Exam 2 Flashcards
What does Reynolds number indicate
Probability of turbulent flow
The higher the Reynolds number, the higher the…
probability of turbulent flow
If R (reynolds #) is < 2000 = ….
Laminar Flow
If R (reynolds #) is > 3000 = ….
Turbulent flow
What is the function of Capillaries
Allow diffusion of interstitial fluid with blood-exchange of hormones, electrolytes, nutrients, etc
What are arterioles? Function?
Small ends of arteries- can contract or dilate controlling blood flow to capillaries
True or false; ultrasound can be used to determine blood flow
true (doppler frequency)
Using doppler frequency to determine blood flow; what would a broad frequency indicate? What about a narrow one?
Broad = Turbulent flow Narrow = Laminar flow
True or false; the Fick test is a test of cardiac output
true
True or false; an indicator dilution is a test of cardiac output
true
What is distensibility
Ability of a vessel to stretch
How does compliance differ from distensibility
Compliance is ability for a vessel to stretch AND hold volume
In arteries; a small change in volume has what effect on pressure
Large change in pressure
In veins; large change in volume has what effect on pressure
small change in pressure
True or false; arteries are 24x more compliant than veins
false; Veins are 24x more compliant than Arteries
True or false; control in blood flow changes via metabolic demand
true
What controls short term change in blood flow to an area
Arterioles and pre-capillary sphincters vasoconstrict or vasodilate
What controls long term change in blood flow to an area
Change in vascularity via Angiogenesis
What is Angiogenesis?
Forming of new blood vessels via old ones
True or false; growth factors and angiogenin are associated with angiogenesis
true
Systemic arteries are designed to do what?
Carry blood under high pressure out to tissue beds
Arterioles and pre-capillary sphincters act as what?
Control valves to regulate local blood flow
What collects blood from capillaries
venules
What returns blood to heart/has dynamic storage capacity
veins
True or false; cardiac output is controlled by local tissue flow
true
Is arterial pressure independent of local blood flow and cardiac output?
Yes, it is
What are the 4 parts of any blood vessel
Endothelium
Elastic tissue
Smooth muscle
Fibrous tissue
A typical artery is mostly composed of what?
Smooth muscle (followed by elastic and then fibrous)
Capillaries are composed solely of what?
Endothelium
The aorta is mostly composed of what?
Elastic tissue (followed by fibrous and then smooth muscle)
True or false; veins are composed equally of elastic tissue, smooth muscle, and fibrous tissue
true
True or false; at any given flow, velocity is inversely proportional to the total cross sectional area
true
What is flow directly proportional to? What is it inversely proportional to
Proportional to change in Pressure
Inversely to Resistance
What is the driving force of blood flow
Pressure gradient
True or false; pressure gradient is proportional to flow
true
True or false; systemic circulation is predominately a parallel circuit
true
Independence of local flow control
Minimize total peripheral resistance (TPR)
and Oxygen rich blood supply to every tissue are all advantages to what?
A parallel circuit blood blood flow
True or false; water is the standard of viscosity (1)
true
True or false; blood is more viscous than plasma
true (blood = 3 and plasma = 1.5)
True or false; velocity decreases when viscosity increases
true
What increases flexibility to RBCs
fibrinogen
Fibrinogen does what?
Increases flexibility of RBC
What is the normal range of Hemocrit
38-45%
What clinical consideration is associated with Hemocrit below 38%
Anemia
What kind of blood flow is streamline, silent, most efficient, and normal
laminar
What kind of blood flow is cross mixing, has vibrational noise, not efficient
Turbulent
Fick principal and Indicator dilutions (dye) are measurements of?
Cardiac output
Doppler ultrasonic flowmeter, vascular flow cufs, and Venous occlusion plesthymography are all measurements of what?
Vessel flow
True or false; veins are 8x more distensible
true
True or false; arterioles are richly innervated by SNS vasoconstrictor fibers (alpha receptors)
true
What is the locate vasodilator theory
active tissues release local vasodilators which relax smooth muscle
Adenosine, CO2, histamine, K+, H+, NO and CO are all examples of what in regards to circulation
vasodilators
True or false; most tissues show some degree of auto regulation of blood flow
true
Long changes in blood flow promote changes in tissue vascularity. When there is increased blood flow to an area for extended periods of time what does endothelium up-regulate?
expression of monocyte chemoattractant protein-1 (MCP-1)
This along with adhesion molecules and growth factors cause angiogensis
What are the 3 types of neovascularization
Vasculogenesis (Mesenchymal cell differentiate into endothelial cells)
Angiogenesis (Formation of new blood vessels by sprouting from existing small vessels)
Arteriogenesis (rapid proliferation of pre-existing collateral vessels)
What is vasculogenesis
Mesenchymal cell differentiate into endothelial cells
What is arteriogenesis? How does it differ from Angiogenesis
Rapid proliferation of preexisting collateral vessels
Arteriogenesis is more rapid and from collateral vessels instead of sprouting from small vessels)
What are the 3 angiogenic triggers?
Mechanical (hemodynamic, shear stress)
Chemical (hypoxia, nitric oxide)
Molecular (Inflammation, decrease in glucose, or angiogenic growth factors (VEGF, PLGF, Angiopoietin)
True or false; angiogenesis can be used therapeutically
true, through protein therapy, gene therapy, or cellular therapy
True or false; healthy endothelium (which is in all blood vessels) can release prostacyclin (PGI2), NO, and endothelin
true
Prostacyclin inhibits platelet aggregation
NO is a vasodilator
Endothelin constricts smooth muscle when endothelium is damaged
What is the functional unit of circulation
capillary
True of false; diffusion, ultrafiltration, and vesicular transport are all mechanisms of exchange in capillaries
true
True or false; functional flow is also called nutritive flow
true
What is functional or nutritive flow associated with
increased oxygen uptake/utilization
Non-fucntional or non-nutritive flow is called such because..
no O2 uptake is exchanged
Which kind of capillary exchange is associated with starling forces (hydrostatic pressure, colloid osmotic pressure)
ultrafiltration
What does hydrostatic pressure gradient (high to low) favor? What about Colloid osmotic pressure (low to high)?
Hydrostatic - favors filtration
Colloid - favors reabsorbtion
What is the function of the protein concentration?
Colloid osmotic pressure (Albumin 75%, Globulins 25%, fibrinogen <1%)
What is associated with the Donnan Effect?
Colloid osmotic pressure
What is the Donnan effect
Describes the discrepancy between what colloid osmotic pressure should be and what is read. Has to do with plasma proteins attracting + ions
True or false; capillary walls are all alike from each other
false; they are very different (tight junctions in BBB, discontinuous in liver, fenestrations in kidneys)
What is the reflection coefficient? What would RC of 0 mean? What about RC of 1?
Reflection coefficient expresses how readily protein can cross capillary walls
RC=0 means all colloid proteins an freely cross walls (no colloid effect)
RC=1 no colloid proteins can cross walls (full colloid effect)
What drains excess fluid from interstitial spaces
Lymph capillaries
True or false; no lymphatic vessels are found in superficial portions of skin, CNS, endomysium of muscle or bones
true
What does the thoracic duct drain? What about right duct?
Right duct- right side of head, right arm, right neck and part of chest
Thoracic- everything else
2/3 of all lymph come from where?
liver and intestines
True or false; any factor that increases filtration and or decreases reabsorption will increase lymph formation
true
How many mL per hour does the thoracic duct drain? How about right duct?
Thoracic = 100 mL/hr
Right= 20 mL/hr
Total lymph = 120 mL/hr
True or false; everyday a volume of lymph equal to 1/2 of your entire plasma volume is filtered
false it is equal to the amount of plasma
What are the functions of the lymphatic system
Return lost protein to vascular system
Drain excess plasma from ISF
Carry absorbed substances/nutrients
Filter lymph from nodes
True or false; arterial BP is created by the interaction of blood with vascular walls
true
During systole are arteries distended? Is BP peaking or falling?
yes they are (systole is contraction)
and peaking
During diastole what are arteries doing? is BP peaking or falling?
arteries are recoiling (diastole is filling)
BP is falling
What is hydraulic filtering?
Stretch (systole) and recoil (diastole) of the arterial tree that normally occurs during cardiac cycle
This saves heart work
As we age artery distensibility decreases, what does this do for hydraulic filtering
it makes it less efficient causing more work on the heart
True or false; systolic BP is at maximum pressure in systemic arteries
true; pressure peaks as blood is ejected from LV into aorta
The minimum BP in the systemic arteries occurs when?
Diastolic BP
What are two factors that contribute to how far the pressure will fall during diastolic BP
Cycle length and Total peripheral resistance (TPR)
True or false; the mean arterial pressure (MAP) is a arithmetical mean between systole and diastole
false; MAP = 1/3 pulse pressure + Diastolic BP (approximation)
Most post-ganglionic SNS terminals release what? What is the predominate receptor for this hormone? What is the response of smooth muscle?
Norepinephrine
Alpha receptors
Smooth muscle constricts (constriction of arterioles reduces blood flow increasing BP, constriction of arteries raise BP, and constriction of veins increases venous return)
SNS stimulation increases vasoconstriction and thus decreasing blood flow while increasing BP every where in the body except where?
Brian (arterioles weakly innervated with SNS)
Lungs (arterioles weakly innervated with SNS)
and Heart (SNS causes release of local vasodilators (adenosine))
True or false; there is a critical arterial pressure in which if falls below arterioles will close completely (bad news bears)
true
True or false; if cardiac output stops, arterial pressure will fall and venous pressure will rise
true
In most tissue beds, blow flow is regulated in proportion to what?
Local metabolism
Consider the resistance in the following tissue beds: Coronary = .40 mmHg/ml/min brain = .13 liver = .08 Kidneys = .10
What is the total peripheral resistance? (TPR)
Which organ will have the greatest flow?
In the following vessels the flow rate is identical, which vessel is offering the greatest resistance to flow?
(A) P1= 50 P2=25
(B) P1=70 P2 = 60
(C) P1=80 P2 = 65
(A) has the greatest change (delta 25)
A broad band doppler reading is indicative of what type of flow? What about narrow?
Broad: turbulent
Narrow: Laminar
What is the equation to find Flow?
F = V x A (Flow = velocity x area)
The vascular compartment with the greatest total cross sectional area is what?
Capillaries
What vascular compartment has the greatest resistance to flow?
arterioles
True or false; maximizing total peripheral resistance is characteristic of a parallel circuit
false (changing maximize to minimize would make it true)
A small change in volume producing a large change in pressure is 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 NO release
What is the effect of SNS on most vascular smooth muscle?
vasoconstriction mediated by alpha receptors
True or false; beta receptors are associated with vasodilation
true
True or false; during widespread SNS tissue beds in the lungs would show a great increase in vascular resistance
false; same is true of brain and heart
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
Equilibrium pressure - arteriole pressure=venous pressure
If cardiac output is stopped, arterial pressure will be expected to fall until it equals what?
critical closing pressure
True or false; mean circulatory pressure is associated with shunts
true
In a healthy young adult what can be said about tissue flow during diastole
maintained by recoil of the arteries (this diminishes as we age)
If you see a patient who’s flow has doubled but their O2 uptake has fallen by half what would you be expect?
Due to shunting
A functional increase in flow and O2 uptake is associated with what?
release of local vasodilators
What increases the plasma colloid osmotic effect by about 50%
Negative changes on protein attracting and holding positive ions like sodium (Na+)
What effect does decreasing velocity have on blood viscosity
increases
How does fibrinogen decrease blood viscosity
Makes RBC’s more flexible
The chronic use of anti-inflammatory drugs could be expected to inhibit what?
angiogesis (occurs in inflammation)
Which brainstem area is tonically active and is associated with a tonic SNS outflow?
neurons anterolateral in the upper medulla and pons
What part of the brain reflects projection of baro and chemoreceptos
Neurons associated with the nucleus tracts solitarius
What are neurons anterolateral in the lower medulla associated with
depressor
What substance is associated with local vasodilation
adenosine
What high resistance micro vessels control local blood flow by integrating multiple input which determine lumen diameter?
arterioles
What may act at the level of the CNS in the development hypotension
NO
True or false; adenosine is an example of a local vasodilatory
true
In the kidney, how does SNS stimulation, increase angiotensin formation?
by stimulation of JG cells to release renin (enzyme that up regulates angiotensin)
In response to a fall in systemic arterial BP, what changes would be counterproductive in offsetting that fall?
increase in ANP release (promotes water and Na loss which would further lower pressure - want this to increase with rise in pressure)
In the face of rising arterial BP, which of the following responses would auto regulate both renal blood flow and glomerular filtration
constriction of the afferent arterioles
What effect does stimulation of baroreceptors, have on sympathetic outflow
decreases
During systole, what is happening to baroreceptor activity
increasing
In the fetus, the ductus arteriosis shunts blood from the pulmonary artery to the aorta returning primarily from what vessel
superior vena cava
True or false; the inferior vena cava bypasses by foramen ovale in fetus
true
What is the function of the ductus venous in the fetus
shunt blood from the umbilical vein into the inferior vena cava (also portal vein)
True or false; in fetus the umbilical vein has the highest O2 content
true
True or false; when the heart receives SNS it causes metabolically induced local increase in blood flow
true
During exercise, does VO2 and TPR go up or down? What about diastolic BP?
VO2 and TPR go up
Diastolic BP could go up, down or stay the same
During exercise, most of the increase in cardiac output is due to what?
increase in heart rate
True or false; as central venous pressure increases cardiac output increases
true
Where is the vasomotor pressor center in the brain
anterolateral portions of upper medulla (NOE projections to IML horn)
Vasoconstrictor
Where is the vasomotor depressor center in the brain
anterolateral lower medulla
vasodilation
Where is the vasomotor sensory area in the brain (baroreceptors)
Posterolateral portions of pons and medulla (nucleus solitarius)
Inhibits the pressure center, lowers BP
True or false; the cardioinhibitory area of the brain is located medial to the dorsal motor nucleus of vagus
true
Where does rapid short term control of BP come from? How about long term?
Short term- from CNS effecting vascular smooth muscle
Long term- from kidneys (renal fluid balance)
True or false; BP is accomplished by either affecting vascular tone or blood volume
true
Baroreceptors are spray type nerve endings especially abundant where? Do they vasodilate or vasoconstrict?
Especially abundant in Carotid sinus and aorta
vasodilatation
Where are low pressure baroreceptors located?
atrial walls and pulmonary arteries
True or false; stretch on atrial walls would signal low pressure baroreceptors- decreasing heart rate in increasing urine production
true
An increase in atrial pressure will cause what response in kidneys?
kidneys excrete excess ECF
In regards to the kidneys; what do afferent arterioles supply? What about efferent arterioles?
Afferent arterioles- supply glomerular capillaries where filtration takes place
Efferent arterioles- drain the glomerular capillaries and give rise to the peritubular capillaries where reabsorption takes place
Afferent = filtrAtion Efferent = rEabsorption
True or false; most auto regulation of both renal blood flow and glomerular filtration takes place at efferent arterioles
false; takes place at afferent (filtration)
What is the normal glomerular filtration rate? What about normal rate of renal blood flow
Filtration - 100 ml/min
renal - 1.25 L/min (25% cardiac output)
Describe how the afferent and efferent arterioles in the kidneys can effect renal blood flow and glomerular reabsorption
Stimulation and subsequent constriction of afferent arterioles will cause decrease in both renal blood flow and GFR
While stimulation and subsequent constriction of efferent arterioles will cause a decrease in renal blood flow but an increase in GFR by creating back pressure
True or false; kidneys can effect BP by excreting more fluid because when extracellular fluid levels rise, the arterial pressure rises as well
true
What hormones decrease renal blood flow?
NOE
Epinpephrine
Antiotensin II
What hormones increase renal blood flow?
prostaglandins (E & I)
Where is renin released from?
JG cells
What causes release of renin?
SNS decrease in NaCl delivery to macula dense hormone stimulation (thyroid, growth)
What enzyme catalyzes the formation of angiotensin I from angiotensin
renin
Where does the conversion of angiotensin 1 to angiotensin 2 take place
lungs
What are the functions of angiotensin 2
stimulate adrenal cortex (aldosterone)
stimulate kidneys
stimulate ADH/vasopressin release
If you were to tie off one renal artery what would happen?
development of hypertension but no uremia
If you were to tie off one renal a. and remove one kidney what would happen?
no development of hypertension or uremia
If you were to tie off both renal a. and remove both kidneys what would happen?
hypertension and uremia
Hypertension generated by tying off a renal a. is called what?
“goldblatt hypertensive model”
Resting oxygen saturation, decrease chemoreflex activation, decrease sympathetic activity are all benefits of what?
slow breathing
How can antioxidants helper keep BP low?
NO from the endothelium relaxes smooth muscle reducting BP
But free radicals can rapidly deactivate NO
So increasing antioxidants to take out free radicals can keep NO around
Vitamins ACE, melatonin, lycopene, selenium, glutathione, superoxide dismutase are all examples of what?
antioxidants
True or false; in fetus pulmonary blood flow is minimal
true; the placenta does the fetal gas exchange
Umbilical arteries that supply the placenta are branches off of what in the mother
anterior iliac a.
Blood from placenta reaches fetus via what/
umbilical v.
Which fetal shunts allow blood to bypass the lungs?
ductus arteriosis and foramen ovale
What fetal shunt allows umbilical and portal blood to bypass the liver
ductus venosus
What has the highest Oxygen concentration in fetal circulation
umbilical v.
True or false; upon birth the shunts foramen ovale, ductus arteriosis, and ductus venosus all shut
true
In the fetus what shunts most blood returning to the heart from the IVC to the left atrium
foramen ovale
In fetus, what shunts most blood returning to the heart from the superior vena cava to aorta
Ductus arteriosus
Patent ductus arteriosus
Ventricular septal defect
transposition of great vessels
and tetrology fallot are all examples of what?
Possible congenital defects of fetal cardiac system
Right Ventricular hypertrophy, large ventricular septal defect, and right ventricular outflow obstruction are signs of what?
Tetrology of fallot
causes Cyanosis (blue coloring of skin) and Dyspnea (breathing difficulty)
What is the greatest stress on the cardiovascular system and can increase cardiac output 5 to 6 fold?
exercise
True or false; during exercise TPR decreases because of vasodilation in active muscle
true
True or false; during exercise SNS causes increased venous return, decreased blood flow to organs, increased blood flow to skeletal muscle and increased smooth muscle tone to maintain higher BP
true
What tissues escape SNS vasoconstriction
Brain
Heart
Lungs
How does SNS during exercise increase venous return
constriction of veins (primarily occurs in lower extremity)
True or false; increased blood flow to active muscle is mediated by SNS during exercise
false; it is mediated by local release of local vasodilators
What is the average blood flow during rest in L/min? What about during exercise
Rest- 5.9 L/min
Exercise- 24L/min
What is VO2 max? What can it range from?
It is the maximum amount of oxygen that one can take up from the lungs to deliver to tissues
Ranges from 1.5L/min (sick patient) to 3.0 L/min (avg. joe) to 6.0 L/min (Billy bad ass)
When can O2 debt happen? What is extra O2 used for?
happens when energy demands cannot be met by oxidative phosphorylation
used to restore metabolite levels (creatine phosphate, ATP)
Metabolize lactate generated by glycolysis
