lecture 11 Flashcards
Why is it better to have high pressure?
Allows for greater control of flow
What do the pulmonary capillaries beds do?
O2 moves into the blood and CO2 leaves, making deoxygenated blood oxygenated
What kind of circuit distribution is the systemic circuit?
Parallel
Why is the systemic circuit described as parallel?
Continual branching of the arterial network with differing flows
Which tissue has constant blood flow regardless of exercising or resting?
Brain
Which tissues decrease in blood flow when exercising begins?
Kidney
Abdominal viscera
GI Tract
Which tissues increase in blood flow when exercise increases?
Heart
Skin
Skeletal muscle
Which tissue has the biggest increase in blood flow during exercise?
skeletal muscle
How is Mean arterial pressure controlled during exercise?
Decrease in total peripheral resistance because of increased cardiac output
Decrease in resistance =
increase in flow
What controls organ resistance and regional flow?
Arterioles
What is the relationship between resistance and radius?
R = 1/r4
Increasing the diameter of a vessel is called?
Vasodilation
decreasing the diameter of a vessel is called?
Vasoconstriction
Vasodilation will cause what in relation to resistance?
Decreased resistance
When under heavy exercise arteries carrying blood to kidneys will what?
Vasoconstrict
A vessel has a diameter of 1 and a flow of 16. The vessel increases its diameter to 2, what is the flow?
256 (16 x 16)
What type of cells are arterioles?
Smooth muscle cells
Why do we have good control of blood flow in the systemic circuit?
because it is under high pressure
Why are veins under less control?
because it is at a low pressure and their purpose is for collecting and carrying back to heart
Total blood flow in =
Total blood flow out
Why does skeletal muscle gain over 300% more blood during heavy exercise?
Because there is a high demand for oxygen
Why does the skin gain more blood flow during exercise?
Because it has to get rid of the excess heat energy produced
What are capillaries?
Small channels that allow transfer of blood
What determines what pressure goes through the capillaries?
Arterioles
What is humeral control of vasoconstriction and vasodilation?
Hormones like adrenaline released into the blood
What is the rule of 16?
increasing or decreasing radius by a factor of two means an increase/decrease of resistance by a factor of 16
