25 Questions
What is the role of arterioles in the circulation?
Direct blood to individual tissues by selectively constricting and dilating
Which vessel type serves as blood reservoirs in the circulatory system?
Veins
What is the main function of elastic arteries?
Act as pressure reservoirs
Which factor is responsible for vasoconstriction and vasodilation?
Smooth muscle cells in the blood vessel wall
What is the relationship between pressure and peripheral resistance in the circulation?
Direct relationship
What is the main function of capillaries in the circulatory system?
Serve as exchange sites
What determines blood flow according to Ohm's law?
Pressure difference and impediment to blood flow
What triggers the release of nitric oxide (NO) in the endothelial cells of blood vessels?
Sudden stretch of small blood vessels
What causes myogenic contraction in the smooth muscle of blood vessel walls?
Stretch-induced vascular depolarization
What is responsible for the long-term control of blood flow in tissues over a period of days, weeks, or even months?
Increase or decrease in the physical sizes and numbers of blood vessels
In acute control of local blood flow, what leads to rapid changes in local vasodilation or vasoconstriction of arterioles and precapillary sphincters?
Markers related to high tissue metabolism
What is the primary function of vasomotion in blood vessels?
To adjust blood flow based on tissue metabolic needs
What greatly influences blood flow and blood pressure?
Changes in the diameter of arteries
What pressure is under tonic sympathetic control?
Arterial pressure
What happens when factors cause arteriole vasoconstriction?
Peripheral resistance increases
What does increased sympathetic activity lead to in veins?
Vasoconstriction
At what value does cardiac output no longer keep up, according to the text?
Approx. 9 L/min
What does the vascular function curve represent?
Venous return as a function of right atrial pressure
What determines the right atrial pressure, end-diastolic volume, and end-diastolic fiber length?
Venous return
What point is the unique operating or equilibrium point of the system in the steady state?
The point where cardiac output and venous return are equal
What is the relationship between right atrial pressure, venous return, end-diastolic volume, and end-diastolic fiber length?
As venous return increases, right atrial pressure increases, and end-diastolic volume and end-diastolic fiber length increase.
What is the value for the right atrial pressure at which venous return is zero and right atrial pressure is at its highest value?
4 mm Hg
What occurs when the two curves intersect in the cardiac and vascular function curves?
Cardiac output is equal to venous return.
What does increased sympathetic activity lead to in veins?
Vasoconstriction
What determines peripheral resistance and how does it affect blood pressure?
Arteriole vasoconstriction increases peripheral resistance, which decreases blood pressure.
Test your knowledge of the factors responsible for maintaining blood flow in the body, the structure and characteristics of microcirculation, the roles of smooth muscle cells in blood vessel walls, and the factors responsible for vasoconstriction and vasodilation. Also, explore the relationship between changes in microcirculation and the regulation of systemic blood pressure.
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