Exam #3 Flashcards
If there is an increase in contractility, how are EF and ESV affected?
Increased contractility =
- Increased EF
- Decreased ESV
If there is an decrease in contractility, how are EF and ESV affected?
Decreased contractility =
- Decreased EF
- Increased ESV
If preload is increased, how is SV/CO affected?
Directly
- Increased preload/EDV = Increased SV/CO
If preload is decreased, how is SV/CO affected?
Directly
- Decreased preload/EDV = Decreased SV/CO
If afterload is increased, how is SV/CO affected?
Inversely
- Increased afterload = Decreased SV/CO
If afterload is decreased, how is SV/CO affected?
Inversely
- Decreased afterload = Increased SV/CO
If afterload is increased, how is MAP affected?
Directly
- Increased afterload = Increased MAP
If afterload is decreased, how is MAP affected?
Directly
- Decreased afterload = Decreased MAP
What five factors affect preload?
- Ventricular filling time
- Ventricular compliance
- Ventricular filling pressure
- Atrial systole contribution to ventricular filling
- Pericardial constraint
How does ventricular filling time affect preload?
Depends on HR:
- Increased HR = Decreased filling time = Decreased EDV and SV
How does ventricular compliance affect preload?
How does this appear graphically?
Less compliance = more stiffness which decreases filling time = Decreased EDV and SV
Increased slope = bad
How does ventricular filling pressure affect preload?
Negative intrathoracic pressure = increased venous return to R heart
- Increased RA pressure = increased EDV and SV
How is afterload estimated?
MAP
Do arteries or veins have greater volume?
Veins have greater volume
Do arteries or veins have greater compliance?
Veins have greater compliance
Do arteries or veins have greater pressure?
Arteries have greater pressure
How does aortic compliance affect pulse pressure (PP) and systolic pressure (SP)?
Inversely
- Decreased aortic compliance = Increased PP/SP
How does SV affect pulse pressure (PP) and systolic pressure (SP)?
Directly
- Increased SV = Increased PP/SP
How does HR affect diastolic pressure (DP) and pulse pressure (PP)?
Directly
- Increased HR = Increased DP/PP due to increased time for runoff and greater arterial volume remaining at end of diastole
How does TPR affect diastolic pressure (DP) and pulse pressure (PP)?
Directly
- Increased TPR = Increased DP/PP due to increased time for runoff and greater arterial volume remaining at end of diastole
How does central venous pressure (CVP) affect venous return?
Directly
- Increased CVP = Increased venous return
If SV and SP/PP are increased, how does this affect MAP?
Directly
- Increased SV = Increased PP/SP = Increased MAP
If HR and DP/PP are increased, how does this affect MAP?
Directly
- Increased HR = Increased DP/PP = Increased MAP
If SV is increased and HR is decreased, how does this affect MAP?
CANCEL OUT
- Increased SV = Increased PP/SP = Increased MAP
BUT - Decreased HR = Decreased DP = Decreased MAP
SO CANCEL
If TPR is increased, how does this affect CO and VR on the Cardiac Function Curve + Vascular Function Curve? WHAT IS THE SHIFT?
Increased TPR = vasoconstriction
- Increased arterial volume, decreased CO/VR
Shifts DOWN
If TPR is decreased, how does this affect CO and VR on the Cardiac Function Curve + Vascular Function Curve? WHAT IS THE SHIFT?
Decreased TPR = vasodilation
- Decreased arterial volume, increased CO/VR
Shifts UP
How does increased HR affect runoff? What does this mean?
Indirectly
- Increased HR = Decreased time for runoff
- Less blood goes to veins (stays in arteries)
How does decreased HR affect runoff? What does this mean?
Indirectly
- Decreased HR = Increased time for runoff
- More blood goes to veins and pools there
The venous system is ____ resistance, ____ pressure and ____ compliance
Venous system =
- LOW resistance
- LOW pressure
- HIGH compliance
What three things are DIRECTLY proportional to RAP?
- Preload
- SV
- CO
What two things are INVERSELY proportional to RAP?
- Atrial filling
- VR (venous return)
Are small arterioles or terminal arterioles more highly innervated by SNS?
Small arterioles are HIGHLY innervated by SNS
During non-nutritive flow, what does blood flow through? Are the precapillary sphincters constricted or dilated?
Blood flows through metarterioles
- Precapillary sphincters constricted
During nutritive flow, what does blood flow through? Are the precapillary sphincters constricted or dilated?
Blood flows through capillaries
- Precapillary sphincters dilated
What determines the overall flow of blood to specific capillary beds?
What determines which capillaries are perfused?
- Arteriole radius determines overall blood flow to specific capillary beds
- Precapillary sphincters determine which capillaries are perfused
What are the most common type of capillary? What type of molecules can pass through?
Continuous
- Hydrophilic molecules pass through clefts/small pores; tight junction
What two types of molecule can pass through fenestrated capillaries?
Water and small hydrophilic molecules pass through fenestrae (perforations), think leaky
What two types of molecule can pass through discontinuous capillaries?
Large molecules (proteins) and water pass through wide gaps
Where are continuous capillaries found (4)?
- Muscle
- Skin
- Lung
- Neural tissue
Where are fenestrated capillaries found?
Kidneys
Where are discontinuous capillaries found?
Liver
What is the plasma and interstitium location in relation to capillaries (in or out)?
- Plasma (INSIDE)
- Interstitium (OUTSIDE
What is the movement of fluid with filtration?
FILTRATION = fluid movement OUT of capillary
What is the movement of fluid with absorption?
ABSORPTION = fluid movement INTO capillary
What type of pressure favors filtration?
Capillary Hydrostatic Pressure (Pc) favors FILTRATION
What type of pressure favors absorption?
Plasma Oncotic Pressure (PIc) favors ABSORPTION
Of arterial pressure, arteriole resistance, venous resistance, and venous pressure, which is inversely proportional to Capillary Hydrostatic Pressure (Pc)?
Arteriole resistance is inversely proportional to Capillary Hydrostatic Pressure (Pc)
Which of the two pressures (Pc and PIc) have the highest pressure?
Pc > PIc > Pi > Pii
What causes ACTIVE vasoconstriction?
+ SNS
What causes ACTIVE vasodilation?
+ Vasodilator (Adenosine)
What causes PASSIVE vasoconstriction?
Remove Vasodilator (Adenosine)
What causes PASSIVE vasodilation?
Remove SNS
What is one of the most potent vasodilators we discussed? What are five others we discussed?
Adenosine
- Bradykinin
- Prostacyclins
- Prostaglandins
- ANP
- NO
What are the four primary vasoconstrictors?
- Angiotensin II
- TXA
- Vasopressin (ADP, ADH)
- Endothelin
What are the three intrinsic mechanisms?
- Autoregulation
- Active hyperemia
- Reactive hyperemia
What is active hyperemia?
Blood flow to an organ is proportional to its metabolic activity
What is reactive hyperemia?
Involves ischemia
- Ischemia causes local buildup of vasodilators → increased blood flow to organ
What are the two theories of autoregulation, and what does each involve?
- Metabolic theory: involves vasodilators
- Myogenic theory: involves vascular smooth muscle
Describe how an increase in pressure would affect autoregulation via the METABOLIC theory.
Increase in pressure → Increased flow → More vasodilators washed out = vasoconstriction WHICH THEN DECREASES FLOW (compensation)
Describe how an increase in pressure would affect autoregulation via the MYOGENIC theory.
Increased pressure → Increased flow but also increases wall tension → vascular smooth muscle contracts = vasoconstriction WHICH THEN DECREASES FLOW (compensation)
Which type of Epi adrenergic receptors cause relaxation/vasodilation?
B2
Which type of Epi adrenergic receptors cause constriction/vasoconstriction?
A1
What action do most tissues perform? What does skeletal muscle do, and why?
Most tissue vasoconstrict
- Skeletal muscle vasodilates due to its higher concentration of and increased affinity for B2 receptors
What type of receptor does Angiotensin II act on? Is this a vasoconstrictor or a vasodilator?
Angiotensin II is a VASOCONSTRICTOR that acts on AT1 receptors
What type of receptor do Vasopressins act on? Are these vasoconstrictors or vasodilators?
Provide two examples of Vasopressins.
Vasopressins are VASOCONSTRICTORS that acts on V1 receptors
- Ex. ADH, AVP
What is the goal of vasodilators? When are they used?
Vasodilators used for hypotension (decreased BP)
- Increase pressure
- Decrease flow
- Decrease vessel volume
What type of adrenergic receptors increase HR and contractility in the heart?
B1
What is the purpose of arterial baroreceptors? Where are these located (2)?
SHORT-TERM regulation of BP by minimizing changes in pressure and responding to stretch
- Found in aorta and carotid sinuses
What receives most of the afferent information and acts as an integrator?
Nucleus Tractus Solitarus (NTS)
What two nerves are utilized by the afferent pathway? What direction does information travel in afferent?
Afferent = baroreceptors to brain
- Uses Vagus and Glossopharyngeal nn.
What two nerves are utilized by the efferent pathway? What direction does information travel in efferent?
Efferent: away from brain
- Uses Vagus and sympathetic nn.
What two centers are utilized by the efferent pathway? To what location does each send information to?
- Vasomotor Center: to peripheral resistance vessels
- Cardiac Center: to heart
If BP is increased, how does this affect AP frequency/STRETCH?
Increased pressure = increased AP frequency/STRETCH
If BP is elevated above normal, which NS is activated and how does this affect MAP? What happens to baroreceptors in this case?
Elevated BP = PNS stimulated
- MAP decreases
- Baroreceptors are stretched
Do baroreceptors or chemoreceptors have a more potent response?
Baroreceptors
Where are chemoreceptors located in the body (2)?
Carotid and aortic bodies
If arterioles are vasoconstrictor, how does this affect Pc and MAP? Is absorption or filtration favored?
What concept is this?
CAPILLARY FLUID SHIFT
Arteriole vasoconstriction = Decreased Pc
- Increased MAP
- Favors absorption
What three changes to circulation occur when the baby is born (NOT involving shunts)?
- Increased BP
- Increased HR
- LV thickens
What is the purpose of the Placental Shunt?
Describe the placenta in terms of flow and resistance system.
Shunts blood away from lower trunk and abdominal viscera
- Placenta is high flow, low resistance and receives 50% of combined cardiac output (CCO)
What is the purpose of the Ductus Venosus?
Shunts oxygenated blood from umbilical vein to IVC/heart (bypasses liver)
What is the purpose of the - Foramen Ovale?
Shunts oxygenated blood from IVC to RA to LA
What is the purpose of the - Ductus Arteriosus?
Shunts blood from left pulmonary artery to aorta (to body, not lungs)
What is the functional issues with Atrial Septal Defect (ASD)?
Foramen Ovale does not close leading to a LA to RA shunt
What is the functional issues with Ventricular Septal Defect (VSD)?
“Hole in heart” leading to LV to RV shunt
What is the functional issues with Patent Ductus Arteriosus?
Ductus Arteriosus does not close leading to an aortic artery to pulmonary artery shunt
What condition often results from Septal Defects?
Pulmonary HTN
Does the fetal heart work in parallel or series? What does this mean for L and R heart cardiac outputs?
Parallel
- L heart and R heart both provide outputs to the body (CO is mixed)
What four things increase dramatically with exercise?
- HR
- CO
- VR (venous return)
- Arteriovenous oxygen difference
What two things increase slightly with exercise?
- SV
- MAP
What one thing decreases dramatically with exercise?
TPR
