Quiz 2 Flashcards
Local control of flow by resistance vessels requires
constant perfusion pressure (MAP)
What are 3 keysites of MAP regulation
heartresistance vesselsblood volume
What are the two ways that the heart is regulated intrinsically? –which one is more significant
- preload–starling’s law2. homeometric–treppe –starlings
sympathetic stimulation (increase/decrease) heart rate and (Increase/decrease) contractility and thus (Increase/decrease) stroke volume and output
increase
Parasympathetic (increase/decrease) HR and CO
decrease
atropine blocks para/sympathetic?
parasympathetic
propanolol block para/sympathetic
sympathetic
muscarinic is receptor for
acetylcholine
b adrenergic is receptor for
norepinephrine
adrenal medulla releases
epi and norepi
adrenal medulla is part of sympathetic/parasymp
symp
norepi and epi do what to heart rate and contractility
increase
Why do athletes have slower heart rate
increased vagal tone and slower intrinsic SA firing rate
t/f adrenal cortex is under control of the sympathetic nervous system
f
adrenal cortex releases what 2 things
corticosteroids and aldosterone
thyroid hormone does what to heart rate and contractility
increase
What is proportionality of resistance to radius
R~ 1/r^4
What are 3 ways that resistance is intrinsically controlled?
- Basal tone/tension2. Myogenic response/ Bayliss3. local metabolites
increased/decreased adenosine leads to vasodilation
increased
increased/decreased PO2 leads to vasodilation
decreased
increased/decreased pH leads to vasodilation
decreased
increased/decreased CO2 leads to vasodilation
increased
increased/decreased K+ leads to vasodilation
increased
autoregulation is a combo of what two things
vasodilators/ myogenic response
washout of vasodilators causes contraction/dilation
contraction
sympathetic innervation and alpha adrenergic receptors that cause ________ are on VSM are present where?
all vascular beds except placenta
does the parasympathetic innervation play a large role in regulation of MAP
no
parasympathetic vasoconstriction/vasodilation
vasodilation
does sympathetic play a large role in MAP reg
yes
sympathetic vasoconstriction/vasodilation
vasoconstriction
There is a resting sympathetic/parasympathetic tone?
sympathetic tone
What contributes to basal tone of VSM?
myogenic and sympathetic
withdrawal of sympathetic tone results in what two things
vasodilation and decreased TPR
norepi constrict/dilate
constrict
epi dilate/constrict
low doses dilate
Vasopressin dilate/constrict
vasoconstrict
Angiotensin II dilate/constrict
vasoconstrict
Histamine dilate/constrict
vasodilate
Bradykinin dilate/constrict
vasodilate
prostaglandin is an endothelial mediator dilate/constrict
DILATE
EDRF (endothelial derived relaxing factor) dilate/constrict
dilate/constrict
endothelin is an endothelial mediator dilate/constrict
constrict
Which sensor is the high perssure senor
cartoid sinus
Do pressor centers have ionotropic and chronotropic effects?
ionotropic and chornotropic effects are not tonically active
What kind of output does pressor center have?
tonic sympathetic vasoconstrictor output to resistance vessel VSM
Depressor cetner acts mainly by…
inhibiting pressor center
Depressor centers have important direct and tonically active vagal effects on what?
heart rate
Depressor centers have some direct _______ effectes e.g. ____ ________ to muscle
vasodilation
pressor center does what to TPR, heart reate, and contractility
increase
CO = ____ * ______
HR*SV
How does cartoid sinus transduce blood pressure?
stretch of in the wall of the sinus transduces blood pressure into a nerve signal that is carried via the sinus nerve to the brainstem pressor and depressor centers
T/F for sinus nerve there is activity present at normal blood pressure?
T
For sinus nerve, as blood pressure increases does nerve activity increase or decrease
as blood pressure decreases does nerve activity increase or decrease
increase
decrease
If MAP goes up, carotid sunus nerve will excite which center?
depressor which will inhibit pressor
Where in circulatory system is cross-sectioal area the greatest
capillaries,
dP for flow from aorta to onset of capillary is
dP for flow from end of capillary to right atrium is
100-30= 70 mmHg
15-5= 10 mmHg
compliace =
dV/dP
veins have more ____ at lower _____
volume
pressures
what is more compliant veins or arteries
veins
how can you change the compliance of veins?
sympathetic activity
What is the relationship between vascular smooth muscles in veins and basal tone?
--what about relationship with local vasodilators?
low basal tone
local vasodilators have no effect
What happens to blood volume when sympathetic stimulation affects compliance of veins?
compliance= dV/dP…..volume in veins goes down, pressure goes up, so blood volume shifts towards heart and increases preload
what is the difference in overall effect of sympathetic stimulation of venous circuit versus arterial circuit?
in venous, volume is shifted
in arterial, resisitance is increased
CVP can tell you what two important things about the right heart
filling pressure and preload
What are four mechanisms that aid venous return
- valves in veins
- muscle contraction
- Respiration
- heart can provide a suction b/c end disastolic pressure is low
What 3 things are determinants of CVP?
- Central Venous Volume
- Venomotor Tone: amt of sympathetic nerve activity to large veins
- capillary pressure
What are two determinants of right atrial pressure
- right atrial volume
- right atrial compliance
How do you regulate blood pressure for the long term
blood volume
what 3 things regulate blood volume
- heart
- brain
- kidneys
what kind of cells release renin
juxtaglomerular
what prompts the release of renin?
- renal sympathetic nerve stimulation
- decreased renal blood pressure
- decreased Na in macula densa
What happens when renin is released
- Steps
- Angiotensiongen that is released form liver is converted to Angiotensin 1
- ACE in the lung converts Angiotensin I to Angiotensin II
What are 3 effects of Angiotensin II
- Angiotensin II is a strong vasoconstrictor –MAP increasex
- Angiotensin II promotes release of Aldosterone release from Adrenal Cortex–salt and water are retained and BV goes up
- . Angio II promotes release of ADH from hypothalamus –water retained and drinking is promoted
If right heart is pumping poorly, what happens to the atrial pressure
increases
Where are the volume receptors?
right atrium
what happens to heart rate when right atrial detects increaes in right atrial volume?
increaes
what 4 things happen when heart senses high atrial volume
- decrease renal sympathetic activity which decreases renin release
- decreases ADH release
- increaes heart rate
4 increases atrial natriuretic factor (ANF) release
What is ANF, what does it do
Atrial Natriuretic Factor
produced by atrial muscle cells—increaes urine and salt secretion
low pressure receptor is synonymous with
volume receptor
What are the four different transcapillary transport processes
- Diffusion
- Carrier medated ie glucose
- pinocytosis
- ultrafiltration through small pores
equation for net fluid movement
k[(Pc+oncotic interstital)-(Pi + onctoic capillary)]
out - in
what ususally stays constant in balance of forces in and forces out in Fick Principle
Forces in usually stay constant
What is ascites
Edema in GI
How is the calculation for Oxygen Consumption?
VO2= CO *( Arterial blood O2 content- Venous blood O2 content)
increase in contractility does what to efficiency of contraciton
decrease
