Renal Physiology Flashcards by Lydia Osborne | Brainscape

Q

When measuring glomerular filtration rate:

The result matches the clearance of the marker if it behaves ideally

A

True

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Q

When measuring glomerular filtration rate:

A single plasma creatinine concentration provides an accurate value

A

False

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Q

When measuring glomerular filtration rate:

Renal blood flow must be measured or calculated

A

False

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Q

When measuring glomerular filtration rate:

Tubular reabsorption of the marker will lead to an erroneously low GFR

A

True

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Q

When measuring glomerular filtration rate:

Glomerular filtration fraction must be measured or calculated

A

False

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Q

Transport processes in the kidney include:

Tubular Secretion of NH3

A

True

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Q

Transport processes in the kidney include:

Reabsorption of 60g glucose per day

A

True

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Q

Transport processes in the kidney include:

Excretion of bicarbonate ions buffered by phosphate

A

False

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Q

Transport processes in the kidney include:

Glomerular fiktration of all molecules under 5nm diameter

A

True

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Q

Transport processes in the kidney include:

Chloride reabsorption by co-transport with Na in the PCT

A

False

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Q

The kidneys:

Have a large arteriovenous oxygen difference

A

False

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Q

The kidneys:

Produce around 180L filtrate a day in a healthy adult

A

True

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Q

The kidneys:

Have no autonomic nervous innervation

A

False

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Q

The kidneys:

Receive around 25% of the cardiac output

A

True

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Q

The kidneys:

Play an important role in Vitamin D synthesis

A

True

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Q

Antidiuretic Hormone:

Decreases the volume of urine passed

A

True

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Q

Antidiuretic Hormone:

Decreases the osmolality of plasma

A

True

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Q

Antidiuretic Hormone:

Increases water reabsorption in the PCT

A

False

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Q

Antidiuretic Hormone:

Acts via DNA transcription

A

False

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Q

Antidiuretic Hormone:

Causes Vasoconstriction

A

True

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Q

Sodium reabsorption in the kidney:

Is the main objective of the countercurrent mechanism

A

False

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Q

Sodium reabsorption in the kidney:

Is the major energy consuming activity of the kidney

A

True

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Q

Sodium reabsorption in the kidney:

Occurs predominantly in the proximal convoluted tubule

A

True

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Q

Sodium reabsorption in the kidney:

Is linked to H+ extrusion in the distal tubule

A

False

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Q

Sodium reabsorption in the kidney:

Is important for glucose reabsorption

A

True

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Q

In the proximal tubule of the nephron:

95% of filtered potassium is reabsorbed

A

False

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Q

In the proximal tubule of the nephron:

90% of filtered water is reabsorbed

A

False

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Q

In the proximal tubule of the nephron:

Sodium is actively reabsorbed

A

True

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Q

In the proximal tubule of the nephron:

Bicarbonate is secreted

A

False

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Q

In the proximal tubule of the nephron:

50% of ammonia is reabsorbed

A

False

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Q

Concerning water handling by the kidneys:

Water is actively transported out of the proximal tubule

A

False

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Q

Concerning water handling by the kidneys:

35% of the filtered water is reabsorbed

A

False

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Q

Concerning water handling by the kidneys:

Water reabsorption in the loop of henle is mainly in the ascending limb

A

False

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Q

Concerning water handling by the kidneys:

Nearly 90% of filtered water is reabsorbed by the kidney

A

False

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Q

Concerning water handling by the kidneys:

Antidiuretic hormone increases the permeability of the proximal tubule to water

A

False

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Q

Potassium:

Concentration in the plasma is a good reflection of total body potassium

A

False

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Q

Potassium:

concentration in the plasma rises in metabolic acidosis

A

True

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Q

Potassium:

excretion increases in hypovolaemia

A

True

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Q

Potassium:

enters cells in the presences of insulin

A

True

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Q

Potassium:

Excretion is promoted by aldosterone

A

True

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Q

The ideal substance for determining glomerular filtration rate:
Is 100% bound to plasma proteins

A

False

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Q

The ideal substance for determining glomerular filtration rate:
Is freely filtered from the plasma

A

True

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Q

The ideal substance for determining glomerular filtration rate:
Is entirely reabsorbed in the tubule

A

False

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Q

The ideal substance for determining glomerular filtration rate:
Is actively secreted by tubules

A

False

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Q

The ideal substance for determining glomerular filtration rate:
Has a molecular weight greater than 69,000

A

False

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Q

Regarding tubular reabsorption of glucose:

The tubular transport maximum for glucose is around 2 mmol/min

A

True

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Q

Regarding tubular reabsorption of glucose:

An increase in GFR increases the risk of glycosuria

A

True

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Q

Regarding tubular reabsorption of glucose:

If the plasma concentration is <8 mmol/L, all will normally be reabsorbed

A

True

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Q

Regarding tubular reabsorption of glucose:

Most reabsorption is via the para-cellular route in the PCT

A

False

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Q

Regarding tubular reabsorption of glucose:

Reabsorption is by co-transport with sodium

A

True

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Q

The following have higher intracellular than extracellular concentration:
Phosphate

A

True

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Q

The following have higher intracellular than extracellular concentration:
Magnesium

A

True

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Q

The following have higher intracellular than extracellular concentration:
Potassium

A

True

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Q

The following have higher intracellular than extracellular concentration:
Calcium

A

False

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Q

The following have higher intracellular than extracellular concentration:
Bicarbonate

A

False

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Q

Anti-diuretic hormone:

Determines whether the majority of water is reabsorbed by the nephron or excreted

A

False

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Q

Anti-diuretic hormone:

Secretion is inhibited by alcohol

A

True

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Q

Anti-diuretic hormone:

Is a steroid

A

False

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Q

Anti-diuretic hormone:

Is synthesized in the posterior pituitary

A

False

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Q

Anti-diuretic hormone:

increases arterial blood pressure

A

True

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Q

Renal autoregulation:

Is effective up to MAP of 200 mmHg

A

False

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Q

Renal autoregulation:

Has a contribution directly from the autonomic nervous system

A

False

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Q

Renal autoregulation:

Involves simultaneous constriction of both afferent and efferent arterioles

A

False

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Q

Renal autoregulation:

Maintains a constant renal artery pressure despite changes in blood flow

A

False

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Q

Renal autoregulation:

Increases glomerular filtration fraction in the presence of hypovolaemia

A

True

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Q

Regarding sodium transport in the kidney:

The main active process occurs on the luminal side of tubular cells

A

False

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Q

Regarding sodium transport in the kidney:

Reabsorption in the loop of henle occurs with potssium and chloride

A

True

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Q

Regarding sodium transport in the kidney:

The majority of reabsorption is regulated by aldosterone

A

False

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Q

Regarding sodium transport in the kidney:

Approximately 1.5kg of salt is reabsorbed by the kidney per day

A

True

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Q

Regarding sodium transport in the kidney:

final sodium excretion is determined by the principle cell

A

True

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Q

Regarding glomerular filtration:

Glomerular capillary hydrostatic pressure is lower than that of most capillary beds

A

False

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Q

Regarding glomerular filtration:

Colloid osmotic pressure in bowmans capsule is almost zero

A

True

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Q

Regarding glomerular filtration:

Colloid osmotic pressure drops alone the lenght of the glomerular capillary

A

False

Q

Regarding glomerular filtration:

20% of renal plasma flow is filtered into bowmans capsule

A

True

Q

Regarding glomerular filtration:

Anions are more readily filtered than cations

A

False

Q

Primary active transport is used in the reabsorption of:

Sodium

A

True

Q

Primary active transport is used in the reabsorption of:

Chloride

A

False

Q

Primary active transport is used in the reabsorption of:

Glucose

A

False

Q

Primary active transport is used in the reabsorption of:

Bicarbonate

A

False

Q

Primary active transport is used in the reabsorption of:

Water

A

False

Q

Aldosterone:

Acts partially on the distal convoluted tubule

A

True

Q

Aldosterone:

Acts via tyrosine kinase linked receptors

A

False

Q

Aldosterone:

decreases the osmolarity of urine

A

False

Q

Aldosterone:

increases potassium excretion

A

True

Q

Aldosterone:

Release is triggered by angiotensin II

A

True

Q

In the loop of henle:

Fluid entering is it approximately isotonic with plasma

A

True

Q

In the loop of henle:

The ascending limb is impermeable to water

A

True

Q

In the loop of henle:

The thin ascending limb is primary responsible for the reabsorption of sodium

A

False

Q

In the loop of henle:

Only 15% of the loops pass deeply into the medulla

A

True

Q

In the loop of henle:

The osmolarity of tubular fluid increases to a maximum of 1200 mOsmol/L

A

True

Q

Angiotensin II:

Decreases aldosterone release

A

False

Q

Angiotensin II:

Decreases osmoreceptor firing

A

False

Q

Angiotensin II:

Causes vasoconstriction

A

True

Q

Angiotensin II:

Causes a decrease in renin secretion

A

True

Q

Angiotensin II:

Has a half life of a few seconds

A

False

Q

The following are involved in renal autoregulation:

Aldosterone

A

True

Q

The following are involved in renal autoregulation:

Aldosterone

A

False

Q

The following are involved in renal autoregulation:

Bradykinin

A

False

Q

The following are involved in renal autoregulation:

Prostaglandin E2

A

True

Q

The following are involved in renal autoregulation:

Vasopressin

A

False

Q

Primary Active transport in the renal tubules:

Are involved in the movement of 3 potassium ions into the cell

A

False. The sodium potassium ATPase pump on the basolateral membrane of the tubular cell pumps 3 sodium ions into the interstitial fluid and 2 potassium ions into the tubular cell.

Q

Primary Active transport in the renal tubules:

Occurs independently of carrier proteins

A

False. The sodium potassium ATPase pump is located on the basolateral membrane of the tubular cell.

Q

Primary Active transport in the renal tubules:

Produces a net positive gradient outside the cell

A

True. This is due to the fact that the sodium potassium ATPase pump on the basolateral membrane of the tubular cell pumps 3 sodium ions into the interstitial fluid and 2 potassium ions into the tubular cell.

Q

Primary Active transport in the renal tubules:

Provides gradients for other processes

A

True. After the sodium ions have been pumped out of the tubular cell by the sodium potassium ATPase pump, other sodium ions move from the luminal fluid into the tubular cell down the gradient created. This releases energy which is used in the process of secondary active transport.

Q

Primary Active transport in the renal tubules:

Involves cleavage of ATP

A

True. ATPase is important in this energy consuming process.

Q

The functions of the kidney include:

Regulation of body fluid buffer stores

A

True. The buffering functions of the kidney are essential in acid base balance. The bicarbonate and ammonia systems are most important.

Q

The functions of the kidney include:

Temperature regulation

A

False. Temperature regulation is not a major function of the kidneys.

Q

The functions of the kidney include:

The production of angiotensin converting enzyme

A

False. Angiotensin converting enzyme is produced mainly by the endothelial cells of the lungs.

Q

The functions of the kidney include:

Regulation of arterial pressure

A

True. This occurs via several mechanisms.

Q

The functions of the kidney include:

Glucose synthesis

A

True. Gluconeogenesis is a function of the kidney.

Q

Consider the following statements regarding transport across renal tubular cell membranes:
Transcellular transport is not important

A

False. Transcellular transport is important. Import on one side of the cells is combined with export on the opposite side.

Q

Consider the following statements regarding transport across renal tubular cell membranes:
Paracellular transport occurs only across tight junctions

A

False. Paracellular transport occurs through both tight junctions and intercellular spaces.

Q

Consider the following statements regarding transport across renal tubular cell membranes:
Paracellular transport occurs via active transport

A

False. Paracellular transport occurs via diffusion and not active transport.

Q

Consider the following statements regarding transport across renal tubular cell membranes:
Paracellular transport is driven by osmotic gradients

A

True. Paracellular transport is driven by osmotic, concentration and electrical gradients.

Q

Consider the following statements regarding transport across renal tubular cell membranes:
Electrical gradients are not utilized in paracellular transport processes

A

False. Paracellular transport is driven by osmotic, concentration and electrical gradients.

Q

Consider the following statements regarding diffusion across a semi permeable membrane:
Rate of diffusion is not dependent on the concentration gradient across the membrane

A

False. Fick’s law states that rate of diffusion across a membrane is proportional to the concentration gradient across that membrane.

Q

Consider the following statements regarding diffusion across a semi permeable membrane:
Graham’s Law states that the rate of diffusion is proportional to the molecular weight of the substance

A

False. Graham’s law states that the rate of diffusion across a membrane is inversely proportional to the square root of the molecular weight of the substance.

Q

Consider the following statements regarding diffusion across a semi permeable membrane:
The surface area of the membrane is important

A

True. Rate of diffusion is proportional to the available area of the membrane.

Q

Consider the following statements regarding diffusion across a semi permeable membrane:
Uncharged weak acids or bases diffuse more readily

A

True. The cell membrane is more soluble for example, to NH3 than NH4 +.

Q

Consider the following statements regarding diffusion across a semi permeable membrane:
The diffusion of weak acids and bases does not depend on pH

A

False. The pH of a solution determines whether or not substances are charged. Uncharged weak acids or bases diffuse more readily across membranes.

Q

The functions of the kidney include:

Production of 1,25 dihydroxy-cholecalciferol

A

True. One of the roles of the kidney is in the process of hydroxylation of Vitamin D3.The kidney produce 1-alpha-hydroxylase which acts on 25-hydroxycholecalciferol to produce 1,25-dihydroxy-cholecalciferol (calcitriol). Calcitriol promotes calcium reabsorption from the intestine and kidneys, and is important in bone mineralisation.

Q

The functions of the kidney include:

Temperature regulation

A

False. Temperature regulation is not a major function of the kidney.

Q

The functions of the kidney include:

Erythropoietin production

A

True. Erythropoietin is a glycoprotein produced by capillary endothelial cells. It acts as a cytokine for erythrocyte precursors in the bone marrow.

Q

The functions of the kidney include:

Glycogenolysis

A

False. Gluconeogensis occurs in the kidneys, not glycogenolysis.

Q

The functions of the kidney include:

Prostaglandin secretion

A

True. Prostaglandins are secreted by the kidneys.

Q

Primary active transport in the renal tubules:

Is involved in sodium transport into the cell

A

False. 3 sodium ions are pumped outward for 2 potassium ions inward.

Q

Primary active transport in the renal tubules:

Involves a carrier protein which imparts energy to the transported substances

A

True. In primary active transport the imparted energy allows the substance to be moved against its electrochemical gradeint.

Q

Primary active transport in the renal tubules:

Involves the activation of ATPase

A

True. When 2 potassium and 3 sodium ions bind to the carrier protein, the ATPase function of the protein is activated.

Q

Primary active transport in the renal tubules:

Provides gradients for secondary active transport

A

True. Gradients are set up via the Na/K ATPase pump to allow the reabsorption of sodium ions via secondary active transport.

Q

Primary active transport in the renal tubules:

Establishes a net negative voltage inside the cell

A

True. 3 sodium ions are pumped outward for 2 potassium ions inward.

Q

Sodium:

Reabsorption is greatest in the proximal convoluted tubule

A

True. Approximately 65% of filtered sodium is reabsorbed in the proximal convoluted tubule.

Q

Sodium:

Reabsorption is dependent on the GFR

A

True

Q

Sodium:

Reabsorption is decreased by aldosterone

A

False. Aldosterone increases the permeability of the luminal membrane to potassium and sodium. It also activates basolateral sodium-potassium-ATPase pumps.

Q

Sodium:

Is pumped into the tubular cell by the Na+/K+ ATPase pump

A

False. Three sodium ions are pumped out of the tubular cell by the sodium potassium ATPase pump.

Q

Sodium:

Is important in glucose reabsorption

A

True. Glucose reabsorption occurs by co-transport with sodium into the tubular cell, again utilising the gradient produced by the Na+/K+ ATPase pump. Glucose then diffuses into the peritubular interstitium.

Q

Consider the following statements regarding glucose reabsorption:
The tubular transport maximum for glucose is 380 mg/min

A

True. There is a tubular transport maximum for glucose, and it is 380 mg/min.

Q

Consider the following statements regarding glucose reabsorption:
Glucose will appear in the urine at a renal threshold of 110 mmol/l

A

False. The renal threshold for glucose is 11 mmol/l.

Q

Consider the following statements regarding glucose reabsorption:
Glucose is reabsorbed by counter transport with sodium

A

False. Glucose is co transported with sodium.

Q

Consider the following statements regarding glucose reabsorption:
Glucose is usually reabsorbed in the distal convoluted tubule

A

False. Glucose reabsorption is in the proximal convoluted tubule.

Q

Consider the following statements regarding glucose reabsorption:
Glucose is completely reabsorbed providing the plasma concentration is normal

A

True. As described in the tutorial, glucose has a tubular transport maximum that is not exceeded at normal plasma glucose concentrations.

Q

Consider the following statements regarding reabsorption of substances by the kidney:Most filtered bicarbonate is excreted by the kidneys

A

False. Bicarbonate is mainly reabsorbed. This reabsorption is essential in maintaining acid base balance, as large amounts of bicarbonate are filtered.

Q

Consider the following statements regarding reabsorption of substances by the kidney:
Bicarbonate reabsorption occurs mainly in the Loop of Henle

A

False. 80% occurs in the PCT.

Q

Consider the following statements regarding reabsorption of substances by the kidney:
The ammonia buffer system is quantitatively the most important

A

True. Less important systems include the phosphate buffer system, and then the urate and citrate systems.

Q

Consider the following statements regarding reabsorption of substances by the kidney:
Potassium is 60-70% absorbed in the proximal convoluted tubule

A

True. The majority of the potassium is absorbed in the PCT.

Q

Consider the following statements regarding reabsorption of substances by the kidney:
Aldosterone is important in potassium reabsorption

A

False. The action of aldosterone is to increase reabsorption of sodium and the excretion of potassium.

Q

Consider the following statements regarding the proximal convoluted tubule (PCT):
Water is reabsorbed here due to the action of aldosterone

A

False. Water is reabsorbed by diffusion.

Q

Consider the following statements regarding the proximal convoluted tubule (PCT):
All of glucose is reabsorbed here in normal circumstances

A

True. All of glucose is reabsorbed as long as the tubular transport maximum is not reached.

Q

Consider the following statements regarding the proximal convoluted tubule (PCT):
15% of water is reabsorbed

A

False. 60–70% of water is reabsorbed in PCT.

Q

Consider the following statements regarding the proximal convoluted tubule (PCT):
Bicarbonate is excreted

A

False. Bicarbonate is mainly reabsorbed here. Hydrogen ions are secreted.

Q

Consider the following statements regarding the proximal convoluted tubule (PCT):
Morphine is secreted here

A

True. Morphine is one of the cations secreted into the PCT

Q

Consider the following statements regarding renin:

Release is from juxtaglomerular cells

A

True. Renin is released from juxtaglomerular cells in the wall of the afferent arteriole.

Q

Consider the following statements regarding renin:

Release is controlled by macula densa, detecting a low sodium flux

A

True. Less filtrate reaches the macula densa and sodium concentration is reduced. This is detected by the macula densa cells and an increase in renin secretion is triggered.

Q

Consider the following statements regarding renin:

Release is increased by antidiuretic hormone

A

False. Renin release is decreased by antidiuretic hormone, which acts to conserve water.

Q

Consider the following statements regarding renin:

Release is increased by hypotension

A

True. Renin is released in response to the low cardiovascular pressures which occur in hypotension.

Q

Consider the following statements regarding renin:

Release is inhibited by beta blockers

A

True. Renin release is increased in response to beta-1 receptor stimulation.

Q

Consider the following statements regarding aldosterone:

Production is increased by sodium chloride ingestion

A

False. Sodium chloride ingestion increase plasma osmolality and will decrease aldosterone production. One of the main roles of aldosterone is sodium reabsorption.

Q

Consider the following statements regarding aldosterone:

Trauma leading to hypovolaemia will result in an increase in aldosterone release

A

True. Hypovolaemia causes renin release, and thus angiotensin II release. Angiotensin causes aldosterone release, with the ultimate effect of increasing sodium and water reabsorption.

Q

Consider the following statements regarding aldosterone:

Reduces the sodium content of sweat

A

True. Aldosterone increases sodium reabsorption from the gut, sweat and saliva.

Q

Consider the following statements regarding aldosterone:

Production increases urinary potassium excretion

A

True. Aldosterone causes the production of potassium channels in the luminal membrane of the cortical collecting duct. Potassium is lost through these.

Q

Consider the following statements regarding aldosterone:

Increases urinary sodium concentration

A

False. Aldosterone is the main determinant of sodium reabsorption.

Q

Consider the following statements about the role of angiotensin II:
It decreases aldosterone release

A

False. Angiotensin II increases aldosterone release.

Q

Consider the following statements about the role of angiotensin II:
It decreases osmoreceptor firing

A

False. Thirst is stimulated due to increased osmoreceptor activation

Q

Consider the following statements about the role of angiotensin II:
It causes vasoconstriction

A

True. This is one of its main roles.

Q

Consider the following statements about the role of angiotensin II:
It causes a decrease in renin secretion

A

True. Angiotensin II causes a decrease in renin secretion as a part of the negative feedback system.

Q

Consider the following statements about the role of angiotensin II:
It has a half life of a few seconds

A

False. Has a half life of a few minutes.

Q

Consider the following statements about ANP:

It causes vasodilatation

A

True. ANP is a potent vasodilator.

Q

Consider the following statements about ANP:

It impairs renal blood flow

A

False. It improves renal blood flow.

Q

Consider the following statements about ANP:

It is released from the coronary sinus

A

False. It is released from the atrial myocytes.

Q

Consider the following statements about ANP:

It is released in response to atrial relaxation

A

False. Is released in response to atrial stretch.

Q

Consider the following statements about ANP:

It increases the filtration coefficient

A

True. This action, combined with afferent arteriolar dilation and efferent arteriolar vasoconstriction increases the net filtration pressure.

Q

When measuring GFR:

Renal blood flow must be measured or estimated

A

False. Renal blood flow is not part of the equation for measuring GFR.

Q

When measuring GFR:

An indicator substance must not undergo reabsorption following tubular excretion

A

True. If it is to be used for accurate assessment of GFR, these properties are important.

Q

When measuring GFR:

The result matches clearance of the indicator if it is renally inert

A

True. An indicator should not be renally altered if it is to accurately reflect GFR.

Q

When measuring GFR:

One would expect 180 L/day to be filtered

A

True. This is the quoted normal figure.

Q

When measuring GFR:

Use of sodium as an indicator would lead to a falsely high GFR

A

False. Sodium is reabsorbed and therefore the urine concentration would be decreased. This would result in an underestimate of GFR.

Q

Consider the following statements about clearance:

Clearance of a substance equals renal excretion divided by the plasma concentration

A

True.

Q

Consider the following statements about clearance:

Clearance of PAH estimates renal plasma flow

A

True. Para-aminohippuric acid (PAH) is 90% cleared by the kidneys from the plasma. PAH clearance is therefore used to estimate renal plasma flow.

Q

Consider the following statements about clearance:

Clearance of inulin is less than that of glucose

A

False. Inulin is almost completely cleared. Its rate of excretion is very close to its filtration rate. Glucose is reabsorbed up to its transport maximum.

Q

Consider the following statements about clearance:

Clearance of free water is greater than that of inulin

A

False. A majority of filtered water is reabsorbed by the renal tubules.

Q

Consider the following statements about clearance:

Clearance of an actively reabsorbed substance must exceed that of inulin

A

False. If a substance is actively reabsorbed, its clearance will be below that of inulin.