Intro to renal

Question 1

What does the kidney help regulate, and what doe this regulated function help maintain?

Answer 1

ECF volume, osmolarity, fluid ion composition (Na, K, H, bicarb); helps maintain blood pressure and blood flow

Question 2

What two other features does the kidney partake in?

Answer 2

Clearance of metabolic end products, toxins and drugs; endocrine includes EPO, active vit D, renin

Question 3

With a standardized patient of 70 kg, what is the percent of weight that is total body water (TBW)? How much is ECF and ICF percentage-wise?

Answer 3

60% (42L); 40% is 28 L; 20% is 14 L

Question 4

What two components make up the ICF?

Answer 4

Plasma (3 L) and extravascular fluid (10 L, interstitial fluid)

Question 5

What is TBW proportional to?

Answer 5

Inversely proportional to percent body fat

Question 6

How is the osmolarity of the ICF compared to the ECF?

Answer 6

The solute concentration is essentially the same

Question 7

What is the only effector organ of regulated water and salt excretion?

Answer 7

Kidneys

Question 8

When does unregulated water and salt loss from TBW occur?

Answer 8

Sweat, feces, insensible skin and lung loss (water only)

Question 9

What can the kidneys do given variable consumption of solutes and water on ECF volume and osmolarity?

Answer 9

They increase or decrease excretion of solutes and water in the urine given how much solute or water is consumed

Question 10

What drives filtration of fluid out of the arterial end? What drives absorption closer to the venous end?

Answer 10

Hydrostatic pressure being greater than oncotic pressure (osmotic pressure in and out of capillary due to protein present or not);
The hydrostatic pressure drops and oncotic pressure is greater

Question 11

What has the greater filtration rate, the glomerular or systemic capillaries?

Answer 11

Glomerular capillaries because of a higher Lp

Question 12

How does CHF cause edema?

Answer 12

It raises the capillary hydrostatic pressure at the venous end

Question 13

Nephrotic syndrome and liver disease cause edema how?

Answer 13

They decrease plasma protein concentration and capillary oncotic pressure; cause isotonic retention of sodium and water as well as decreased circulating volume

Question 14

What determines water movement across the cell membrane? What type of movement does water undergo, active or passive? What does water do relative to solute?

Answer 14

Permeating and non-permeating solute concentrations in the ICF and ECF; passive;
water follows solute, with the latter being transported actively or passively

Question 15

How does water move across its cell membrane?

Answer 15

From higher concentration to lower concentration through the lipid bilayer or aquaporins

Question 16

What happens to ECF volume, ECF osmolarity, ICF volume and osmolarity with IV isosmotic fluid gain to the ECF? Crit and protein levels?

Answer 16

Increase, no change, no change, no change

Question 17

What happens to ECF volume and osmolarity, ICF volume and osmolarity with isosmotic fluid loss? Crit and protein levels?

Answer 17

Decrease, no change, no change, no change; protein and crit increased

Question 18

What happens to ECF volume, ECF osmolarity, ICF volume and ICF osmolarity due to sweating and/or water deprivation?

Answer 18

Decreases, increases, decrease, increase

Question 19

What happens to the ECF osmolarity, ICF volume and ICF osmolarity, and ECF volume with high NaCl intake without fluids? What happens to ICF Na concentrations? Why?

Answer 19

Increases, decreases, increase, increase;

They remain unchanged due to Na-K pump activity balancing Na entry

Question 20

What happens with ECF volume, ECF osmolarity, ICF volume and ICF osmolarity given syndrome of inappropriate ADH (SIADH)?

Answer 20

Increase, decrease, increase, decrease

Question 21

What happens with ECF osmolarity, ICF volume and ICF osmolarity and ECF volume when there is adrenal insufficiency and decreased renal NaCl reabsorption?

Answer 21

Decrease, increase, decrease, decrease

Question 22

What happens to a cell in response to increases in ECF osmolarity? What’s this process called?

Answer 22

Cells activate uptake mechs to increase ICF osmolarity to drive water into the cells; regulatory volume increase!!!

Question 23

What happens to a cell in response to decreases in ECF osmolarity? What’s this process called?

Answer 23

Cells activate efflux mechs to decrease ICF osmolarity to drive water out of cells (regulatory volume decrease)

Question 24

What do you have to watch out for when trying to restore ECF osmolarity to normal?

Answer 24

A high rate of infusion may cause dangerous cell swelling if RVI had previously occurred, or dangerous cell shrinking if RVD had occurred

Question 25

What is the main consequence of variable cell volume?

Answer 25

Concentration of intracellular metabolites changes, and that could affect metabolic reactions dependent on substrate concentration and substrate affinity for enzymes

Question 26

What are the basic processes of the kidney? What process is NOT a renal process?

Answer 26

1. Filtration (ultrafiltrate made with organic and inorganic solutes at concentrations similar to plasma)
2. Reabsorption (moving solutes and water from kidney tubule lumen to peritubular surface)
3. Secretion (movement of ONLY solutes from peritubular side to the lumen)
4. Synthesis (Hormones/organic solutes made/degraded that appear in blood or urine, like ammonium, bicar, renin, EPO, active vit D)
   Excretion (amount of solute and water eliminated in urine)

Question 27

How are solutes and water handled by the kidney? What about those NOT metabolized by the kidney?

Answer 27

Excreted = Filtered + Secreted + Synthesized - Reabsorbed;

Same as above but remove the synthesized part

Question 28

What are three main components of renal function? Which blood supply takes care of filtration and reabsorption? Where does this process start and end?

Answer 28

1. Glomerular filtration
2. Tubular secretion
3. Tubular reabsorption;
   the same blood supply;
   Proximal tubule and collecting duct