Renal-Block 4
If there is constriction of the efferent arteriole this will result in an increase in Renal plasma flow (RPF) and a decrease in hydrostatic pressure as well as a decrease in the GFR:
False
Proteins commonly pass through the filtration slits in the filtration process
False
State some functions and properties of the DCT:
Function: 1. Reabsorption -Na+ and secretion of K+ -Bicarbonate and secretion of H+ -Cl- (thiazide sensistive transporters) 2. Secretion of ammonium 3. Parathyroid Regulated Ca 2+ Reabsorption Properties: 1. Relatively impermeable to water 2. Higherst Na/K ATP-ase activity 3. Receptors for Aldosterone
1) The vasa recta is only seen in the juxtamedullary nephron
T
IMCQ# If a substance has transport maximum for reabsorption, it means A. It is passively reabsorbed B. Below threshold it will be completely reabsorbed C. Only a constant fraction can be reabsorbed. D. Reabsorption is not affected by increase's in plasma concentration of the substance
B Below threshold it will be completely reabsorbed
State some functions of the collecting tubules and ducts:
1. In the collecting ducts there are Aquaporins that are under the influence of vasopressin. Theses aquaporins are associated with the reabsorption of water from the urine. 2.There are the Principal cells which have receptors for Aldosterone and they have an influence on sodium and potassium balance. Together, aldosterone and vasopressin are able to control the amount of water that is reabsorbed. 3. The Intercalated cells participate in acid-base homeostasis via the secretion of H+ ions and bicarbonate. The intercalated cells play an important role in the kidney's response to acidosis and alkalosis.
If a person undergoes prolonged fasting, then his urine will most likely have increased levels of which of the following? A. Ketones B. Fats C. Glucose D. Amino acids
A Ketones
Amino acids are almost completely reabsorbed from the glomerular filtrate via secondary active transport in the: A. proximal tubule. B. loop of Henle. C. distal tubule. D. cortical collecting duct. E. medullary collecting duct.
A proximal tubule.
When you are excreting a maximally concentrated urine, the greatest amount of water is being reabsorbed by the: A. proximal tubule. B. thin descending limb of Henle's loop. C. ascending thin limb of Henle's loop. D. thick ascending limb of Henle's loop. E. collecting ducts.
A proximal tubule.
Which of the following changes tends to increase GFR? a) Increased afferent arteriolar resistance. b) Decreased efferent arteriolar resistance. c) Increased Glomerular capillary filtration. d) Increased Bowmans capsule hydrostatic pressure. e) Decreased Glomerular capillary hydrostatic pressure.
c) Increased Glomerular capillary filtration.
1) Given these vessels: 1. Capillary tuff 2. Efferent arteriole 3. Peritubular capillary network 4. Afferent arteriole 5. Renal vein 6. Vasa recta Arrange the vessels in order starting from the Glomerulus region. a) 1,2,3,4,5,6 b) 2,3,5,4,6,1, c) 3,2,1,4,5,6 d) 4,1,2,3,6,5 6,4,5,3,1,2
d) 4,1,2,3,6,5
1) A decrease in plasma proteins results in? a) Increase in oncotic pressure b) No change in oncotic pressure c) Increased tubular reabsorption d) Decrease in oncotic pressure e) Increase in Glomerulus capillary pressure
d) Decrease in oncotic pressure
1) Juxtaglomerular cells secrete. a) Anti Diuretic Hormone b) Aldosterone c) Angiotensin 1 d) Renin e) Vasopressin
d) Renin
See and Practice Starling force equations & Image on questions 33
question number 30, 31,32.
Hydrostatic pressures of the capillaries favors filtration:
True
Hydrostatic pressures of the interstitium opposes filtration and favours reabsorption:
True
In the tubuloglomerular feed back mechanism, if there is a decrease of blood flow, this will stimulate cells to release prostaglandins which in turn will cause vasodilation of the afferent arteriole thus resulting in more blood flow:
True
In the tubuloglomerular feed back mechanism, if there is an increase of blood flow, this will stimulate cells to release adenosine which in turn will cause constriction of the afferent arteriole thus resulting in less blood flow:
True
Proteins in the Bowman's space indicates that the functional integrity of filtration barrier has been compromised
True
T/F: 1) The Peritubular capillary net work is located in the cortex:
True
SL Renal#
(*IMAGE)
56) State some facts about the PCT:
*(see image)
1) State the two factors that determine flux across the Glomerulus:
*Permeability* (includes size and charge) *Glomerular filtration pressure* (includes hydrostatic pressures and oncotic pressures)
IMCQ# A 42-year-old man is injected a substance that is freely filtered not absorbed and not secreted. Which of the following can is following statements would apply? A. Its clearance is equals GFR B. There is a net secretion of the substance C. There is net reabsorption of the substance D. Its clearance is same as PAH
A Its clearance is equals GFR
If a substance if freely filtered and neither absorbed nor secreted or metabolized in the nephron how will its clearance change with increasing plasma concentrations? A. clearance will not change B. clearance increases C. clearance decreases
A clearance will not change
Certain ions and molecules, for examples H+ and penicillin are most likely secreted from the peritubular capillary network into which of the following locations? A. Convoluted tubules B. Peritubular capillaries C. Loops of Henle D. Collecting ducts
A. Convoluted tubules Explaination: This question is focusing on the structure of a nephron. The H+ and pencillin are a trap to make you think about the absorption of ions in the segments to trap you into choosing your loops. You first have to know what the pertiubular capillary networks are on a Nephron and understand that these capillaries fuse their materials into the structure underneath it. These peritubular capillaries are found on TOP of the *Proximal Convuluted Tubules" along with the WHOLE NEPHRON. Convuluted Tubule written without the Proximal is also a trap to make you think this is not part of the nephron at all. However, the next thing to think about is where most of the H+ ions secretion would take place. Your Proximal Convuluted tubule composes of your NA/H+ antiport (which allows for Bicarb reabsorption) and your NA/H+ antiport (which helps for Cl- reabsorbtion and formate secretion). These are the signature processes seen in the Proximal Convulted Tubules. Loop of Henle = know for the Na, Cl-, and K- transporter. Collecting ducts= mainly K+ reabsorption. Not H+ absorption which is what this question has to do, as it secretes the H+ instead of absorbing it. A. Convuluted Tubule is the best answer choice.
IMCQ# A 23-year- old man after 2-day history of acute diarrhea complains of feeling weak and dizzy. His blood pressure is 90/60 . He looks ill. In this patient which of the hormone is responsible for both sodium & water retention A. Angiotensin 1 B. Aldosterone C. ANP D. ADH E. Epinephrine
B Aldosterone
IMCQ# A 42-year-old with history of drug poisoning had acute injury to his kidneys resulting in damage to his renal medulla. In this individual functioning of which segment of the nephron will be most affected? A. Bowman's capsule B. Collecting ducts C. Early distal tubule D. Glomerulus E. Proximal tubule
B Collecting ducts
Which of the following substances will be more concentrated at the end of the proximal tubule than at the beginning of the proximal tubule? A. Glucose. B. Creatinine. C. Sodium. D. Bicarbonate. E. Phosphate.
B Creatinine.
Which of the following will be decreased in a patient with persistent diarrhea for 6 days? A. Production of ammonia by the proximal tubule B. Filtered load of bicarbonate C.Anion gap D. Hydrogen ion secretion by the distal nephron E.Production of new bicarbonate by the distal nephron
B Filtered load of bicarbonate
IMCQ# A 33-year- old man has an aldosterone secreting tumor. This stimulates the tubuloglomerular response. This feedback regulates which of the following? A. Angiotensinogen B. GFR & renal blood flow C. Potassium excretion D. Sodium excretion E. Water retention
B GFR & renal blood flow
Which of the following endogenous substances leads to a decrease in renal blood flow A. Angiotensin II B. Acetylcholine C. ANP D. Dopamine E. Nitric oxide
C ANP. ANP wants your to LOWER your blood pressure. If your blood pressure is too high, then you want to use your ANP.
Which of the following physiological mechanisms facilitates the ability of the kidneys to produce concentrated urine? A. Active transport B. Passive transport C. Countercurrent mechanism D. Diffusion
C Countercurrent mechanism
IMCQ# A-38-year-old man comes to his physician for evaluation of his high blood pressure. He was diagnosed with bilateral renal artery stenosis. His GFR is greatly reduced. In this patient the percentage of NaCl reabsorption in the proximal tubule would? A. Decrease B. Increase C. Remain the same
C Remain the same
A nephron segment was microdissected from the kidney of an experimental animal and studied in vitro. No active sodium reabsorption was detected and the segment was impermeable to water. The segment is: A. proximal tubule. B. thin descending limb of Henle's loop. C. ascending thin limb of Henle's loop. D. thick ascending limb of Henle's loop. E. distal tubule.
C ascending thin limb of Henle's loop. Explaination: your ascending loop of henle is impearable to water but permeable to solutes. your descending loop of henle is pemearble to water but imperable to solutes. Not proximal tubule because thats where 67% of water and Na+ absorption occure.
Under conditions of maximal ADH secretion the majority of water reabsorption occurs in the: A. Descending limb of the Loop of Henle B. Collecting Duct C. Proximal Tubule D. Distal Tubule E. Ascending Loop of Henle
C. Proximal Tubule Explaination: Most of the fluids and Na+ will be Reabsorbed in the proximal tubule. 67%. 1. Ascending loop of henle= reabsorbs 25% 2. Distal tubule= reabsorbs 5% 3.Collecting duct= reabsorbs 3% 4. Descending loop of henle= N/A
Aldosterone secretion is increased when there is decrease in the plasma concentration of one of the following? A.Angiotensin II B.Potassium C.Sodium D.Renin E. Adrenocorticotrophic hormone (ACTH)
C. Sodium Explaination: Think, when does Aldosterone play a role? During blood pressure. Think of the Ras System. Aldosterone helps bring blood pressure back up when its low by making sure Salt and Water is retained as Aldosterone tell you kidneys to hold on to Salt (Sodium, Na+) and Water. RAS Overview: 1. Renin comes in when BP is low. 2. When BP is low, your body doesnt have enough salt. 3.Renin goes into bloodstream. 4. Triggers chain reaction to create Angiotension. This signals adrenal glands to release another hormone called Aldosterone. 5. Angiotension converts to Angiotension II via ACE enzyme 6. Angiotension makes tiny blood vessels narrower and Aldoesterone tells your kidneys to hold onto the Sodium and water. 7. This help raise your blood pressure. So Aldosterone is increased when you have low sodium, Na+ or salt in your plasma concentration.
The reabsorption of phosphate in the proximal tubule is due to which of the following? A. Active cotransport with chloride ion B. Active cotransport with calcium ion C. inhibition by parathyroid hormone (PTH) D. inhibition by calcitonin E. passive diffusion down its electrochemical gradient
C. inhibition by parathyroid hormone (PTH) Explaination: The question is saying and confirming that Reabsorption of the phosphate does occur in the proximal tubule. The question wants to know WHY does this occur. Option A: Does a co-transport with a Cl- ion help phosphate get through? No because this is linked in general with other ions like Formate, K+, and Na+. Not phosphate. Option B. Does a co-transport with Ca2+ help phosphate get reabsorbed? There is not specific segment that emphasized this so must be in general.Option D. Calcitonin is a mild regulator of calcium so it doesnt deal directly with phopsphate. Option E. we cant assume that phosphate can easily diffuse across the electrochemical gradient. The membrane ideal for postive charge small molecules as the membrane is (-). (-) molecules are difficult to diffuse across. Option C. is the answer choice because PTH does deal with phosphate. PTH inhibits phosphate reabsorption in the proximal tubule of the kidney, so if we want to reabsorb phosphate, we have to inhibit the mechanism of Parathyroid Hormone (PTH) so we can achieve this.
IMCQ# The following values are obtained from a patient- glomerular capillary pressure-69 mm Hg, capillary oncotic pressure -30 mm Hg, hydrostatic pressure in Bowman's space -15 mm Hg & no proteins present. Calculate the net filtration pressure. A. 6 mm Hg B. 10 mm Hg C. 15 mm Hg D. 24 mm Hg E. 28 mm Hg
D 24 mm Hg
A patient with artherosclerosis shows signs of chronic renal failure attributed to poor renal perfusion and ischemic necrosis of the nephrons. Which of the following endogenous substance causes renal blood flow to decrease? A.Nitric oxide B.Atrial natriuretic peptide C.Acetylcholine D.Angiotensin II
D Angiotensin II Reasoning: This makes sense because 1. ANP= helps decrease blood pressure 2. Angiotensin II= helps increase blood pressure 3. A patient with poor renal perfusion means blood is not filtering properly which is affecting the GFR. 4. In this case, we want to encourage proper filtration. 5. In the RAS System, in an attempt to INCREASE BLOOD pressure, a cascade of events is going to occur to allow Angiotensin II to constrict your blood vessels (specifically the Efferent Arteriole: used for Low blood pressure) 6. By constricting the Efferent Arteriole (right), this will increase the Hydrostatic pressure of the GC (PGC), thus help to increase your GFR 7. In this patient case, we want to increase out GFR so it can go to other tissues.
A patient has a tumor of the adrenal gland, causing hypersecretion of aldosterone. The plasma concentration of which of the following is increased above that found in a normal individual on an identical diet? A. Renin. B. Angiotensin II. C. Potassium ions. D. Atrial Natriuretic Peptide. E. Magnesium
D Atrial Natriuretic Peptide.
Which one of the following is a non-steroid hormones which is most likely secreted by the atria of the heart and helps regulate blood pressure? A. Erythropoietin B. Thyroxine C. Antidiuretic hormone D. Atrial natriuretic hormone
D Atrial natriuretic hormone Explaination: Atrial Natriuretic Hormone (ANP) plays a role to keep your blood pressure low.
Which of the following changes is most likely to cause an increase in the glomerular filtration rate? A.Contraction of mesangial cells B.Blockage of the ureter C.Release of renin from the juxtaglomerular apparatus D.Dilation of the afferent arterioles E. Volume depletion
D Dilation of the afferent arterioles Explaination: Mneumonic: 1. "For Increase GFR & PGC, dialate your Left (Afferent), constrict your Right (Efferent)" 2. "For decrease in GFR & PGC, constrict your Left (Afferent), and dialate your right (Efferent)
What is the filtration fraction? A. RPF/RBF B. RPF/GFR C. Kf x P D. GFR/RPF
D GFR/RPF
A malnourished patient with chronic low dietary K+ intake was found to have severe alkalosis. Which of the following could explain this? A. Renal acid secretion is reduced B. Extracellular fluid volume is expanded. C. H+/K+ ATPase in the collecting duct is inhibited. D. K+ ions move out of the cells and H+ enter cells. E. Carbonic anhydrase activity in the proximal tubule is reduced.
D K+ ions move out of the cells and H+ enter cells.
Which of the following is true about nephrons? A. Nephrons are the non-functional units of the kidney B. About 15-20 percent of nephrons are cortical nephrons and 80-85 percent are juxtamedullary C.The first part of the nephron loop begins at the distal convoluted tubule D. The nephron loop connects the proximal and distal convoluted tubules E. The distal convoluted tubules of several nephrons empty into the proximal collecting tubule
D The nephron loop connects the proximal and distal convoluted tubules
In a normal kidney which of the following conditions would cause an increase in the glomerular filtration rate(GFR)? A.constriction of the afferent arteriole B.a decrease in the hydrostatic pressure of the glomerulus C.an increase in the capsular hydrostatic pressure D.a decrease in the concentration of plasma proteins in the blood
D a decrease in the concentration of plasma proteins in the blood Explaination: what causes an increase in GFR? Afferent vs Efferent mneumonic: "high GFR is 10"
Phosphate reabsorption by the kidney: A. occurs mainly along the distal tubule and collecting duct. B. depends on a transluminal fluid potential difference C. is controlled by the secretion of angiotensin II. D. is inhibited by parathyroid hormone. E. occurs mainly in the thick ascending limb.
D is inhibited by parathyroid hormone.
Which of the following pressures which contributes nothing to normal net filtration pressure? A. hydrostatic pressure of the glomerular capillary B. hydrostatic pressure of the Bowmans spce C. oncotic pressure of the glomerular capillary D. oncotic pressure of the Bowmans space
D oncotic pressure of the Bowmans space
1) The first step in urine formation is reabsorption:
False
All (100%) of bicarbonate gets reabsorbed in the early part of the proximal tubule:
False
All negatively charged particles have an easy time getting through the filtration barrier:
False
An obstructive uropathology will cause a decrease in the hydrostatic pressure of the Bowman's space:
False
Bicarbonate is reabsorbed directly into the cells of the early proximal tubule
False
If there is *dilation* of the afferent arteriole this will cause a decrease in GFR and a decrease in RPF:
False
If there is constriction of the *afferent arteriole* this will cause an *increase* in GFR and an *increase* in RPF:
False
If there is dilation of the efferent arteriole this will result in an increase in hydrostatic pressure, a decrease in RPF and an increase in GFR
False
Oncotic pressures of the blood or plasma opposes reabsorption and favours filtration:
False
Oncotic pressures of the interstitial fluid in the Bowman's space is very high due to high concentration of proteins:
False
RBC are usually noticed in the bowman's space because they can easily pass through the filtration barrier
False
Small molecules with a radius of greater than 35 Angstrom (A) are commonly referred to as freely filterable:
False
The pedicles of the podocytes are positively charged
False
About 50% of the amino acids are reabsorbed in the early proximal tubule:
False (100% is reabsorbed)
All (100%) of the urea is reabsorbed in the early proximal tubule:
False (only about 50% is reabsorbed)
About 5% of Glucose is reabsorbed in the early proximal tubule:
False :100% is reabsorbed
(Study images and Drawings)
Questions 44-46
A cation particle that is 21A would have a better chance than an anion particle that is 19A getting through the filtration barrier:
True
A child with a Nephrotic syndrome indicates that they will have a decrease in the oncotic pressures in the lumen of blood vessels and an increase in oncotic pressures in the Bowman space hence the reason for having ascities and widespread edema:
True
As blood enters the Glomerulus and it gets filtered, it is now called the ultra filtrate:
True
Glucose, sodium, chloride and urea are all called freely filterable compounds
True
In the tubuloglomerular feed back mechanism, if there is a decrease in blood flow, this will stimulate cells to release rennin which in turn will activate the Angiotensin system with the end result of Aldosterone being released from the renal glands. The rennin can also cause vasoconstriction of the efferent arterioles:
True
The early proximal tubule is associated with reabsorption:
True
The presence of proteins in the urine can indicate that the Starling force - πBS is mostly affected
True
The thick ascending limb is impermeable to water:
True
The two types of auto regulation of the renal system are the myogenic response (reaction of arterioles related to blood pressure) and the tubuloglomerular feedback mechanisms
True
1) Where is the juxtaglomerular apparatus is found? a) Cortex b) Inner medulla c) Outer medullar d) Minor calyx e) Major calyx
a) Cortex
An Increase in Efferent arteriolar resistance would cause: a) Increase in RPF, increase PGC and increase GFR. b) Decrease in RPF, increase PGC and increase GFR. c) Decrease in RPF, decrease PGC and decrease GFR. d) Increase in RPF, increase PGC and decrease GFR. e) Decrease in RPF, decrease PGC and decrease GFR.
b) Decrease in RPF, increase PGC and increase GFR.
1) Which of these substances cannot pass through the filtration membrane under normal conditions? a) Water b) Sodium ions c) Hemoglobin d) Chloride ions e) Bicarbonate ions
c) Hemoglobin
50) (see image*) Which of the following will be most likely abnormally high? a) Hydrostatic pressure in the renal capillaries b) Oncotic pressure in the Bowman's space c) Hydrostatic pressure in the Bowman's space d) Oncotic pressure in the Urethra e) Hydrostatic pressure in the Bladder
c) Hydrostatic pressure in the Bowman's space
SL Renal# 1) If the GFR is very high, which of the following can result in such a case? a) Everything is reabsorbed including waste that are normally disposed b) Needed substances cannot be reabsorbed quickly enough thus are not lost in the urine c) Needed substances cannot be reabsorbed quickly enough thus are lost in the urine d) The changes in GFR has no effect on substances lost in the urine e) Needed substances will be reabsorbed very quickly thus most will be lost in the urine
c) Needed substances cannot be reabsorbed quickly enough thus are lost in the urine
Which of the following is filtered most readily by the Glomerular capillaries? a) Albumin in plasma b) Neutral dextran with a molecular weight of 25000 c) Polycationic dextran with a molecular weight of 25000 d) Olyanionic dextran with a molecular weight of 25000 e) Red blood cells
c) Polycationic dextran with a molecular weight of 25000 Explanation: The filterability of solutes in the plasma is inversely related to the size of the solute (molecular weight) Also, positively charged molecules are filtered more readily than are neutral molecules or negatively charged molecules of equal weight.
1) This patient presented to you with puffiness of the face and other regions of his body. From your understanding of Physiology which of the following correctly describes this scenario? a) This patient most likely has a Nephrotic syndrome and will be spilling proteins into the Bowman's space but πBS will be normal. b) This patient has a Nephritic syndrome condition that is resulting in hematurea and Oligouria with some proteins spilling into the capillaries from the Bowman's space and the πBS will be abnormal. c) This patient has wide spread edema due to a break down in the integrity of the filtration barrier of the renal system and the patient is now spilling Albumin into the Bowman's space thus there will an abnormal πBS. d) This patient had too much of a large protein meal and the proteins are causing a high hydrostatic pressure in the Bowman's space thus resulting in wide spread swelling.
c) This patient has wide spread edema due to a break down in the integrity of the filtration barrier of the renal system and the patient is now spilling Albumin into the Bowman's space thus there will an abnormal πBS.
SL Renal# 1) The juxtaglomerular apparatus is formed where the _________________ projects between the afferent and efferent arteriole next to the Bowman's capsule. a) Proximal convoluted tubule b) Proximal Loop of Henle c) Most distal part of the collecting duct d) Distal convoluted tubule e) Descending thick tubule
d) Distal convoluted tubule
SL Renal# 1) Given these parts of the functional unit of the kidneys, arrange them in order as fluid flows from the filtration membrane through the nephron. 1. Distal tubule 2. Renal corpuscle 3. Proximal tubule 4. Collecting duct 5. Loop of Henle a) 1,2,3,4,5, b) 2,1,3,4,5, c) 3,4,5,1,2, d) 5,4,3,2,1 e) 2,3,5,1,4
e) 2,3,5,1,4
Of the filtrate that enters the nephron, about what percentage is reabsorbed during urine formation? a) 15% b) 45% c) 80% d) 67% e) 99%
e) 99%
1) Increasing the afferent arteriolar resistance would cause: a) Increase in RPF, increase PGC and increase GFR. b) Decrease in RPF, increase PGC and increase GFR. c) Increase in RPF, decrease PGC and increase GFR. d) Increase in RPF, increase PGC and decrease GFR. e) Decrease in RPF, decrease PGC and decrease GFR.
e) Decrease in RPF, decrease PGC and decrease GFR.
Which of the following is true about the juxtamedullary nephron? a) The juxtaglomerular apparatus is very far away from the outer medulla region b) The juxtaglomerular apparatus is found deep in the inner medulla region c) They don't have a thin ascending limb d) They don't have a proximal convoluted tubule e) It is associated with a thin ascending and descending limb
e) It is associated with a thin ascending and descending limb