Blood is a body fluid found in the circulatory system of vertebrates. It is in constant circulation to meet the body’s supply needs of nutrients and oxygen and to remove waste products.
The circulatory system is an organ system made up of the heart, blood and blood vessels all working together. The flow of blood throughout the body is dependent on the heart and blood vessels. The heart is the muscle that pumps blood through the blood vessels.
Blood vessels are a network of arteries, veins and capillaries. Arteries carry blood rich in oxygen from the heart to the rest of the body. Veins carry blood poor in oxygen from the body to the heart. Capillaries connect arteries and veins, they help in the exchange of elements between blood and tissues. Capillaries are the smallest blood vessels and have the thinnest walls while arteries are the largest blood vessels with the thickest walls. Arteries are the deepest blood vessels found deep inside the muscles and the veins are the most superficial blood vessels located towards the skin. This is the reason why most blood samples are collected from veins and also why they are used for drug administration.
When blood flows through vessels it exerts a force against the walls. This is called blood pressure. Blood pressure is the force per unit area exerted by blood flowing through a vessel. This force causes blood vessels the expand and contract. The expansion and contraction of blood vessels is necessary for maintaining blood flow through the body. This is mainly in the arteries.
There are two types of pressure, the systolic and the diastolic pressure.
During contraction blood leaves the heart with a force which it exerts on the arterial walls this is the systolic pressure. Diastolic pressure is residual pressure. It is the pressure exerted when the heart relaxes between beats.
Systolic pressure is always higher than diastolic pressure. Systolic pressure ranges from 90-120 mmHg for a normal healthy person and diastolic pressure ranges from 60-80mmHg in a healthy person. So normal blood pressure range is between 90/60 – 120/80 mmHg. Pressure below this range is considered hypotension and pressures above is known as hypertension.
Hypertension refers to blood pressure of 140/90 mmHg and above. Pressures between 120/80 and 140/90 increase risk of developing hypertension.
Hypertension is a condition that is not often detected as it generally doesn’t really present symptoms. Hypertension can be detected when you check your blood pressure regularly. Blood pressure varies from person to person. Some peoples’ pressure maybe higher than others.
Hypertension occurs when blood vessels such as the arterioles narrow. This causes the blood to exert high pressure on the walls of the vessel. This causes the heart to work harder the maintain the pressure. Eventually over time the heart may enlarge this is an adaptive mechanism but its injuries to the body. It enlarges and weakens. The narrowing of blood vessels may be caused by deposition of cholesterol due to increased intake.
There are two types of hypertension; primary hypertension and secondary hypertension.
Primary hypertension is that which develops progressively over time while secondary hypertension is that which is caused by an underlying disease or even medication. This type may occur suddenly and higher unlike primary. Conditions that may lead to secondary hypertension are; kidney disease, adrenal gland tumors, thyroid disorders, obstructive sleep apnea. Medications such as birth control pills, over-the-counter pain relievers, decongestants, cold remedies, illegal drugs such as cocaine and amphetamines.
Risk factors of hypertension;
- Age;
- Gender; men develop hypertension more than women
- Race; African Americans are more likely to develop hypertension than whites
- Family history
- Weight
- Lack of exercise
- Smoking or chewing tobacco
- Too much salt in diet
- Excessive intake of alcohol
- Stress
- Too little potassium in diet
- Some chronic conditions.
Excessive pressure exerted by blood on your arteries can damage blood vessels and consequently organs. Uncontrolled high blood pressure can cause complications such as;
- Heart failure
- Stroke
- Aneurysm
- Metabolic syndrome
- Dementia
- Kidney damage
- Vision problems due to thickened, narrow or torn blood vessels in your eyes.
Hypertension is a condition that has no specific cure. It cannot be treated but can only be managed.
Hypertension can be managed using medications, diet, exercise and change of lifestyle. The last four factors also serve as preventive measures.
