Flashcards in Chapter 14 - Guyton Deck (19):
Blood flows at a rate of:
Transports blood to tissue under high pressure 100 mmHg.
aorta and arteries
Control site for blood flow and major resistance site for circulation.
Major site of water and solute exchange between blood and tissues.
Returns blood to the heart under low pressure, serves as reservoir for blood.
superior and inferior vena cava, veins, venules, venous sinuses
Site of oxygen and carbon dioxide exchange.
What has the largest total cross-sectional area of the circulation?
capillaries (1000x aorta)
Velocity of blood flow from greatest to least.
The majority of blood volume at any given time is located where?
in the veins
Where is the largest pressure drop in circulation?
Cardiac output is mainly controlled by:
local tissue flow
Does local blood flow or cardiac output control arterial pressure?
no (nervous system and then renal for long term)
Flow (Q) through a blood vessel is determined by:
the pressure difference (P1-P2) between the two ends of a vessel and resistance (R) of the vessel
What is laminar flow?
velocity of blood in the center of the vessel is greater than toward the outer edge creating a parabolic profile (silent)
What are some causes of turbulent flow?
high velocities, sharp turns in circulation, rough surfaces in the circulation, rapid narrowing of blood vessels (makes murmurs)
What is conductance?
measure of blood flow through a vessel for a given pressure difference, increases in proportion to the fourth power of the diameter (more sensitive to change in diameter of a vessel)
integrating the velocities of all the concentric rings of flowing blood and multiplying them by the areas of the rings (laminar flow)
Would a single upper extremity amputee have higher, lower, or normal blood pressure?
Amputation of a limb or surgical removal of a kidney also removes a parallel circuit and reduces the total vascular conductance and total blood flow (i.e., cardiac output) while increasing total peripheral vascular resistance. (higher than normal blood pressure)