Arteries Flashcards
(9 cards)
What are arteries?
Arteries are high pressure vessels that carry blood away from the heart.
Eg. Pulmonary artery, aorta.
What are arteries composed of?
Composed of 3 layers, outer and inner layers of connective tissue. The middle layer is muscle and elastic connective tissue.
What causes a pulse?
A pulse is caused by the increase in the diameter of the arteries following heart contraction. The arteries recoil each time the heart relaxes.
What is an aneurysm?
An aneurysm is the ballooning of an artery caused by pressure of blood flowing through a weakened area. An aneurysm in the brain may cause a stroke.
How does blood move through the arteries?
Blood moves from artery –> arteriole –> capillary which are progressively smaller.
How are the diameter of arterioles controlled?
The diameter of the arterioles are controlled by nerves. A constriction of the smooth muscles causes vasoconstriction which reduces blood flow. Relaxation causes vasodilation and increases blood flow.
What happens during blushing?
Tiny sphincter muscles control movement of blood into capillaries. Blushing is caused when vasodilation occurs in the arterioles leading to the face. O2 rich blood appears red. As few as 1/50 of muscle capillaries are open during rest.
How does the body react when a person is frightened?
When a person is frightened blood is channeled to vital organs like the heart, brain and large muscles to aid in the “flight or fight response”. Less blood flows to the skin making it pale.
What is atherosclerosis?
Fat can accumulate in the blood and attach to the artery walls. Calcium and minerals can attach to the fat forming a hardened plaque. This is called atherosclerosis. This narrows the blood vessels and increases blood pressure. Can cause heart failure if coronary arteries are blocked.
