Lecture 18 Flashcards
What is the average resting CO in L/min?
5 L/min
What is the average exercising CO L/min?
25 L/min
What is the % change in CO flow to the heart from resting to exercising?
No change, it remains the same at ~4%
T or F? CO flow to the brain increases during exercise.
False, blood flow to the brain decreases, skeletal muscle increases.
T or F? Active tissue can require up to 20x increase in blood flow.
True
CO can increase to approximately ____ times normal during exercise.
6
CO alone cannot meet the demand of active tissues, what must happen to help increase blood flow to the tissues?
Changes in microcirculation, vasoconstriction.
Smooth muscle in small arteries and arterioles can be stimulated to contract or relax via ____ signals, _____ stimuli, ______, and changes in _____ environment
nervous signals, hormonal stimuli, stretch, chemical environment
T or F? Contraction of arteries and arterioles require an action potential to stimulate contraction.
False, no action potential needed
What 3 main categories regulates blood flow?
SNS
Local chemical factors
Long-term angiogenesis
T or F? The PNS innervates the majority of blood vessels.
False, PNS does not innervate the majority of blood vessels but does regulate dilation of some blood vessels in specific areas of the body, such as the genitals. SNS innervates blood vessels.
The SNS causes generalized vasoconstriction and venoconstriction due to stimulation of ________ receptors.
α1-adrenergic
The ____ and _____ circulations have poor SNS vasoconstrictor innervation so are spared the vasoconstrictor effect.
coronary ; cerebral
Local ____, and release of _____ _______, is the primary controller of coronary and cerebral blood flow.
metabolism;vasodilator substances
Stimulation of B2 receptors causes __________ in few vascular beds.
Vasodilation