195 terms

Kin 603 - Exam 2 Study Guide

Quiz 3 &4 (1-20) Chapter 4 Notes (21-92) Chapter 5 Notes (93-175) Mini-Exam 2 (176-195)
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Assuming a constant SAP, vasoconstriction will result in a (n):
A. Decrease in venous blood volume.
B. Increase in venous blood volume.
C. No change in venous blood volume.
D. Increase in arterial blood volume.
E. No change in arterial blood volume.
A. Decrease in venous blood volume.
T/F? The performance of the heart is largely determined by the distribution of CO between compliant and non-compliant vascular beds.
True
The vascular function curve plots CVP as a function of flow (CO). This curve demonstrates that an increase in CO results in a decrease in CVP. This statement is ____ because ____.
A. False; an increase in CO causes an increase in CVP as shown by the cardiac function curve.
B. False; there is no relationship between CO and CVP.
C. True; an increase in CO causes redistribution of blood volume to the peripheral circulation which means CVP must decrease.
D. True; an increase in CO results in a decrease in CVP due to the decrease in diastolic filling time.
E. None of the above.
C. True; an increase in CO causes redistribution of blood volume to the peripheral circulation which means CVP must decrease.
Which of the following is/are true regarding the venules?
A. They are the most compliant portion of the circulation and contain a large fraction of total blood volume.
B. They contain a high density of innervation from the sympathetic nervous system.
C. They are the site of the lowest resistance on the venous side of the circulation.
D. All of the above are true.
E. Only "a" and "c" are true.
A. They are the most compliant portion of the circulation and contain a large fraction of total blood volume.
T/F? The cardiac function curve plots flow (CO) as a function of venous pressure (CVP). This curve demonstrates that an increase in CVP results in an increase in CO and is another way of expressing the Frank-Starling relationship.
True
T/F? The walls of the veins contain no smooth muscle.
False; venous walls are lined with smooth muscle
T/F? The four primary determinants of CO are HR, myocardial contractility, preload, and afterload.
True
T/F? Veins are not innervated by the sympathetic nervous system.
False; veins are innervated by SNA
Which of the following statements regarding the venous circulation is/are true?
A. It is more compliant than the arterial circulation.
B. The most compliant portion of the circulation is the venules.
C. Veins comprise the majority (~70%) of the vasculature and a large portion of the total blood volume.
D. All of the above are true statements.
E. Only "b" and "c" are true statements.
D. All of the above are true statements.
T/F? A passive change in venous volume occurs in response to a change in resistance on the arterial side of the circulation.
True
T/F? Cardiac and peripheral vascular factors contribute equally to the maintenance of SAP during upright posture.
False; peripheral vascular factors, rather than cardiac mechanisms, appear to be crucial to maintaining SAP during upright posture
Prolonged periods of upright posture can result in a decrease in CO, SAP, and CVP. A decrease in CVP can ultimately lead to a decrease in cerebral blood flow and cerebral blood pressure. Reductions in cerebral blood flow and pressure can result in ____?
A. Stroke
B. Cerebral ischemia
C. Hemorrhage
D. Deafness
E. A great Saturday night
B. Cerebral ischemia
T/F? The hydrostatic indifference point is a point in the vasculature where pressure is independent of posture. That is, it is the point where pressure does not change even if there is a change in the hydrostatic component of arterial pressure.
True
T/F? Based on the shape of the venous volume-pressure curve, pooling of blood in the dependent limbs is minimized during upright posture due to the decrease in compliance at high transmural pressures.
True
T/F? During upright posture, decreases in central venous pressure (cardiac filling pressure) occur before any changes in mean arterial pressure.
True
Which of the following is NOT one of the major problems associated with upright posture?
A. Having a heart a considerable distance above the feet.
B. Having a large proportion of the total blood volume below the level of the heart.
C. Having to return blood to the heart against gravity.
D. Having a large proportion of total blood volume in compliant veins.
E. All of the above are problems associated with upright posture.
E. All of the above are problems associated with upright posture.
T/F? The muscle pump can generate just as much pressure as the left ventricle.
True
T/F? The muscle pump can only increase CVP if there are working, or competent, venous valves.
True
During periods of passive upright posture, MAP is regulated primarily by:
A. Cardiac mechanisms (increases in CO and HR)
B. Peripheral vascular mechanisms (vasoconstriction)
C. Both cardiac and peripheral vascular mechanisms
D. None of the above
B. Peripheral vascular mechanisms (vasoconstriction)
During the early stages of upright posture (or simulated upright posture with lower body suction):
A. There is an almost immediate decrease in MAP
B. There is an immediate decrease in PP but no change in MAP
C. There is a decrease in CVP and CO but no change in MAP
D. None of the above
C. There is a decrease in CVP and CO but no change in MAP
What is a determinant of SAP?
CO (or Q) is a determinant of SAP
What is the regulated variable of the cardiovascular system?
SAP is the regulated variable of the cardiovascular system
What are the cardiac factors (2) that control cardiac output?
Heart rate
Myocardial contractility
What are the coupling factors (2) that control cardiac output?
Preload
Afterload
The ____ function curve depicts the dependence of CO on CVP, while the ____ function curve depicts the dependence of CVP on CO.
The cardiac function curve depicts the dependence of CO on CVP.
The vascular function curve depicts the dependence of CVP on CO.
The vascular function curve is dependent/independent of the Frank‐Starling relationship.
Independent
What is the dependent variable (response; y-axis) and independent variable (stimulus; x‐axis) of the vascular function curve?
CVP = dependent variable (response; y-axis)
CO = independent variable (stimulus; x‐axis)
Vascular Function Curve: Relationship is completely independent of the ____ and instead depends primarily on characteristics of ____.
Independent of the heart
Characteristics of peripheral vasculature
What are the characteristics (3) of the peripheral vasculature that the vascular function curve is dependent upon?
TPR, vascular (arterial and venous) compliances, and blood volume
Veins are ~____x more compliant than arteries.
~20x
Vascular Function Curve: The inverse relationship of CVP & CO shows what when CO is suddenly decreased?
Blood flow from arteries to veins is temporarily greater than rate the heart pumps blood from veins to arteries
T/F? Since cardiovascular system is a closed loop, CO and venous return must be equal under steady state conditions.
True
CO depends primarily on what variable?
RAP or CVP (Starling law of the heart)
What is the dependent variable (response; y-axis) and independent variable (stimulus; x‐axis) of the cardiac function curve?
CO = dependent variable (response; y-axis)
CVP = independent variable (stimulus; x‐axis)
The cardiac function curve shows that an increase in CVP, or RAP, results in a(n) ____ in CO.
Increase
If you plot both the vascular and cardiac function curves on the same graph, a demonstration of the interaction between ____ and ____ is shown.
Interaction between heart & vasculature
Equilibrium point is defined as what?
The intersection of cardiac & vascular function curves
Coordinates of the equilibrium point define what kind of values for CO and CVP?
"Normal" prevailing (operating) values for CO and CVP
SNA increases contractility & shifts the vascular function curve in what direction?
Up and to the left
SNA results in a ____ CO at a ____ level of CVP (reduced ESV)
Greater CO at lower level of CVP
Changes in ____ alter both cardiac & vascular function curves.
TPR
Increased TPR produces what change in the vascular function curve and the cardiac function curve?
Vascular function curve shifted down but has same CVP intercept
Cardiac function curve shifted down & right
T/F? Increased TPR decreases afterload so there is less CO for any given CVP.
False; increased TPR increases afterload so there is less CO for any given CVP.
If the vascular function curve shifts more than the cardiac function curve due to changes in TPR, the equilibrium point will have what location relative to the control point?
Below and to the left of the control point
Most of the blood in the body is on the ____ side of the circuit (~____%)
Venous side of the circuit (~25%)
Veins and venules are ____ compliant than arteries and arterioles.
More compliant
____ are most compliant portion of the circulation.
Venules
At normal transmural (distending) pressures, veins are ____ in diameter than arteries.
Larger in diameter
Veins comprise ~____% of total vasculature.
~70% of total vasculature
Venous walls are lined with what type of muscle?
Smooth muscle
Is there more/less smooth muscle lining venous walls than arteries.
Less smooth muscle than arteries
Blood flows from arteries to veins because of what?
Pressure gradient
Pressure gradients change with changes in what?
Blood flow
Veins experience constant/variable pressure profiles.
Variable
Passive changes in venous volume include what (4)?
Volume mobilization
Shift from P2 to P1 due to constriction of arterioles
Elastic recoil of venous walls
Single V-P curve
Active changes in venous volume include what (4)?
Decrease V, constant P1
Shift in V‐P curve
Decrease compliance at P1
"Stiffer" veins at P1 with SNA
The magnitude of the passive effects of the change in venous volume depends on what?
Operating point of V‐P curve
Passive effects on venous volume occur in response to what?
Resistance changes on arterial side of the circulation
Resistance changes on the arterial side of the circulation affects what (2)?
Compliance and operating point of V-P curve
Flow‐dependent venous pressure and volume is determined by what factors (3)?
Blood volume is fixed/constant
Increased CO
Constant vascular resistance
A higher flow increases/decreases the pressure drop across veins, which raises/lowers CVP.
A higher flow increases the pressure drop across veins, which lowers CVP
Increased arterial pressure slightly increases/decreases arterial volume which further increases/decreases CVP.
Increased arterial pressure slightly increases arterial volume which further decreases CVP.
Dilation of resistance vessels has what effect on the pressure drop across them (resistance vessels)?
Reduces pressure drop
Dilation of resistance vessels leads to an ____ in arteriolar, capillary, and venular pressures/volumes.
Increase arteriolar, capillary, venular pressure & volume
Dilation of resistance vessels has what effect on the pressure drop across compliant veins? Blood volume is shifted into the ____ away from the ____.
Steepens pressure drop across compliant veins
Shifts volume into peripheral veins away from central veins
T/F? Veins offer infinite resistance to flow.
False; veins offer finite resistance to flow.
The pressure gradient across veins increases/decreases in proportion to blood flow.
Increases in proportion to blood flow.
T/F? Each segment of the venous system has its own resistance & compliance.
True
The pressure gradient from arterioles across veins determines what (2)?
Passive effects of blood flow on venous volume
Volume of blood available for ventricular filling
Performance of the heart is determined primarily by what?
Peripheral circulation
Increased CO results in active redistribution of CO via what?
SNA
T/F? Distribution of blood flow determines the distribution of blood volume.
True
Blood volume available to the heart is a function of what?
Distribution of blood volume in the peripheral circulation
Redistribution of constant CO alters the distribution of blood volume between what organ types (2)?
Compliant and noncompliant organs
What type of organ has a low compliance?
Skeletal muscle
What type of organ has a high compliance?
Splanchnic
Are veins innervated?
Yes
Veins are innervated by what fibers?
Only by sympathetic -adrenergic fibers
Does the responsiveness of veins to SNA vary from region to region?
Yes
What types of veins are highly reactive to SNA (2)?
Mesenteric and superficial (cutaneous) veins
In general, ____ veins are unresponsive to SNA (except ____).
Deep veins are unresponsive (except mesenteric)
Veins of skeletal muscle contain how much sympathetic innervation?
Very little
Small venules, which are the ____ compliant and contain ____ fraction of total blood volume (~____%) contain ____ innervation
Small venules, which are the most compliant and contain major fraction of total blood volume (~25%) contain very little innervation
What is the problem of venous resistance?
If venoconstriction raises resistance, the beneficial effect on CVP is opposed.
The venous system comprises ____% of the total vasculature and ___% of the total blood volume is located in the venules.
The venous system comprises 70% of the total vasculature and 25% of the total blood volume is located in the venules.
T/F? Veins are not highly compliant and have associated resistances, pressures, and volumes.
False; veins are highly compliant and have associated resistances, pressures, and volumes
Are veins flow‐dependent?
Yes
T/F? Veins can passively and actively move blood and influence CVP.
True
Venous volume mobilization is due to what?
Elastic recoil
Venoconstriction is due to what?
Sympathetic innervation
CVP is also highly influenced by the distribution of CO between ____ and ____ vascular beds.
Compliant and noncompliant vascular beds
Man's greatest problem with the venous system occurs in what type of posture and during what kind of stress?
Upright posture and during heat stress
The heart is ~____ meters above the feet.
~1.2-1.5 meters
~75% of blood volume is in what?
Compliant veins
~____% of total blood volume is below the level of the heart and must be driven back to the ____.
~70-75%
Right atrium
____ characterized by a fall in CVP, decreased CO, and, if severe enough a fall in SAP accompanied by dizziness, lightheadedness, nausea, etc.
Orthostatic intolerance
Mean pressure generated by the heart is ~____ mmHg.
~100 mmHg
The zero pressure reference level is located at the level of what? (Pressure is 0 with respect to atmospheric pressure)
At level of RA (Venostatic level)
What is the term for the point in the vasculature where pressure is independent of posture & represents "center of gravity" for the vascular system.
Hydrostatic Indifference Point (HIP)
What is HIP determined by (2)?
Determined by distribution of compliances in upper & lower body
What results from a reduction in compliance or reduction "pooling" in dependent limbs (2)?
Cranial shift of HIP & restrict fall in CVP
T/F? Only a small increase in blood volume is required to shift the hydrostatic indifference point (HIP).
False; requires large increase in blood volume to shift HIP
What are the two major problems associated with upright posture in humans?
1) Most of the blood volume is below "venostatic level" in distensible/compliant vessels rather than stiff vessels.
2) Blood volume is too small to fill the entire vascular container in upright posture.
If veins were as noncompliant as arteries, what would happen to the hydrostatic effect of upright posture?
It would be minimal
What are the two features or characteristics inherent to the veins themselves that can minimize the pooling of blood in the veins of the dependent limbs to minimize the fall in CVP?
1) Shape of the venous volume-pressure (compliance) curve
2) Venous valves
What portion of the venous compliance curve is the primary reason for orthostatic intolerance?
Steep or compliant portion is primary reason for orthostatic intolerance
T/F? Veins are relatively stiff at high pressures.
True
Without what portion of the venous compliance curve would upright posture be impossible?
Stiff portion
Blood pooling is limited at highest/lowest transmural pressures.
Highest
What portion of the venous compliance curve do humans operate on in supine posture? What does this portion allow for?
*Humans operate on steep portion in supine posture
*Steep portion also allows for adjustments to hemorrhage
Venous Compliance Curve: Large volume can be removed with only a small decrease in what?
Distending pressure
At onset of upright posture, the hydrostatic column of blood from the veins in feet to the heart, is broken up by a series of what?
Venous valves
Over time, blood flows from arteries into dependent veins causing what to happen? What does this create?
*Venous valves are forced open
*Creates uninterrupted hydrostatic column between RA & feet
With all of the venous valves open, ~600 ml of blood is displaced away from the ____ to the ____.
Away from the central circulation to the dependent veins of legs
Patients with incompetent or congenitally absent venous valves suffer what?
Severe orthostatic intolerance
As soon as patients with a severe orthostatic intolerance stand, what happens (3)?
1) As soon as they stand there is an uninterrupted hydrostatic column (no time-dependent effect)
2) Abrupt pooling
3) Sudden loss of filling pressure results in inability to maintain CO and leads to immediate syncope (fainting)
The sudden loss of filling pressure that patients with a severe orthostatic intolerance experience when they stand, results in the inability to do what? What does this lead to?
*Sudden loss of filling pressure results in inability to maintain CO
*Leads to immediate syncope (fainting)
What are two ways in which a patient with a severe orthostatic intolerance is able to stand with ease? How is this possible?
*Can stand with ease in water up to the level of the diaphragm or with tight elastic stockings
*Fluid & stockings cancel the hydrostatic increase in transmural pressure below heart level
Totally passive upright posture ____ is a potentially lethal stress for humans
Head-up tilt (HUT)
During HUT, blood continues to pool due to what?
Blood continues to pool due to delayed compliance
During HUT, high capillary pressure results in what?
High capillary pressure results in net filtration
During HUT, the decline in ____ causes CO to fall below levels required to maintain arterial pressure, which leads to loss of consciousness & lethal effects of ____ if supine posture is not restored quickly.
Ventricular filling pressure
Cerebral ischemia
Combined with competent venous valves, what can also serve as an effective pump to drive blood back to the heart?
Skeletal muscles in the legs can serve as an effective pump to drive blood back to the heart
The muscle pump (skeletal muscle in the legs) can generate ~____ driving force.
~90 mmHg driving force
T/F? CVP & SV can be rapidly restored ONLY with very intense muscle contractions (muscle pump).
False; CVP & SV rapidly restored by only modest muscle contractions
Muscle tone in absence of movement can determine volume of blood displaced into legs in upright posture due to what?
Rhythmic changes in antigravity muscles
Intramuscular pressures are reduced due to what events (3)?
Prolonged bed rest
Surgery
Possibly following space flight
Respiratory Pump: breathing changes the ____ in the great veins of thoracic cavity.
The transmural pressure
Respiratory Pump: deepening of inspiration in upright posture lowers ____ & increases pressure gradient between ____ and ____.
Lowers intrathoracic pressure
Increases pressure gradient between RA and point where IVC enters thoracic cavity
Due to an acute change in blood volume distribution with the onset of orthostasis, ~ ____ of blood moves into the legs and ~____ moves into the veins of the pelvis and buttocks regions.
About 500-600 ml of blood moves into the legs and ~200-300 ml moves into veins of pelvis and buttocks regions
CO falls during upright posture so the volume of blood moved out of the central circulation must be what?
Larger
T/F? A substantial reduction in blood volume and CVP precede any significant decrease in pulse pressure, mean pressure, or tachycardia.
True
What are the immediate responses of the central circulation to upright posture (6)?
1) Decreased RAP from ~5 mmHg to 0 mmHg
2) MAP may remain unchanged or increase due to vasoconstriction (arterial baroreflex response)
3) Decreased CO by ~20%
4) Decreased SV ~40%
5) Decreased heart & central blood volume 20-30%
6) Abrupt increase in HR
T/F? Cardiac mechanisms, rather than peripheral vascular factors, appear to be crucial to maintaining mean pressure in upright posture.
False; peripheral vascular factors, rather than cardiac mechanisms, appear to be crucial to maintaining mean pressure in upright posture
Complete autonomic blockade of the heart increases/decreases CO by 51% during head-up tilt (compared to 26% before blockade), but has no effect on ____!
Decreases (reduces) CO during HUT
No effect on mean pressure
Regional Circulations: during upright posture, blood flow to what organs (5) is reduced? What is this reduction in blood flow due to?
1) Brain
2) Splanchnic organs
3) Kidneys
4) Skeletal muscle
5) Skin
*Due to sympathetic vasoconstriction (except brain)
During upright posture, the fall in cerebral blood flow is only about half what it would be without what process?
Cerebral autoregulation
Cardiopulmonary baroreceptors are "____ pressure" baroreceptors located where (3)?
"Low pressure" baroreceptors in atria, pulmonary artery, and great veins
Cardiopulmonary baroreceptors are ____ from the arterial pressure signal.
Hydraulically isolated
T/F? Cardiopulmonary baroreceptors receive input or feedback about the arterial pressure.
False; cardiopulmonary baroreceptors receive no input or feedback about the arterial pressure due to them being hydraulically isolated from the arterial pressure signal
What happens to HR during upright posture?
HR increases to ~90 bpm
What happens to CO if we increase HR further by electrically pacing the ventricles?
CO would not significantly increase!
When HR during upright posture is increased why isn't CO significantly increased?
An increase in CO would decrease CVP which would cause a decrease in SV (Starling relationship) and introduce a self-limiting control on CO
What is the only way to increase CO with CVP close to zero?
Raise RAP by activating muscle pump or with blood infusion
What are the major target organs of cardiopulmonary baroreflexes in humans (2)?
Skin and skeletal muscle
What reflex adjustments (3) occur due to the selective inhibition of cardiopulmonary baroreceptors?
Slow ramp of LBNP (-1 mmHg min-1)
Gradually reduce RAP from 5 to 0 mmHg
No measurable change in MAP until -20 mmHg LBNP
Cardiopulmonary Baroreflexes: there is a "perfect" regulation of aortic pressure variables via ____ despite a decreased SV & CO.
Peripheral vasoconstriction
Arterial Baroreflexes: upon standing both CVP & arterial pulse pressure fall and carotid sinus pressure falls below aortic pressure due to what?
A difference in hydrostatic pressure
Arterial baroreflexes cause most of the ____ vasoconstriction as well as the increase/decrease in HR.
Most of the splanchnic vasoconstriction and increase in HR appear to be due to arterial baroreflexes
Arterial Baroreflexes: which signal (due to change) accounts for most of the neural responses & adjustments?
Arterial baroreflexes appear to be activated the most when aortic pulse pressure begins to fall
Cardiovascular Responses to Head-Up Tilt: what results (4) from increasing the HUT angle (first phase)?
*Decrease in Central Venous Pressure
*Increase in Sympathetic Activity
*Increase in Plasma Norepinephrine
*Increase in Vasoconstriction
Cardiovascular Responses to Head-Up Tilt: what results (7) from a prolongation of tilt of 90 degrees (second phase)?
*Decrease in Central Venous Pressure
*Decrease in Arterial Pulse Pressure
*Increase in Sympathetic Activity
*Increase in Plasma Norepinephrine
*Increase in Heart Rate
*Increase in Vasoconstriction
*Increase in PRA which produces Angio. II-Aldosterone
Cardiovascular Responses to Head-Up Tilt: what results (8) when the regulation of BP fails (third phase)?
*Decrease in Central Venous Pressure
*Decrease in Arterial Pulse Pressure
*Increase in Sympathetic Activity
*Increase in Plasma Norepinephrine
*Increase in Heart Rate
*Increase in Vasoconstriction
*Increase in PRA which produces Angio. II-Aldosterone
*Increase in Vasopressin
Cardiovascular Responses to Head-Up Tilt: what results (8) when syncope (fainting) occurs (fourth phase)?
*Cardiac Depressor Reflex
*Increase in Plasma Epinephrine
*Increase in Vagal Activity
*Bradycardia
*Decrease in Sympathetic Activity
*Vasodilation
*Increase in PRA which produces Angio. II-Aldosterone
*Increase in Vasopressin
What does an increase in peripheral vascular blood flow ("maldistribution" of CO) in upright posture lead to?
Immediate hypotension
Post-exercise Orthostatic Intolerance: immediately (and up to 2 hours) post-exercise there is a decrease in ____, which leads to ____.
Decrease in SAP leads to post-exercise hypotension
Post-exercise Orthostatic Intolerance: what is the decrease in SAP immediately (and up to 2 hours) post-exercise caused by?
Persistent muscle vasodilation not compensated by an equal increase in CO leads to a decreased SAP
T/F? In a patient with post-exercise orthostatic intolerance, immediately (and up to 2 hours) post-exercise, CO falls faster than muscle vasodilation "wears off" which leads to a decrease in SAP.
True
Post-exercise Orthostatic Intolerance: the slow reversal of muscle vasodilation and high CO (and muscle blood flow) with no muscle pump results in what (2)?
Decrease in CVP and SV
Post-exercise Orthostatic Intolerance: does increasing HR help raise SAP?
Increasing HR does not help
Post-exercise Orthostatic Intolerance: as CVP approaches zero, nothing can be done to raise CO (the heart cannot pump what it does not receive), unless what happens (2)?
Unless muscle pump is activated or lie supine
Post-exercise Orthostatic Intolerance: a supine posture will raise ____ and prevent ____, but ____ will persist.
Supine posture will raise CVP and prevent syncope (fainting), but hypotension will persist
Heat-Induced Orthostatic Intolerance: what is a prime example of a maldistribution of CO?
Severe heat stress causes an associated increase in skin blood flow (SkBF) to highly compliant circulation
Heat-Induced Orthostatic Intolerance: during severe heat stress, when there is an associated increase in skin blood flow (SkBF) to the highly compliant circulation, what is true of the CO distribution (2)?
CO not distributed to withstand orthostasis (or many other severe stressors)
CO well distributed for temperature regulation only
Heat-Induced Orthostatic Intolerance: a heat-induced increase in CO has what effect on CVP?
Lowers CVP close to zero
Heat-Induced Orthostatic Intolerance: during what type of postural (upright/supine) heat stress can CO increase up to ~12 L/min and what organ receives up to ~8 L/min of that increased CO?
Supine heat stress
Skin
Heat-Induced Orthostatic Intolerance leads to a decrease in RAP due to what?
Decrease in RAP due to high skin blood flow (SkBF)
T/F? Heat-Induced Orthostatic Intolerance: splanchnic circulation is second only to skin compliance in humans
False; skin compliance is second only to splanchnic circulation in humans
Heat-Induced Orthostatic Intolerance: the decrease in TPR is due to what?
Whole-body cutaneous vasodilation
Heat-Induced Orthostatic Intolerance: normally, CO can increase to ~2-3 L/min by pacing the heart or with drug infusion but during heat stress CO can increase up to ~12 L/min. What is this large increase in CO due to (3)?
1) Inotropic effect on the heart
2) Hyperventilation (respiratory pump)
3) Vasoconstriction of splanchnic vasculature
To prevent a fall in CVP during upright posture and heat stress, what must happen (4)?
1) Vasoconstrict cutaneous vasculature
2) Vasoconstrict splanchnic vasculature
3) Vasoconstrict both vascular beds (both vascular beds normally constricted in upright posture)
4) Vasoconstrict skin (skin vasoconstricts with upright posture during heat stress)
T/F? During upright posture and heat stress, even with vasoconstriction, skin blood flow remains significantly elevated.
True
Autonomic Dysfunction (Autonomic Neuropathy): patients with autonomic neuropathy have persistent fall in SAP and reach syncopal levels unless they activate what?
Muscle pump
Autonomic Dysfunction (Diabetic Neuropathy): long-term diabetes can result in degeneration of ____ and ____ nerves (especially in the feet)
Degeneration of sensory and autonomic nerves
Autonomic Dysfunction (Orthostatic Hypotension): defect is in ability to vasoconstrict and increase vascular resistance due to degeneration of what?
Autonomic nerves
Which of the following is NOT one of the major problems associated with upright posture?
A. Having a heart a considerable distance above the feet.
B. Having a large proportion of the total blood volume below the level of the heart.
C. Having a large proportion of total blood volume in compliant veins.
D. Having an effective muscle pump to act as a second heart on the return side of the circuit.
D. Having an effective muscle pump to act as a second heart on the return side of the circuit.
Which of the following is/are true regarding the hydrostatic indifference point?
A. It is determined by the distribution of compliances between the upper and lower body.
B. A decrease in lower body compliance will shift the HIP cranially (i.e., toward the head & heart).
C. A cranial shift in the HIP will minimize the fall in RAP during upright posture.
D. All of the above are true.
E. None of the above are true.
D. All of the above are true.
Which of the following is/are true regarding arterial baroreflexes and upright posture?
A. Activation of arterial baroreflexes occurs once pulse pressure begins to decrease.
B. Vasoconstriction of the splanchnic circulation is due to an increase in SNA from arterial baroreceptors.
C. Activation of arterial baroreflexes occurs after the cardiopulmonary baroreflexes have been activated.
D. All of the above are true.
E. None of the above are true.
D. All of the above are true.
Which of the following statements is/are true regarding cardiopulmonary baroreceptors?
A. They are located primarily in the atria, pulmonary artery, and in the great veins.
B. They are hydraulically isolated from the arterial pressure signal.
C. The major target organs are skin and skeletal muscle.
D. All of the above are true.
E. None of the above are true.
D. All of the above are true.
The vascular function curve plots CVP as a function of flow (CO). This curve demonstrates that an increase in CO results in a decrease in CVP. This statement is ____ because ____.
A. False; an increase in CO causes an increase in CVP as shown by the cardiac function curve.
B. True; an increase in CO causes a redistribution of blood volume to the peripheral circulation, which means CVP must decrease.
C. False: there is no relationship between CO and CVP.
D. True; an increase in CO results in a decrease in CVP due to the decrease in filling time available for the heart.
B. True; an increase in CO causes a redistribution of blood volume to the peripheral circulation, which means CVP must decrease.
Which of the following statements regarding the cardiac function curve is/are true?
A. It illustrates that an increase in CVP results in an increase in CO.
B. It graphically illustrates that changes in RAP are the primary determinant of venous return and CO.
C. It is the exact opposite (i.e., inverse) of the Frank-Starling relationship.
D. All of the above are true.
E. None of the above are true.
A. It illustrates that an increase in CVP results in an increase in CO.
Prolonged periods of upright posture can result in a decrease in CO, SAP, and CVP. A decrease in CVP can ultimately lead to a decrease in cerebral blood flow and cerebral blood pressure. Reductions in cerebral blood flow and pressure can result in ____?
A. Blindness.
B. Deafness.
C. Cerebral ischemia.
D. Decreased pulmonary blood flow.
C. Cerebral ischemia.
Which of the following statements regarding the vascular function curve is/are true?
A. It is another way to plot the Frank-Starling relationship.
B. It illustrates an inverse relationship between CO and CVP due to redistribution of blood volume to the peripheral circulation.
C. It illustrates how an increase in CO can raise CVP because when CO increases blood volume in compliant vascular beds decreases due to the increase in myocardial contractility.
D. All of the above are true.
E. None of the above are true.
B. It illustrates an inverse relationship between CO and CVP due to redistribution of blood volume to the peripheral circulation.
One of the hallmarks of postexercise orthostatic intolerance is:
A. A sustained increase in muscle vasodilation and muscle blood flow that is not compensated by an appropriate increase in CO.
B. A large increase in CO that is greater than the vasoconstriction in the skeletal muscle vascular beds.
C. A large increase in HR that helps maintain CO, CVP, and SAP.
D. All of the above are hallmarks of postexercise orthostatic intolerance.
E. None of the above are hallmarks of postexercise orthostatic intolerance.
A. A sustained increase in muscle vasodilation and muscle blood flow that is not compensated by an appropriate increase in CO.
Which of the following is NOT a determinant of CO:
A. Heart rate.
B. Preload.
C. Myocardial contractility.
D. Afterload.
E. Transmural pressure.
E. Transmural pressure.
Which of the following is/are true regarding sympathetic innervation of veins?
A. Veins are only innervated by alpha adrenergic fibers.
B. In general, deep veins tend to be less responsive to SNA than superficial veins, with the exception of mesenteric veins.
C. The highly compliant venules have very little sympathetic innervation.
D. All of the above are true.
E. None of the above are true.
D. All of the above are true.
Which of the following is/are true regarding arterial baroreceptors?
A. They only respond by changing cardiac mechanisms (HR, CO) during upright posture.
B. They are more responsive to changes in pulse pressure.
C. The receive input from the central circulation (i.e., they detect changes in CVP).
D. All of the above are true.
E. None of the above are true.
B. They are more responsive to changes in pulse pressure.
The coupling factors, preload and afterload:
A. Only afterload can influence (change) CO because afterload is a determinant of CO.
B. Only preload is determined by CO as described by the vascular function curve.
C. Can both be influenced by CO because they are both determined by CO.
D. All of the above.
C. Can both be influenced by CO because they are both determined by CO.
The pressure gradient across the venous segments is primarily determined by:
A. Changes in radius and resistance.
B. Changes compliance from venules to large veins.
C. Changes in TPR.
D. Changes in blood flow into the venous segments, primarily the venules.
D. Changes in blood flow into the venous segments, primarily the venules.
During the early stages of upright posture (or simulated upright posture with lower body suction), the initial hemodynamic response is:
A. A decrease in CVP.
B. A decrease in SAP.
C. An increase in CO.
D. A decrease in PP.
A. A decrease in CVP.
T/F? Peripheral vascular factors are more important to maintaining SAP than cardiac mechanisms during upright posture.
True.
Competent venous valves during upright posture:
A. Open immediately and create a large increase in the column of blood filling the veins.
B. Create a time-dependent increase in venous blood volume and minimize the decrease in CVP during the initial/early stages of upright posture.
C. Create a time-dependent decrease in the column of blood filling the veins, which increases CVP during prolonged upright posture.
D. None of the above.
B. Create a time-dependent increase in venous blood volume and minimize the decrease in CVP during the initial/early stages of upright posture.
During upright posture, the muscle pump:
A. Can generate almost as much pressure as the left ventricle.
B. Can increase CVP and SV.
C. Is only effective with competent venous valves.
D. All of the above.
D. All of the above.
With increased SNA and myocardial contractility, the cardiac function curve is:
A. Shifted down and there is a decrease in CO for a given CVP compared to control due to decreased preload.
B. Not changed.
C. Shifted up and there is an increase in CO for a given CVP compared to control due to a decrease in end-systolic volume.
D. None of the above.
C. Shifted up and there is an increase in CO for a given CVP compared to control due to a decrease in end-systolic volume.
Passive changes in venous blood volume:
A. Occur in response to venoconstriction and/or venodilation.
B. Occur in response to changes in CO.
C. Occur in response to vasoconstriction and/or vasodilation.
D. Occur in response to large changes in MAP.
C. Occur in response to vasoconstriction and/or vasodilation.