Flashcards in Mutafova Deck (25):
What does an increase in venous tone do the venous return?
Increases venous return
temperature regulation is the principal function of the cutaneous sympathetic nerves (cold causes (blank) due to SNS stimulation; heat causes (blank) due to SNS withdrawal)
(blank) dominates in skeletal muscle at rest
What does high CO2 in the brain cause?
What does low CO2 in the brain cause?
What metabolite is cerebral circulation highly dependent on?
Three areas where sympathetic innervation is highest in regards to regulating blood flow
What is total peripheral resistance?
The total resistance to blood flow from the aorta back to the right atrium
What is the relationship between blood flow, mean arterial pressure, and resistance?
Q = MAP/R
Blood flow will increase with increased MAP
Blood flow will decrease with decreased R
What two variables determine MAP?
MAP = CO * TPR
During inspiration, what happens to cardiac output?
It is increased. More negative intrapleural pressure = greater flow to IVC
What happens upon standing?
Blood pools in lower extremities.
Pushes fluid into interstitium.
Decreased blood volume and venous return.
Sensed by baroreceptors.
Increase sympathetic activity to heart and blood vessels.
Venoconstriction, increased CO, increased contractility, increased HR
What happens during hemorrhage?
Decreased blood volume sensed by baroreceptors.
Increased sympathetic out flow to heart and blood vessels.
In the heart, increased HR and contractility.
In the blood vessels, vasoconstriction and increased total peripheral resistance.
What system is involved in a prolonged response to mild hemorrhage?
What is stroke volume dependent on? (two variables)
EDV - ESV
(blank) is always decreased during exercise, while (blank) is always increased.
What increases blood flow to exercising muscles?
How is blood pressure maintained with all of the vasodilatation that occurs during exercise?
Vasoconstriction in non-exercising muscles
Areas that exhibit active hyperemia?
Brain, heart, skeletal muscle
Areas that exhibit reactive hyperemia?
Heart and skeletal muscle (also brain)
In which organs is sympathetic innervation most important?
Skin > skeletal muscle >>> brain and heart
Is blood flow to the brain controlled by intrinsic or extrinsic factors?
CO2 is the main metabolite that affects flow.
Is blood flow to the skeletal muscles controlled by intrinsic or extrinsic factors?
Both! At rest, extrinsic sympathetic innervation.
During exercise, metabolic factors cause vasodilatation.
Is blood flow to the heart controlled by intrinsic or extrinsic factors?
Intrinsic! Mostly metabolites like adenosine and O2.