Principles of the vascular system Flashcards
What is the function of arteries and arterioles?
Arteries and arterioles are responsible for delivering oxygen-rich blood and nutrients from the heart to organs and tissues throughout the body.
What is the function of venules and veins?
Venules and veins are responsible for carrying deoxygenated blood back to the heart, completing the circulation loop. They also serve as reservoirs for blood volume.
What is the function of capillaries?
Capillaries are tiny, thin-walled vessels that facilitate the exchange of gases (oxygen and carbon dioxide) and the transfer of nutrients between the blood and the surrounding tissues. They link arterioles to venules.
Can you name an example of an artery that is an anatomical end artery?
The central retinal artery is an example of an anatomical end artery. It does not have anastomosis (connection) with other arteries.
What is the unique characteristic of coronary arteries?
Coronary arteries are considered functional end arteries, meaning they have limited anastomosis. However, the anastomosis between coronary arteries is often insufficient.
What is an anastomosis?
An anastomosis is a connection between two blood vessels, allowing for alternative routes of blood flow.
What is the function of anastomoses?
Anastomoses ensure continued tissue perfusion when one artery is compromised or blocked, providing an alternative pathway for blood flow.
Can you provide an example of an anastomosis?
The Circle of Willis is an example of an anastomosis located at the base of the brain. It connects the major arteries supplying the brain, allowing for collateral circulation if one of the arteries becomes occluded.
What is the function of the ascending aorta?
The ascending aorta carries oxygenated blood from the left ventricle of the heart. It gives rise to the coronary arteries, which supply blood to the heart muscle.
What is the function of the arch of the aorta?
The arch of the aorta is located above the level of the T4/T5 disc. It branches to supply blood to the head, neck, and upper limbs.
What is the function of the descending aorta?
The descending aorta extends from the top of the arch to the level of the T4/T5 disc. It continues as the thoracic aorta, supplying the posterior thoracic body wall, lungs, and diaphragm.
What is the function of the descending thoracic aorta?
The descending thoracic aorta extends from the T4/T5 level to the T12 level. Its branches supply the posterior thoracic body wall, lungs, and diaphragm.
Where is the abdominal aorta located and what does it supply?
The abdominal aorta extends from the level of T12 to L4 and supplies blood to the abdominal contents, gonads, abdominal body wall, diaphragm, and other structures in the abdominal region.
What are the branches of the abdominal aorta?
The branches of the abdominal aorta include the common iliac arteries, which bifurcate into the external iliac artery and internal iliac artery. The external iliac artery continues under the inguinal ligament, while the internal iliac artery supplies the pelvis and perineum.
How does blood flow to the upper limb?
Blood flow to the upper limb starts with the subclavian artery, which becomes the axillary artery. The axillary artery further branches into the brachial artery, which then gives rise to the radial and ulnar arteries, supplying the forearm and hand.
How does blood flow to the lower limb?
Blood flow to the lower limb starts with the external iliac artery, which becomes the femoral artery. The femoral artery then continues as the popliteal artery, which further branches into the anterior tibial artery, posterior tibial artery, and the fibular artery.
What is the role of veins in the venous system?
Veins transport blood towards the heart and act as a reservoir for blood. They have thinner walls compared to arteries and lack significant amounts of elastin and smooth muscle. Veins often have a larger lumen and may contain valves that ensure unidirectional flow of blood.
What are venous valves?
Venous valves are inward projections of the intima (inner layer) of the vein, strengthened by collagen and elastic fibers. They are semi-lunar cusps attached to the venous wall. Their function is to ensure one-way blood flow towards the heart and prevent backflow.
Where are venous valves absent?
Venous valves are absent in the inferior vena cava and in the veins of the head and neck.
What can happen if veins dilate and increase in pressure?
If veins dilate due to increased pressure, the valves may not close properly, resulting in the condition known as varicose veins. Varicose veins are enlarged, twisted veins that usually occur in the legs and can cause discomfort and cosmetic concerns.
