Cardiovascular Disorders I Chapter 14 Biology I F.Sc First Year Lec # 33

#biology11class #biologyfirstyear #FSc #chapter14 #Transport Like Our Facebook page. -----------------------------------   / bismacademy   ------------------------------------ Hypertension. It is a condition of high blood pressure. Effects. On blood vessels.. Prolonged high blood pressure damages the lining of the blood vessels and On Heart muscles. It also leads to weakening of heart muscles (which have become thickened due to the continuous strain imposed on them), with declining efficiency of the pumping action of the heart. Congestive Heart Failure. Blood may then be retained in the heart and lungs, often leading to fatal condition called congestive heart failure. Thrombus Formation and Hypertension. Thrombus It is a solid mass or plug of blood constituents (clot) in a blood vessel. Thrombosis is the formation of thrombus. Effects. Blockage. This mass may block (wholly or only in part) the vessels, in which it forms, Embolus. It may be dislodged and carried to some other location in the circulatory system, in which case it is called an embolus. Thromboembolism It is leading cause of deaths in western civilization. Causes. Thrombus formation may be due the following: i) Irritation or infection of lining of blood vessels. ii) Reduced rate of blood flow, due to long periods of inactivity. iii) Pneumonia and tuberculosis, emphysema Heart attack (Myocardial infarction). Definition. Blockage of blood vessel in the heart by an embolus (or by locally formed thrombus) causes necrosis or damage to portion of heart muscles, a condition known as a heart attack or technically myocardial infarction, Causes. Heart attack is due to disruptions of control system of the heart with accompanying arrhythmias, especially ventricular fibrillation. Precautions. We can avoid the above mentioned situations if we : i) Avoid too much fatty food (especially rich in cholesterol). ii) Maintain normal body weight. iii) Control blood pressure by regular walk and exercise. iv) Do not smoke. Stroke. Definition. If the normal flow of blood is blocked by an embolus (or a locally formed thrombus), in a blood vessel in the brain, and causes necrosis, or death, of the surrounding neural tissue (owing to lack of O2 ), the condition is called a stroke or cerebral infarction. Severity. The symptoms of the stroke vary depending on the part of the brain that has been damaged. Haemorrhage. Definition. It is the discharge of blood from blood vessels. Especially important is the brain haemorrhage. Causes. It results from bursting of any of the arteries supplying the brain. When the wall of the arteries becomes hard and loses its elasticity - and higher blood pressures would result in brain haemorrhage. Precaution. To avoid brain haemorrhage, the blood pressure must be controlled between normal limits. In almost all the above mentioned problems, It is important to take following preventive measures:  Taking in of less cholesterol in our food.  Maintenance of normal blood pressure.  Do not become over weight.  Do not smoke.  Do regular exercise.  Avoid stress and tension