- Excretion of wastes - Regulation of ECF, volume, osmolarity, and blood pressure - Homeostatic regulation of pH - Production of hormones (erythropoietin, renin, and vitamin D3)

Unit 3: Renal Flashcards by Salina H Huy

Role of Kidneys:

Excretion of wastes
Regulation of ECF, volume, osmolarity, and blood pressure
Homeostatic regulation of pH
Production of hormones (erythropoietin, renin, and vitamin D3)

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Renal corpuscle =

Renal corpuscle = glomerulus + Bowman’s capsule

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Vascular component of nephron:

Afferent Arteriole -> Glomerulus (capillary bed #1) -> Efferent Arteriole -> Peritubular Capillaries (capillary bed #2)

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Tubular component of nephron:

Bowman’s capsule -> Proximal Tubule -> Loop of Henle -> Distal tubule -> Collecting duct

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Filtration is the amount of a ______ solute from the _____ to ______

_____ to _____

SPECIFIC
glomerulus -> Bowman’s capsule

blood to lumen

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Excretion is the movement of solutes and water _____ the body
This is what ends up being ____

____ to _____

out of
urine

lumen -> external environment

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Reabsorption is the transport of a specific solute from the ______ of the nephron to the _____

lumen
capillaries

lumen -> blood

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Secretion is the transport of a specific solute from the ______ to the nephron

capillaries

blood -> lumen

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Reabsorption and secretion at _______ is unregulated

proximal tubule

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Reabsorption and secretion at _____ is regulated

distal tubule + collecting duct

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Excretion =

Excretion = Filtration - Reabsorption + Secretion

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Specific Filtration = amount of _____ from glomerulus to Bowman’s capsule over time

Units:

SPECIFIC solute

mg/min

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Bulk Filtration = volume of _______ from glomerulus to Bowman’s capsule over time

Units:

plasma (water with dissolved solutes)

mL/min

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Average value for GFR in L/day? mL/min?

180 L/day or 125 mL/min

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What percent of plasma is filtered per time?
Filtration fraction =

Filtration fraction = GFR/RPF
125 mL/600 mL ~20%

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Glomerulus lumen -> ______ -> _______ -> _______ -> Lumen of Bowman Capsule

Fenestrations/Pores in Endothelium
Basement Membrane
Filtration Slit of Epithelium

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Fenestrations/Pores in Endothelium:

Luminal surface lined with _______ charged glycocalyx proteins that covers the
fenestrations and can repel larger negatively
charged molecules

Fenestrations are too
small for ______ to pass through

negatively

RBCs and cells

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Basement membrane:

______
charged
glycoproteins,
collagen, and
other proteins,
Acts like a coarse
sieve, excluding
most _______

Negatively

plasma proteins

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Filtration Slit of Epithelium:

Slit diaphragm =
Nephrin and
podocin, that
form a two-layer
sieve

Excludes _______

any remaining small proteins

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By the time you reach lumen of bowman capture

-
-

You should have:
- Water
- Ions
- Small molecules

Should not have:
- Plasma proteins
- RBCs/Platelets
- Cells

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Why is filtration in glomerular capillaries so much greater?

Factors affecting filtration:
1.
2.
3.

Net filtration pressure
Permeability
Surface area

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Surface area of filtration slits can be affected by ______, contraction of them _____ surface area

mesangial cells
decreases

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Components of the “filtration barrier” in order:

Endothelium with fenestrations
Basement membrane (basal lamina)
Podocytes

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If glutamate is negatively charged at physiological pH and lysine is positively charged, for which do you think filtration is greater?

A. F lysine < F glutamate
B. F lysine > F glutamate
C. F lysine = F glutamate

B. F lysine > F glutamate

Filtration barrier is negatively charged, lysine positively charged filters through b/c it is attracted

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GFR is determined by... GFR =

Kf x net filtration pressure GFR = Kf x (PH - pi - Pfluid)

Net filtration pressure =

Net filtration pressure = Hydrostatic pressure - oncotic pressure - pressure from Bowman's capsule

Hydrostatic pressure (PH) changes by changing the ______ of afferent and efferent arterioles

resistance

Renal threshold is plasma concentration at which ______ occurs

saturation *LAST plasma concentration where excretion rate is zero

Once transporters are saturated, substrate will be _____

excreted

Renal threshold for glutamate is ______ renal threshold for lysine

higher than harder for glutamate to filter through, HIGHER plasma [ ] needed

In normal glucose handling, there is 100% ______ of glucose In diabetes, there is an _____ of glucose in plasma, goes past ______ which is why we see ______ in urine

reabsorption increase renal threshold glucose

Transport maximum is the _____ transporters can move a substance into or out of the nephron

rate

Any solute which does NOT get _______ can be used to estimate GFR Examples:

secreted or reabsorbed creatinine, inulin

There are multiple forms of _____ like by GI, Lungs, Kidneys, NOT _____ to kidneys

clearance exclusive

Clearance is the volume of ______ cleared of ______ per time

plasma substance (x)

Clearance (x) =

Clearance (x) = (urine flow x [x]urine) / [x] plasma

The higher the renal clearance, the more _____ that is CLEARED of the substance

plasma

Inulin is an ______ indicator of GFR because I have to give it to the patient Creatinine is an _____ indicator of GFR

exogenous endogenous, in our bodies

Glucose has _____ clearance because it is ______

0% 100% reasbsorbed

Which are true of clearance? A. Equals amount of solute cleared from plasma per time B. Is an expression of flow C. Always equals GFR D. Renal clearance is just one form of clearance E. None are correct

B. Is an expression of flow D. Renal clearance is just one form of clearance

400 mL of liquid Each marble is 100 mg There are 4 red marbles All the marbles are removed. What volume has been cleared of red marbles? A. 0 mL B. 200 mL C. 400 mL D. Other

C. 400 mL

If plasma creatinine has doubled, that means GFR has _____ A. Halved B. Doubled C. Quadrupled D. None of the above

halved Clearance (x) = urine flow x [x] urine / [x] plasma

The filtration rate of substance Z is 30 mg/min and the excretion rate is 42 mg/min. Which is/are true? A. Z is net secreted B. GFR of this substance is > 180 L/day C. Excretion is greater than GFR D. None are correct

A. Z is net secreted *I can only make a statement about GFR in a substance if it is neither secreted or reabsorbed, which is not the case Correct version of B would be: Clearance of this substance > GFR

Clearance > GFR =

Clearance > GFR = Secretion

Clearance < GFR =

Clearance < GFR = Reabsorption

Mean arterial blood pressure is primarily regulated by renal-related hormones:

Aldosterone (ANG II), ADH, and ANP

Which is NOT a classic mechanism of aldosterone? A. simple diffusion into target cell B. binding to intracellular receptor C. upregulation of cAMP D. transcription of channel subunits E. low volume triggers release of renin

C. upregulation of cAMP E. low volume triggers release of renin

What are the consequences of hyperaldosteronism? A. Hyponatremia B. Hypokalemia C. Hypotension D. High ANG II

B. Hypokalemia (less K+) More sodium reabsorbed -> more K+ excreted Hyperaldosteronism would cause HYPERnatremia, HYPERtension,

How could ANP increase GFR? A. Increase fluid pressure in Bowman's capsule B. Dilate the efferent arteriole C. Dilate the afferent arteriole D. Relax mesangial cells

C. Dilate the afferent arteriole D. Relax mesangial cells

Increasing fluid pressure in Bowman's capsule and dilating the efferent arteriole would _____ GFR

DECREASE

Which is NOT an effect of ANG II? A. Thirst B. Increased ADH C. Vasoconstriction D. Upregulate ANP E. All are effects of ANG II

D. Upregulate ANP

In dehydration... A. ANG II is released, increasing blood pressure B. Aldosterone is upregulated because blood volume is low C. Both volume and osmolarity stimulate ADH release D. Water is reabsorbed independent of sodium reabsorption

A. ANG II is released, increasing blood pressure C. Both volume and osmolarity stimulate ADH release D. Water is reabsorbed independent of sodium reabsorption *Increase in plasma osmolarity INHIBITS adrenal cortex and aldosterone release and Na+ reabsorption

After consumption of 1.5 L of a hyperosmotic drink (choose all that apply): A. Osmolarity stimulates but volume inhibits ADH release B. ANP increases GFR and decreases Na+ reabsorption C. Heart rate is slowed

A. Osmolarity stimulates but volume inhibits ADH release B. ANP increases GFR and decreases Na+ reabsorption C. Heart rate is slowed *ANP inhibits JG cells

Consequences of hyposecretion of ADH include: A. Hypovolemia (decrease blood volume) B. Hypotension (decrease blood pressure) C. Hyponatremia (decrease [sodium] in blood)

A. Hypovolemia (decrease blood volume) B. Hypotension (decrease blood pressure) *ADH is responsible for water reabsorption, so if you have less reabsorption less volume

Which makes a good diuretic? A. ANP agonist B. ADH antagonist C. Aldosterone antagonist D. Water

diuretic = more water excretion A. ANP agonist -> increases GFR B. ADH antagonist -> decreases water reabsorption C. Aldosterone antagonist -> water follows sodium, decreases Na+ and water reabsorption D. Water

ADH is main determinant to _____ of urine

osmolarity

Loop of Henle: Functions: - Site of production of _____ urine - Create/maintain ______ gradient in medulla Mechanisms: - -

dilute osmotic - Countercurrent multiplication (loop of Henle) Countercurrent: flow is parallel, opposite directions - Countercurrent exchange (vasa recta)

Countercurrent multiplication (loop of Henle) is the _____ process that _____ the medullary osmotic gradient

active, establishes

Countercurrent exchange (vasa recta) is the _____ process that helps ____ the gradient

passive, maintains

Proximal tubule: ____osmotic fluid Distal tubule: ____osmotic fluid

Isosmotic Hyposmotic fluid (low concentration of solutes, high concentration of water)

More H+ = _____ the pH

lower

The normal pH of the body is

7.38-7.42

Acidosis: pH _____ 7.4 Alkalosis: pH ____ 7.4

Acidosis: pH < 7.4 Alkalosis: pH > 7.4

What are the sources of acid within our body? - - Primary acid input from ______ = CO2

- Diet - metabolism

Buffers work like a _____, taking up H+ and making sure it doesn't add to ______

sponge pH change (keeps pH stable)

If H+ increases in our body... A. HCO3- will also increase B. H+ reacts with bicarb to produce carbonic acid C. CO2 net combines with water to produce H2CO3

B. H+ reacts with bicarb to produce carbonic acid

pH Homeostasis _____ are our first line of defense Then is _____ which is FAST (75%) Then is _____ which is SLOW (25%) Need to exhaust _____ to see others at play

Buffers respiratory renal buffers

Origin of the disorder: Respiratory: begins with changes in _____ Metabolic: begins with changes in _____

CO2 H+

When we have a metabolic disturbance, our compensation is always going to be ______

respiratory

Metabolic acidosis is caused by _______ or ________ Most common cause (from ______) Compensation:

increased H+, decreased HCO3- Respiratory compensation with hyperventilation

Hyperventilation is the ________ for acidosis

compensation

During periods of acidosis, type ____ intercalated cells secrete ____ and reabsorb ____

A secrete H+ reabsorb bicarbonate and K+

During periods of alkalosis, type ____ intercalated cells secrete ____ and reabsorb ____

B secrete HCO3- and K+ reabsorb H+

Disturbances of acid-base balance are associated with disturbances in _______

K+ balance

Acidosis tends to lead to... A. Hyperkalemia B. Hypokalemia

A. Hyperkalemia

Metabolic alkalosis is caused by _______ or _______ Most common cause (from ______) Compensation:

decreased H+, increased HCO3- vomiting Respiratory compensation with hypoventilation

Respiratory acidosis is caused by _______ Increased _____ drives reaction to the right, increasing H+

hypoventilation (like COPD) CO2

Respiratory Acidosis: ____ pH Initial disturbance: Compensation:

decreased pH Initial disturbance: Increased pCO2 Compensation: increased HCO3- Compensation: Renal/absorb HCO3-/Secrete H+

Respiratory Alkalosis: ____ pH Initial disturbance: Compensation:

increased pH Initial disturbance: decreased pCO2 Compensation: decreased HCO3- Compensation: Renal/secrete HCO3-/Absorb H+

Metabolic Acidosis: ____ pH Initial disturbance: Compensation:

decreased pH Initial disturbance: decreased HCO3- Compensation: decreased PCO2 Compensation: Respiratory/Hyperventilation

Metabolic Alkalosis: ____ pH Initial disturbance: Compensation:

increased pH Initial disturbance: increased HCO3- Compensation: increased PCO2 Compensation: Respiratory/Hypoventilation

The day Amanda was diagnosed... Normal pH: 7.38 – 7.42 PCO2 = 40 mm Hg H+ = .00004 mEq/L HCO3- = 24 mEq/L Amanda: Plasma glucose: 800 mg/dL urinary glucose: > 100 mg/dL pH: 7.30 urinary ketones: > 20 mg/dL plasma HCO3-: 19 mEq/L respiratory rate: 30 breaths/min plasma CO2: 30 mm Hg plasma [K+]: 6 mM What acid-base disorder does Amanda have? A. Metabolic acidosis B. Metabolic alkalosis C. Respiratory acidosis D. Respiratory alkalosis

A. Metabolic acidosis decreased pH decreased HCO3- decreased pCO2

Symptoms: decreased pH increased pCO2 increased HCO3- The most probable diagnosis for this patient is: A. Chronic diarrhea B. Overconsumption of antacids C. COPD D. Respiratory acidosis

C. COPD D. Respiratory acidosis

A 45-year-old man who was admitted with nausea, vomiting, and abdominal pain with a PaCO2 of 85.5 mm Hg, PaO2 of 43.5 mm Hg, pH of 7.61, and plasma bicarbonate concentration of 82.0 mEq/l. Normal pH: 7.38 – 7.42 PCO2 = 40 mm Hg PO2 = 100mmHg H+ = .00004 mEq/L HCO3- = 24 mEq/L What acid-base disorder does this patient have? A. Metabolic acidosis B. Metabolic alkalosis C. Respiratory acidosis D. Respiratory alkalosis

B. Metabolic alkalosis increased pH increased HCO3- increased pCO2