Cardiovascular System

Structures Heart-pump Arteries, veins, and capillaries-carries blood Lymph system-returns excess fluid

Function of the Cardiovascular System Transport nutrients and oxygen to the body Transport waste products from the cells to the kidneys to be excreted Distribute hormones and antibodies throughout the body Help control body temperature & maintain electrolyte imbalance

Heart Two sided double pump Weighs less than a pound Slightly larger than a fist 5 inches in length Located between lungs Slightly left of sternum

Heart

Heart When heart stops beating: Life stops Lose consciousness after 5 seconds without oxygen After 15-20 seconds, muscle twitches After 4-5 minutes, brain cells begin to die and cannot be replaced.

Heart Terms Apex-conical tip-bottom of heart Base- topmost (superior) Atrium-top chambers of heart Ventricles-bottom chambers of heart

Heart Right side of heart Pumps deoxygenated blood to the lungs Carbon dioxide is exchanged Pulmonary Circulation Left side of heart Pumps oxygenated blood throughout the body Systemic Circulation

Hepatic Circulation Path of blood from the intestines, gallbladder, pancreas, stomach, and spleen through the liver. Liver Stores and modifies nutrients through liver Removes or alters toxic substances so can be eliminated through urinary system

Anatomy Atria Ventricles Septum Superior/Inferior Vena Cava Coronary Sinus Pulmonary Artery Pulmonary Veins Aorta Atrioventricular valves-separate atria/ventricles Semilunar valves-separate ventricles from outgoing vessels (pulmonary artery/aorta)

Anatomy Continued Tricupsid Valve Bicupsid valve Pulmonary Semilunar Valve Aortic semilunar valve

Anatomy of Heart

Cardiac Tissue Endocardium-lines inside of heart-smooth Myocardium-thickest layer-muscle Pericardium-double membrane-provides lubrication between heart and surrounding tissues Pericardial Sac

Blood Flow

Cardiovascular-day 2 Chapter 11

Heart Activity Controlled by autonomic nervous system Hormones Fluid balance Only muscle tissue to create its own stimulation

Electrical Nodes The heart is the only muscle that can stimulate its own contractions Sinoatrial (SA) cells in the right atrium start the heart –AKA pacemaker Atrioventricular (AV) node sends an impulse into lower portions of the heart AV bundle or bundle of His stimulates the Purkinje fibers Purkinje fibers cause the ventricles to contract

Blood Vessels Veins Arteries Capillaries Carries blood to the heart Carry deoxygenated blood Except for pulmonary Dark red Arteries Carries blood away from the heart Carries oxygenated blood Bright red Capillaries Exchanges oxygen/CO2/nutrients

Average blood volume is 5-6 L Beats 86,000 to 144,000 times each day All blood is circulated in one minute

Two arteries that branch off ascending aorta Coronary Arteries Two arteries that branch off ascending aorta Provide blood supply to heart

Assessment Techniques Measuring pulse and blood pressure Listening to heart sounds Determining cardiac output Measuring muscle activity with electrocardiography Inserting a cardiac catheter Using echocardiography Health care workers assess the activity of the heart as an indicator of overall body condition.

Assessment Techniques (Cont.) Pulse Surge of blood against the walls of the arteries Eight pulse points on the body Normal pulse rate for adults is 60 to 90 beats/min Blood pressure Force of blood against the walls of the arteries Systolic pressure Ventricles of the heart contract Diastolic pressure Ventricles relax Normal blood pressure 120/80 mm Hg Varies greatly among people A healthy systolic pressure is usually less than 120 mm Hg. Diastolic pressure should be less than 90 mm Hg.

Assessment Techniques (Cont.) Heart sounds Lub-dub sound of the heart Results from opening and closing of the valves Heard through a stethoscope Murmurs Abnormal or extra sound May be benign or indicate a disorder Thrill Vibration felt by touch over an artery Caused by an abnormal flow of blood When you listen to your heart through a stethoscope, the beats you hear are the valves slamming shut.

Assessment Techniques (Cont.) Electrocardiography The pattern of electrical activity in heart contractions is measured graphically Normal and abnormal heart activities have characteristic wave patterns Each section of the electrocardiogram pattern indicates a specific part of the heart’s electrical activity.

EKG Figure 14-8 shows a normal electrocardiogram pattern with descriptions. From Grauer K: A practical guide to ECG interpretation, ed 2, St. Louis, 1998, Mosby.

Assessment Techniques (Cont.) Cardiac catheterization A catheter is used to measure the pressure in the chambers of the heart, to take blood samples, and to view obstructions in the vessels A tube is inserted through the blood vessels into the heart Dye is then released and traced using x-ray imaging To allow viewing of an image of the inside of the arteries, ultrasound transducers are inserted into the tip of the catheter.

Assessment Techniques (Cont.) Echocardiography (ECHO) Uses ultrasonic waves to show the structures and motions of the heart Transducer plots the sound echoes to produce a graphic picture During a transoesophageal echocardiography, the back of the throat is numbed.

Disorders of the Cardiovascular System Aneurysm Area of a blood vessel that bulges because of a weakness in the wall Atherosclerosis Narrowing of blood vessels caused by deposits of fatty material containing calcium and cholesterol Cardiac arrhythmia Disturbance of the heart’s rhythm caused by a defect in the heart’s pacemaker cells or by damage to heart tissue Most aneurysms occur in the aorta, but they can occur in other vessels. Atherosclerosis is sometimes called hardening of the arteries; it can occur in any part of the body.

Disorders of the Cardiovascular System (Cont.) Cardiovascular disease General term for the combined effects of arteriosclerosis and atherosclerosis Conditions called coronary artery disease (CAD) CAD may manifest as: Heart attack Peripheral artery disease (PAD) Angina Stroke Cardiovascular disease is responsible for more than 29% of all deaths in the United States. CAD is the leading cause of death of men and women in the United States. Discuss prevention and treatment of CAD.

Disorders of the Cardiovascular System (Cont.) Congenital heart disease A group of disorders that affect about one in eight newborns each year in the United States Defects include Narrowing of vessels (stenosis) to the heart and atrial or ventricular septal defects Coarctation of the aorta and patent ductus arteriosus (opening between the pulmonary artery and aorta that does not close at birth) Describe and discuss symptoms of and treatment for congenital heart disease.

Disorders of the Cardiovascular System (Cont.) Congestive heart failure (CHF) Inability of the heart to pump blood adequately to meet the body’s needs Right sided failure-caused fluid build up in the body, especially lower extremities Left sided failure-causes fluid build up in the lungs Usually caused by disease in another body system Leads to inadequate respiratory and kidney function CHF may occur suddenly or over a period of time. Discuss symptoms and treatment of CHF.

Disorders of the Cardiovascular System (Cont.) Hypertension High blood pressure Primary hypertension Cause of hypertension unknown Secondary hypertension Hypertension caused by other conditions, such as kidney disease and adrenal disorders Hypertension occurs in about 1 in 5 people in the United States. Discuss symptoms and treatments for hypertension.

Disorders of the Cardiovascular System (Cont.) Myocardial infarction AKA heart attack Results from blockage of the blood vessels to the heart by a clot (embolism) Cardiac arrest Occurs when large area of the heart is affected and may stop functioning Describe symptoms and treatment for myocardial infarction.

Disorders of the Cardiovascular System (Cont.) Phlebitis Inflammation of a vein, often with formation of a clot (thrombus) Results from damage to the vessel wall or prolonged sitting or standing If thrombus breaks free, it may lodge in a small artery and cause tissue damage or sudden death Discuss symptoms and treatment for phlebitis.

Disorders of the Cardiovascular System (Cont.) Rheumatic heart disease A condition in which the heart muscle and valves are damaged by a recurrent bacterial infection that usually begins in the throat Bacteria produces a toxin that causes inflammation and damage to the heart valves Varicose veins A condition in which veins become enlarged and ineffective Explain the term rheumatic. Rheumatic heart disease is most common in children between the ages of 5 and 15. Discuss the symptoms of and treatment for rheumatic heart disease. Discuss the appearance of varicose veins.

Issues and Innovations Heart replacement and transplants 1967: First heart replacement Approximately 2000 heart transplantations are performed each year in the United States First artificial heart, the Jarvik-7, was connected to an external power source and pump 2001: AbioCor self-contained artificial heart Designed to extend life for people with end-stage heart failure who had no other clinical options Helps provides a good quality of life The older mechanical hearts required the patient to be attached to a large console that required that the patient be essentially bedridden.

Issues and Innovations (Cont.) Figure 14-11, B, shows the placement of AbioCor heart in the body. Courtesy ABIOMED, Inc., Danvers, Mass.

Issues and Innovations (Cont.) The U.S. Food and Drug Administration (FDA) approved use of the SynCardia Temporary Total Artificial Heart in 2005 Used in patients with irreversible failure of the ventricles Designed to support life functions until a transplant becomes available In 2014, the 1300th implant of the SynCardia total artificial heart was performed The goal of SynCardia CardioWest Temporary Total Artificial Heart (TAH) is to develop smaller, more portable devices.

Issues and Innovations (Cont.) Cholesterol controversy Waxlike substance Used in body to make: Cell membranes Hormones Vitamin D Carried by proteins (lipoproteins) Found in two lipoprotein forms High-density lipoprotein (HDL) Takes cholesterol to the liver Low-density lipoprotein (LDL) Blocks the arteries Cholesterol does not mix in water. An elevated blood cholesterol level is one of the major risk factors for development of heart disease. More than 50% of heart attacks and almost 20% of strokes are linked to high cholesterol levels. HDL should be greater than 40 mg/dL. LDL should be less than 100 mg/dL. Triglycerides should be less than 150 mg/dL. A lipoprotein profile every 5 years or more often is recommended.

Issues and Innovations (Cont.) Cholesterol controversy In 2013, the American Heart Association and American College of Cardiology released new guidelines on cholesterol management A calculator of risk for developing atherosclerotic cardiovascular disease uses nine pieces of information Gender Age Race Total cholesterol HDL Systolic BP Current treatment for high pressure Diabetes Smoking Prescribing a statin medication to reduce cholesterol is recommended for anyone with cardiovascular disease.

Issues and Innovations (Cont.) Harvard research study: LDL versus HDL cholesterol Type of fat, not amount, changes cholesterol level Limit intake of saturated fats, and eliminate trans-fats Monounsaturated and polyunsaturated fats were determined to lower LDL and raise HDL levels Olives, canola oil, avocados, fish, and most nuts Saturated fats raise LDL and HDL levels Whole milk, butter, cheese, red meat, chocolate, and coconut oil Trans fats are the worst fats Margarines, vegetable oils, shortening, and most fast foods Discuss ways to increase HDLs and lower LDLs. Discuss ways to decrease amount of saturated fats and eliminated trans fats in your diet. Discuss treatment for high cholesterol.