Cardio Lec 7 Flashcards
Main job of chemoreceptors
regulate breathing rate
When co2 levels rise, chemoreceptors
send signal to breathing center & force you to incr breathing rate
Main factors that increase bp
high blood vol & vasoconstriction
Blood is considered an __ fluid
extracellular
Movement of water determined by what forces?
osmotic pressure & hydrostatic/filtration pressure
Osmotic pressure
water being pulled TOWARDS the compartment
Hydrostatic pressure
pulls AWAY
The more hydrostatic pressure you have
you can cause fluid to move out of the vessel (filtration)
Filtration refers to
fluid being pulled OUT of the capillary
Reabsorption refers to
fluid being pulled BACK IN to the capillary
Capillary fluid exchange refers to
whether fluids get filtered or reabsorbed across the capillary
Capillary hydrostatic pressure refers to
bp against vessel walls
Capillary hydrostatic pressure favors
filtration (fluid out of capillary)
On which side is pressure greater?
arterial side
Tissue hydrostatic pressure refers to
pressure that fluid in interstitial exerts against vessel wall
Tissue hydrostatic pressure opposes __ & favors __
capillary hydrostatic pressure; reabsorption
Colloid osmotic pressure refers to
osmotic pressure of blood
Colloid osmotic pressure favors
reabsorption (causes fluid to move in)
Interstitial osmotic pressure favors
filtration (causes fluid to move out)
Net filtration pressure (sum of diff pressures) determines
fluid movement either out or back in
CHP + COP Interstitial =
fluid out
Interstitial HP + COP plasma =
fluid in
Lymphatics protect against __ by
edema; picking up excess fluid that venous side wasn’t able to reclaim
What can cause edema
anything that causes lymphatic blockage, anything that could cause hydrostatic pressure on the venous side to increase, or anything that would cause hydrostatic pressure of blood to increase (cause more fluid out or make it less able for fluid to be reclaimed on venous side)
If anything were to increase capillary osmotic pressure would that promote or inhibit edema formation?
inhibit
If anything were to increase capillary hydrostatic pressure would that promote or inhibit edema formation?
promote
If anything were to increase interstitial osmotic pressure would that promote or inhibit edema formation?
promote
If anything were to increase interstitial hydrostatic pressure would that promote or inhibit edema formation?
inhibit
Fluids leave on the __ end via __& are reclaimed on the __ side due to ___ hydrostatic pressure
arterial; filtration; venous; reduced
What % of fluids leave via filtration, what % is left behind
85%; 15% (picked up by lymphatics)
Lymphatics transport ___ back into the blood stream
interstitial fluid (15%)
Lymphatic capillaries are closed end tubes
t
As lymph capillaries get full they __
contract which propels fluid forward
Fluid is filtered on the __ side, __% gets reclaimed by __ & __% gets picked up by lymph capillaries that return it back to blood stream
arterial; 85%; venous side; 15%
If there is a venous obstruction what happens to the hydrostatic pressure on the venous side of the capillary
goes UP due to blockage somewhere downstream
If venous hydrostatic pressure isn’t reduced it is much more difficult for
fluids to be reclaimed on venous side (that 85%) -> edema formation
Venous obstruction causes
phlebitis (venous clot), pregnancy (venous press incr due to weight of baby) & r. sided heart failure (blood backs up to r. atria -> vena cava -> veins -> decr press on venous side -> difficult for fluid)
Edama causes
elevated bp, any venous obstruction, leakage of plasma proteins into interstitial fluid, decreased plasma protein production, & lymphatic drainage obstruction
How does this cause edema: leakage of plasma proteins into interstitial fluid
if plasma leaking in interstitial -> causes increase in osmotic pressure of interstitial -> reduces osmotic pressure in capillaries
How does this cause edema: decreased plasma protein production
if you don’t have enough plasma proteins in the blood -> blood osmotic pressure falls -> more difficult for fluid to be maintained WITHIN capillaries
How does this cause edema: lymphatic drainage obstruction
that 15% of fluid left behind can’t get picked up by lymphatics -> accumulates in interstitial
How does this cause edema: elevated bp
increased capillary hydrostatic press -> fluids leave capillary -> accumulate in interstitial
How does this cause edema: venous obstruction
causes capillary hydrostatic pressure on venous side to increase -> if pressure doesn’t get reduced -> more difficult for that 85% fluid to get reclaimed -> raises capillary hydrostatic pressure on venous side
Which organ plays a huge role in fluid & blood vol regulation
kidneys
Amount of reabsorption is adjustable & depends on state of hydration
t
Amount of water that we retain or excrete affects blood vol
t
ADP/vasopressin has ability to raise bp
t
ADP produced by __ & stored by __
hypothalamus; posterior pituitary
ADH released in response to
osmoreceptor stimulation
Are osmoreceptors stimulated when osmolarity in blood is too low or too high?
high -> means you are dehydrated -> ADH produced -> decreases urine vol to retain more water -> dilutes plasma osmolarity back to where should be
Does salt increase osmolarity too?
yes -> start producing adh -> thirst & water retention
Stretch receptors stimulated by incr blood vol ->
reduces ADH production -> urine output goes up -> blood vol reduced back to norm (cause water loss reduces blood vol & raises osmolarity)
RAA system
helps keep bp constant
Renin activates
angiotensin 1 (does nothing) from angiotensinogen (inactive)
Angiotensin 1 converted to __ by __
angiotensin 2 by ACE
Angiotensin 2
POTENT vasoconstrictor -> raises bp & tpr by: stimulating thirst & aldosterone prod
In response to low bp -> low blood flow to kidneys -> renin secreted ->
converts angiotensinogen -> angiot 1 (does nothing) -> ACE converts to angiot 2 -> ELEVATES bp (vasoconstricts, stimulates aldosterone, thirsty)
RAA system should be inactivated when
bp, blood vol, salt, or blood flow across system
People with htn: RAA system is not able to shut off
t
People with htn usually have elevated renin levels & can’t shut them off
t
ACE inhibitors
stop conversion of angio 1 -> angio 2
ARB’s
bind & block receptors that angio would bind to
Atrial Natriuretic peptide (ANP) produced by __ in response to __
atria; stretch
ANP inhibits
aldosterone & adh to reduce blood vol to be able to reduce atrial stretch
CO is equal to
venous return
Hemodynamics refers to
factors affecting flow
Blood will only move if there is a
pressure gradient (high->low)
What generates pressure in the cardiovascular system
heart pumping
Pressure in aorta is __; pressure in r. atria is
high; low (BIG PRESSURE DIFF)
