femoral veins

Anatomy of the Cardiovascular System (cont’d) The Circulatory System – The cardiovascular system or circulatory system circulates blood through the blood vessels. – Systemic circulation includes the arteries, capillaries, and veins everywhere in the body, except in the lungs. – Pulmonary circulation includes the arteries, capillaries, and veins going to, within, and coming from the lungs.

Figure 5-11 Circulation of the blood

Physiology of a Heartbeat Heart contracts and relaxes in a regular rhythm coordinated by the conduction system – Sinoatrial node (SA node), or pacemaker of the heart, initiates the electrical impulse that begins each heartbeat

Pacemaker Abnormal heartbeats can be controlled by an artificial pacemaker that is run on batteries

Physiology of a Heartbeat (cont’d) Heart contracts and relaxes in a regular rhythm coordinated by the conduction system – Atrioventricular node (AV node) receives the impulse to contract from the SA node – Purkinje fibers, a network of nerves, cause both ventricles to contract simultaneously

Figure 5-12 Conduction system of the heart

Heartbeat Each heartbeat is called a cardiac cycle: two atria contract then two ventricles contract (systole), and the entire heart relaxes (diastole) A normal heart beats 70 times per minute. Makes a “lub-dub” sound as the valves of the heart are opening and closing.Makes a “lub-dub” sound as the valves of the heart are opening and closing.

Physiology of a Heartbeat (cont’d) Two Heartbeat Phases – Systole (contraction) – Diastole (resting period)

Electrocardiogram (ECG or EKG) A test that records the electrical activity of the heart. The P wave represents contraction (systole) of the atria. The QRS wave contraction of the ventricle The T wave The relaxation of the muscle (diastole) Question: What are some problems associated with the Sinoatrial Node? How can it be fixed?

Figure 5-13 Exercise increases the heart rate John Garrett © Dorling Kindersley

Diseases and Conditions Myocardium – Acute coronary syndrome – Angina pectoris – Cardiomegaly – Cardiomyopathy – Congestive heart failure (CHF) – Myocardial infarction (MI)

Figure 5-14 Peripheral edema Antonia Reeve/Photo Researchers, Inc.l

Diseases and Conditions (cont’d) Heart Valves and Layers of the Heart – Endocarditis – Mitral valve prolapse (MVP) – Murmur – Pericarditis – Rheumatic heart disease

Figure 5-15 Vegetation on the mitral valve Abrahas/Custom Medical Stock Photo, Inc.

Diseases and Conditions (cont’d) Conduction System – Arrhythmia – Bradycardia – Fibrillation – Flutter – Heart block

Figure 5-16 Arrhythmias on an EKG tracing

Diseases and Conditions (cont’d) Conduction System – Premature contraction – Sick sinus syndrome – Tachycardia – Asystole – Palpitation

Diseases and Conditions (cont’d) Blood Vessels – Aneurysm – Arteriosclerosis – Bruit – Coronary artery disease (CAD) – Hyperlipidemia – Hypertension (HTN) – Hypotension – Peripheral artery disease (PAD)

Figure 5-27 An aneurysm (b) Michael English, M.D./Custom Medical Stock Photo, Inc.

Figure 5-18 Mild atheromatous plaque SIU BioMed/Custom Medical Stock Photo, Inc.

Figure 5-19 Severe atherosclerotic plaque in an artery C. Abrahams, M.D./Custom Medical Stock Photo, Inc.

Diseases and Conditions (cont’d) Blood Vessels – Peripheral vascular disease (PVD) – Phlebitis – Raynaud’s disease – Varicose veins

Figure 5-23 Severe varicose veins in the leg SPL/Photo Researchers, Inc.

Laboratory and Diagnostic Procedures Blood Tests – Cardiac enzymes – C-reactive protein (CRP) – Homocysteine – Lipid profile – Troponin

Laboratory and Diagnostic Procedures (cont’d) Diagnostic Heart Procedures – Cardiac catheterization – Cardiac exercise stress test – Electrocardiography (ECG, EKG) – Electrophysiologic study (EPS)

Figure 5-22 Electrocardiography Jupiter Images – PictureArts Corporation/Brand X Pictures-Royalty Free

Figure 5-23 An EKG tracing

Laboratory and Diagnostic Procedures (cont’d) Diagnostic Heart Procedures – Holter monitor – Pharmacologic stress test – Telemetry

Figure 5-21 Treadmill exercise stress test Fotopic/Miles Simons/Phototake NYC

Laboratory and Diagnostic Procedures (cont’d) Radiology and Nuclear Medicine Procedures – Angiography – Echocardiography

Figure 5-24 Echocardiogram Custom Medical Stock Photo, Inc.

Figure 5-25 Doppler ultrasonography Matt Meadows/Science Photo Library/Photo Researchers, Inc.

Medical and Surgical Procedures Medical Procedures – Auscultation – Cardioversion – Sclerotherapy – Vital signs

Figure 5-26 Defibrillation Pearson Education/PH College

Figure 5-27 Pulse points

Figure 5-28 Carotid pulse Michal Heron/Pearson Education/PH College

Figure 5-29 Measuring the blood pressure

Medical and Surgical Procedures (cont’d) Surgical Procedures – Aneurysmectomy – Cardiopulmonary bypass – Carotid endarterectomy

Medical and Surgical Procedures (cont’d) Surgical Procedures – Coronary artery bypass graft (CABG) – Heart transplantation – Pacemaker insertion

Figure 5-30 Open heart surgery F. Schussler/PhotoDisc/Getty Images

Figure 5-31 Pacemaker (left) English/Custom Medical Stock Photo, Inc. (right) Alvis Upitis/Jupiter Images-PictureArts Corporation/Brand X Pictures-Royalty Free

Medical and Surgical Procedures (cont’d) Surgical Procedures (cont’d) – Percutaneous transluminal coronary angioplasty (PTCA) – Pericardiocentesis – Valve replacement – Valvoplasty – Radiofrequency catheter ablation

Figure 5-32 Balloon angioplasty

Figure 5-33 Stent

Figure 5-34 Valve replacement surgery Custom Medical Stock Photo, Inc.