Basic Kidney Function Flashcards Preview

Urinary Exam 1 > Basic Kidney Function > Flashcards

Flashcards in Basic Kidney Function Deck (31):
1

What is osmolarity?

The sum of the moles of each component of a solution: 2mM solution of MgCl2=6mM per liter (2x3(Cl) + 2x 1(Mg))

2

Major difference in osmolality and osmolarity?

Osmolality: the moles of solute per kilogram of solvent
Osmolarity: number of moles per liter in solution

3

What is osmolality?

Moles of a solute per kilogram of solvent

4

What concentration of NaCl is isosmotic to cells?

150mM

5

How many liters of water is filtered by kidneys each day?

180L

6

What is the process of producing hypo-osmotic urine?

Thick ascending limb of Henle's loop reabsorbs more solute than water

7

What is the process of producing hyper-osmotic urine?

Water reabsorbed from lumen into a hyper-osmotic medullary interstitium

8

How are medullary interstitial cells made hyper-osmotic?

1.) Addition of Na+ to interstitium
2.) Vasculature that minimizes removal of Na+
3.) Recycling urea between medullary collecting ducts and deep portions of loops of Henle

9

What are the seven major renal functions?

1.) Water of and electrolyte balance
2.) Acid base balance
3.) Excretion of waste
4.) Arterial blood pressure
5.) Red blood cell
6.) Vitamin D production
7.) Gluconeogenesis

10

What are the three fundamental elements of renal function?

1.) Glomerular filtration
2.) Tubular secretion
3.) Tubular reabsorption

11

What are podocytes?

Cells that wrap around the capillaries of the Bowman's capsule

12

What are the macula densa?

A sensor of tubular Na+ content that exerts renal control of granular cells

13

Where are the macula densa (juxtaglomerular apparatus) located?

Between the afferent arteriole and the distal convoluted tubule

14

What innervates the macula densa and what does it release?

Sympathetic innervation for release of renin

15

What is the macula densa response to blood sodium levels being too high?

Contraction of the afferent arteriole

16

What is the Bowman's filtrate most similar to?

Blood plasma minus large proteins

17

What does the descending limb do?

Reabsorbs water out of the tubule (impermeable to ions)

18

What does the ascending limb do?

Reabsorbs ions out of the tubule (impermeable to water)

19

What is meant by counter current?

As ions are absorbed out into the tubule from the ascending limb the ions pull water out from the descending limb

20

What is the distal convoluted tubules function?

To reabsorb more ions (Na, Cl, etc.)

21

Function of the proximal convoluted tubule?

Reabsorb water, Na+, glucose, AA

22

What does the collecting duct reabsorb?

Water, Urea

23

What is the function of the juxtaglomerular apparatus?

Control blood pressure

24

How do the kidneys regulate Ca++ and phosphate?

Excrete Ca++ in urine
Activates vitamin D

25

How do kidneys regulate acid-base balance?

By excreting or producing H+

26

What is renal excretion rate dependent on?

Rate of filtration
Rate of reabsorption
Rate of secretion

27

Formula for excretion rate:

Ux x V
Ux= [x]
V= urine flow per unit time

28

What is renal clearance?

The virtual amount of plasma that would be completely cleared of a solute in a given amount of time (mL/min)

29

Example: what does it mean if the renal clearance of urea is 65mL/min?

That the kidneys remove all of the urea present in 65mL of plasma each minute

30

Renal clearance formula:

Cx= (Ux x V)/Px

Px= [x] in systemic blood plasma

31

Function of PTH?

Ca++ reabsorption
Phosphate (i) excretion
Hydroxylation of Vitamin D precursor into active Vitamin D