Renal - High Yield Information

Question 1

The functional unit of the kidney is the…

Answer 1

Nephron

Question 2

The nephron consists of…

Answer 2

Glomerulus
Proximal Tubule
Loop of Henle
Distal Tubule
Collecting Duct

Question 3

What effect do Starling forces have in the nephron?

Answer 3

Starling forces across the glomerular capillaries provide the driving force for the ultrafiltration of plasma from the glomerualr capillaries into Bowman’s capsule

Question 4

Glomerular filtrate is devoid of/has very little…

Devoid = entirely lacking

Answer 4

cellular elements - red/white blood cells and platelets
protein

Filtrate is otherwise identical to plasma

Question 5

What is the purpose of autoregulation in the kidney?

Answer 5

it allows GFR and RBF to remain contant depsite fluctuations in arterial blood pressure between 80 and 180 mmHg

Question 6

Define

Juxtaglomerular Apparatus (JGA)

What is it? What does it do?

Answer 6

important feedback mechanism
regulates renal blood flow and GFR

Question 7

What structures make up the JGA?

Answer 7

Macula Densa
Extraglomerular Mesangial Cells
Granular Cells

Granular cells produce renin

Question 8

What can be used to measure GFR?

Answer 8

Creatinine and inulin

Plasma Creatinine concentration is used to measure GFR Clinically

Question 9

The clearance of PAH is equal to…

Answer 9

the effective renal plasma flow

Question 10

Renal Blood Flow is about ____% of CO

Answer 10

25%

Question 11

What does Renal Blood Flow do?

Answer 11

indirectly determines GFR
Modifies the rate of solute and water reabsorption by the proximal tubule
Delivers O2, nutrients, and hormones to the cells of the nephron
Returns CO2 and reabsorbed fluid and solutes to general cirulation
Delivers substrates for excretion in the urine

Question 12

What are the major hormonal regulators of GFR and RBF?

Answer 12

Sympathetic Nerves
Angiotensin II

prostaglandins, NO, endothelin, natriuretic peptides, bradykinin, and adenosine affect GFR and RBF too

Question 13

The major body fluid compartments are…

Answer 13

Extracellular Fluid (ECF)
Intracellular Fluid (ICF)

Question 14

Na+ is confined to the…

Answer 14

ECF

Question 15

What is the result of Na+ being confined to the ECF?

Answer 15

the amount of Na+ in the body determines the volume of the ECF

Question 16

_ of the volume of total body water is in the ICF

Answer 16

2/3

Question 17

_ of the volume of total body water is in the ECF

Answer 17

1/3

Question 18

Plasma volume makes up _ of the ECF

Answer 18

1/4

Question 19

Why are plasma and interstitial fluid nearly identical in composition?

Answer 19

Most plasma constituents are freely exchanged across the capillary wall

except for the lack of plasma proteins in IF

Question 20

What causes the significantly different compositions between the ECF and ICF?

Answer 20

Cell membrane barrier

Question 21

Fluid balance is controlled by…

Answer 21

Regulation of ECF volume by maintaining salt balance
Regulation of ECF osmolarity by maintaining water balance

Question 22

Changes in ECF volume occur by…

Answer 22

changing Na+
Because of the osmotic holding power of Na+, changing a body’s total Na+ content changes ECF volume

alters arterial blood pressure in the same direction

Question 23

What is the major cation in the ECF?

Answer 23

Na+

Question 24

How is salt intake and output controlled?

Answer 24

Intake is uncontroled
Output is closely regulated by the kidney by changing urine concentration of Na+

Question 25

How do blood pressure regulating mechanisms vary GFR and amount of Na+ filtered/reabsorbed?

Answer 25

GFR and Na+ filtered are varied by adjusting the caliber of the afferent arterioles supplying the glomeruli Na+ reabsorption is varied by varying secretion of aldosterone which promotes Na+ reabsorption in renal tubules

Question 26

# T or F Varying Na+ filtration and reabsorption has no effect on ECF Volume?

Answer 26

False | varying Na+ filtration/reabsorption alters ECF volume

Question 27

Changes in ECF osmolarity occur by...

Answer 27

changing H2O balance

Question 28

Why is varying H2O balance important?

Answer 28

It is vital in avoiding osmotic shifts between the ECF and ICF cells

Question 29

What occurs in the ECF when there is excess H2O?

Answer 29

ECF solutes are diuted H2O is driven into the cells due to ECF hypotonicity

Question 30

What occurs in the ECF when H2O is deficit?

Answer 30

ECF solutes are concentrated H2O is driven out of the cells and into hypertonic ECF

Question 31

What helps prevent the fluxes of excess/deficit H2O?

Answer 31

ADH (primarily) and thirst (lesser extent) stimulated by hypothalamic osmoreceptors

Question 32

Volume concentration and expansion refer to...

Answer 32

ECF volume

Question 33

# Define Isosmolar Volume Expansion or Contraction

Answer 33

If ECF volume changes and the solute concentration remains the same

Question 34

# Define Hyperosmolar Expansion or Contraction

Answer 34

If ECF volume changes but the solute concentration increases

Question 35

# Define Hypo-osmolar Expansion or Contracton

Answer 35

If the ECF volume changes but the solute concentration falls

Question 36

What is the overall function of the four major segments of the nephron? | Proximal Tubule, LoH, Distal Tubule, Collecting Duct

Answer 36

Determine the composition and volume of the urine by the processes of selective reabsorption of solutes and water and secretion of solutes

Question 37

# Define Tubular Reabsorption

Answer 37

allows the kidney to retain the substances that are essential and regulate their levels in the plasma by altering the degree to which they are reabsorbed

Question 38

What are the major solutes/ions reabsorbed by the nephron?

Answer 38

Na+ Cl- K+ HCO3- Ca2+ PO4-3 organic anions and cations water

Question 39

The nephron reabsorbs _ % of filtered water, _ % of filtered sugar, and _ % of filtered salt

Answer 39

99% filtered water 100% filtered sugar 99.5% filteres salt

Question 40

How do the distal segments of the nephron participate in reabsorption?

Answer 40

They have a more limited reabsorptive capacity The final adjustments in the comosition and volume of urine and most of the regulation by hormones occur in these segments

Question 41

Tubular Secretion

Answer 41

Secretion of substances into tubular fluid is a means for excreting various byproducts of metabolism, exogenous organic anions and cations (i.e. drugs), and toxins from the body

Question 42

What regulates NaCl reabsorption in the kidneys?

Answer 42

Various hormones (Angiotensin II, Aldosterone, ADH, Natriuretic Peptides) Sympathetic Nerves Starling forces

Question 43

What is the major hormone that regulates water reabsorption?

Answer 43

ADH

Question 44

How is K+ homeostasis maintained by the kidneys?

Answer 44

They adjust K+ excretion to match dietary K+ intake, and by the hormones insulin, epinephrine, and aldosterone which regulate the distribution of K+ between the intracellular fluid and ECF

Question 45

What regulates K+ secretion by the distal tubule and collecting duct?

Answer 45

Na+ reabsorption plasma [K+] aldosterone changes in tubular fluid acid base disturbaces

Question 46

What regulates Ca2+ reabsorption by the thick ascending limb and distal tubule?

Answer 46

Primarily PTH and Vitamin D (calcitriol) | both stimulate Ca2+ reabsorption

Question 47

What inhibits PO43- reabsorption by the proximal tubule?

Answer 47

PTH

Question 48

How do the kidneys maintain acid-base balance?

Answer 48

Through excretion of H+

Question 49

How do the kidneys prevent the loss of the HCO3- in the urine?

Answer 49

By reabsorbing virtually all the HCO3- filtered at the glomeruli

Question 50

Both the reabsorption of filtered HCO3- and the excretion of acid are accomplished by...

Answer 50

The secretion of H+ by the nephrons

Question 51

The thick ascending limb is _ to water.

Answer 51

impermeable

Question 52

How does the thick ascending limb reabsorb Na+ in the apical membrane?

Answer 52

via a Na+-K+-2Cl- cotransporter

Question 53

How does the thick ascending limb reabsorb Na+ in the basolateral membrane?

Answer 53

via a Na+-K+ ATPase

Question 54

The distal convoluted tubule is _ to water

Answer 54

impermeable

Question 55

How does the distal tubule reabsorb Na+?

Answer 55

via a thiazide-sensitive apical membrane NaCl cotransporter

Question 56

Cortical collecting duct principal cells reabsorb _ and secrete _.

Answer 56

Reabsorb Na+ Secrete K+

Question 57

The kidneys return _ to the body and produce urine with a total solute concentration greater than...

Answer 57

water plasma

Question 58

What is the purpose of the countercurrent multiplication system?

Answer 58

To return water to the body via the blood stream

Question 59

What does it mean that the Loops of Henle are countercurrent multipliers?

Answer 59

They create an osmotic gradient in the kidney medulla

Question 60

What does it mean that the vasa recta are countercurrent exchangers?

Answer 60

They passively help maintain the medullary gradient

Question 61

The collecting ducts have a low _ , which can be increased by _.

Answer 61

Low water permeability increased by ADH