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
In a healthy young adult comment about tissue flow during diastole?
maintained by recoil of the arteries
In a healthy young adult comment about tissue flow during systole?
it is stretched
If blood flow to a tissue doubles and AV O2 difference falls, what is increase in flow most likely due to?
shunting
What increases the plasma colloid osmotic effect by about 50%?
negative changes on protein attracting and holding postive ions like sodium
What does the plasma colloid osmotic effect do?
pulls fluid back in
What protein holds positively charged ions like sodium?
albumin
What effects are attributed to slow breathing?
increased resting oxygen saturation, decreased sypathetic activity, decreased chemoreflex activation, decreased mean arterial blood pressure
What effect does decreasing velocity have on blood viscosity?
increases blood viscosity
What does increasing velocity have on blood viscosity?
decreases blood viscosity
How does fibrinogen decrease blood viscosity?
makes RBC’s more flexible
Considering vascular function as central venous pressure increases, what happens to venous return?
decreases
Considering vascular function as central venous pressure decreases, what happens to venous return?
increases
Considering vascular function as central venous pressure increases, what happens to cardiac function?
increases
What is the term for when central venous pressure and venous return meet on the graph?
mean circulatory filling pressure
What is the mean circulatory filling pressure equal to?
max central venous pressure
The chronic use of anti-inflammatory drugs could be expected to inhibit what process?
angiogenesis
Consider following data:
avg. capillary hydrostatic P=17mmHg
avg. capillary colloid osmotic P=28mmHg
avg. interstitial hydrostatic P=-2mmHg
avg. interstitial colloid osmotic P=9mmHg
filtration=reabsorption because 19mmHg=19mmHg
Which brainstem area is tonically active and is associated with tonic SNS outflow?
neurons anterolateral in the upper medulla and pons
Which brainstem area is associated as the depressor center?
neurons anterolater in the lower medulla
What substance is associated with local vasodilation?
adenosine, NO, CO, etc…
What high resistance microvessels control local blood flow by intergrating multiple input which determine lumen diameter?
arterioles
What is the equation for distensibility and what determines the distensibility of a vessel?
D=^V/^PxV
the vessel with the bigger distensibility number is more distensible than the other
What is the equation for compliance of a vessel and how is compliance determined?
C=^V/^P
bigger compliance number is more compliant than the other vessel
What may act at the level of the CNS in the development of hypotension?
nitric oxide
In the kidney, how does SNS stimulation, increase angiotensin formation?
by stimulation of the JG cells to release renin
What does the release of renin lead to?
formation and release of Angiotensin I which then forms Angiotensin II
What does angiotensin II release?
aldosterone
In response to a fall in systemic arterial blood pressure, what changes would offset the fall?
increase in SNS stimulation, increase in renin release, decrease in ANP release, increase in vasopressin, increase in aldosterone and ADH
In the face of rising arterial blood pressure, what responses would autoregulate both renal blood flow and glomerular filtration?
constriction of afferent arterioles
In a response to a fall in systemic arterial blood pressure, what responses would autoregulate renal blood flow and increase glomerular filtration?
constriction of the efferent arterioles
What effect does stimulation of baroreceptors have on sympathetic outflow?
decreases/inhibits
During systole, what happens to baroreceptor activity?
increases and causes sympathetic activity to drop off
In the fetus, the ductus arteriosis shunts blood from the pulmonary artery to the aorta returning primarily to what vessel?
superior vena cava
In the fetus, the foramen ovale shunts blood to what vessel?
inferior vena cava
What is the function of the ductus venosus in the fetus?
shunt blood from the umbilical vein into the inferior vena cava bypassing the liver
In what tissue beds does sympathetic nervous system stimulation cause a metabolically induced local increase in blood flow?
heart
During exercise, what will normally decrease?
VO2 and TPR
During exercise, what will normally increase?
heart rate, active muscle blood flow, diastolic blood pressure
During exercise most of the increase in cardiac output is due to what?
increase in heart rate
With chronic exercise, improvement in cardiac output is due to what?
increase in stroke volume
