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Renal System and Acid / Base
Week 5 Renal System and Acid/Base
290
Anatomy
Graduate
07/07/2014

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Term
How many nephrons in each kidney?
Definition
1 million
Term
What part of the nephron that surrounds the capillaries?
Definition
Bowman's capsule
Term
What are the three segments of the loop of henle (She wants to know their functions too.) just answer what are the three segments in order from the bowman's capsule
Definition
Descending thin segment - ascending thin segment - thick segment of the ascending.
Term
The nephron tubular segment starts at the ? and ends at the ?
Definition
Starts at the nephron's bowman's capsule and ends at the end of the distal tubule. After the distal tubule is where the collecting ducts begin the connection between the two is a segment of the nephron known as the connecting tubule.
Term
Collecting ducts of the nephron also referred to as?
Definition
collecting tubules
Term
Whats the difference between the nephron tubular and collecting ducts? What do those cells do?
Definition
Different types of cells. On the collecting ducts there are more principal cells and more intercalated cells. Therefore it is here where aldosterone and ADH act on the nephrons.
Term
The most proximal part (segment) of the collecting duct system is called?
Definition
The collecting duct. It is located at the end of the distal convoluted tubule.
Term
What part of the proximal tubule helps with increasing the rate of absorption and how does that happen?
Definition
micro villi increase the surface area for absorption and interaction with substances
Term
What is a big difference between thick ascending loop of henle and thin descending loop of henle
Definition
Thin descending have no micro villi but is very permeable to H20 while the thick ascending loop of henle has lots of villi which makes it very absorbant to ions but not permeable to H20
Term
what percentage of ion reabsorption is done at the ascending loop of henle?
Definition
25%
Term
Explain the blood supply of the nephron
Definition
Renal artery is the main supply for kidney. It branches to segmental arteries which supplies different section of the entire kidney. That then branches to interlobar arteries which travel around the renal pyramids. On top of the renal pyramids are the multiple nephrons (they look like vines on the perimeter of the kidney) which then get supplied by small branches of arteries known as arcuate arteries (those look like the hoses that run in large rows in a field) from there the smaller arteries branch off to individual interlobular arteries which then supply along the chain of glomerula to invididual afferent arteriole.
Term
The juxtamedullary nephron has an extra capillary bed known as the?
Definition
vasa recta which run allong the loop of henle which in the juxtamedullary nephron is completely below the cortex and in the medulla.
Term
Whats a big difference between the juxtamedullary nephron and cortical nephron?
Definition
The cortical nephons make up 75% of the nephrons and their body is mostly in the cortex and only a small part of its loop of henry is in the medulla.
Juxtamedullary nephrons are more important in ion concentration.
Term
What are pressures high in the glomerulra capillaries in the bowman capsule?
Definition
b/c pressure needs to remain high from the afferent artery through the bowman's capsule to still be high enough to supple blood down the efferent artery to peritublar capillaries further along the nephron
Term
what percentage of blood supplies the kidneys.
Definition
20%
Term
Whats unique in the kidneys with their arteriole / capillary / venoule system?
Definition
There is an arteriole (Afferent arteriole) that supplies a large capillary bundle (known as the glomerular capillaries) which then empties into anoter arteriole instead of a venoule known as the EFFERENT arteriole to more capillaries and then FINALLY into venoule.
Term
At the bowman's capsule what type of mechanism is occuring? filtration/secretion/reabsorption or exretion?
Definition
Filtration
Term
At what part of urine formation doe we have tubular secretion and resorption?
Definition
peritubular capillaries
Term
What are the only two mechanisms to be removed from the body via the urinary system
Definition
1. Secretion from the peritubular capillaries
2. filtration at the glomerular capillaries
Term
Excretion = X - Y + Z
Definition
Excretion = Filtration - Reabsorption + secretion
Term
What are the two types of nephrons and what percentage of each are in the kidneys
Definition
1. Cortical Nephrons = 75%
2. Juxtamedullary nephrons = 25%
Term
Describe the difference in tightness of the junctions in the nephron
Definition
The nephron starts at the glomerulus capillaries and goes into tubules which are generally loose in their junctions. The junctions grow much tighter as you progress through the nephron to the collecting ducts which have the tightest junctions.
Term
What are the three determinants of the glomerular filtration rate? What are their individual pressures in mm Hg?
Definition
1. glomerular hydrostatic pressure (60mmhg)
2. Glomerular colloid osmotic pressure (-32mmHg)
3. Bowman's Capsule Pressure (-18 mmHg)
Term
What is the bowmnan's capsule colloid osmotic pressure?
Definition
ZERO! There should never be filtration of proteins into the bowman's capsule in a healthy human.
Term
If the symbol πB was present on net filtration equation it represents what determining factor of pressure?
Definition
Bowman's capsule osmotic pressure. (pathological and normally it is zero)
Term
How much reabsorption is possible at the glomerula capillary in the bowman's capsule
Definition
ZERO. The body has the pressures so high going out purposely to prevent any reabsorption. Also there is no venuole end like we see in capillaries in the periphery which would allow for lower pressure to reabsorb fluid. This is done purposely to make sure there is always filtration!
Term
How would constricting the afferent and efferent arterioles at the glomerular effect the GFR?
Definition
xxx
Term
The filtration factor is derived from?
Goes down if?
Definition
FF = GFR / Renal plasma flow (RPF)
Goes down if decrease GFR and increase RPF.
Term
What influences the net filtration pressures the most?
Definition
The glomerular colloid osmotic pressure. See power point. Due to water leaving at the beginning portion of the glomerular capillary on the afferent side then there is less fluid on the efferent side so now that protein still present in the blood has even a stronger pressure because there is less fluid for the same amount of protein. As a result less water will want to leave the capillaries on the efferent side because proteins there have a much strong pulling effect to keep them in the capillaries as a result of so much water lost at the beginning afferent side.
Term
What factors will decrease filtration and decrease GFR
Definition
1. decrease hydrostatic pressure of glomerulus
2. Increase osmotic pressure in glomerulus will keep fluid in the capillary and not let it filter out
3. increase Pb which means increase hydrostatic pressure in bowman's capsule which will counter the capillaries attempt to filter out. This caused by blockages in the kidney distal to the tubule.
Term
decrease Filtration and GFR results in more urine or less?
Definition
less
Term
Name three factors that will increase filtration and increase GFR
Definition
1. Increase πB osomotic pressure in bowman's capsule from more proteins leaving the capillaries
2. decrease πG osomotic pressure in glomerula means not enough protein to hold onto water
3. Increase Pg hydrostatic pressure in the glomerular capillaries will cause a large pressure forcing out the capillaries in bowman's capsule
Term
Why is filtration effected more by osmotic pressures than hydrostatic pressures in the kidneys
Definition
The kidneys nephrons and filtration rates are effected less by hydrostatic pressures because of the ability to increase or decrease the diameter of the afferent and efferent arterioles supplying blood to the glomerular capillaries. The body therefore can adjust the pressures from the heart to best meet the needs of filtration. Osmotic pressure is more labile and has more of an effect on filtration. If protein escapes into bowman's capsule you have a large effect. If protein is low in the capillaries that too will significantly increase your filtration. ect..
Term
net filtration pressures average around?
Definition
10 mmHG
Term
Average GFR is?
Definition
125 ml/min
Term
The filtration coefficent is expressed as Kf. It is derived from?
Definition
GFR / Net filtration pressure (NFP)
125 / 10 = 12.5 ml/min per mm Hg
Term
Why do the nephrons have a significantly higher filtration coefficent than the capillaries in the peripheral tissues?
Definition
Kidnes have higher filtration coefficent because of its greater permeability of the capillaries (AKA due to its increase conductivity)
Term
What happens to nephrons with chronic diabetes the leads to adecrease in filtration coefficent
Definition
Diabetes causes glomerular injury resulting in decrease permeability. The glomerulus is thickened at the basement membrane
Term
Describe the glomerular capillary filtration barrier functioning parts
Definition
basement membrane has negatively charged glycoproteins that prevent proteins (which are negative too) from passing through. Podocytes also have a negative charge that prevents proteins from leaving. H20 and small ions can pass through the podocytes via filtration through the fenestrations of the endothelium then through the basement membrane and then through the slit pores that empty into the bowman's capsule.
Term
What do filtration slits do during filtration in glomerular capillaries? what controls them?
Definition
Filtration slits also known as slit pores are on the outer layer of the glomerular capillaries. They are the final holes that H20 and small ions can leave through. This opening can be squeezed closed by cells (NOT SMOOTH MUSCLE) those cells are called mesangial cells
Term
what are the three hormones produced in the kidneys
Definition
1. renin
2. erythropoietic factor
3. 1, 25 dihydroxycholecalciferol
Term
Renin angitensin aldosterone system responds to what changes in what ions
Definition
Decrease in over all sodium or change in the ratio of Na and Cl
Term
What is renin and what does it do?
Definition
Renin is an enzyme that converts angiotensin to Angiotensin I
Term
Where does angiotensin I get converted to II and by what?
Definition
Angiotensin I converted by angiotensin converting enzyme in the lungs to angiotensin II
Term
Angiotensin II can stimulate increase secretion of aldosterone from the glomerulosa of the adrenal cortex which will result in
Definition
increase Na reabsorption and K secretion in late Distal tubule and collecting duct.
Term
What four areas does angiotensin II effect?
Definition
1. Increase Aldosterone release
2. tubuloglomerula feedback
3. vasoconstriction of peripheral vessels
4. ?
Term
Can cortisol bind to the mineralcorticoid receptors in the kidneys?
Definition
Normally no. The original shape of cortisol can bind to the aldosterone receptors known as mineralcorticoid receptors. However there are enzymes that change the shape of the cortisol hormone so that it cannot fit into the receptor anymore. A deficiency in this would present as if you had too much aldosterone.
Term
ANP acts on what cells of the kidney. Where does ANP come from?
Definition
principal cells. ANP comes from the stretch of the atrium when there is large volumes in circulation . The ANP hormone binds to a enzymatic protein receptor on the membrane of principle cells in the kidney which activates guaynine cyclase and activates kinase that phosphorylates proteins which block reabsorption of Na from the lumen. And thereby decreases BP
Term
Name three ways ANP works to decrease BP? What exactly do all these ways have in common
Definition
1. Increase Renin release
2. Decrease Aldosterone
3. Increase GFR

All three result in increase Na and H20 excretion.
Term
Name two ways calcium can be reabsorbed
Definition
1. Cross the cell via active and passive transport 2. in between cells H20 and Ca can squeeze through (paracellular)
Term
Name 7 functions of the kidney
Definition
1. Regulation of extracellular fluid volume and BP
2. Regulation of osmolarity
3. maintenance of ion balance
4. homeostatic regulation of pH
5. excretion of waste
6. production of hormones
7. gluconeogenesis
Term
What % of the plasma entering the bowman's capsule in the afferent artery enters the capsule?
Definition
20%. But 19% of this is reabsorbed before it is reaches the bladder.
Term
As the hydrostatic pressure from the afferent end of the glomerulus decreases towards the efferent end; what is happening to the osmotic pressure and why? Is it going up or down?
Definition
The osmotic pressure increases towards the efferent end of the glomerulus because there is a higher ratio of proteins to water. (B/c a lot of water is lost in filtration prior) The lower the ratio of protein to the surrounding plasma fluid means those proteins have a higher pressure.
Term
The end of the collecting ducts at the largest section is known as?
Definition
The duct of bellini
Term
What percentage of the cardiac output goes to the kidneys?
Definition
20%
Term
Filtration can only occur if the pressure inside the capillaries is less or higher than the pressure out?
Definition
Pressure inside the capillaries must always be higher than the pressure outside in order for filtration to occur.
Term
Kf is also known as?
Definition
the ultrafiltration coefficent
Term
Kf is affected by?
Definition
surface area and contraction of mesangial cells. So Kf describes how permeable a membrane is. The more surface area than the more places for substances to move across and therefore the more permeable that membrane can be. If the surface of the glomerulus is damaged then there are less areas for filtration and the Kf is lowered. If mesangial cells are contracting then that will decrease the surface area as well and lower the Kf.
Term
What two diseases cause an increase in the thickness of the basement membrane?
Definition
1. HTN
2. DM
Term
what are three characteristics that decide whether or not a molecule can be filtered at the glomerulus?
Definition
-molecular weight and radius
-charge on molecule
-shape of molecule (globular and rigid, less clearance)
Term
what is the difference between transcellular and paracellular transport? What are the types of transport that follow these paths?
Definition
Transcellular tx occurs through the cell while paracellular occurs between two cells. This describes re-absorption the movement of water and solutes from the lumen through the endothelium to the capillaries. Movement between cells or through cells is done by active transport, passive transport and osmosis.
Term
what does obligatory reabsorption refer to?
Definition
Water must follow solutes in higher concentration so its obligated! So since 65% of ions are reabsorbed in the proximal tubule then an equal ratio of water is also reabsorbed.
Term
what does the transport maximum (Tm) for glucose refer to? What is the Tm for glucose?
Definition
Refers to the maximal amount of glucose that the kidneys are able to reabsorb from filtration and not waste. The Tm for a health person is approximately 375 mg/ min. DKA patients will have such high sugars that these active transport systems cannot keep up and therefore we have glucose in the urine.
Term
Name 7 functions of the kidney
Definition
1. Regulation of extracellular fluid volume and BP
2. Regulation of osmolarity
3. maintenance of ion balance
4. homeostatic regulation of pH
5. excretion of waste
6. production of hormones
7. gluconeogenesis
Term
What % of the plasma entering the bowman's capsule in the afferent artery enters the capsule?
Definition
20%. But 19% of this is reabsorbed before it is reaches the bladder.
Term
Normal osmolarity reflects? Whats the range
Definition
Reflects the osmotically active particles not the weight. Normal range is
Term
When you drink a liter of water does the osmolarity of the plasma change? What happens to the urine osmolarity?
Definition
The plasma molarity has a very minimal change but the urine osmolarity has a very large change as the kideny excretes the large amount of water that you don't need.
Term
Why does the osmolarity of the urine double at the descending loop of henle as it was from the glomerulus?
Definition
The descending loop of henle is very permeable to water and the body absorbs a large amount 65% here. So there is a large amount of solutes remaining in the tubule which causes the osmolarity to go up.
Term
At what point in the nephron system does the body begin removing solutes and bringing down the osmolarity of the urine?
Definition
On the ascending loop of henle and distal tubule a large amount of solutes (mostly Na and Cl) are reabsorbed to the body and this dilutes the urine and therefore dilutes the urine.
Term
Normally with the help of ADH where will more H20 be reabsorbed by aqua porins?
Definition
In the late distal tubule and collecting ducts.
Term
where is NaCl reabsorbed...late or early distal tubule?
Definition
Early distal tubule.
Term
Is more water reabsorbed in the cortex region or medulla region of the nephron?
Definition
Cortex
Term
Whats the main difference between peritubular capillaries and vasa recta capillaries?
Definition
Peritubular capillaries are mainly found in the cortical nephrons and primarly serve the functions of secretions and reabsoption due to their rich capillariy beds against the nephron tubules. The vasa recta capillaries are mostly in the juxtaglomerular nephrons and heavily focused in the loop of henle where they serve more of an osmosis purpose. Vasa recta also known as osmotic exchangers.
Term
What/and where is the most contributing factor for the countercurrent multiplier?
Definition
Active transport mechanisms in thick ascending loop of Henle which transport Na, Cl and K out of the nephron and back into the plasma.
Term
What is countercurrent multiplier in the kidneys
Definition
This is mechanism used in the kidenys that uses energy to maintain a concentration gradient so that the kidney's don't excrete the full 20% that is filtered out of the blood at the glomerularis. IF that was so then there would be an imbalance to the concentration gradients that are vital to life for action potentials. The kidney does this via the anatomy of the kidney's nephrons. So the descending loop of henle has lots of aqua porins but no active transport. So lots of H20 leaves the nephron during its descent through the loop of henle. Now there are higher concentrations of solute as the urine begins to travel up the ascending loop. The ascending loop of henle has no aqua porins so no H20 is reabsorbed. But it does have active transport pumps which use energy to remove Na, Cl, and K to the interstitial space. Now remember the loop of henle is in the same general space. So the more those active pumps pump solutes into the interstitial space in the ascending limb that will create a multiplying effect to draw more H20 (increase osmosis) out of the proximal limb of henle because the solutes effect all the interstitial space. H20 follows Na. Since there are on aqua porins in the ascending loop to allow H20 to flow into the interstitium then the water will flow from the descending loop at a higher rate. Multiplying effect!!
Term
What does the obligatory urine volume refer to?
Definition
amount of urine volume necessary to remove the waste present
Term
In renal disease what happens with the obligatory urine volume?
Definition
The damaged kidneys are not able to concentrate urine with solutes as effectively and the obligatory urine volume is therefore increased. So it takes more overall volume of urine excretion to get all the waste disolved and out of the body versus a healthy kidney which can remove the same amount of waste in only half of the volume of excretion.
Term
whats the main difference between central and nephrogenic diabetes in relation to ADH
Definition
central DI there is not enough ADH production. While nephrogenic DI there is enough ADH but the kidneys are not responsive.
Term
Osmotic diuretics works on what part of the kidney nephron? What is its mechanism of action?
Definition
Works mostly on the proximal tubules by inhibiting water and solute reabsorption by increasing the osmolarity of tubular fluid.
Term
Loop diuretics work on what part of the kidney? what is its mechanism of action?
Definition
Works on thick ascending loop of henle and inhibits Na, K , Cl co-transport.
Term
Why are diuretic effects limited?
Definition
The renin angio aldosterone system begins to kick in and take control of solute excretion and overall reabsorption
Term
Name two types of osmotic diuretics. How doe they work?
Definition
1. mannitor
2. sucrose
They are osmotically active and when they enter the tubules they cannot be reabsorbed by anything so they hold alot more H20 in the tubules with them.
Term
Whats the main transport protein that is inhibited by the loop diuretics and where in the nephron is this occuring?
Definition
Effects the Na/Cl/K (all in one) co-transporter in the thick ascending limb of henle.
Term
Downside of loop diuretics as a result of shutting down the _____ pump what does that do to other Ion balances in the body?
Definition
They eventually decrease the osmolarity of the intersitial space. This then can effect aldosterone resulting in hypokalemia since aldosterone now will release more K. Also there is more of a loss of H ions (alkalosis develops) because more H ions are excreted since there is higher Na in the lumen than more coutnertransport of h out into the lumen and Na into the interstial space.
Term
How do carbonic anhydrase diuretics work?
Definition
Carbonic Anhydrase inhibitors work by inhibiting H secretion and HCO3 reabsorption which results in reduction of Na reabsorption.
Term
Where is erythropoietin released and what stimulates its release? Acts on where to increase RBC production?
Definition
Released in AFFERENT Arterioles by juxtaglomerular cells. Stimulus for secretion are hypoxia and decreased RBF. Acts on the bone marrow to increase RBC production.
Term
What disease would decrease aldosterone? And result in the decrease sodium resorption and how would that effect their serum K levels?
Definition
Addison's disease is where the adrenal gland destroys the parts of the cortex and results in decrease aldosterone. Less aldosterone means lower reabsorption of Na which means lower serum Na levels and as a result higher K serum levels.
Term
Ureters are lined by?
Definition
transitional epithelial cells with layers of smooth muscle. Smooth muscles help with peristaltic contractions to makes sure the urine gets to the bladder
Term
What is the function of the rugae in the bladder?
Definition
The function of the rugae is to allow the bladder, or other tissue, to expand when needed. When the bladder is not full, the rugae are folds in the tissue. However, as the stomach fills it expands by unfolding the rugae. Upon emptying, the reformation of the rugae causes the bladder to recede to its former size.
Term
Whats unique about the center of trigone?
Definition
Part of the bladder in the lowest part where urine drains into the urethra. This is area does not have rugae and instead is smooth to allow for easy flow of urine out of the bladder.
Term
How many urethral sphincters are there? What are the differences between the two?
Definition
Internal urethra is subconscious control and made up of smooth muscle. The external urethra is made up of skeletal muscle. Conscious control will releax it and allow urine to pass.
Term
What nerve innervates the external sphincter?
Definition
pudendal nerve
Term
What is the name for the smooth muscle that surrounds the bladder and helps contract it when stimulated by what nerve after stretch fibers activated.
Definition
Detrusor smooth muscle surrounds the bladder and is stimulated by stretch receptors. The efferent nerve to the detrusor is a parasympathetic nerve called the pelvic nerve.
Term
Whats the difference in mechanism of action between innervation of the smooth muscle by sympathetic and parasympathetic nerve in the bladder.
Definition
Sympathetic stimulation via the hypogastric suppresses contraction of the detrusor smooth muscles of the bladder while parasympathetic stimulation via the stretch reflex and pelvic nerve will contract the detrusor muscles.
Term
Why are babies incontinent?
Definition
Its reflexive and infants lack the comprehension for voluntary release of the external sphincter. Also they lack alot of skeletal muscle to control the external sphincter.
Term
At what pressure in the bladder would the external sphincter likely open up against voluntary control?
Definition
500 mL. Not only the pressure from this large volume will do this but also the involuntary contractions of smooth muscle from the micturition reflexes will too.
Term
What are some common age related changes in kidney / urinary system?
Definition
Decline in the number of functional nephrons
Reduction of GFR
Reduced sensitivity to ADH
Problems with the micturition reflex
Term
Faconi syndrome results in? what part of the nephron most commonly effected?
Definition
Causes an overall decrease in reabsorption bicarb, phosphate, glucose and/or amino acids at the proximal tubules
Term
Renal failure or insufficiency refers to a reduction in what?
Definition
GFR. The degree of remaining normal GFR decides where it is failure or insufficiency
Term
Renal Insufficiency the remaining normal GFR capacity is only?
Definition
25-30%
Term
In renal failure the remaining functional GFR capacity is only? While in end stage renal failure that number drops to?
Definition
Renal failure: 10-25%
End stage renal disease: <10-15%
Term
vasculitis and acute glomerulonephritis cause what kind of renal failure
Definition
intra-renal failure
Term
tubular necrosis – ischemia,toxins, heavy metals, CCl4 cause what type of renal failure
Definition
intra-renal failure
Term
heart failure causes what type of renal failure
Definition
pre-renal
Term
renal artery stenosis causes what kind of renal failure
Definition
pre-renal
Term
kidney stones cause what kind of renal failure
Definition
post-renal
Term
Prostate disease causes what kind of renal failure
Definition
post-renal
Term
chronic renal disease is slow and changes the physiology / structure of the kidney by causing ____ and ____ of surviving nephrons
Definition
hypertrophy and vasodilation
Term
hypertrophy, vasodilation and increase arterial pressure on the nephrons will result in?
Definition
increase glomerular pressure and increase filtration.
Term
pH changes effects what functions of the body the most?
Definition
enzymatic functions and proteins.
Term
most important buffer in the intracellular are?
Definition
protein buffers. Hemoglobulin can act like a buffer in the blood.
Term
What are the three types of buffers. Why does the body need more than one buffer?
Definition
1. bicarb
2. proteins
3. phosphate
Need verious types of buffers to serve different areas of the body such as extracellular or intracellular. Also each of these buffers have different pKAs which will change the pH in different proportions depending on what the body needs and how fast.
Term
Where does bicarb have a bigger role..extraceullular or intracellular? Why?
Definition
Extracellular. Why? B/c it is more easily regulated in the blood between the lungs and kidneys.
Term
what is the process that occurs with carbonic anhydrase and bicarb ect..
Definition
Term
The majority of CO2 is transported in the blood as? Minority of CO2 is transported?
Definition
Majority of Co2 is converted to HCO3 while a very small amount is free floating as CO2. (that free form is your partial pressure)
Term
What happens to pH with alveolar ventilation changes? What is the normal alveolar ventilation
Definition
Normal alveolar ventilation is 1. The more alveolar ventilation then the pH will rise and person becomes more alkalotic.
Term
What happens to alveolar ventilation when the pH becomes more acidoitc
Definition
Increase alveolar ventilation
Term
Where are the chemorecpeptors located in brain. (3x)
Definition
1. medulla obligota
2. carotid sinuses
3. Aortic notch
Term
pH of urine can be influenced by proteins. Proteins will cause it to be more acidic or basic
Definition
acidic
Term
The majority 85% of bicarb reabsorption is done in the ___ of the nephron
Definition
proximal convoluted tubule
Term
pH of urine can be influenced by proteins. Proteins will cause it to be more acidic or basic
Definition
acidic??
Term
Phosphate is mostly reabsorbed in the?
Definition
80% reabsorbed in the proximal tubule.
Term
What are two ways for the two ammonium ions to leave the cell after they are made from glutamine metabolism.
Definition
1. Ammoninium ions can leave via counter active transport with Na.
2. Ammonium ions can loose a H ion and become ammonia. Ammonia unlike its ion version can passively leave the cell into the tubule lumen. The remaining H ion can also leave via active transport and the other buffer systems.
Term
The most powerful buffer system in the kidney is which system? Why?
Definition
Ammonium/ammonia system because the active transport of an ammonium ion will result in the removal of 4x H ions. While the phosphate system only allows for binding of one h ion to each phosphate. THe bicarb system only results in removal of one H ion too at a time.
Term
Na and H pumps are cotransport or counter transporters?
Definition
Countertransport
Term
Are K and Na pumps counter or co-transport
Definition
counter
Term
glucose and Na pumps are co or counter-transport
Definition
co-transport
Term
What cells secrete potassium?
Definition
Principal cells
Term
What cells reabsorb potassium
Definition
intercalated cells
Term
Explain autoregulation and how it is important for glomerular pressure
Definition
Autoregulation by the arterioles of the afferent and efferent arterioles ensures that even with wide pressure changes between 60-160 at the afferent artery will not greatly effect the glomerular filtration hydrostatic pressure, thus ensuring the homeostatic filtration amount is consistent.
Term
explain what happens when there is increase arterial pressure and how myogenic mechanism of the smooth muscle autoregulates
Definition
An increase in pressure to the gomerular capillaries will result in greater filtration beyond what is the normal amount. The arterioles have built in mechanisms to quickly adjust to higher pressures. Higher pressures means more stretch on the endothelium of the arterioles. That results in an influx of calcium which excites the smooth muscle and causes it to contract more. (constrict) More constriction means less blood flow to glomerular capillaries and brings it back to homeostasis.
Term
explain macula densa feedback
Definition
The macula densa is an area with macula densa cells that are on the distal convoluted tubule. These cells are chemoreceptors that pick up the osmolarity of sodium chloride in the late thick ascending limb. These cells are positioned close to the afferent arteriole and the juxtaglomerular cells on the afferent and efferent arterioles. The whole function of the macula densa is to make sure there is enough blood pressure to the glomerular capillaries to make sure our kidneys are able to function properly and excrete waste / maintain homeostasis. The only way it knows if BP is adequate is by indirectly measuring the NaCl levels in the late thick ascending loop of henle. If there is a low BP then there is low Filtration volume. Low filtration volume means less NaCl. So most of that NaCl will have be reabsorbed by the time it got to these receptors. So they realize something's wrong and they need to increase the filtration rate by increasing the hydrostatic pressure in the glomerulus by:
1. vasodilate the afferent arteriole to increase blood flow the glomerular capillary to increase filtration rate and hopefully get more NaCL to the macula densa to shut them up.
2. It also signals juxtaglomerular cells via prostaglandin release to release renin. Renin acts on the efferent arterioles to constrict them. That causes backup of blood into the glomerulus which means more hydrostatic pressure and more filtration and hopefully more NaCl to float by the macula densa to shut them up.
Goal? Feedback! It adjusts noticing there is less NaCl so it increases NaCl by increasing hydrostatic pressure in the glomerulus.
Term
What stimulates ADH to be released from posterior hypothalamus to stimulate increase water reabsorption in the collecting ducts?
Definition
ADH is stimulated by baroreceptors and osmoreceptors in the brain to low osmolarity and low BP. ADH also stimulates renin to be released which will vasocontrict after it changes angiotensin 1 to 2.
Term
When would you have a thirst mechanism activated? When ADH is increased or lowered?
Definition
Increased! Because ADH increase means you want more water in the body so at the same time your body will want to drink more water to help the kidney's conserve water and dilute the higher osmolarity that was present to stimulate ADH release in the first place.
Term
What type of aquaporins are made in response to ADH and where are they located?
Definition
Aquaporin 2s respond to ADH. They are located in the late distal tubule and collecting ducts.
Term
explain the mechanism of action of ADH on the cells in the nephron
Definition
ADH is an
Term
How do renin inhibitors work? 3x
Definition
decrease aldosterone
directly inhibit Na+ reabsorption
decrease efferent arteriolar resistance
Term
Increase in blood volume stretches the right atria which will release ANP. ANP will decrease blood volume via three ways...
Definition
1. Decrease renin release
2. decrease aldosterone release
3. increase GFR
Term
Will ANP release increase or decrease GFR?
Definition
Increase! The atrial stretch receptors sense too much volume in the right atrium and want to decrease the volume. So it does this by making the kidney's pee out the extra volume.
Term
ANP does the exact opposite of what hormone?
Definition
Aldosterone
Term
whats the ratio between bicarb and co2 in order to have a 7.4 pH
Definition
20:1 ratio
Term
The anion gap refers to a measurement of what?
Definition
The anion gap represents the missing unmeasured amount of anions not measured with serum lab tests. The unmeasured anions always in the body can change. Normal it reflects proteins, phosphates, lactate,
Term
Anion gap can occur as a result of an increase in acids or a loss of?
Definition
increase in acids organic and inorganic
Term
Increase anion gap can be caused by?
Definition
1. lactic acidosis
2. DKA
3. ASA overdose
4. methanol overdose
Term
normal intracellular fluid is around ___ L
Definition
28L
Term
Normal interstitial fluid is approximately _____ L
Definition
11 L
Term
Normal plasma fluid level is approximately ____ L
Definition
3.0L
Term
Extracellular fluid includes interstitial and plasma volume and that total is around _____L
Definition
14.0L
Term
The biggest factor in why different people have different total body water is effected from the amount of ___ they have
Definition
fat
Term
Will the leaner or more fat person have the larger percentage of total body weight
Definition
Leaner people will have more total body water %
Term
Where is our thirst mechanism located?
Definition
In the perioptic nuclei of the posterior hypothalamus
Term
What stimulates a feeling of "thirst"?
Definition
The osmolarity of the blood is sensed by osmolality sensors which are preoptic nuclei in the hypothalamus.
Term
name five factors that stimulate thirst
Definition
1. increased osmolarity
2. decreased blood volume
3. decrease blood pressure
4. increase angiotensin II
5. dryness of mouth.
Term
What's one reflex that prevents us from drinking too much water when our body tells us we need volume?
Definition
The stomach will become distended and that stretch on the stomach tells the brain to stop eating and to stop being thirsty because the stomach is full and everything in it needs to be digested and absorbed first.
Term
when aldosterone is working on salivary glands, sweat, colon its mechanism of action is?
Definition
increase Na retention/reabsorption
Term
Do not correct Na levels too quickly because it will do what to the brain?
Definition
Brain shrinkage.
Term
clearance is defined in terms of ___ per min
Definition
mL / min
Term
To get an accurate clearance you have to use a specific substance with what characteristics? Name a common substance used for this.
Definition
The substance first must be able to be filtered into the nephron. Then it cannot be reabsorbed or secreted along the nephron. The filtered amount must = the amount excreted. That will tell you the clearance rate of whats filtered compared to volume in systemic circulation. A substance often used is Inulin or creatinine.
Term
creatinine hows downsides to estimating GFR. What are they?
Definition
Some Creatinine may be secreted into the nephron however its less than 10%
Term
what are the characteristics of a substance you would use to determine renal plasma flow? Whats an example of a good substance for this
Definition
the substance would have to be both filtered and secreted. Example is para-aminohippuric acid PAH
Term
Why is para-aminohippuric acid PAH not perfect for determining Renal plasma flow?
Definition
10% doesn't enter the nephron and instead goes to the veins and tissue of the kidneys. So we have to correct the answer we get and add 10% to it.
Term
what kind of pump do thiazide diuretics work on and where in the nephron does this take place
Definition
thiazide diuretics work on Na / Cl cotransport pumps in the early distal tubule by blocking them from reabsorbing Na/Cl from the urine to the interstitial fluid. By doing so more H20 will remain in the lumen of the nephron along with the NA and hence why people will pee more.
Term
whats the difference between intercalated discs and principal cells in relation to K.
Definition
Principal cells secrete potassium into the lumen of the nephron by a one way pump while intercalated cells absorb back potassium through countertransport with H ions. The acid H ions are secreted into the urine by this.
Term
does autoregulation effect urine flow?
Definition
NO! Autoregulation only controls renal blood flow to ensure the GFR is maintained at the body's homeostatic level.
Term
angiotensin works by increasing?
Definition
renal tubular sodium reabsorption
Term
Does ANP increase or decrease GFR..Why
Definition
ANP increases GFR because ANP is only released when there is excess volume of blood returning to the right atrium. The excess blood volume stretches receptors that release ANP that then dilate the afferent arteriole of the glomerulus to increase hydrostatic pressure and filter more volume out of the body via urination and thereby decreasing systemic volume.
Term
If the urine is very concentrated then you would presume ADH levels would be high or low?
Definition
Higher. Which means lots of water reabsorbed via aquaporins leaving very hyperosmolar urine to be excreted.
Term
most of the water reabsorption occurs in the medulla or cortex? And where exactly at that area?
Definition
Most water reabsorption occurs in the cortex at the distal convoluted tubule
Term
does the vasa recta or peritubular serve as the countercurrent exchanger?
Definition
vasa recta of the juxtaglomerular nephrons. The vasa recta has very low blood flow and accounts for only 1-2% of blood supply.
Term
at what point in the nephron is the nephron lumen isoosmolar to the interstitial fluid and why?
Definition
At the proximal tubule there is approximately 65% of water reabsorption that leaves the tubule to the interstial space that has more solutes than does the lumen of the nephron. This results in a equal osmolarity (= # of solutes) between the nephron lumen and interstitial fluid. To change this balance the nephron later down the tubule will actively pump ions against their gradient which will then cause a "multiplier" effect to force water to follow the Na.
Term
what is obligatory urine volume?
Definition
In order for the body to remove waste it needs fluid for it to dissolve in so that it can flow out of the body via excretion. Otherwise the waste would accumulate as trash and clog everything up. So the obligatory urine volume is the amount of fluid needed to dissolve all the waste from the body in order to get it out via excretion.
Term
nephrogenic diabetes is failure to produce or respond to ADH?
Definition
Respond
Term
central diabetes insipidous is failure to produce or respond to ADH?
Definition
produce
Term
Causes of nephrogenic diabetes insipidus
Definition
drug induced renal damage: lithium, analgesicspyelonephritis, hydronephrosis, chronic renal failure loop diuretics
Term
5 things that cause hypokalemia
Definition
1. excess insulin
2. loop and osmotic diuretics
3. aldosterone
4. diarrhea
5. metabolic alkalosis
Term
Will alkalosis cause hypo or hyper kalemia
Definition
Hypokalemia
Term
spirlactone will increase or decrease K?
Definition
Increases K levels because it blocks the mineralcorticoid receptors in principal cells that normal increase Na/K exchangers and results in less exchange from the inerstitium so more k left in blood while more Na left in pee so water will follow and body will be diuresed.
Term
Where are the ureteral openings in the bladder located? What surrounds them?
Definition
The ureteral openings in the bladder are posterior and at the bottom of the bladder. Above them are multiple folds known as rugae that expand when there is volume and fold up when there is no pee collection. Below the ureters is the center of trigone which has a very different shape than rugae. It is smooth and lined to allow urine to freely pass down into the urethra.
Term
describe the micturition reflex
Definition
The as the bladder fills with urine it stimulates stretch receptors that relay information to the brain. Along the way at the spinal cord there is a relay (reverberant pathway) that also sends an EFFERENT signal via parasympathetic to the bladder to contract. The more the stretch the more the efferent signals to tell the bladder to contract more. The strengths of the contractions intensify in proportion to the increasing volume in the bladder.
Term
name two types of abnormal tubular function
Definition
1. franconi syndrome
2. Renal tubular acidosis
Term
franconi syndrome is a disease to what part of the nephron
Definition
proximal tubule.
Term
two common causes of franconi sydnrome are?
Definition
1. heavy metal ingestion
2. genetics
Term
what disease will cause decrease K excretion and Na absorption.
Definition
addison's disease
Term
what disease will cause decreased Na+, Ca++, HCO3- reabsorption, hypotension
Definition
barter's syndrome
Term
what disease results in decrease H20 reabsorption and hypernatremia
Definition
Central DI
Term
whats the role of carbonic anhydrase in the buffer system of the body?
Definition
It combines CO2 and H2O together to form H2CO3.
Term
What enzyme catalyzes the formation of bicarb and H2CO3? Where is this enzyme found?
Definition
carbonic anhydrase found in red blood cells catalyze the hydration of CO2 with H20 to form bicarb HC03 and H2CO3
Term
what does chloride shift refer to in relation to red blood cells and buffer system
Definition
Bicarb and Chloride are always moving in opposite directions in order to maintain a consistent negative charge. So if bicarb leaves hemoglobin than Cl enters.
Term
do the kidneys secrete volatile or non-volatile acids?
Definition
Non-volatile acids
Term
Explain how the kidney's contribute to acid/base balance of the body
Definition
Kidney's excrete H, excrete non-volatile acids such as H2SO4, H3PO4, reabsorb bicarb, make new bicarb, and secrete H ions.
Term
what kind of pump is used for bicarb reabsorption? Where is the majority of bicarb reabsorbed?
Definition
Counter active transport H / Bicarb pumps are used primarily in the proximal tubule to reabsorb approximately 85% of Bicarb. For every bicarb reabsorbed then there is 1x H ion secreted.
Term
How does the intercalated discs in the collecting tubules differ in how they secrete H ions and reabsorb HCO3?
Definition
hydrogen ion secretion in the collecting tubule is mediated by a H+ ATPase pump in the luminal membrane and a Cl-HCO3- exchanger in the basolateral membrane
Term
IF a person is in resp alkalosis how will the body respond in regards to
1. reabsorption of HCO3
2. secretion of H ions
3 HCO3 secretion
Definition
1. Decrease reabsorption of HCO3
2. Decrease Secretion of H ions
3. Increase HCO3
Term
why is there a rebound alkalosis from diuretics?
Definition
Loop diuretics block Na/K/Cl pumps at the thick ascending loop of henle. This results in larger amounts of ions in the lumen. Large concentrations of negative Cl ions in tubular lumen will favor H + ions to move from the cells/interstital fluid to the lumen in the distal tubule. Also due to effects of aldosterone; Na can be exchanged for K or for H if low levels of K. So Loop diuretics block K reabsorption at the K/Na/Cl pumps on thick ascending which means further down the nephron at the collecting ducts there are less K ions in the interstitial fluid. For aldosterone to work here it needs K in the interstitial fluid to excrete out in exchange for Na. So Now it makes up for this lack of K because of diuretics and exchanges H ions instead for Na reabsorption. This further causes metabolic alkalosis.
Term
in a normal human the total anions should equal or be more than the total cations
Definition
equal
Term
why is unmeasured cations normally omitted from the anion gap? What are the tow omitted cations?
Definition
Cations have a + charge. Mag and Ca are omitted from the anion gap because their concentrations are so small that they are not needed to evaluate the anion gap.
Term
Normal Anion Gap is? Why isn't zero if we already know anions = cations
Definition
8-16. There are more unmeasured anions than there are cations. So when you do the equation out there are more MEASURABLE cations (More unaccounted for anions which would have brought this number down to zero) resulting in a number that is not zero.
Term
acids are anions or cations?
Definition
Anions and usually are unmeasurable in the blood so we account for them in the anion gap equation.
Term
why is there no change in the anion gap for hypercholoremic acidosis?
Definition
The anion gap remains unchanged because chloride is measurable first of all so its factored into the equation. Secondly there is more chloride in the blood/interstitium therefore favoring more bicarb secretion and decrease bicarb reabsorption to balance the electronegativity of the plasma from the high Cl.
Term
For pathologies such as DKA or lactic acidosis there is an increase in the anion gap but what happens to the chloride?
Definition
Cl is normal or doesn't effect the anion gap. That is why conditions such as DKA and lactic acidosis is called normochloremic acidosis.
Term
if Cx < CInulin then there was tubular secretion,reabsorption, or neither?
Definition
Tubular reabsorption
Term
if Cx > CInulin then there was tubular secretion,reabsorption, or neither?
Definition
Tubular secretion
Term
if Cx = CInulin then there was tubular secretion,reabsorption, or neither?
Definition
Neither. Just like inulin all of substance x at the bowman's capsule is excreted in the urine without any of it being reabsorbed and without any more of x being added to the urine via secretion.
Term
In descending order list who has more total body water. Infants, Men, Women
Definition
Infants > Men > Women
Term
normal mL of fluid intake is ?
Definition
2,300 mL
Term
normal mL of output for the body is?
Definition
2,300 mL
Term
Normal insensible loss is around ___ mL. Insensible loss is from ____ and ______
Definition
700mL of insensible loss daily from the skin and lungs.
Term
describe the thirst mechanism of the body
Definition
Osmolarity receptors in the hypothalamus detect high concentrations of solute and recognize the body needs more fluid. So it stimulates ADH release to retain fluid and to stimulate body to want to drink more water.
Term
name five stimuli for thirst
Definition
Increased osmolarity
Decreased blood volume
(cardiopulmonary reflexes)
Decreased blood pressure
(arterial baroreceptors)
Increased angiotensin II
Other stimuli:
- dryness of mouth
Term
tubularglomerular feedback will vasoconstrict which arteriole
Definition
efferent arteriole
Term
the most important determinant of Extracellular fluid volume is?
Definition
Na
Term
increase ingestion of Na results in inc or dec of renin?
Definition
Decrease renin because your BP/ECFV will go up as a result of exogenous salt being added therefore RAAS doesn't need to do the same thing.
Term
Cells shrink due to ___natremia
Definition
hypernatremia.
Term
Hyponatremia will cause cells to shrink or swell
Definition
swell
Term
what kind of rapid Na change will potentially cause vessels to tear in the brain?
Definition
Shrinking from hypernatremia
Term
glutamine is broken down into ___ and ____
Definition
2 bicarbs and 2 NH4 ammonium ions
Term
What is the difference between ammonia/ammonium buffer systems in the collecting ducts compared to tubules?
Definition
In the tubules there is active transport of NH4 (4x hydrogens) and by passive diffusion of NH3 versus in the collecting ducts there is passive removal of only NH3 (3x hydrogen) which then can bind to H+ ions in the tubular lumen
Term
the unmeasured anions in the body is what contributes to the anion gap. The more unmeasured anions than the larger the gap. Name some of these unmeasured anions
Definition
1. SO4
2. PO4
3. Albumin
4. inorganic acids
5. lactic acid / ketones
Term
Name four conditions that can cause metabolic acidosis with a normal anion gap but large Cl count.
Definition
1. diarrhea
2. renal tubular acidosis
3. addison's disease
4. carbonic anhydrase inhibitors. (some of the transport of HCO3 requires CL for countertransport so if HCO3 is not being made by CA then CL will remain in the peritubular capillaries and interstitial fluid.
Term
normal renal plasma flow is? What substance do we use to test this? What characteristic of this substance is necessary for it to be an effective test of renal plasma flow?
Definition
Normal renal plasma flow is approximately 625 mL/min. We use PAH para-aminohippuric acid to test the renal plasma flow. Its not reabsorbed and almost all of it is excreted by the body via filtration at the glomerulus and secretion at the peritubulars.
Term
What is the purpose of inulin? What is a substitute for using inulin? What does it reflect?
Definition
Inulin is not a natural substance found in the body. It is unique in that it can only leave the blood via filtration a the glomerulus. It cannot be secreted or reabsorbed at the peritubular capillaries. Therefore it is a good indicator as to how healthy the glomerulus and the overall filtration abilities of both kidney's. The clearnance of inulin gives us the GFR of a person. A substitute for this substance is creatinine.
Term
What is normal renal blood flow? How is it determined? How much of the entire systemic blood flow goes to the kidneys?
Definition
Renal blood flow is approximately 1,200 mL/min and the body sends about 20% of its blood to the kidneys. To determine renal blood flow you need to know the hematocrit and renal plasma flow. RBF = RPF / (1-hematocrit). Why do we 1-hematocrit? Hematocrit is a percentage out of 100% or out of "1". IF we minus out the hematocrit we are left with the systemic plasma concentration in the blood. The plasma concentration is what we want to divide by because it will lets us know how much blood we are actually flowing at our kidneys in comparison to whats available in the entire body. So now if we apply this to a sick person then if a person has kidney's that don't do a great job at filtering and secretion of nasty waste that is building up in the body then we got a problem. Renal plasma flow would be lower (lets say 500) because that reflects the kidney's poor job at filtration and secretion. If the body's CBC was normal and say their hematocrit was 42%. Then we would change the percentage lab value of hematocrit back to a decimal of 0.42. Then 1-0.42 = 0.58. The 0.58 is the plasma in the body. 500/0.58 = 862 mL/min. Thats bad! What if someone was also anemic and their RPF was bad too at 500 and hematocrit now is only 28% ? 500/0.28 = 694 mL/min. EVEN WORSE. So for healthy blood flow with all the waste that needs to get removed we need good kidneys and good complete blood values.
Term
What is the filtration fraction? Whats its significance? How is it determined?
Definition
Filtration fraction is just one look at one specific area of the kidney as a way to see how it is functioning. Filtration fraction only reflects filtraiton. And filtration only occurs at the glomerulus in the bowman's capsule. So filtration fraction is reflective of how healthy a glomerulus is by its ability to filter and also reflects the arterioles systems going to it and from it since they also influence its ability to filter. Normal filtration fraction is GFR/RPF. Why? Well RPF is reflective of the total amount of plasma both kidneys can completely remove from the blood running through the kidneys. GFR is only one part of the RPF. RFP is filtration plus secretion while GFR is reflective of only filtration. So we divide GFR from the RPF to get a fraction of how much the glomeruluar filtration is contributing to the overall excretion and removal of plasma from blood. Normal kidneys will remove 20% of all plasma passing by it in the renal blood flow.
Term
the tightest junctions in the nephron are located where?
Definition
in the collecting tubules
Term
vasa recta asscoiated with what types of tubules
Definition
medullary nephrons
Term
Are there more juxtaglomerular or cortical nephrons?
Definition
cortical nephorns make up 75% of all nephrons
Term
What is the SBP in the renal artery?
Definition
100 mm Hg
Term
what is the venous pressure of a peritubular artery
Definition
18 mm Hg
Term
Kf estimated by X / Y. Normal Kf is?
Definition
Kf = GFR / Net filtration pressure
Kf = 125 mL/min / 10 mm Hg.
Kf = 12.5 mL/min/mm Hg
Term
Kf is affected by what two things?
Definition
1. surface area of the glomerulus
2. Contraction of mesangial cells.
Term
Do capillaries have smooth muscle?
Definition
NOOOOOOOOOOO
Term
WHat increases the thickness of the glomerular capillary membrane?
Definition
1. Diabetes
2. HTN
Term
What characteristics of a molecule will decide whether or not it is filtered?
Definition
1. its size / shape
2. its charge
3. weight
Term
A molecule that is globular or rigid will have more chance or less chance for clearance / filtration?
Definition
LESS!!! RBCs are globulin and they don't filter. Also rigid means its less likely to squeeze through the endothelial fenestration
Term
what type of movement of ions is done between cells? paracellular or transcellular
Definition
paracellular
Term
what structure in the proximal tubule is unique to it and allows for more reabsorption?
Definition
Microvilli in the proximal tubule allow for more surface area and therefore more reabsorption. Also the junctions are loose / leaky.
Term
How would filtration fraction at the glomerular capillaries effect peritubular capillaries.
Definition
Well if a larger percentage of plasma is filtered at the glomerular capillaries then the concentration of blood the leaves the glomerulus to the peritubular capillaries will be much more viscous. Therefore the oncotic pressure of proteins will be higher at the peritubulars if the filtration fraction is higher at the glomerulus.
Term
The only time glucose would not be fully reabsorbed in the proximal tubule would be when?
Definition
If glucose threshold for reabsorption is exceeded.
Term
what are the different ways glucose is reabsorbed into the blood? where does this occur
Definition
All glucose should be reabsorbed from the lumen at the proximal tubule either through passive diffusion via Glut 1 and 2 channels or secondary active co-transport with Na.
Term
transport maximum for glucose is? what is glucoses renal threshold?
Definition
375 mg/min is the most amount of glucose the kidney's can reabsorb. While renal threshold refers to the amount of glucose in the renal blood that must be present before it is filtered out into the ultrafiltrate. That is around 250 mg/dl.
Term
Na/K pumps on the _____border aid in Na re-absorption
Definition
Basolateral border
Term
When we refer to "leaky" membranes we are typically referring to what route of transport?
Definition
paracellular (in between cells) if cells are tight then things can't slip between them.
Term
65% of mag re-absorption occurs where?
Definition
thick ascending limb of henle
Term
is the thick loop of henle permeable to H20
Definition
NO. It only moves ions
Term
The nephron is not permeable to urea at what parts of it?
Definition
late distal and collecting tubules.
Term
Donnan effect refers to?
Definition
GFR response to constriction of the efferent arteriole. The GFR will increase to a certain point of applying constriction to the efferent arteriole but after too much constriction then the GFR drops.
Term
what does endothelin hormones do to afferent and efferent arterioles? where does it come from?
Definition
Endothelin comes from local damaged endothelium. It causes vasoconstriction.
Term
angiotensin II works primarily on which arteriole of the kidney? How is GFR and RBF effected?
Definition
works mainly on the efferent arteriole to cause constriction and that results in increase GFR and decrease RBF.
Term
what hormone primarily constricts the afferent arteriole of the kidney?
Definition
adenosine
Term
bradykinin will vasodilate or vasoconstrict?
Definition
vasodilate
Term
What does dopamine do to the kidney?
Definition
Dopamine causes vasodilation of arterioles in kidneys while it causes vasoconstriciton on the peripheral arteroles. which means more GFR and more RBF
Term
Is the built in autoregulation of the renal blood flow influenced by hormones or nervous system?
Definition
NO. ITs independant and will do what ever necessary to filter wastes even if it means sacraficing some of the renal blood flow for GFR
Term
Name two mechanisms that contribute to autoregulation in the kidneys
Definition
1. Myogenic mechanism. Increase BP means increase stretch which elicits smooth muscle contraction to turn down BP
2. Tubuloglomerular feedback: the arterioles in the glomerular will feedback to make sure always enough GFR. So efferent will constrict and afferent will dilate.
Term
the macula densa cells of the distal tubula of the juxtaglomerular apparatus also signal the ______ to ______ to increase GFR if they sense a decrease in Na or NA/Cl concentrations
Definition
Macula densa cells via prostaglandin chemical messengers stimulate AFFERENT arterioles to vasodilate to increase GFR and increase Na/Cl concentrations.
Term
Most of renin is secreted from the afferent or efferent arterioles. Angiotensin mostly stimulates efferent or afferent?
Definition
Most renin is from the afferent arterioles while angiotensin causes constriction to the efferent arterioles.
Term
Name two mechanisms that contribute to autoregulation in the kidneys
Definition
1. Myogenic mechanism. Increase BP means increase stretch which elicits smooth muscle contraction to turn down BP
2. Tubuloglomerular feedback: the arterioles in the glomerular will feedback to make sure always enough GFR. So efferent will constrict and afferent will dilate.
Term
high protein diet does what to GFR And RBF?
Definition
increases GFR and RBF because of high glromerular pressures and hyperfiltration. Why? Because more protein means more amino acids and amino acids do get filtered. But they get reabsorbed 100% in the proximal tubule by Na co-transport. As a result more Na get reabsorbed with more amino acids. Cl follows Na usually and so does H20. So blood volume goes up. As volume goes up so does hydrostatic pressure in the glomerulus. Also macula densa senses less Na and less Cl. So it also tells afferent to release renin to cause angiotensin to constrict efferent to cause increase GFR.
Term
nicotine, nausea and morphine cause ADH release or inhibition?
Definition
More ADH release.
Term
cardiovascular reflex stimulation occurs when blood loss is > ________. that stimulates ADH release
Definition
>10%
Term
Whats the difference in the location of aquaporins 2, 3, 4 in the late distal tubule and collecting ducts?
Definition
aquaporins 2 area made and placed on the luminal side in response to ADH. While Aquaporins 3 and 4 are on the basolateral side.
Term
ADH can influence an increase in urea reabsorption where?
Definition
inner medullary duct
Term
PTH causes increase in Ca reabsorption and decrease re-absorption of ?
Definition
PO4 at the proximal tubule.
Term
normal range of specific gravity for urine
Definition
1.003-1.030
Term
concentration of urine depends on 2x things
Definition
1. amount of ADH
2. osmolarity of medulla interstitum from countercurrent mulitplier mechanism in loop of henle of juxtaglomerular nephrons and countercurrent exchanges in the vasarecta
Term
countercurrent exchange mechanisms occur in the vasarecta or peritubular cappilaries?
Definition
vasarecta. Here there is almost no change in blood osmolarity entering or leaving the medulla. Blood flow in vasa recta is low. All of this is in the medulla and refers to juxtaglomerular nephrons.
Term
erythropoeietin secreted from the ___arterioles of the kidney
Definition
afferent arterioles
Term
which adrenal disease will decrease aldosterone? Which adrenal disease will increase aldosterone?
Definition
addison's is autoimmune destruction of the adrenal gland resulting in decrease aldosterone secretion while cushing's disease is excess glucocorticoid and subsequently some extra aldosterone release.
Term
what nerve senses stretch in the stomach and then causes contraction of ____ muslces?
Definition
pelvic nerve senses stretch in stomach and innervates parasympathetic nervous system to cause detrusor muscle contraction
Term
external bladder sphincter controlled by?
Definition
pudendal nerve. Pudendal nerve to external sphincter under voluntary control causes skeletal muscle relaxation
Term
the most important buffer intracellular is bicarb ? or proteins? or phosphate?
Definition
proteins!!!pKa is near 7.4. Proteins include albumin and globulin
Term
where can you find carbonic anhydrase?
Definition
1. lungs
2. hemoglobin
3. epithelial cells
Term
phosphate is more common in the intracellular or extracellular space?
Definition
intracellular
Term
normal urine pH is
Definition
6 or between 4.5-8.0
Term
explain phosphate buffer system in the urine
Definition
out of the plasma filtrated 80% of phosphate is reabsorbed at the proximal tubules. The rest continues through the nephron and acts as hydrogen acceptors which allows for HCO3 to continue to be produced.
Term
NH4 transported to tubule lumen by Na counter transport
Definition
Term
If pH is 7.4 then the ratio of HCO3 to PCO2 is?
Definition
20
Term
does alkalosis or acidosis cause over excitability of nervous system and tetany
Definition
alkalosis
Term
it takes how many days for full effect of renal compensation?
Definition
3-5 days
Term
what kind of diseases result in loss of base and therefore metabolic acidosis?
Definition
renal tubular acidosis
diarrhea and loss of HCO3
Term
excess aldosterone will cause metabolic acidosis or acidosis? What happens..
Definition
Metabolic alkalosis. increase reabsorption of Na and HCO3 while loss of H cations
Term
purpose clinically of using anion gap?
Definition
allows for differential diagnosis. A person in metabolic acidosis from renal failure will have an inc anion gap while a person in metabolic acidosis from diarrhea will not have an anion gap that is elevated.
Term
most common culprit for increase anion gaps from organic acids?
Definition
organic acids such as lactate and ketones
Term
most common culprits for increasing anion gaps from inorganic acids
Definition
chronic renal failure and accumulation of inorganic acids such as HSO4 and HPO4
Term
a decrease in anion gap is not normal but perhaps may be from?
Definition
hypocalcemia or hypomagnesium
Term
Normally the unmeasured ___ are more than the unmeasured ______
Definition
UA > UC
Term
what is the total body water for females compared to males. Why?
Definition
Females have more fat than men so they have less water. Females have approximately 50% of their body weight is water while men its 60% or 42 liters.
Term
The fastest response to low BP is via?
Definition
barorecptors
Term
decrease blood volume stimulates ____ receptors while decrease blood pressure stimulates ______ receptors
Definition
decrease blood volume --> cardiopulmonary receptors.
2. Decrease blood pressure ---> baroreceptors
Term
strong sympathetic response will effect the kidney how?
Definition
1. constriction of afferent and causes decrease GFR and RBF and decrease Na so body can hold onto fluid to maintain pressure
2. Increase Na reabsorption via alpha adrenergic receptors increasing Na/K and Na/H pumps
3. increases renin release.
Term
What does ANP do to periphery and what does it do to epi and NE production
Definition
It decreases Epi and NE production and causes vasodilation of periphery. (opposite of symp)
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