GIZELLE WILKINSON
SUBJECT: ESSENTIAL HYPERTENSION
STUDENT NUMBER: M00037713
CLINICAL SCIENCES II
INTRODUCTION
Essential hypertension, otherwise known as primary or idiopathic hypertension, is a condition of raised blood pressure with no identifiable cause. Secondary hypertension occurs when blood pressure elevation results from a specific and potentially treatable cause. These include renal diseases, endocrine causes, congenital cardiovascular causes and pregnancy.
This study however, will focus on essential hypertension so as to avoid unnecessary confusion. Blood pressure is relative to each individual and tends to vary markedly depending on height and weight. Levels of blood pressure can also vary depending on the characteristics of the population such as age and ethnic background. (Kumar & Clarke, 2007)
The factors that determine the arterial blood pressure are cardiac output (CO) and peripheral resistance (PR). CO is the amount of blood pumped out of the left ventricle per minute. PR is the amount of friction encountered by the blood as it flows through the lumen of the arteries. (Marieb,2006) It can be increased or decreased by various factors which will be described later.
Blood pressure is recorded in terms of the systolic and diastolic. As blood is pumped through the body, it exerts pressure on the walls of the arteries. The systolic pressure is the pressure against these walls when the heart contracts, and the diastolic pressure is the pressure against the walls when the heart relaxes. (Medline Plus)
A normal blood pressure ranges from 120/70 to 140/85. Any reading which exceeds this range is considered as high, and hypertension id diagnosed when the patient presents with at least three consistent readings above the normal range.
AETIOLOGY
The aetiology of essential hypertension is said to be multifactorial. Genetic factors are contributory as studies show that children of hypertensive
References: 1. Bartram T. (1995) Encyclopedia of Herbal Medicine Grace Publishers, Dorset. 2. Bennet P.N., Brown M.J. (2003) 9th ed. Clinical Pharmacology Churchill Livingstone, London. 3. Chevalier A (2000) 2nd ed. Encyclopedia of Herbal Medicine. Dorling Kindersley, London, 4 5. Galbraith A. , Bullock S., Mamas E., Hunt B., Richards A. (1999) Fundamentals of Pharmacology: A Text for Nurses and Health Professionals. Prentice Hall, Harlow. 6. Kumar P., Clarke M. (2007) 6th ed. Clinical Medicine Elsevier Saunders, London. 7. Lakhani SR., Dilly SA., Finlayson CJ. (1998) 2nd ed. Basic Pathology : An introduction to the Mechanisms of Disease Arnold, London. 8. Marieb EN. (2006) 8th ed. Essentials of Human Anatomy and Physiology Benjamin Cummings, London. 11. Mills S., Bone K. (2000) Principles and Practice of Phytotherapy Churchill Livingstone , London 12