Blood pressure or BP is the pressure exerted by the flow of blood on the walls of the arteries; it is determined by the force and amount blood pumped by the heart and by diameter of the arteries. it consist of the two components systolic pressure and diastolic pressure, these are normally 120/80 mgof mercury respectively, when the blood pressure exceed these value it leads to a condition called high blood pressure or hypertension, there are two types of hypertension primary hypertension and secondary hypertension, primary hypertension is without specific identifiable cause, secondary hypertension is elevated blood pressure that results from underlying identifiable often correctable cause, only about 5 to10 % hypertension cases are thought to result from secondary causes, the most common causes of the secondary hypertension are kidney disease ,adrenal gland disease, narrowing of the aorta and sleep apnea, Hypertension common symptoms are Headache,Dizziness,Blurred vision, and in severe cases confusion and coma are possible. Small portable instruments called a sphygmomanometer usually measure Blood pressure, It consist of an air pump, pressure gauge and rubber cuff. The instrument measures the blood pressure in units called millimeter of mercury (mmhg). A blood pressure reading of 120/80mmHg is considered normal, where as the blood pressure of 140/90mmHg or higher is considered High Blood pressure or Hypertension
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Most of the secondary mechanisms associated with hypertension are generally fully understood, and are outlined at secondary hypertension. However, those associated with essential (primary) hypertension are far less understood. What is known is that cardiac output is raised early in the disease course, with total peripheral resistance (TPR) normal; over time cardiac output drops to normal levels but TPR is increased. Three theories have been proposed to explain this:
Inability of the kidneys to excrete sodium, resulting in natriuretic factors such as Atrial Natriuretic Factor being secreted to promote salt excretion with the side-effect of raising total peripheral resistance.
An overactive renin / angiotensin system leads to vasoconstriction and retention of sodium and water. The increase in blood volume leads to hypertension.
An overactive sympathetic nervous system, leading to increased stress responses.
It is also known that hypertension is highly heritable and polygenic (caused by more than one gene) and a few candidate genes have been postulated in the etiology of this condition.Prevention:
Prevention of hypertension only goes as far as the cause; one can adjust lifestyle related causes but genetics, race, age and gender are outside the realm of change.
- Modifiable factors include diet, weight-loss, exercise and stress management.
- Low-sodium and low-fat diets can reduce cardiovascular risks and keep arteries clear of plaque and blood volume at normal levels.
- Losing even 10% of body weight can have fantastic benefits towards health, including reversal or prevention of HTN, dropping systolic pressures several points.
- Exercise maintains a healthy heart, thus healthy cardiac contractions and functions. The heart is a muscle too, working out the cardiac muscles makes the heart beat more efficiently, thus pumping blood around the body more effectively.
- Stressors can negatively affect blood pressure by activating the sympathetic nervous system, thus fight or flight responses which increase heartrate and blood pressure. Chronic stress can lead to regular and frequent activation of the system and repeated high blood pressure.
- Effective management of stress can reduce this particular risk.