Hash hockey Flashcards
In most tissue beds, blood flow is regulated in proportion to what?
local metabolism (determined by local tissue flow)
What type of blood pressure is regulated independent of cardiac output and local flow?
arterial blood pressure
How do you determine what tissue bed has the greatest flow? Total peripheral resistance is at what value?
greatest flow = lowest resistance
TPR = .08 or less
What organ can have greater flow compared to cardiac output? (About 102%)
lungs
How do you determine what vessel would have the greatest resistance to flow?
great resistance to flow = greatest change in pressure
A BROAD band Doppler reading is indicative of what type of flow? Normal/abnormal?
broad = turbulent (generally abnormal)
A NARROW band Doppler reading is indicative of what type of flow? Normal/abnormal?
narrow = laminar (generally normal)
How do you determine the flow in a vessel?
flow = velocity x cross sectional area (CSA)
What vascular compartment has the greatest total cross sectional area?
capillaries
What vascular compartment has the single largest total area?
aorta
What are 3 important characteristics of parallel circuitry? How is total peripheral resistance affected?
- independent of local flow control
- maximized oxygen delivery to tissues
- decreases work load on the heart
- MINIMIZES total peripheral resistance
A SMALL change in volume producing a LARGE change in pressure is characters of what 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 (on healthy endothelium)
Release of what substance on endothelium inhibits platelet aggregation and relaxes smooth muscle?
prostacyclin (PGI2)
Release of what substance on endothelium constrict smooth muscle and may contribute to vasoconstriction when endothelium is damaged by hypertension?
endothelin
What is the effect of sympathetic nervous stimulation on most vascular smooth muscle?
vasoconstriction mediated by ALPHA receptors
During widespread sympathetic nervous system stimulation, which tissue bed would show the least increase in vascular resistance?
lung
What are the 3 exceptions to widespread vasoconstriction causing decreased blood flow due to SNS stimulation?
heart, brain, lungs
As a tissue becomes more active, how is blood flow to that tissue increased?
tissue releases local vasodilators
At a given mean circulatory filling pressure what happens to venous return as central venous pressure increases?
decreases
If cardiac output is stopped, arterial pressure will be expected to fall until it equals what?
critical closing pressure
If cardiac output is stopped WITH A SHUNT, arterial pressure will be expected to fall until it equals what?
mean circulatory filling pressure
In a healthy young adult comment about tissue flow during diastole and systole…
diastole = maintained by recoil of the arteries systole = arteries stretch
If blood flow to a tissue doubles from 200 ml/min to 400 ml/min, and the AV-O2 difference falls from .05 ml O2/ml to .025 ml O2/ml. Comment on the increase in flow…what is it caused by?
it is likely due to shunting
If blood flow to a tissue doubles, and the AV-02 stays the same. Comment on the change…what is it caused by?
it is a functional increase in flow, due to an increase in tissue metabolism
What increases the plasma colloid osmotic effect by about 50%?
negative charges on protein attracting/holding positive ions like sodium (Donnan Effect)
What is the plasma colloid osmotic effect?
function of protein concentration
What are 4 important factors that attribute to slow breathing (6 breaths/minute)?
- increased resting oxygen saturation
- DECREASED sympathetic activity
- decreased chemoreflex activation
- decreased mean arterial blood pressure
What effect does decreasing velocity have on blood viscosity?
increases
- slower = thicker
- faster = thinner
How does fibrinogen decrease blood viscosity?
makes RBC’s more flexible
How do you determine the mean circulatory filling pressure?
mean circulatory filling pressure = where venous return is 0
The chronic use of antiinflammatory drugs could be expected to inhibit what processes?
angiogenesis (inflammatory response)
How do you determine filtration (hydrostatic) and reabsorption (osmotic) ratio?
filtration = (capillary hydrostatic P - interstitial hydrostatic P) reabsorption = (capillary colloid osmotic P - interstitial colloid osmotic P)
Which brainstem area is tonically active and is associated with a tonic SNS outflow? (also associated with vasoconstriction and stimulates cardiac activity)
neurons anterolateral in the upper medulla and pons (pressor center)
Which brainstem area is associated with vasodilation and decreased cardiac activity? Which brainstem area is associated with sensory information?
decreased cardiac activity = neurons anterolateral in the lower medulla (depressor center)
- posterolateral of pons/medulla = sensory
What substances are associated with local vasodilatation?
adenosine, CO2, NO, histamine, K+ ions, H- ions
What substances are associated with local vasoconstriction and decreasing of renal blood flow?
norepinephrine, angiotensin II, ADH
What high resistance microvessels control local blood flow by intergrating multiple input which determine lumen diameter?
arterioles
How do you determine distensibility? How do you determine compliance value?
D = (change in volume/change in pressure x original volume) C = change in volume/change in pressure
What substances may act at the level of the CNS in the development of hypotension?
nitric oxide and serotonin (vasodilators)
What substances may act at the level of the CNS in the development of hypertension?
ACH, norepinephrine (vasoconstrictors)
In the kidney, how does SNS stimulation, increase angiotensin formation?
by stimulation of the JG cells to release renin
In response to a fall in systemic arterial blood pressure, what changes would be counterproductive (not helpful) in offsetting that fall?
increase in ANP release (increase would not help)
In response to a fall in systemic arterial blood pressure, what changes would be productive (helpful) in offsetting that fall?
- increase in SNS stimulation
- increase in renin release
- increase in vasopressin release
In the face of rising arterial blood pressure, what response would autoregulate both renal blood flow and glomerular filtration?
constriction of the afferent arterioles
What effect does stimulation of baroreceptors, have on sympathetic outflow?
decreases (negative feedback response)
During systole, what is happening to baroreceptor activity?
increases (decreasing SNS activity)
During diastole (low pressure), what happens to heart rate, urine production, and secretion of ADH?
- decrease HR
- increase urine production
- decrease secretion of ADH
In the fetus, the ductus arteriosis shunts blood from the pulmonary artery to the aorta returning primarily from what vessel?
ductus arteriosis = superior vena cava
In the fetus, the foramen ovale shunts blood from the pulmonary artery to the aorta returning primarily from what vessel
foramen ovale = inferior vena cava
In fetal shunts, what 2 structures allow blood to bypass the lungs? Liver?
lungs = ductus arteriosis and foramen ovale liver = ductus venosus
What is the function of the ductus venosus in the fetus?
shunt blood from the umbilical vein into the inferior vena cava
In which of the following tissue beds does sympathetic nervous system stimulation cause a metabolically induced local increase in blood flow?
heart
In which of the following tissue beds does sympathetic nervous system stimulation cause a metabolically induced local DECREASE/constriction in blood flow?
- active skeletal muscle
- GI tract
- brain
During exercise, which of the following normally decreases? Increases?
decrease = VO2 (and TPR) increase = heart rate, active muscle blood flow, diastolic blood pressure
During exercise most of the increase in cardiac output is due to which of the following?
increase in heart rate
Exercise training can have what effect on stroke volume?
increase SV
After exercise, oxygen debt is repayed to the muscles through what 3 systems?
- phosphocreatine system (8-10 sec)
- glycogen-lactic acid system (1.5 mins)
- aerobic system (unlimited w/ O2 and nutrition)
