What is Blood Pressure?

Blood Pressure Primer

The heart is one of the most important organs in the human body. It is a muscular organ about the size of a fist, located near the left of the breastbone. 

What does the heart do?

The heart constantly pumps blood throughout the body. It never stops pumping blood, whether we are working, playing, sleeping or relaxing the heart keeps pumping blood. Whenever a heart is beating, it is pumping blood into the body. On average a heart beats 100,000 times a day, to push 5,000 gallons of blood through the entire body every single day.

Why does the heart pump blood into our bodies?

Blood is life! Blood transports oxygen and various nutrients to the lungs and tissues. The blood transports oxygen from the lungs to the cells of the body, where it is needed for the chemical processes that occur in our bodies in order to maintain life; these chemical processes are also known as metabolism. The nutrients in the blood include vitamins, amino acids, glucose, minerals, and fatty acids that are used to nourish tissues and building blocks of the body. Circulation of blood in our bodies is essential to keep us alive.

The Cardiovascular System

How does the heart pump blood throughout the human body? Our blood is pumped through a network of arteries and veins called the cardiovascular system. Arteries are blood vessels that carry blood away from the heart. Whereas veins are blood vessels that carry blood low in oxygen from the body back to the heart to be enriched in oxygen – a process also known as reoxygenation. Arteries and veins are part of two closed systems of blood vessels that begin and end at the heart. Blood vessels are like tubes. Arteries and veins both have three layers of walls:

  • The Outer Layer made of collagen and elastic fibers. The fibers enable the veins and arteries to stretch to a limited extent.
  • The Middle Layer made of smooth muscle and elastic fibers. Arteries have a thicker middle layer than veins.
  • The Inner Layer made of elastic fiber and collagen. 

Capillaries are another type of blood vessels that are part of the cardiovascular system. They are the smallest and most numerous blood vessels in the body. They connect the vessels that carry blood away from the heart (arteries) to the vessels that return blood to the heart (veins). They primarily support the exchange of materials between the blood and tissue cells.

The Chambers and Valves of the Heart

The heart produces the force needed to pump blood through the cardiovascular system. The heart uses chambers to receive incoming blood and to pump it out. The heart also has valves that are used to keep blood flowing in the right direction. If heart valves do not close and open properly, the heart’s ability to pump blood through the body can be affected. Heart valve malfunctions can lead to heart failure. The heart has four chambers and four heart valves. The chambers are:

  • The Right atrium is where the blood from the veins is received and before it is pumped to the right ventricle.
  • The Right ventricle is where blood from the right atrium is received before it is pumped to the lungs to be loaded with oxygen.
  • The Left atrium is where the oxygenated blood from the lungs is received before it is pumped to the left ventricle.
  • The Left ventricle is the strongest chamber and is responsible for pumping oxygen-rich blood to the rest of the body. Our blood pressure is created by the forceful contractions generated in the left ventricle to push blood through the cardiovascular system.

Blood Pressure in a Nutshell

Blood pressure is the pressure exerted against the walls of blood vessels by circulating blood as it is pumped out of the heart’s left ventricle through the body. When the heart squeezes to push blood through the arteries, the blood pressure goes up. When the heart relaxes, the blood pressure goes down.