Renal Function

Question 1

What is the nephron?

Answer 1

Functional unit of the kidney

Question 2

Five main parts of the nephron

Answer 2

Glomerulus, PCT, Loop of Henle, DCT, Collecting duct

Question 3

Primary function of the glomerulus

Answer 3

Filters blood to form glomerular filtrate

Question 4

What does the glomerulus prevent from filtering?

Answer 4

Cells and large proteins

Question 5

Where is the proximal convoluted tubule located?

Answer 5

Cortex

Question 6

Main role of the PCT

Answer 6

Bulk reabsorption of filtrate

Question 7

Approx. % of filtrate reabsorbed in PCT

Answer 7

~75%

Question 8

What important substance is fully reabsorbed in the PCT (below threshold)?

Answer 8

Glucose

Question 9

Which nephron segment secretes most H⁺?

Answer 9

Proximal tubule

Question 10

Where is the Loop of Henle located?

Answer 10

Medulla

Question 11

Descending loop permeability

Answer 11

Permeable to water

Question 12

Ascending loop permeability

Answer 12

Impermeable to water

Question 13

Main function of Loop of Henle

Answer 13

Establish medullary osmotic gradient

Question 14

What system is created by the Loop of Henle?

Answer 14

Countercurrent multiplier

Question 15

Where is the distal convoluted tubule located?

Answer 15

Cortex

Question 16

Primary role of the DCT (distal convoluted tubule )

Answer 16

Fine-tuning electrolytes and acid–base balance

Question 17

Which ions are reabsorb in the distal convoluted tubule ?

Answer 17

Na⁺, Ca²⁺, Mg²⁺, HCO₃⁻

Question 18

What hormones regulate the DCT?

Answer 18

Aldosterone, AVP (ADH)

Question 19

What controls water permeability in the collecting duct?

Answer 19

AVP (ADH)

Question 20

What solute helps maintain medullary hyperosmolality in the collecting duct?

Answer 20

Urea

Question 21

What are NPN compounds?

Answer 21

Nitrogen-containing metabolic wastes

Question 22

Three major NPN compounds

Answer 22

Urea, creatinine, uric acid

Question 23

Primary source of urea

Answer 23

Protein metabolism in liver

Question 24

Is urea filtered by the glomerulus?

Answer 24

yes

Question 25

Is urea partially reabsorbed?

Answer 25

yes

Question 26

Is creatinine reabsorbed by tubules?

Answer 26

no

Question 27

Source of creatinine

Answer 27

Muscle creatine phosphate breakdown

Question 28

Why is creatinine useful clinically?

Answer 28

Reflects GFR

Question 29

Source of uric acid

Answer 29

Purine metabolism

Question 30

% of filtered uric acid excreted

Answer 30

~6–12%

Question 31

Low urine pH increases risk of what with uric acid?

Answer 31

Stones

Question 32

Primary hormone regulating water balance

Answer 32

AVP (ADH)

Question 33

AVP is released in response to what?

Answer 33

↑ osmolality or ↓ blood volume

Question 34

Effect of AVP on kidneys

Answer 34

Increases water reabsorption

Question 35

Dehydration causes urine to be

Answer 35

Concentrated

Question 36

Water excess causes urine to be

Answer 36

Dilute

Question 37

Primary regulator of sodium balance

Answer 37

Renin–angiotensin–aldosterone system

Question 38

Aldosterone effect on sodium

Answer 38

Increases reabsorption

Question 39

Hormone released by kidney in response to hypotension

Answer 39

Renin

Question 40

Aldosterone effect on potassium

Answer 40

Increases secretion

Question 41

Renin starts which system?

Answer 41

RAAS

Question 42

Effect of RAAS

Answer 42

↑ Blood pressure, ↑ Na⁺/H₂O retention

Question 43

Hormone released by kidney during hypoxia

Answer 43

Erythropoietin

Question 44

Erythropoietin function

Answer 44

Stimulates RBC production

Question 45

Active form of vitamin D made by kidney

Answer 45

1,25-dihydroxyvitamin D₃

Question 46

Vitamin D function

Answer 46

Calcium and phosphate regulation

Question 47

Renal prostaglandins increase what?

Answer 47

Renal blood flow

Question 48

What is clearance?

Answer 48

Volume of plasma cleared of a substance per minute

Question 49

Gold standard endogenous marker for GFR

Answer 49

Creatinine

Question 50

What specimen is needed for creatinine clearance?

Answer 50

Serum + 24-hour urine

Question 51

What is eGFR based on?

Answer 51

Serum creatinine + demographics

Question 52

Marker that rises early in AKI

Answer 52

Cystatin C

Question 53

What is acute kidney injury (AKI)?

Answer 53

Sudden decline in kidney function

Question 54

Three categories of AKI

Answer 54

Prerenal, intrinsic, postrenal

Question 55

Common lab finding in AKI

Answer 55

↑ BUN, ↑ creatinine

Question 56

What is glomerular disease also called?

Answer 56

Glomerulonephritis

Question 57

Key signs of glomerular disease

Answer 57

Hematuria, proteinuria, edema

Question 58

Defining feature of nephrotic syndrome

Answer 58

Heavy proteinuria (>3 g/day)

Question 59

Major consequence of nephrotic syndrome

Answer 59

Edema

Question 60

What is pyelonephritis?

Answer 60

Bacterial kidney infection

Question 61

Common symptoms of pyelonephritis

Answer 61

Fever, flank pain, UTI symptoms