Exam 2 Sample Exam Flashcards
What is in proportion with cardiac output?
local tissue flow
What is independent of local flow and cardiac output?
arterial blood pressure
Consider the resistance in the following tissue beds:
coronary = .4, brain = .13, liver = .08, kidneys = .10
What is the total peripheral resistance?
less than 0.8
Greater resistance is greater or lesser flow?
lesser flow
Pulmonic flow is in series with systemic flow T/F?
true
Using data from question 2, which tissue bed would have greatest flow?
liver (lower resistance is greater flow)
Following vessels the flow rate is identical, which vessel is offering the greatest resistance to flow?
P1=50 P2=25 P1=70 P2=60 P1=80 P2=65
P1=50 P2=25 =25
greater change in pressure is greater resistance to flow
In most tissue beds, blood flow is regulated in proportion to which of the following?
local metabolism
A broad band Doppler reading is indicative of what type of flow?
turbulent flow
A narrow band Doppler reading is indicative of what type of flow?
laminar flow
If a vessel with a length of 100 cm has a cross sectional area of 0.5 cm^2, and velocity of flow of 10 cm/sec. The pressure drop across that length is 10 mmHg. What is the flow in that vessel?
300 mL/min
10x.5=5x60=300
The vascular compartment with the greatest total cross sectional area is what?
capillaries
A greater cross sectional area is indicative of what?
slower blood flow
What are characteristics of parallel circuitry?
independence of flow control, maximizes oxygen delivery to tissues, minimizes total peripheral resistance, and decreases work load on heart
A small change in volume producing a large change in pressure is a characteristic of which vascular compartment?
systemic arteries
A large change in volume producing a small change in pressure is characteristic of which vascular compartment?
systemic veins
Acetylcholine binding to the vascular endothelium has what effect?
vasodilation by causing nitric oxide release
What is the effect of sympathetic nervous stimulation on most vascular smooth muscle?
vasoconstriction mediated by alpha receptors
Is there parasympathetic effects on vascular smooth muscle?
no, they are effected by local vasodilators
What are the local vasodilators?
adenosine, NO, CO, K+, H+, PGE and PGI series prostaglandins, histamine
During widespread sympathetic nervous system stimulation, which tissue bed would show the least increase in vascular resistance?
lung, brain, and heart
As a tissue becomes more active, how is blood flow to that tissue increased?
tissue releases local vasodilators which override sympathetics
At a given mean circulatory filling pressure what happens to venous return as central venous pressure increases?
decreases
At a given mean circulatory filling pressure what happens to venous return as central venous pressure decreases?
increases
If cardiac output is stopped, arterial pressure will be expected to fall until it equals what?
critical closing pressure
If cardiac output is stopped, arterial pressure will be expected to fall until it equals what when a shunt is involved?
mean circulatory filling pressure