About 5 percent of the total blood volume is in the systemic capillaries at any given time. Another 10 percent is in the lungs. Smooth muscle cells in the arterioles where they branch to form capillaries regulate blood flow from the arterioles into the capillaries.
Veins carry blood toward the heart. After blood passes through the capillaries, it enters the smallest veins, called venules. From the venules, it flows into progressively larger and larger veins until it reaches the heart.
In the pulmonary circuit, the pulmonary veins transport blood from the lungs to the left atrium of the heart. This blood has a high oxygen content because it has just been oxygenated in the lungs. Systemic veins transport blood from the body tissue to the right atrium of the heart. This blood has a reduced oxygen content because the oxygen has been used for metabolic activities in the tissue cells. An aortic dissection occurs when the inner layer lining of the aortic wall tears and separates from the middle layer of the wall.
Aortic dissection is frequently fatal. Among which of the following groups is aortic dissection most common? More Content. Click here for the Professional Version. Blood Vessels: Circulating the Blood Blood travels from the heart in arteries, which branch into smaller and smaller vessels, eventually becoming arterioles.
Blood Vessels and Lymph Nodes. Was This Page Helpful? Yes No. Effects of Aging on the Heart and Blood Vessels. Biology of the Blood Vessels. Biology of the Heart.
This is called "vasodilation". Vasodilation lowers the blood pressure. Drugs that cause the diameter of the blood vessels to change are called vasoactive drugs. Drugs that make blood vessels constrict are used to treat low blood pressure and are called vasocontrictors. Drugs that relax the blood vessels and make them relax are used to treat high blood pressure. They are called vasodilators.
Image 1: Blood Vessels. Arteries in red carry oxygen rich blood from the left side of the heart to the tissues and organs. After oxygen leaves the blood and moves into the tissues, the level of oxygen in the blood becomes low.
The veins in blue carry blood that has a low level of oxygen back to the right side of the heart. Blood from the veins is pumped from the right side of the heart through the blood vessels of the lungs, where new oxygen is picked up. Download Blood Vessels Lab Manuals.
See more from our free eBook library. Functions of the Blood. Anatomy of the Heart. Pulmonary and Systemic Circulation. Circulatory System Pathologies.
When you select "Subscribe" you will start receiving our email newsletter. Use the links at the bottom of any email to manage the type of emails you receive or to unsubscribe. See our privacy policy for additional details. Learn Site. Get our awesome anatomy emails!
0コメント