Long Term Flashcards
what controls long term pressure
how much extracellular fluid you have in body
balance b/w fluid intake and output
if blood volume increases, vascular capacitance:
is not altered
if blood volume increases, arterial pressure will
increase
rising arterial pressure causes kidneys to
excrete excess volume, returning pressure to normal
level of extracellular fluid volume in body determines
long term arterial pressure
when arterial pressure falls below 50, what happens to urinary output
there is nourinary output
if arterial pressure is increased to 200 what happens to urinary output
it increases 8x
diuresis means
increase in urinary output
increased arterial pressure means what for urinary output
increase
increase in pressure causes what to happen to sodium
increase in sodium output
if water leaves
sodium leaves
pressure diuresis
Increased urinary output in response to increasing pressure
pressure natriuresis.
The increase in pressure causes an approximate equal increase in sodium output
if you infuse saline into dog what happens to CO
increases
if you infuse saline into dog what happens to urinary output
increases
if you infuse saline into dog what happens to arterial pressure
increases
what determines each person’s arterial pressure?
water and salt output has to equal water and salt intake - long term they have to be equal
equilibrium point
where intake and output curves intersect and is an individuals long term arterial pressure.
if BP increases what will system do
increase urine until pressure goes back down to equilibrium
anything that increases arterial pressure will cause
urinary output to go up until it goes down to equilibrium point
if there is decrease in arterial pressure what will happen to urinary output
decrease
if equilibrium point determine BP why is everybody’s BP a little bit different
there are two ways to determien long term arterial pressure:
shift salt and water intake or shift ability of kidneys to excrete fluid at a particular pressure
the two ways to determine long term arterial pressure
The degree of pressure shift of the renal output curve for water and salt
Some abnormality has caused the renal output curve to shift 50 mmHg to the right
Salt and water intake line
Increase intake of salt and/or water
in most people renal function curve is steep and chanages in salt take
only have have a modest effect on arterial pressure
review graph on pg 9
9
a human can change salt and water intake trremendously and not alter
BP
most people are salt _____
insensitive
if you are salt sensitive, it means that
the chronic renal output curve is much less steep, so increase in salt or water changes pressure and you have to change renal output to change it
what can cause salt sensitive
loss of functional nephrons due to kidney injury
excessive formation of antinatriuretic hormones
reduction in kidney mass or injury to kidney
what can cause loss of functional nephron
kidney injury
nephron is
functional unit of kidney
can kidney regenerate new nephrons
no
what happens to nephron number as you age
decrease
once a nephron is gone
its gone :(
each nephron contains
a tuft of glomerular capillaries called the glomerulus
a long tubule in which the filtered fluid is converted into urine.
if kidneys are destroyed, only way to remove extracellular fluid is
dialysis
what happens to BP to someone in renal failure
increase - you can’t get rid of the fluid
antinatriuretic hormones do what
hormones that reabsorb sodium and water in kidney to increase blood volume
examples of antinatriuretic hormones
angiotensin II
aldosterone
if person has too much renin released they are
incresing sodium reabsorption, pressure will get higher
antiotensin II at level of adrenal gland, does what
increases release of aldosterone
hyperaldosterone can lead to
hypertension
aldosterone increases
sodium reabsorption, extracellular fluid volume, arterial pressure
hypertension itself will cause
renal damage
hypertension that causes renal damage is causing
more hypertension
diabetes causes renal
damage
diabetes is a risk factor for
hypertension
greater than normal increase in arterial pressure is reuired to raise renal output sufficiently to maintain:
a balance b/w intake and output of salt and water
why does increasing fluids increase arterial pressure
see chart pg 13
mean circulatory filling pressure
average pressure necessary to cause filling of the circulation with blood
the higher the blood volume, what happens to mean circulatory filling pressure
the higher
the higher mean circulatory filling pressure, the more
venous return
increase extracellular fluid volume, then what happens
increase blood volume, increase mean circulatory filling pressure, increase venous return
mean systemic circulatory pressure
pressure in systemic circulation w/out the heart
arterial pressure =
CO x TPR
hemorrhaging pt what would happen to mean circulatory filling pressure
decrease
hemorrhaging person with decreased mean circulatory filling presure, how do we get blood back toheart?
baroreceptors fire less and veins will constrict (decrease compliance) so even though there’s less blood we can compensate to bring more blood to heart
increase in arterial pressure has to do with what tow different things
CO x TPR
what is thought to happen is that increased in cardiac output increases arterial pressure, and also the tissues do what
autoregulation
describe tissue autoregulation
they will constrict themselves if they get too much blood, to increase arterial pressure
changes in long term artierial pressure
anything that increases renal vascular resistance
if increase in renal vascular resistance, more pressure is needed to
excrete same amount of salt and water
what things would increase peripheral resistance in kidney
atherlosclerotic plaques
anything that decreases number of functional nephrons will do what
make it harder to cause same amount of urine flow, so pressure has to be higher
changes in total peripheral resistance do not change
long term arterial pressure
review pg 15
15
review pg 16
16
ace blocks levles of
angiotensin II
angiotensin II is a
vasoconstrictor
pacemaker in the heart is the thing that is firing
fastest
a mean arterial pressure greater than what is considered hypertensive
110
diastolic blood pressure greater than what is hypertension
90
what can the lethal effects of hypertension be
excess workload on the heart - will cause heart failure over time
stroke
injury of kidneys
athletic hypertrophy vs. hypertension causing hypertorphy
they are different kinds of hypertrophy, they don’t understand why
if a lot of left kidney is removed and entire right kidney is removed what happens to pressure right after
increases
if you put the rats who have had most of kidney removed put them on .9% NaCl what happens to their mean arterial rpessure
it goes way up
why does the salt make the rats with removed kidneys arterial pressure go way up
they need the extra pressure to get rid of the salt in the water that they are drinking b/c you removed a bunch of their kidney
they also drink more b/c the salt water doesn’t quench their thirst
review pg 19
19
read pg 20
20
read pg 21
21
read pg 22
22
kidneys themselves can sense when pressure
falls
when pressure decreaes in kidney what is released
renin
renin substrate converts angiotensinogen into
angiotensin I
angiotensin I is turned into Angiotensin II by what enzyme
converting enzyme
what enzyme do ACE inhibitors block
converting enzyme, so block effects of angiotensin II
ACE inhibitors do what
enhance effects of bradykinin
block angiotensin II
what does angiotensin II do
vasoconstriction
renal retention of salt and water
how long does it take for vasoconstriction to happen with angiotensin II
minutes - very quickly
how long does it take for angiotensin II to increase salt and water retention
days
there are beta 1 receptors in kidney, that when there is sympathetic stimulation what will happen
increase renin release
if BP falls, decrease in pressure is sensed in kidney and kidney releases
renin
when BP falls sympathetic activity goes up and what happens in kidney
NE activate beta receptors which further activate renin release
effects of angiotensin II in kidney causes kidney to
retain salt and water
what is direct effect of angiotensin II in kidney
Increases tubular reabsorption of sodium and water
Decreases renal blood flow
what is indirect effect of angiotensin II in kidney
Potent stimulator of aldosterone release from adrenal glands
Increases sodium reabsorption in renal tubules
explain the renin dependent “one kidney” goldblatt hypertension experiment
pg 26
pts with stenosis of renal artery of single remaining kidney what would happen
renin dependent hypertension
what is the clinical significance of the two kidney hypertension
Stenosis of a single renal artery caused by atherosclerosis, in a person who has two kidneys
review pg 27
27
describe hypertension in preeclampsia
toxemia of pregnancy - ischemic placenta. it’s in pregnant women. usually goes awway after baby is born
neurogenic hypertension
Strong stimulation of the sympathetic nervous system
Hypertension in the Upper Part of the Body Caused by
coarction of the aorta
risk factors for hypertension
sedentary lifestyle, weight gain, too much salt
most hypertension the cause is
unknown
the best medicine for hypertension
exercise
what is primary hypertension
hypertension with unknown cause
what is another name for primary hypertension
essential hypertension
describe graphical analysis of arterial pressure in essential hypertension
it will shift left to the level your BP has increased
the larger the shift left in graphical analysis of hypertension the
higher the BP is
thiazide diuretics for hypertension what do they do
work at kidney to try to remove extracellular fluid
beta blockser for hypertension what do they do
block/diminish sympathetic stimulation on beta receptors
ACE inhibitors for hypertension what do they do
decrease production of angiotensin II
ACE inhibitors, what does ACE stand for
Angiotensin-converting enzyme
ARBs what do they do for hypertension
block the receptor that angiotensin works at
what does ARB stand for
angiotensin II receptor blockers
calcium channel blockers for hypertension how do they work
smoth muscles contract with calcium - this limits the contraction of the heart (and I think arteries?) so vessels would dilate
