Blood is a combination of plasma and cells that circulate through the entire body. It is a specialized bodily fluid that supplies essential substances around the body, such as sugars, oxygen, and hormones. Blood consists of plasma, red and white blood cells, and platelets. Plasma: This constitutes approximately 55 percent of blood fluid in humans.55 percent Plasma is 92 percent water, and the contents of the remaining 8 percent include: carbon dioxide, glucose, hormones, proteins, mineral salts, fats, vitaminsvitamins The remaining 45 percent of the blood mainly consists of red and white blood cells and platelets. Each of these has a vital role to play in keeping the blood functioning effectively.

Blood pathways

Blood pressure Blood pressure is the measure of the force of blood pushing against blood vessel walls. Blood pressureblood The heart pumps blood into the arteries(blood vessels), which carry the blood throughout the body. heartarteries High blood pressure, also called hypertension, is dangerous because it makes the heart work harder to pump blood out to the body and contributes to hardening of the arteries, or atherosclerosis, to stroke, kidney disease, and to the development of heart failure. High blood pressurehypertensionheartatherosclerosisheart failure

What Is "Normal" Blood Pressure? A blood pressure reading has a top number (systolic) and bottom number (diastolic). The ranges are: Normal: Less than 120 over 80 (120/80) Prehypertension: over Stage 1 high blood pressure: over 90-99high blood pressure Stage 2 high blood pressure: 160 and above over 100 and abovehigh blood pressure High blood pressure in people over age 60: 150 and above over 90 and above People whose blood pressure is above the normal range should consult their doctor about steps to take to lower it.

What Causes High Blood Pressure? The exact causes of high blood pressure are not known, but several factors and conditions may play a role in its development, including: Smoking Being overweight or obeseoverweight Lack of physical activityphysical activity Too much salt in the diet Too much alcohol consumption (more than 1 to 2 drinks per day) Stress Older age Genetics Family history of high blood pressure Chronic kidney disease Adrenal and thyroid disordersthyroid disorders Sleep apnea