For example, they include the pulmonary artery and the aorta. The aorta is the main artery carrying blood away from the heart. The heart forcefully pumps blood out to keep it moving around the body. Elastic arteries must be flexible to handle surges of blood.
They expand as the heart pushes blood out. Smooth muscle fibers make up the walls of muscular arteries. The muscles allow these arteries to expand and contract.
These changes in size control how much blood moves through the arteries. Arterioles are the smallest type of artery. They distribute blood from larger arteries through networks of capillaries. The outer layer of arterioles also contains smooth muscle that allows for expansions and contractions. The same layers make up arteries and veins, but veins are thinner and have less muscle, allowing them to hold more blood.
Venules are the smallest type of vein. They have very thin walls to hold lots of blood. They feed low-oxygen blood through capillaries from arteries directly into veins.
The blood then moves back to the heart through a series of veins of increasing size and muscle. Veins and arteries consist of three layers :. The cardiovascular system refers to the heart and blood vessels together. The system makes up a closed circuit of vessels that transport blood around the body. The cardiovascular system is essential to support human life.
It is the first major organ network to develop in an embryo. All body tissues need oxygen and nutrients to survive. They also require the removal of waste substances that are a byproduct of metabolism. The heart pumps blood around the body. It must work constantly and with enough force to ensure all bodily tissues receive enough blood to function.
Disruptions to the cardiovascular system can have severe consequences. Cardiovascular diseases are a group of disorders that affect the heart and blood vessels, such as coronary heart disease.
These diseases are the leading cause of death worldwide, accounting for around Arteries are a type of blood vessel that transports blood away from the heart. Serious conditions can affect all types of blood vessels. Most people are aware of health conditions that plague larger blood vessels, from atherosclerosis hardening of the arties to varicose veins.
But even tiny capillaries can be affected. Capillary leak syndrome is a rare disease in which the walls of these tiny blood vessels leak, flooding surrounding tissues with blood. It can lead to severe swelling and dangerously low blood pressure, according to the National Institutes of Health.
Blood vessels act as a force field for the brain. Blood vessels are part of an important defense system known as the blood-brain barrier. A network of blood vessels and tissue comprised of closely-spaced cells helps keep harmful substances from reaching the brain, the National Cancer Institute explains.
The blood-brain barrier allows some essential substances, such as water, oxygen, and carbon dioxide, to pass into the brain, but keeps bacteria and other dangerous substances out. Although general anesthetics can pass through the blood-brain barrier, many important medications, including some anti- cancer drugs , are unable to, presenting challenges for doctors treating many serious and debilitating diseases that affect the brain, the NCI notes.
These include brain cancer and Parkinson's disease. Blood vessels are affected by the weather. The circulatory system helps maintain body temperature. Blood vessels expand to release heat, allowing you to cool down, and narrow or constrict to conserve heat, according to the National Library of Medicine. In extreme cases, such as when your feet are exposed to very cold or wet conditions for prolonged periods of time — a condition called trench foot — the constriction of blood vessels can shut down circulation, causing skin tissue to die, according to the U.
Centers for Disease Control and Prevention. Another consequence of extreme exposure is frostbite, which can happen after just a few minutes in freezing conditions. Blame that ice cream headache on your blood vessels. Anyone who likes popsicles or ice water may be familiar with the uncomfortable sensation known as brain freeze.
When something cold touches the warm roof of your mouth, local blood vessels constrict to minimize heat loss, then relax to restore blood flow. The heart's anatomy is that of a pump that beats billions of times over a lifetime. Why is the diagnosis of coronary artery disease CAD in women delayed? The Society of Thoracic Surgeons. One reason for delayed diagnosis of coronary artery disease CAD in women may be that current testi What are the symptoms of an arteriovenous malformation AVM in the brain?
Geoffrey P.
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