Unit 1 Renal Flashcards by diego rivera

How does high salt intake contribute to greater excretion calcium in the kidneys

Since Ca2+ is coupled to Na+ reabsorption in the PCT, when there’s an increase in salt intake theres a decrease in salt reabsorption theres also a decreased Ca2+ reabsorption (inc. excretion).

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What percent of Calcium is reabsorbed in the PCT?

65%

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What is the MOA of calcium reabsorption in the PCT

Electrochemically- paracellularly

As the lumen have a net positive potential, calcium moves passively (REGULATED by Na+ reabsorption)

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What is the MOA of calcium reabsorption in the TAL

Electrochemically- paracellularly

As the lumen develops a net positive potential due to the NKCC co transporter, calcium is reabsorbed paracellularly

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What parts of the nephron reabsorbs calcium

PCT, TAL, DCT

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What is the MOA of calcium reabsorption in the DCT

Actively-transcellular

PTH regulated process

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What percent of calcium is reabsorbed in the TAL?

20%

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What percent of calcium is reabsorbed in the DCT

7-10%

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What can alkalemia do to calcium?

It can cause hypocalcemia. this is because theres less protons binding to proteins, which leads free calcium to bind to proteins. this causes less active calcium, thus hypocalcemia.

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What is low when someone has diarrhea?

Bicarb—-> metabolic acidosis

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What is low when someone is throwing up excessively?

HCl—-> metabolic alkalosis and hypochloremia

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What kidney arterioles does angiotensin II affect?

Both afferent and efferent, BUT efferent more

Causes vasoconstriction

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How does angiotensin II affect the filtration fraction?

A2 causes decreased RFF due to constriction of both renal arterioles.

GFR decreases overall as well but not as much as RPF due to increased constriction of efferent arteriole, which slightly increases GFR

Therefore, FF is increased

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How does an increased FF change peritubular capillary oncotic pressure

Since more plasma is filtered into the glomerulus, this leaves more a higher protein concentration leaving the efferent arteriole, thus the oncotic pressure of the peritubular capillaries is higher.

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What does the JGA regulate?

BP, GFR, renin secretion

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Where is the JGA located?

Between the afferent arteriole and DCT

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What components make up the JGA?

Mucula Densa

Juxtaglomerular cells

Mesangial cells

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Function/location of macula densa

Regulate NaCl concentration
-if NaCl is high in DCT–> inhibits renin release (from JG cells)–> dec. aldosterone–> inc. Na excretion

-if NaCl is low in DCT–> stimulates renin release (from JG cells)–> inc. aldosterone–> inc. Na reabsorption

Located in the DCT where it meets afferent arterioles

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Function/location of JG cells

Location: in the afferent arterioles near the macula densa

Regulates BP by secretion/inhibition of renin

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Function/location of mesangial cells

between JG cells and macula densa

function = unknown

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what can cause post-renal damage

Kidney stones, they can block ureters, cause back flow which can lead to AKI

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Roadmap of how decreased renal artery resistance and lead to increased oxygen consumption.

Dec. resistance—> inc. flow–? increases hydrostaic pressure of arteriole–> Inc GFR –> Inc. sodium (normal) in tubule —> more transporters needed for reabsorption —> more Na-K ATPase —> increased O2 consumption

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Calculate new plasma osmolarity of 80kg man who drank 2L of water

288 mOsm/L

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What transporter is messed up in type 1 RTA

All in DCT and CD

-H+ ATPase –> decreased H+ secretion –> metabolic acidosis

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What transporter is messed up in type 2 RTA

In PCT -Na/H+ exchanger ---> Decreased reabsorption of Bicarb--> Metabolic acidosis -Na/Bicarb cotransporter --> decreased reabsorption of bicarb---> metabolic acidosis

What transporter is messed up in type 4 RTA

in DCT and CD -Na transporters insensitive to aldosterone---> ENaC isnt working--> decreased Na+ reabsorption--> dec. proton pump activity--> dec. proton excretion--> metabolic acidosis

which RTA's have hyperkalemia?

type 4 because aldosterone transporters arent working---> decreased K+ exchange---> dec. K+ excretion ---> hyperkalemia

Which RTA's have hypokalemia?

Type 1 and 2 this is due to decreased sodium reabsorption in proximal and distal convoluted tubules which leads to increased sodium reabsorption in the collecting duct, which leads to increased potassium excretion --> hypokalemia

Which RTA has kidney stones

RTA type 1, due to very alkaline urine.

What is the free water clearance equation?

V - Cosm = V - (Uosm x V)/ Posm answer can be negative

What does a negative Ch2o mean?

Body is conserving water

What does a positive Ch2o mean?

Body is excreting excess water

Why does the single effect have a greater effect of concentrating urine in the presence of ADH?

Because it further increases the medulla osmolarity in the TAL. This, along with ADH, further increases the drive of water out of the collecting duct and into the interstitium, which leads to the urine being more concentrated

Which diuretic is the ONLY one that decreases calcium excretion

Thiazides

What type of stone is present in RTA type 1

Calcium phosphate

What conditions typically causes calcium phosphate stones

hyperparathyroidism

What conditions typically causes calcium oxalate stones?

Hyperoxaluria. Calciuria and oxaluria present

What conditions are typically cause uric acid stones

gout

What conditions typically cause struvite stones

UTI's with urease bacteria present

What diuretic like response is present in barterr syndrome

Loop diuretics (TAL)

What diuretic like response is present in gitelmann syndrome

Thiazide (DCT)

What is Conn syndrome

Primary hyperaldosteronism- adrenal glands produce excess aldosterone

What is the shape of cystine kidney stones

hexagonal

ARPKD

small cysts in small people (kids)

ADPCD

large cysts in large people (adults)

Wilms tumor gene and inheritance

WT1/2, AD

Von Hippel Lindau disease gene and inheritance

VHL, AD

Tubular sclerosis gene and inheritance

TSC1/2, AD

What do calcium phosphate stones look like under microscope

Wedge shaped prisms. They look like quart crystals

What do calcium oxalate stones look like under the microscope?

Dumbell or envelope shape

WHat do struvite stones look like under the microscope?

Coffin lid. Looks like a rectangle within a rectangle

What do uric acid stones look like under the microscope?

Rhomboid, foot-ball shaped, yellowish and brown

What do cystine stones look like under the microscope?

Hexagonal (6 sides), Benzene ring

What parts of the nephron handles potassium

PCT, TAL, DCT/CD

How is potassium handled in the PCT

Passive paracellular reabsorption via electrochemical gradient

How is potassium handled in the TAL

Passive paracellular reabsorption via positive luminal potential created by NKCC co transporter

How is potassium handled in the DCT/CD

Secreted via principal cells (Na+ exchanges for K+) Reabsorbed via alpha intercalated cells by proton-potassium exchanger

What percent of potassium is reabsorbed in the PCT

65%

What percent of potassium is reabsorbed in the TAL

25%

What percent of potassium is reabsorbed in the DCT/CD

depends on diet

What parts of the nephron handles magnesium

PCT,TAL,DCT

How is magnesium handled in the PCT

passive reabsorption parracellularly

How is magnesium handled in the TAL

Passive paracellularly due to positive luminal potential via NKCC cotransporter

How is magnesium handled in the DCT

Active transport via TPRM6 (Mag-Cal co transporter

What percent of magnesium is reabsorbed in the PCT

15-20%

What percent of magnesium is reabsorbed in the TAL

60-70%

What percent of magnesium is reabsorbed in the DCT

5-10%

What affects potasium reabsorption

Diet, aldosterone, acid-base disturbances

What part of the nephron handles phosphate

Mostly the PCT, barely the DCT or CD

How does the PCT handle phosphate?

Actively via the Na+/phosphate cotransporter

What effects PCT reabsorption of phosphate

High Phosphate= dec. reabsorption inc PTH = dec. reabsorption

What percentage of phosphate is reabsorbed in the PCT?

70-80%

Why is glutamine so important in the kidneys (PCT/CD)

It is broken down into ammonia and bicarb via glutaminase. Therefore creating ammonia to buffer H+ in the urine and also bicarb for reabsorption and to buffer H+ in the blood

What role does ammonia play in the TAL

It is moved into the interstitium to increase medullary osmolarity, and decrease osmolarity in the tubular lumen

What role does ammonia play in the CD

It moves into tubular lumen as ammonia to buffer H+ (turns into ammonium). This is called diffusion trap.

How does potassium levels affect ammonia production

Hypokalemia--> increases production Hyperkalemia--> decreases production

Unit 1 Renal Flashcards

(76 cards)