Exam 4- renal lab Flashcards
the functional unit of the kidney is the
nephron
The nephron consists of a renal [a], for filtration, and a renal [b] for reabsorption and excretion
corpuscle
tubule
Glomerular filtration is a______ process in which fluid passes from the lumen of the glomerular capillary into the glomerular capsule of the renal tubule
passive
the [a] capillaries surrounding the renal tubules reclaim the reabsorbed substances and return them to the general circulation. These capillaries arise from the [b] arterioles
peritubular
efferent
the diameter of the afferent arteriole is ______than the diameter of the efferent arteriole, restricting blood flow out of the glomerulua
larger
select the two components of blood that are NOT normally filtered through the glomerular wall
plasma proteins
blood cells
the job of the tubule is to _______all the beneficial substances from its lumen and allow wastes to travel down the tubule for elimination from the body
reabsorb
the nephron consists of the
proximal convoluted tubule glomerululs distal convoluted tubule renal capsule/Bowman's capsule loop of henle
the renal corpuscle consists of the
glomerululs
renal capsule/Bowman’s capsule
the renal tubule consists of the
collecting duct
distal convoluted tubule
loop of henle
proximal convoluted tubule
Place the following blood vessels and renal structure in their correct order
afferent arteriole glomerulus efferent arteriole peritubular capillary interlobular vein
During the process of renal reabsorption, fluid and solutes move from the
renal tubule into the peritubular capillaries
IN Pex 9.1 What happened to the glomerular capillary pressure and filtration rate after you increased the radius of the afferent arteriole?
glomerular capillary pressure increased
filtration rate increased
If you increase the afferent arteriole radius and keep all other variables constant, the GFR would
increase
If you increase the efferent arteriole radius and keep all other variables constant, the GFR would
decrease
If you decrease the efferent arteriole radius and keep all other variables constant, the volume of urine flowing into the urinary bladder would
increase
If you decrease the afferent arteriole radius and keep all other variables constant, the volume of urine flowing into the urinary bladder would
decrease
Caffeine consumption leads to increased urine formation,
This is due to
dilation of the afferent arteriole
Stimulation of the Sympathetic NS will tend to
constrict the afferent arteriole, constrict the efferent arteriole with an overall decrease in GFR
______forces (hydrostatic and osmotic pressure gradients) drive protein-free fluid between the blood in the glomerular capillaries and the filtrate in Bowman’s capsule
starling
Increases in which of the following forces favor FILTRATION
osmotic pressure in Bowman’s capsule
Blood pressure in the glomerular capillaries
which of the following forces most directly limits/decreases filtration
filtrate pressure in Bowman’s capsule
the glomerular filtration rate can be increased most directly by
decreasing the afferent arteriole resistance
The amount of blood entering the glomerular capillaries that is filtered is the filtration fraction. According to the introduction of activity 2 this is
20%
What happened to the glomerular capillary pressure and filtration rate after you increased the blood pressure in the L source beaker in activity 2PEX9
filtrate pressure increased, filtration rate decreased
Name a medical condition that causes the same pathology as the “closed valve” between the collecting duct and urinary bladder besides a tumor
A kidney stone
What happened to the filtration pressure in Bowman’s capsule and filtration rate after you closed the one way valve between the collecting duct and urinary bladder?
filtrate pressure increased, filtration rate decreased
In a person in hemorrhagic shock what might happen to blood flow to the kidney
the blood flow would decrease
In a person in hemorrhagic shock what might happen to the GFR
the GFR would decrease
The important relation that underlies the observed increase in GFR when afferent arteriole BP increases is
pressure and flow are directly proportional
which does NOT have a significant impact on the GFR
renal tubule length
How can an increase in GFR from increased blood pressure be beneficial to the body?
Increased GFR would increase urine volume and urine output, decreasing plasma volume and therefore decreasing BP. This can be beneficial when BP is elevated
the reason glomerular capillary pressure and glomerular filtration remain relatively constant despite changes in blood pressure is because the nephron has the capacity to alter
its afferent and efferent arteriole radii
Match the equipment with the body part it is simulating
first beaker on the L side of the screen aka source beaker for blood
2nd beaker on the L side of the screen aka drain beaker for blood
flow tube with adjustable radius
2nd flow tube with adjustable radius
blood from general circulation
renal vein
afferent arteriole
efferent arteriole
if all other variables are kept constant, how does the efferent arteriole radius affect the GFR
decreased arteriole radius will
increase the GFR
if all other variables are kept constant, how does the afferent arteriole affect the GFR
increased arteriole radius will
increase the GFR
If Blood pressure were to drop what changes in the nephron would allow the kidney to maintain its normal GFR
afferent arteriole dilation
efferent arteriole dilation
When you compared the GFR and the glomerular capillary pressure with baseline (first run) increasing afferent arteriole radius
(remember the baseline/first run had Af radius of .5/Ef radius of .45 and pressure of 90 m
the second run changed the BP to 70 mm
and the third run increased the AF radius to .60 mm)
vasodilation did improve the low glomerular capillary pressure and filtration rate almost to baseline values
On your 4th trial you return af radius to .5mm and decreased ef radius to .35, all at a pressure of 70mm Hg
the result was
vasoconstriction did improve the low glomerular capillary pressure and filtration rate but only marginally
in activity 3 you both increased the afferent radius and decreased the efferent radius (from baseline) and maintained the low BP of 70 mm
The result was
GFR and Glomerular P rose above the baseline values
when you started activity 3 you were asked to change the afferent radius to .5mm and the efferent radius to .45 mm.
Why did PEX ask you to select an afferent radius that was wider than the efferent radius?
n the kidney the afferent vessel contains plasma and blood.
This is filtered and 20% of the serum leaves the artery. This enters bowman’s capsule and is then modified in the nephron.
the efferent arteriole is smaller because it contains less blood.
The ability to change the diameter of both arterioles helps modify the filtering pressure. As the efferent arteriole radius decreases it increases the resistance to flow, allowing for more filtration at the glomerulus. Having a smaller efferent arteriole increases filtration.
On the other hand increasing the radius of the afferent arteriole increases blood flow and increases filtration
for a given beaker/systemic blood pressure which had the greatest effect on GFR
a change in diameter of the Afferent arteriole
In activity 3 the afferent arteriole dilated in response to a decrease in systemic blood pressure. This is a direct example of
an appropriate response of the myogenic system
List 3 mechanisms studied in PEx that affect GFR.
Afferent radius
Efferent radius
BP
elect the choice(s) that would increase GFR
increased glomerular blood pressure
afferent arteriole vasodilation
efferent arteriole vasoconstriction
In this experiment ,both at the same pressure, the change in radius between the afferent arteriole and efferent arteriole is .15 mm for both trials yet the GFR is greater at .6/.45 then at .5/.35
resistance is inversely proportional to the 4th power of the radius
resistance is proportional to 1/r4
and therefore resistance is proportional to (1/.454-1/.64) vs (1/.354- 1/.54)
the movement of filtered solutes and water from the lumen of the renal tubules into the interstitial space is
reabsorption
peritubular capillaries arise from the
efferent arteriole
As filtrate passes through the nephron, the renal process of reabsorption describes the movement of water and solutes
from the tubule lumen, into the interstitial space and, finally, into the peritubular capillaries
the Maximum solute concentration refers to the solute concentration in
the interstitial space
ADH -antidiuretic hormone-affects the permeability of
the collecting duct
ADH aid the reabsorption of
water
the reason the solute concentration in the proximal tubule is initally the same as serum is that
water and plasma solutes filter into bowman’s capsule then enter the PCT
What happened to the urine volume and concentration as the solute gradient in the interstitial space increased
urine volume decreased
urine concentration increased
tubule fluid osmolarity will ALWAYS be greatest in the
bottom of the loop of henle
tubule fluid volume will ALWAYS be greatest in the
proximal convoluted tubule
ADH acts
in the collecting duct to increase water reabsorption
Explain how the reabsorption of solutes affects water reabsorption
water follows solutes therefore when solutes are reabsorbed they “pull” water with them.
tubule fluid osmolarity is always greatest in one area of the nephron
Tell me that location and explain why this is the area with the greates tubule fluid osmolarity
the bottom of the loop of henle this is because the descending loop is permeable to water but impermeable to solutes. solutes are not able to leave, increasing osmolarity.
there are a ________number of glucose carriers in each renal tubule cell
finite
glucose is first absorbed by_______at the apical membrane of the proximal tubule cells
secondary active transport
glucose is first absorbed along with _______at the apical membrane of the proximal tubule cells
sodium ion
in the proximal tubule the APICAL membrane refers to the side that faces the
lumen of the tubule
in the proximal tubule the basolateral membrane refers to the side that faces the
interstitial tissue
glucose enters the interstitial tissue along the basolateral membrane by
facilitated diffusion
When there are no glucose carriers why is the glucose concentration the same in bowman’s capsule and the urinary bladder the same
without glucose carriers glucose is filtered but not absorbed
How does ADH affect the renal processing of plasma glucose
ADH has no direct effects on renal processing of plasma glucose
glucose reabsorption in the nephron includes
2ndary active transport along the apical membrane of proximal tubule cells
Which is false
the # of glucose carries in a nephron can be altered as needed by the body
What happened to the glucose concentration of urine in the bladder after glucose carriers were added to the proximal tubule
glucose concentration in the bladder decreased
Glucose carrier proteins are located in the
proximal convoluted tubules
When the concentration of glucose in the filtrate exceed the transport capacity of carrier proteins then
the transport maximum has been reached
Why do diabetics have polyuria-large urine volume?
when the transport maximum for glucose is exceeded glucose remains in the filtrate/preurine.
this means there are more particles in the preurine. The particles in the preurine compete with the particles in the interstitial tissue to keep water in the tubule. In this case glucose is a particle that pulls water (keeps it) in the nephron
aldosterone acts on the [a] convoluted tubule cells to promote the reabsorption of [b] from the filtrate and the secretion of [c] from the body
distal
sodium
potassium
the primary action of ______ is to increase the permeability of the collecting duct to water so that more water is reabsorbed
ADH
which of the following has a role in altering the urine volume and concentration
ADH
aldosterone
the total solute concentration gradient in the interstitial spaces surrounding the tubule lumen
all
In the presence of ADH potassium concentration in the urine increases because
water is reabsorbed into the interstitial space concentrating urine
In the presence of ADH and aldosterone potassium concentration in the urine increases because
more potassium is secreted into the distal tubule, preurine is then concentrated in the collecting ducts
What most directly stimulates the release of aldosterone
the presence of angiotensin 2
the principal determinant for the release of ADH is
n increase in body osmolarity
ADH is produced in the
hypothalamus
in response to abnormally low plasma osmolality aldosterone will increase
sodium reabsorption along the distal tubule and the collecting duct
aldosterone leads to the reabsorption of sodium and secretion of potassium. Why does this affect water absorption or secretion?
the sodium potassium pump works with an uneven ratio. three na sodium particles are reabsorbed for two potassium particles are secreted. There is a net increase of 1 particle absorbed so 1 water follows
also the membrane is more permeable to K…it is more likely to diffuse and exert less pull on water
What hormonal manipulations would you perform to increase reabsorption of sodium ions without increase blood volume
Increase adosterone and decrease ADH
fill in the blanks
H2O + CO2 ↔[a]↔ H+ + [b]
H2CO3
HCO3-
the body’s 3 major chemical buffering systems are the _____systems
phosphate
protein
bicarb
match the characteristics of these 2 buffering systems
hours to days
minutes to hours
renal
respiratory
The fastest compensatory mechanism for maintaining pH homeostasis in the human body is
chemical buffers
the renal system compensates for
respiratory acidosis
respiratory alkalosis
when you increased the blood pCO2 in activity 3 of PEX 10
blood pH declined initially
the renal system compensates for
respiratory alkalosis
respiratory acidosis
lowering the serum PCO2 simulates
respiratory alkalosis due to hyperventilation
metabolic acidosis (low pH) is characterized by low plasma ________ (not pH,…I just told you that. Which molecule?
HCO3-
when assessing changes in fixed acids, those that the kidney can adjust, one looks at serum_____ levels
HCO3-
respiratory acidosis has a
pH under 7.35 and a pCO2 greater than 45
what effect did raising the PCO2 have on the [H+] and the [HCO3-] in the urine
H+] increased
and
[HCO3-] decreased
the renal system can compensate for
both respiratory and digestive pH changes
with renal compensation for respiratory acidosis the pH of the urine
decreased due to [H+] increase
metabolism in the body cells in activity 10-4 most directly simulates the rate of
cellular respiration
the body system that compensates for metabolic alkalosis is
respiratory
tidal volume and breaths per minute increase with increased metabolism because
increased metabolism produces more CO2
select the choices that could lead to metabolic acidosis
strenuous exercise ketoacidosis excess ETOH ingestion diarrhea salicylate (aspirin) poisoning
excessive vomiting results in
loss of acid, metabolic alkalosis
when metabolic rate decreases
breaths/minute decreases
diarrhea
loss of bicarbonate from intestine leads to metabolic acidosis
vomiting
loss of H+ from stomach leads to metabolic alkalosis
constipation
excess resorption of HCO3- leads to metabolic alkalosis
etoh overdose
metabolic acid due to excess acetic acid (vinegar
strenuous exercise
buildup of lactic acid leads to metabolic acidosis
