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Cardiovascular system. AKA CIRCULATORY SYSTEM. CARDIOVASULAR SYSTEM. Consists of heart, blood vessels, and blood Transportation system O2 and nutrients to body cells CO2 and metabolic waste away from cells. Heart. Muscular “pump” Located in the mediastinal cavity Btwn lungs
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Cardiovascular system AKA CIRCULATORY SYSTEM
CARDIOVASULAR SYSTEM • Consists of heart, blood vessels, and blood • Transportation system • O2 and nutrients to body cells • CO2 and metabolic waste away from cells
Heart • Muscular “pump” • Located in the mediastinal cavity • Btwn lungs • Behind sternum • Above diaphragm
Three layers & septum • Endocardium—smooth inner lining • Myocardium—thick muscle middle layer • Pericardium—outer covering • Muscular wall that divides rt. & lt. • Prevents blood flow btwn rt. & lt.
Chambers • Four chambers • Two upper—ATRIA • Two lower—VENTRICLES • RA receives blood as it returns from body cells • RV receives blood from RA • RV pushes blood thru pulmonary artery to lungs • LA receives oxygenated blood from lungs • LV receives oxygenated blood from LA • LV pushes blood thru aorta to be carried to the body cells
Valves • Tricuspid btwn RA & RV • Pulmonary btwn RV & pulmonary artery • Mitral btwn LA & LV • Aortic btwn LV & Aorta (largest artery)
Heartbeat Cycle • Electrical impulses originating in the heart causes the myocardium to contract • One cycle consists of a period of contraction (systole) & rest (diastole) • Atria contract to push blood into the ventricles • While atria relax & refill, ventricles contract
Heartbeat Cycle cont… • Blood in rt. Side of heart is low in O2 & high in CO2 • When it gets to the lungs CO2 is released (exhaled) and O2 is picked up • So now blood in lt side of the heart is high in O2 and low in CO2
Blood Vessels • Arteries • Vessels that carry blood away from the heart • Aorta • Largest artery in body: eventually branches into arterioles • Veins • Vessels that carry blood back to the heart • Venules are smallest branches • Inferior & superior vena cava are largest veins in the body
Blood Vessels cont… • Capillaries • Connect arterioles with venules • Have thin walls (one layer of cells) • Allow oxygen & nutrients to exit thru to cells • Allow carbon dioxide & waste products from cells to enter
Blood Composition • 5-6 quarts circulate continually • Transports: • Oxygen • Carbon dioxide • Nutrients • Metabolic waste • Heat • Hormones
Blood Composition cont… • Plasma—fluid part, 90% water • Erythrocytes (rbc)—contains (hemoglobin) to carry iron, O2 & CO2 • Leukocytes (wbc)—main function is to fight infection • Thrombocytes—aka platelets, contains enzymes for clotting
Components of blood
Anemia • Inadequate amount of erythrocytes, &/or hemoglobin • Iron deficient—inadequate iron • Aplastic—caused by injury to bone marrow • Little or no production of RBC: can be fatal • Pernicious—poor absorbtion of vitamin B12 • Sickle cell—chronic inherited disease • Occurs almost exclusively in African-Americans
Anerurysm • Ballooning out of weak area of wall of artery • Most common sites are cerebral, aortal, and abdominal • If it ruptures, could cause death
Atherosclerosis • Fatty plaques of cholesterol on walls of arteries • Causes narrowing (stenosis)-reduces flow • If plaque breaks, it can circulate thru blood stream (emboli) • Tx is low cholesterol diet, exercise, meds
Congestive Heart Failure (CHF) • Heart muscle does not beat adequately to supply bloods needs of the body • Symptoms: edema, dyspnea, pallor, cynosis, distention of neck veins, weak, rapid pulse, cough with pink frothy sputum • Tx: drugs, diuretics oxygen therapy, bedrest, low sodium diet.
Embolus & Hemophilia • Foreign substance circulating in blood: air, blood clot, bacterial clump, fat globule • Inherited disease, where blood is not able to clot • Occur almost always in males
Hypertension • Systolic > 150 mmHg • Diastolic > 90 mmHg • Tx: medications, diuretics, lower stress, avoiding tobacco, losing wt
Leukemia • Malignant disease of bone marrow or lymph tissue • Can be acute or chronic • Tx: chemo, radiation, bone marrow transplant
Myocardial Infarction (heart attack) • Blockage in coronary artery cuts off blood supply to the heart • Affected heart tissue dies (infarct)
Myocardial Infarction (heart attack) cont… • Symptoms: severe crushing pain in chest, jaw, neck, arm • Pressure in chest • Perspiration • Cold clammy skin • Dyspnea • Change in blood pressure • Tx: CPR, (inc. defibulator ad lib) • Anticoagulants • Medications
Risk factors for cardiovascular diseases • Risk factor—factors in the environment, or chemical, physiological or genetic element, that are thought to “pre-dispose” an individual to the development of a disease • Over 1 million people a year will have a fatal episode of some type of cardiovascular disease!
Two categories of risk factors: • Things that cannot be changed: • Age • Heredity • Gender • Race • Things that can be changed • Smoking • Hypertension • Cholesterol level • Physical inactivity • Obesity • Excessive stress