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Questions and Answers
Which of the following is NOT a component of the circulatory system?
Which of the following is NOT a component of the circulatory system?
Which layer of the heart is responsible for contracting and pumping blood?
Which layer of the heart is responsible for contracting and pumping blood?
Which type of blood vessels have the thickest tunica media?
Which type of blood vessels have the thickest tunica media?
Which layer of the heart is the thickest?
Which layer of the heart is the thickest?
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Which layer of the heart contains the Purkinje fibers?
Which layer of the heart contains the Purkinje fibers?
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What is the function of the cardiac skeleton?
What is the function of the cardiac skeleton?
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Which part of the conducting system generates and propagates waves of depolarization?
Which part of the conducting system generates and propagates waves of depolarization?
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Which layer of the vessel wall is composed of concentric layers of helically arranged smooth muscle cells?
Which layer of the vessel wall is composed of concentric layers of helically arranged smooth muscle cells?
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Which layer of the vessel wall contains a network of unmyelinated autonomic nerve fibers that release the vasoconstrictor norepinephrine?
Which layer of the vessel wall contains a network of unmyelinated autonomic nerve fibers that release the vasoconstrictor norepinephrine?
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Which type of arteries distribute blood to the organs and help regulate blood pressure by contracting or relaxing the smooth muscle in the media?
Which type of arteries distribute blood to the organs and help regulate blood pressure by contracting or relaxing the smooth muscle in the media?
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Which layer of the vessel wall may contain up to 40 layers of large smooth muscle cells interspersed with a variable number of elastic lamellae?
Which layer of the vessel wall may contain up to 40 layers of large smooth muscle cells interspersed with a variable number of elastic lamellae?
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Which of the following is a component of the lymphatic vascular system?
Which of the following is a component of the lymphatic vascular system?
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Which of the following describes the function of the circulatory system?
Which of the following describes the function of the circulatory system?
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What is the total length of vessels in the human body?
What is the total length of vessels in the human body?
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Which of the following is NOT a component of the blood vascular system?
Which of the following is NOT a component of the blood vascular system?
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Which type of blood vessel has large perforations without diaphragms, allowing maximal exchange of macromolecules and easier movement of cells?
Which type of blood vessel has large perforations without diaphragms, allowing maximal exchange of macromolecules and easier movement of cells?
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Which type of capillaries have sieve-like structures that allow more extensive molecular exchange and are found in organs with rapid interchange of substances, such as the kidneys, intestine, choroid plexus, and endocrine glands?
Which type of capillaries have sieve-like structures that allow more extensive molecular exchange and are found in organs with rapid interchange of substances, such as the kidneys, intestine, choroid plexus, and endocrine glands?
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Which type of blood vessel carries blood back to the heart and has valves to prevent backflow?
Which type of blood vessel carries blood back to the heart and has valves to prevent backflow?
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What is the main function of capillaries?
What is the main function of capillaries?
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Study Notes
Structure and Function of Blood Vessels
- Arterioles are small blood vessels with a diameter of 1 mm and have a thin subendothelial layer, circularly arranged smooth muscle cells in the media, and a thin adventitia.
- Capillaries are the smallest blood vessels and function in networks called capillary beds to permit and regulate metabolic exchange between blood and surrounding tissues.
- The density of the capillary bed is related to the metabolic activity of the tissues, with high metabolic rates requiring more capillary beds.
- Capillaries consist of a simple layer of endothelial cells rolled up as a tube surrounded by a basement membrane. They have an average diameter of 4-10 micrometers and are the major site of water and solute exchange between blood and tissues.
- There are three histologic types of capillaries: continuous, fenestrated, and discontinuous/sinusoids, each with different levels of metabolic exchange.
- Continuous capillaries have tight occluding junctions between endothelial cells and are found in muscle, connective tissue, lungs, exocrine glands, and nervous tissue.
- Fenestrated capillaries have sieve-like structures that allow more extensive molecular exchange and are found in organs with rapid interchange of substances, such as the kidneys, intestine, choroid plexus, and endocrine glands.
- Discontinuous capillaries/sinusoids have large perforations without diaphragms and are found in the liver, spleen, some endocrine organs, and bone marrow, allowing maximal exchange of macromolecules and easier movement of cells.
- Venules are small veins that resemble capillaries and are the primary site for white blood cells to adhere to the endothelium and leave the circulation at sites of infection or tissue damage.
- Veins carry blood back to the heart and have valves to prevent backflow. They have different sizes, with small and medium veins located close to corresponding muscular arteries, and large veins being big venous trunks close to the heart.
- The lymphatic vascular system returns fluid from tissue spaces to the blood. Lymphatic capillaries collect excess interstitial fluid as lymph, which merges to form larger lymphatic vessels that connect with the blood vascular system.
- Lymphatic vessels have thin walls, increasing amounts of connective tissue and smooth muscle, and valves. Lymph nodes are interposed in the path of larger lymphatic vessels, and large lymphatic trunks, such as the thoracic duct and right lymphatic duct, empty into the large veins.
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Description
Test your knowledge on the structure and function of blood vessels with this informative quiz. Learn about the different types of blood vessels, their characteristics, and their role in the circulatory system. Challenge yourself with questions on arterioles, capillaries, venules, veins, and the lymphatic vascular system.
