Chapter 10 Flashcards
Decreased firing of a baroreceptor does what to MAP? (increase or decrease)
Increase
Vasoconstriction of arterioles does what to MAP? (increase or decrease) and how?
Increase; increase resistance
Increased blood volume does what to MAP? (increase or decrease) and how?
Increase; increase stroke volume and increase cardiac output
Increased parasympathetic tone does what to MAP? (increase or decrease) and how?
decrease; decrease heart rate which decreases cardiac output
Decreased venous capacitance does what to MAP? (increase or decrease) and how?
increase; heart gets more blood (veins hold less) which increases venous return, increases stroke volume, and increases cardiac output
What happens when the distance between cells and the blood are increased?
rate of diffusion decreases
what happens if arterial end pressure increases?
hypertension, increase mean arterial pressure
What is edema caused by?
- increased permeability of capillary walls (more pores on capillary beds)
- reduction of plasma proteins
- increased venous pressure
- blockage of lymph vessels
histamine
Vasodilator of arterioles (increases permeability of capillary walls)
What does increased permeability of capillary walls do to reabsorption and filtration?
decreased reabsorption and increased filtration
what does a reduction in plasma proteins do to reabsorption?
decrease reabsorption
what is the main cause of congestive heart failure?
increased venous pressure
what causes elaphantitis?
blockage of lymph vessels
t/f: with edema, elastic fibers are worn out meaning the skin is constantly stretched out and cannot recoil
true
what pressure is the elasticity of the skin partially responsible for?
hydrostatic pressure of interstitial fluid
hydrostatic capillary pressure/ capillary blood pressure
Pc
plasma-colloid osmotic pressure
π p
interstitial fluid hydrostatic pressure
P IF
interstitial fluid-colloid osmotic pressure
π IF
In or out: Capillary blood pressure
Out
In or out: plasma-colloid osmotic pressure
in
In or out: interstitial hydrostatic pressure
in
In or out: interstitial colloid-osmotic pressure
out
Net exchange pressure
(Pc + π IF) - (π p + P IF)
out - in
how do veins serve as a blood reservoir?
don’t recoil
How do veins increase cardiac output?
increased alpha-1 stimulation
How is resistance and blood flow affected by a large radius in veins?
decrease resistance and increase blood flow
t/f: veins are capacitance vessels
true
t/f: veins are responsible for volume and arterioles are responsible for pressure
true
t/f: arteries have more collagen fibers which make them more durable
false
t/f: veins don’t recoil until alpha-1 tells them to
true
what does an increase in venous capacity do to venous return?
decrease
what is venous capacity?
holding blood in the veins and not returning the blood to the heart
t/f: minimal constriction of veins due to sympathetic activity increases flow
true
what does arteriolar constriction do to flow? venous return? cardiac output? heart contractility?
decrease all
what does arteriolar dilation do to flow? venous return? cardiac output? heart contractility?
increase all
what does sympathetic activity do to venous capacity?
decrease
what does skeletal muscle do for venous return?
facilitate it
What does standing on your feet too long cause?
blood pooling in the lower extremities
how do veins help return blood to the heart when standing?
valves in veins break up the pressure gradient
t/f: venous valves prevent backflow
true
what does breathing in do to venous return, stroke volume, and pressure?
increase; increase; decrease
cardiac suction effect
decrease pressure in heart causing an increasing in pressure gradient, leads to increase in venous return
pressure imparted to blood by cardiac contraction
increase venous pressure causing increase in pressure gradient, lead to increase venous return
increase in sympathetic vasoconstrictor activity
increase venous pressure causing increase pressure gradient; decrease venous capacity, leads to increase venous return
skeletal muscle pump
increase venous return causing increase in pressure gradient; leads to increase venous return
respiratory pump
decrease pressure in chest veins causing increase in venous return; leads to increase venous return
how is blood volume increased
passive bulk-flow shift of fluid from ISF to plasma and salt & water retention
increase in blood volume
increase venous pressure causing increase pressure gradient; leads to increase venous return
how is mean arterial pressure affected by blood volume
increased blood volume increases venous return, which increases stroke volume, which increases cardiac output, which increases MAP
how is mean arterial pressure affected by respiratory activity
increase resp. activity increases venous return, which increases stroke volume, which increases cardiac output, which increases MAP
how is mean arterial pressure affected by skeletal muscle activity
1: increase skeletal muscle activity increases venous return, which increase stroke volume, which increases cardiac output, which increases MAP
2: increase skeletal muscle activity causes local metabolic control which increases the arteriolar radius (dilation), which decreases TPR which increases MAP
baroreceptor reflex
affect heart rate and TPR, monitors MAP
how do baroreceptors make short term adjustments
change cardiac output and total peripheral resistance via autonomics
how do baroreceptors make long-term adjustments
increase total blood volume and increase cardiac output
carotid sinus baroreceptor
regulates blood flow to brain, sensitive to external pressure
aortic arch baroreceptors
only triggered after significant decrease in blood pressure
baroreceptor reflex in response to an increase in blood pressure
increased blood pressure above normal → increase carotid sinus and aortic arch receptor potential → increase rate of firing in afferent nerves → cardiovascular system → decrease symp. cardiac nerve activity, decrease symp. vasoconstrictor nerve activity, increase parasymp. activity → decrease heart rate, decrease stroke volume, arteriolar and venous dilation → decrease cardiac output and decrease TPR → decrease blood pressure to normal
baroreceptor reflex in response to a decrease in blood pressure
decrease carotid sinus and aortic arch receptor potential → decrease rate of firing in afferent neurons → cardiovascular center → increase symp. cardiac nerve activity, increase symp. vasoconstrictor nerve activity, and decrease parasymp. nerve activity → increase heart rate, increase stroke volume, and arteriolar and venous constriction → increase cardiac output and increase TPR → bring blood pressure back up to normal
increasing MAP does what to parasymp tone? symp. tone?
increase parasymp. tone, decrease symp. tone (decrease HR)
decreasing MAP does what to parasymp tone? symp. tone?
decrease parasymp. tone, increase symp. tone (increase HR)
t/f: the body is more adapted to respond to an increase in BP than a decrease in BP
false
where are osmoreceptors and volume receptors found?
hypothalamus, kidney, and atria
What do osmoreceptors and volume receptors do?
alter salt and water balance to alter volume
hypertension BP
140/90
t/f: secondary hypertension is due to a definitive cause
true
cardiovascular hypertension recommended treatment
diet and exercise
renal hypertension symptoms
tumor in kidneys which produce renin
what is endocrine hypertension caused by?
hormones
neurogenic hypertension
nerves are not sensitive enough
what does hypertension do to heart workload, TPR, and internal pressure?
increase heart workload, increase TPR, and increase internal pressure
t/f: primary hypertension has a known cause
false
primary hypertension causes
- salt management
- Na+K+ pump problems
- pressure on medulla
- nitric oxide
- digitalis-like compounds
hypotension BP
> 90/60 +/-
orthostatic hypotension
position based, light headed when you stand up from laying down
hypovolemic shock
extreme blood loss
cardiogenic shock
weak heart
vasogenic shock
vasodilation
two types of vasogenic shock
septic and anaphylactic
neurogenic shock
defective vasoconstrictor tone
t/f: flow is constant through every level of circulation
true
t/f: flow velocity varies due to cross sectional area
true
where is the highest pressure in an artery
beginning
where is the highest resistance and velocity in an artery
when radius is decreased or TPR is increased
t/f: flow through an artery is the same
true
flow equation
flow = pressure gradient/ vascular resistance
pressure throughout circulation
aorta > arteries > arterioles > capillaries > veins
what would happen if pressure was greater in veins than capillaries?
blood would pool in capillaries
t/f: you would want blood to slow down at point of exchange when the most area is available for exchange of the products
true
main pressure reservoir vessels
arteries
what is resistance affected by
viscosity, surface area/length, and radius
what is viscosity
determined by ratio of RBC to plasma and how much protein is in the plasma
t/f: blood thinners change viscosity
false
t/f: length of blood vessel is essentially constant
true
t/f: the radius of a blood vessel can be regulated
true
what does a decrease in radius do to resistance and blood flow?
increase resistance and decrease flow
what is the major determinant of resistance
radius (1/r^4)
flow rate equation
(pressure gradient)*(radius^4)
t/f: arterioles and capillaries have no elastic fibers
true
where to arteries transport blood
heart to organs
t/f: arteries serve as a pressure reserve
true
anatomy of arteries
large diameter/radius, low resistance, lots of elastic fibers, lots of collagen fibers
blood pressure
force exerted by blood against vessel wall and depends on volume of blood within the vessel
compliance
how easily something can be stretched
constant BP
volume of blood entering arteries = volume of blood leaving arteries
t/f: constant BP always occurs
false
how much blood leaves the heart in systole?
stroke volume amount
how much blood leaves the heart in diastole?
none
t/f: pressure in ventricles> pressure in arteries
false
where does laminar smooth flow of pressure occur?
capillaries
MAP equation
1/3 systole + 2/3 diastole
t/f: arteriolar pressure is dependent on compliance
tur
pulse pressure equation
systolic - diastolic
t/f: alpha 1 vasoconstricts when stimulated and vasodilates when relaxed
true
what happens if there is no resistance?
no pressure, no flow, DEATH
t/f: flow through the body is constant while flow to certain organs is variable
true
what does vasoconstriction do?
decrease tissue activity, increase oxygen and symp. stimulation, cold, angiotension 2
arteriolar resistance
converts pulsatile systole to diastole pressure changes in arteries to the non-fluctuating pressure seen in capillaries
vasodilation
increase tissue activity (adenosine, prostaglandins, osmolarity), nitric oxide, decrease oxygen, sympathetic stimulation, histamine and heat
local control of blood flow
influences cardiac output to organ
chemical mediators
t/f: local control is believed to act on vascular endothelium not smooth muscle
true
local control via nitric oxide
smooth muscle relaxation
endothelin (local control)
smooth muscle contraction (vasoconstriction)
Angiogenesis
new vessel growth (affected by local control)
histamine
vasodilator
relative hyperemia
post-occlusion increase of blood flow which is beneficial for returning local chemical composition to normal quality
what does vasodilation cause
increase blood flow, active hyperemia
active hyperemia
above normal blood, needs more oxygen and nutrients and remove wastes
reactive hyperemia
post occlusion increase of blood flow that is beneficial for returning local chemical composition to normal QUICKLY
vasodilator affects
- decrease oxygen
- increase carbon dioxide
- increase pH (co2 and lactate build up if glycolysis is used
- increase K+ (faster than pump)
- increase osmolarity
- increase adenosine
- increase shear stress
myogenic influence of blood flow
arterial smooth muscle stretches which increase tone
extrinsic control of blood flow
sympathetic tone and cardiovascular control center
sympathetic tone on blood flow
overridden in exercise (skin), norepinephrine, cerebral vasculature is under local control (20%)
cardiovascular control center
medulla and regulation of MAP via baroreceptors
calcified aorta affect
decreased compliance (work harder to get blood out) which increase systolic pressure, not recoiling or stretching, increase diastolic pressure, decrease pulse pressure, increase MAP
t/f: there is parasympathetic control on blood flow
false
norepinephrine binds to what receptor to regulate blood flow?
alpha1 for vasoconstriction
vasoconstriction affect on flow of blood
increase myogenic activity
increased oxygen
decrease carbon dioxide and other metabolites
increase endothelin
increase sympathetic stimulation- vasopressin; angiotensin II, cold
alpha 1 receptor: location, chemical mediator, arteriolar smooth muscle response
all arteriolar smooth muscle except in the brain, norepi from sympathetic fibers and adrenal medulla, epinephrine from adrenal medulla, vasoconstriction
Beta 2 receptor: location, chemical mediator, arteriolar smooth muscle response
arteriolar smooth muscle in heart and skeletal muscles, epinephrine from adrenal medulla, vasodilation
initial lymphatic vessel function
remove ISF fluid (reabsorb)
What would happen to ISF fluid if lymph nodes decrease
increase
t/f: whatever is in the plasma ends up in the ISF
true
t/f: the capillaries are the site of exchange
true
what type of cells are capillaries lined with?
simple squamous
hypoxic
too much swelling causes the fluid to increase the cell from the blood supply causing a decrease in the rate of diffusion and ultimately causing death
surface area of capillaries
600 m^2
what percentage of blood volume is in the capillaries?
5%
t/f: pores in capillaries exclude proteins
true
where are the pores in the capillaries and what are their function?
between endothelial cells; allow for passage of water-soluble compounds
t/f: different types of capillaries will allow for movement of different types of solutes and particles across the surface
true
t/f: lipid soluble molecules can readily pass through endothelial cells in the lipid bilayer./plasma membrane
true
what is flow of the capillaries regulated by?
smooth muscle in metarterioles
t/f: when metarterioles are constricted, the capillaries exchange material
false
t/f: when metarterioles are dilated, the capillaries exchange material
true
precapillary sphinter
not innervated increased myogenic tone sensitive to local metabolic changes increase in metabolic activity: relax decrease metabolic activity: constrict
what do metabolically active tissues do to density of capillaries
increase density
arteriolar vasodilation effects
increase total blood flow
increase total volume
increase surface area
decrease diffusion distance between cell and open capillary
what is blood flow through an organ controlled by
degree of resistance from arterioles (controlled by sympathetic tone and metabolic activity)
number of open capillaries, controlled by action of the same local factors on pre capillary sphincters
passive diffusion
down concentration gradients and solubility
how do water soluble molecules diffuse
through pores
how do lipid soluble molecules diffuse
through plasma membrane
t/f: capillary wall limits passage of everything other than plasma proteins
false
how are plasma proteins diffused into ISF
they aren’t
how are exchangable proteins diffused into ISF
facilitated diffusion
what does bulk flow do
maintain pressures– regulate distribution of ECF between plasma and ISF
ultrafiltration
more fluids out of capillary into ISF (plasma → ISF)
ultrareabsorption
reabsorb into capillary before going back to heart (ISF → plasma)
What does decreasing plasma volume do?
decrease blood pressure, decrease outward pressure, increase reabsorption
t/f: hydrostatic capillary pressure lowers BP bc of frictional loss
true
what does plasma colloid osmotic pressure create?
osmotic effect - water moves from ISF → plasm (caused by proteins)
Hydrostatic pressure of ISF is caused by
elasticity of the skin and atmospheric pressure (lower at high altitude)
positive net exchange pressure
ultrafiltration
negative net exchange pressure
reabsorption
role of lymphatic system
return ISF to heart
how much lymph is reabsorbed per day
3 liters/day
Lymphatic anatomy
- slight overlap with endothelial cells
- allow fluid in but not out
- travels to lymph node
Lymphatics function
transport plasma proteins and bacteria
sympathetic affect on lymphatics
increase pumping of lymph vessels towards venous outlet
role of lymphatics
- empty into vena cava (MAJOR)
- transport fat from digestive tract (half lymph vessel associated)
- screen against foreign invaders
- return escaped proteins
t/f: if plasma proteins are accumulated in the ISF instead of being returned by lymphatics, ultrafiltration ________ and reabsorption ________
increases, decreases
