CCMA training notes: Cardiovascular system and Blood

  • Cardiovascular system  

  • Anatomy 

  • The Vascular System:  

  • Arteries: Are large blood vessels that always carry blood away from the heart. In most cases, the blood is oxygen-rich EXCEPT for the pulmonary arteries, which hold oxygen-poor blood. The largest artery is the aorta. Arteries are thick-wailed and elastic so they can expand and contract with the blood pressure. 

  • Veins: Are large blood vessels that always carry blood TO the heart. In most cases, veins hold oxygen-poor blood EXCEPT for the pulmonary veins, which hold oxygen-rich blood. The largest veins are the superior and inferior and the vena cava. Veins form a low-pressure collecting system to return oxygen-poor blood to the heart. They also contain valves to keep the blood flowing to the heart, minimizing back flow.  

  • Arterioles: Arteries get smaller and smaller eventually becoming arterioles. These deliver blood to the capillaries.  

  • Capillaries: These tiny vessels are the smallest in the body. They form a network of vascular beds linking the arterial system with the venous system  

  • Venules: Are smaller veins linking to capillaries  

  • The Heart:  

  • Also called Pump: works constantly to maintain the blood flow needed throughout the entire body  

  • Pericardium: also known as pericardial sac is a double walled membranous sac that encloses and protects the heart between the membranes is pericardial fluid that acts as a lubricant to reduce friction when the heart moves 

  • Muscular walls of the heart = Epicardium, myocardium, and endocardium  

  • Atria: two out of four chambers that the heart is composed of  

  • Ventricles: two out of four chambers that the heart is composed of  

  • Heart has four valves  

  • Aorta: The major artery takes oxygenated blood from the heart to the body  

  • Superior & Inferior vena cava: bring oxygen-poor blood from the body to the heart  

  • Pulmonary veins: bring oxygenated blood from the lungs into the heart  

  • Pulmonary arteries: take oxygen-poor blood from the heart back to the lungs to be re-oxygenated  

  • The Heart’s Electrical System:  

  • Composed of...  

  • Sinoatrial node  

  • Atrioventricular node  

  • Bundle of His  

  • Purkinje fibers  

  • Ensures that the heart that the heart beats constantly to move the blood through the body  

  • Spreads from sinus node throughout left and right atria causing the atria to contect and expelling its volume of blood into the ventricles  

  • Spreads from bundle branches throughout left and right ventricles which causes the ventricles to contract, forcing them to expel their volume of blood out into the general circulation  

  • The Heart’s Vascular System:  

  • Coronary Arteries: bring oxygen-rich blood to the heart muscle itself but can become blocked causing a heart attack  

  • Coronary Veins: move oxygen-poor blood out of the heart muscle in much the same way as the systemic circulation works 

  • The Blood:  

  • It Is a fluid tissue of the body. Blood plasma forms about 55% of blood and the formed elements for 45% of the blood.  

  • Plasma: Is a straw-colored fluid that contains nutrients, hormones, and waste products from the metabolic reaction in the body and respiration. Plasma is 91% water, and the remaining 9% consists of proteins (fibrinogen).  

  • Serum: Is plasma fluid after the blood cells and proteins have been removed. 

  • Formed Elements: These cells include erythrocytes, leukocytes, and thrombocytes.  

  • Erythrocytes: These are the red blood cells (RBCs) produced in red bone marrow. Their job is to transport oxygen to the tissues. 

  • Hemoglobin: is the oxygen-carrying proteins in the RBC that attaches to the oxygen molecules.  

  • Leukocytes: These are the white blood cells (WBCs) and are components of the body’s immune system defending againist pathogens and foreign substances. The leukocytes include... 

  • Neutrophils  

  • Basophils  

  • Eosinophils  

  • Lymphocytes  

  • Monocytes  

  • Thrombocytes: These are known as platelets and are important in blood clotting.  

  • Physiology 

  • Blood Flow Through the Body:  

  • Pulmonary Circulation: Refers to the flow of blood between the heart and lungs. The pulmonary arteries carry deoxygenated blood out of the right ventricle and into the lungs. In the lungs, carbon dioxide from the inhaled air. The pulmonary veins carry the oxygenated blood from the lungs into the left atrium of the heart.  

  • Systemic Circulation: This refers to the flow of blood to all parts of the body except for the heart. Technically, the heart blood flow is called coronary circulation. Oxygenated blood flows out of the left ventricle and into the arterial circulation. The veins carry deoxygenated blood into the right atrium. From here, blood flows into the pulmonary circulation before being pumped out of the heart into the arteries again.   

  • Blood Flow Through the Heart:  

  • Right Atrium: Receives oxygen-poor blood from all tissues, except the lungs, through the superior and inferior venae cavae. Blood flows out of the right atrium through the tricuspid valve into the right ventricle.  

  • Right Ventricle: Pumps the oxygen-poor blood through the pulmonary semilunar valve and into the pulmonary artery, which carries it to the lungs.  

  • Left Atrium: Receives oxygen-rich blood from the lungs through the four pulmonary veins. Blood flows out of the left artium, through the mitral valve, and into the left ventricle.  

  • Left Ventricle: Receives oxygen-rich blood from the left artium. Blood flows out of the left ventricle through the aortic semilunar valve and into the aorta, which carries it to all parts of the body except the lungs.  

  • Venae Cavae: Oxygen-poor blood is returned by this to the right atrium, and the cycle repeats.  

  • Pulse and Blood Pressure:  

  • Pulse: Is the rhythmic pressure against the walls of an artery when the heart contracts.  

  • Blood pressure: Is the measurement of the amount of systolic and diastolic pressure exerted against the walls of the arteries.  

  • Systolic pressure: Occurs when the ventricles of the heart contracts. This is the highest blood pressure on the artery wall.  

  • Diastolic pressure: Occurs when the ventricles relax. This is the lowest pressure of the blood on the artery wall.  

  • Common Diseases and Disorders 

  • Congenital Heart Defects:  

  • Refers to structural abnormalities caused by the failure of the heart to devlop normally before birth.  

  • There are numerous congenital heart defects, but these are just three examples...  

  • Aortic Valve Stenosis  

  • Arrhythmogenic Right Ventricular Dysplasia  

  • Atrioventricular Canal Defect  

  • Artery Diseases:  

  • They can occur in the peripheral arteries and in the coronary arteries. Here’s a few...  

  • Atherosclerosis: Is the hardening and narrowing of the arteries from the buildup of cholesterol plaque on the interior walls of the arteries. 

  • Coronary Artery Disease (CAD): This is also called coronary heart disease (CHD) or ischemic heart disease and refers to atherosclerosis of the coronary arteries.  

  • Ischemia: Is a condition where there is an insufficient supply of oxygen in the tissues due to restricted blood flow to a part of the body. In cardiac ischemia, there is a lack of blood flow and oxygen to the heart muscle itself.  

  • Angina: Is also called angina pectoris and there are severe episodes of chest pain due to inadequate blood flow to the myocardium, or heart muscle.  

  • Myocardial Infarction:  

  • This is a heart attack caused by occlusion or blockage of one or more coronary arteries caused by plaque buildup.  

  • Heart Failure:  

  • Congestive heart failure (CHF): Occurs mostly in the elderly after the heart has been weakened or damaged by other conditions or diseases. It is a chronic condition in which the heart cannot pump out all the blood it receives, causing congestion of blood.  

  • Left-sided heart failure: if the heart fails on the left side, it causes an accumulation of fluid in the lungs, also called pulmonary edema.  

  • Right-sided heart failure: If the heart fails on the right side, it causes fluid to build throughout the rest of the body causing edema first in the feet and legs and then worsening to other parts of the body.  

  • Cardiomegaly: Is an abnormal enlargement of the heart as it tries to compensate for its decreased pumping ability.   

  • Carditis:  

  • It is an inflammation of the heart. There are several types depending on which part of the heart is inflamed...  

  • Endocarditis: Is an inflammation of the endocardium, or inner lining of the heart. If the inflammation is caused by bacteria, it is called bacterial endocarditis.  

  • Pericarditis: Is an inflammation of the pericardium. It typically causes a fluid buildup in the pericarditis sac which restricts movement of the heart and its ability to pump blood to the body.  

  • Myocarditis: Is an inflammation of the heart muscle itself, or myocardium. It is often seen as a complication of a viral infection.  

  • Diseases of the Myocardium:  

  • Myocardium: Is the heart muscle itself  

  • Cardiomyopathy: term used to describe all diseases of the heart muscles  

  • Dilated cardiomyopathy: Is a disease of the heart muscles that causes the heart to become enlarged and to pump in a weaker fashion. The disease progression is slow and is often discovered only when the disease is advanced. 

  • Hypertrophic cardiomyopathy: Is a disease that involves abnormal thickening of the heart muscle making it harder for the heart to pump.  

  • Restrictive cardiomyopathy: Refers to the heart muscle becoming stiff and less flexible, preventing expansion and filling with blood between heart contractions.  

  • Arrhythmias: 

  • Asystole: A flat line refers to a complete lack of electrical activity in the heart indicating no heart contraction and no blood pumping through the body. This is one of the conditions required for a medical provider to certify death.  

  • Cardiac Arrest: Is an event in which the heart abruptly stops beating, preventing blood from being pumped through the body.  

  • Sudden Cardiac Death: Results when treatment of cardiac arrest is not provided within a few minutes.  

  • Heart block: This is an arrhythmia caused by the electrical signal moving through the heart being partially or completely blocked from reaching the ventricles.  

  • Bradycardia: This is an abnormally slow resting heart rate.  

  • Tachycardia: This is an abnormally fast resting heart rate.  

  • Ventricular fibrillation: This is a rapid, irregular, and useless contraction of the ventricles. The heart muscle basically quivers, and little blood is pumped through the body.  

  • Palpitation: This is a pounding or racing heartbeat with or without irregularity in rhythm.  

  • Atrial fibrillation: This is a common type of tachycardia resulting from abnormal contractions of the atria. The atria contracts rapid, uncontrolledd twitching of the muscular heart wall.  

  • Conditions of the Blood Vessels:  

  • Vasculitis: Is an inflammation of a blood vessel.  

  • There are several types. For example, arteritis specifically refers to inflammation of the artery.  

  • Angio stenosis: This is an abnormal narrowing of a blood vessel.  

  • Hemangioma: This is a benign tumor formed by blood and lymph vessels. It is often considered to be a birthmark.  

  • Hypoperfusion: Means that there is insufficient perfusion, or blood flow, through a body part or organ.  

  • Aneurysm: Refers to a weak spot in an artery. The weak spot begins to fill up with blood causing the artery to balloon out due to blood pressure. There is a risk of this area bursting which can be fatal.  

  • Arteriostenosis: Refers to the narrowing of an aretery diminishing the blood flow to the area.  

  • Venous Insufficiency: This condition is where there is insufficient venous circulation because of partial blockage in a vein or leaking through vein valves.  

  • Phlebitis: Is an inflammation of a vein.  

  • Thrombophlebitis: This is when the vein contains a lot (thrombus) blocking the flow of blood.  

  • Thrombosis: Refers to a blood clot in the vessel. If a clot is in the coronary artery, it is called coronary thrombosis. If it is a deep vein, it is called a deep vein thrombosis.  

  • Embolism: Is a sudden blockage of a blood vessel by either air (air embolism) or fat (fat embolism).  

  • Peripheral Vascular Disease: These disorders of blood vessels include those located outside of the heart and brain and include those of legs, arms, stomach, and kidneys.  

  • Raynaud’s Disease: This is a peripheral arterial occlusive disease where cold or stress causes intermittent.  

  • Blood Disorders:  

  • Hemochromatosis: This genetic disorder is when the intestines absorb too much iron. The excess iron accumulates in organs causing damage.  

  • Leukopenia: This is a decrease in the number of white blood cells in the blood.  

  • Polycythemia: This is an abnormal increase in red blood cells in the blood because the bone marrow produces too many.  

  • Sepsis: Is a bacterial, viral, or other pathogenic infection of the blood. It is sometimes called blood poisoning.  

  • Thrombocytopenia: Is a condition in which there is an abnormally small number of platelets in blood. 

  • Hemorrhage: Is the loss of a significant amount of blood in a short time.  

  • Thrombocytosis: Is an abnormal increase in platelets in the blood.  

  • Hyperlipidemia: Describes elevated cholesterol and fatty substances in the blood. 

  • Leukemia: Is a type of blood cancer where there is a progressive increase in the number of abnormal white blood cells produced by blood-forming tissues and other organs and in the blood. There are several types depending on the cause.  

  • Anemia: Is an abnormally low number of red blood cells in the blood. There are several types depending on the cause.  

  • Blood Pressure Disorders:  

  • Hypertension: Is abnormally high blood pressure and there are several types depending on the cause. Normal blood pressure is less than 120/80 mmHg, and it begins when the blood pressure becomes more than this. Life-threatening hypertension levels are 180/120 mmHg or greater.  

  • Hypotension: Is abnormally low blood pressure, there are several types depending on the cause, and is considered to be 90/60 mmHg.