Health & Living
The Blood Vessels
Blood vessels are one of the main components of the circulatory system. With the heart, blood vessels help distribute blood to the pulmonary circuit and the systemic circuit. The pulmonary circuit moves deoxygenated blood from the heart to the lungs, while the systemic heart distributes oxygenated blood throughout the body. Blood vessels are categorized as arteries, veins, and capillaries.
Vessel Wall
Blood Vessels are composed of three walls called tunics. The first layer, the tunica intima, is the innermost layer of a blood vessel. The tunica intima is in direct contact with the blood. Chemicals that allow blood vessels to dilate and constrict are secreted from the tunica intima. The second layer, tunica media, is made up of smooth muscle, collagen, and fiber. The tunica medica helps strengthen the vessel and controls the pressure. The third layer, tunica externa, is made up of loose connecive tissue. This layer connects the vessel to the tissues around it.
Blood Pressure
Blood pressure is the amount of force the blood exerts on the vessel. It is measured as a ratio of systolic blood pressure over diastolic blood pressure. Systolic blood pressure is the highest amount of pressure during ventricular contraction. Diastolic blood pressure is the minimum amount of pressure during ventricular contraction. Blood pressure can be measured electronically or manually, using a sphyngometer and a stethoscope.
Blood Pressure and Health
It is important to maintain a normal blood pressure because it prevents arteries from narrowing and weakening. A high blood pressure means that the blood is putting a strain on the vessels causing the vessel to become thicker and less flexible. A thicker vessel increases the risk for clots and other heart diseases. A normal blood pressure can be maintained by eating a well balanced diet and excercising regularly. Excercise makes the heart stronger and a stronger heart can pump blood with less effort. This "decreased" effort puts less force on the arteries, preventig them from weakening. The best excercise to reduce blood pressure are aerobic excercises because it keeps the heart pumping without causing too much strain on the body. Approximately 175 minutes of light to moderate excercise per week is recommended to keep a normal blood pressure.
Arteries and Veins
Arteries and veins transport blood to and from the heart. Arteries are high pressured vessels that carry oxygenated blood away from the heart. Arteries are characterized by their thick muscular wall which creates enough pressure to move blood and distribute it throughout the body to provide oxygen to the organs. In contrast, veins have a thinner muscular wall. Veins transport deoxygenated blood to the heart. Due to their ability to hold a high volume of blood, veins are also referred to as capacitance vessels. Together, arteries and veins ensure that blood is constantly circulating the body and providing oxygen.
