The Cardiovascular System The heart beats about 100,000 times/day, 35 million times/year In a resting adult the heart rate is about 75 beats/minute Cardiology is the study of the normal heart and the diseases of the heart It is between the 2 lungs in the thoracic cavity Myocardium – cardiac muscle tissue, responsible for the pumping action of the heart

Heart It has 4 chambers 2 Atria at the top 2 ventricles at the bottom Partition between the left ventricle and the right ventricle is the interventricular septum

Valves Valves prevent blood from flowing the wrong direction Sometimes valves must be replaced The aortic valve is the most commonly replaced heart valve

Conduction system of the heart Pacemaker – 1% of the cardiac muscles fibers are different from all other. They can generate action potentials over and over and do so in a rhythmical pattern. They set the rhythm for the heart and form the conduction system which ensures the cardiac chambers to contract in a coordinated manner.

Artificial Pacemaker A device that sends out small electrical currents to stimulate the heart to contract. A pacemaker consists of a battery and impulse generator and is usually implanted beneath the skin just inferior to the clavicle.

Monitoring A recording of the electrical changes that accompany the heartbeat is called an electrocardiogram (EKG) Blood pressure – Systolic over Diastolic pressure. Systolic refers to the stage of contraction. Diastolic refers to the phase of relaxation. A normal adult blood pressure is 120/80.

Diseases Congestive heart failure – the heart is failing to pump. If the left side fails – it can’t pump out all the blood and it backs up into the lungs. The result is pulmonary edema – fluid accumulation in the lungs that can lead to suffocation. If the right side fails – blood backs up in the systemic vessels. The result is peripheral edema – swelling in the feet and ankles. Common causes – coronary artery disease, long-term high blood pressure, and valve disorders.

Exercise and the Heart Aerobic exercise – activity that works large body muscles for at least 20 minutes, elevates cardiac output and accelerates metabolic rate. Regular exercise helps to reduce blood pressure, anxiety, and depression and controls weight.

Path of blood through the body Deoxygenated blood enters your heart through the Inferior Vena Cava (blood from the lower part of your body) and the Superior Vena Cava (blood from the upper part of your body).

Path of blood through the body It then enters the Right Atrium. It passes through the tricuspid valve into the Right Ventricle. It goes out through the Pulmonary Artery into the lungs where it becomes oxygenated.

Path of blood through the body It reenters the heart through the Pulmonary Veins entering the Left Atrium. It passes through the bicuspid valve (also known as the mitral valve) into the Left Ventricle. It then receives a strong contraction and goes through the aortic valve and into the aorta where it goes out to the body. This oxygenated blood now is delivered to the cells of the body.

Terms and conditions Atherosclerosis – progressive disease characterized by the formation in the walls of large and medium sized arteries of lesions called atherosclerotic plaques. Arteries are hardened by calcium deposits in the walls. HDL’s – decrease blood cholesterol levels “good cholesterol” LDL’s – promote atherosclerosis, so its known as “bad cholesterol” Myocardial infarction – a complete obstruction to blood flow in a coronary artery. MI commonly called a heart attack. Infarction means the death of an area of tissue because of interrupted blood supply.

Terms and conditions Cardiac catheterization – procedure that is used to visualize the heart coronary arteries, chambers, valves and great vessels. Cardiopulmonary resuscitation (CPR) – artificial establishment of normal or near normal respiration and circulation.

Terms and conditions ABC’s of CPR A – Airway B – Breathing C - circulation Palpitation – a fluttering of the heart or abnormal rate or rhythm of the heart Cardiac arrest – term meaning cessation of an effective heartbeat. The heart may be completely stopped or in ventricular fibrillation