Renal Physiology

Question 1

Hypertonic Expansion

Answer 1

Hypertonic NaCl

NaCl tablets - no liquid involved

Question 2

Isotonic Expansion

Answer 2

Isotonic Saline

Lactated Ringers Solution

Question 3

Hypotonic Contraction

Answer 3

Chronic sweating (NaCl depletion)
Adrenocortical Insufficiency (no NaCl retention)

Question 4

Hypertonic Contraction

Answer 4

Sweating without fluid replacement

Diabetes Insipidus

Question 5

Isotonic Contraction

Answer 5

Diarrhea

Hemorrhage (whole blood loss)

Question 6

ECF 14L
ICF 28L
TBW 42L
IF 10.5L
Plasma 3.5L

20-40-60 rule

Answer 6

20% body weight 1/3 TBW
40% body weight 2/3 TBW
60% body weight (kg)
3/4 ECF
Plasma 1/4 ECF

Question 7

Juxtaglomerular apparatus consist of

Answer 7

Macula densa - thick LOH meets DCT
Juxtaglomerular/granular cells - secrete renin
Extraglomerular mesangial cells - smooth muscle involved in blood flow via sym system

Question 8

Filtration Fraction

Answer 8

GFR/RPF normally 20%

Constrict AA = smaller GFR & RPF same FF

Constrict EA = greater GFR, large FF

Question 9

GFR

Answer 9

Kf x Pf

Controlled by BP and AA, EA resistance

Question 10

Myogenic response

Answer 10

Fast

Increase MAP, greater Na+ influx -> Ca2+ -> SM contracts

Question 11

Tubuloglomerular Feedback

Answer 11

Up to one minute

Increase MAP = increase GFR and Na & Cl to macula densa, increase in ATP & adenosine release via mesangial cells -> calcium increase -> vasoconstriction of AA (inhibit renin release via juxtagl. Cells) to decrease GFR

Question 12

Function of ANP and BNP

Answer 12

Decrease Na reabsorption (CT)

Released during high blood volume, reduces blood pressure

ANP - (Atrium stretched)
BNP - (ventricle stretched - natriuretic peptide)

Both cause vascular relaxation of intraglomerular mesangial cells and AA and constriction of EA

Inhibit Renin release, inhibit ADH, inhibit aldosterone,

Question 13

Inulin clearance

Answer 13

E=F

C inulin = GFR

Question 14

Creatinine Clearance

Answer 14

E = F + S

All filtered, Never re absorbed

C creat = GFR

GFR inversely proportional to [serum]

Question 15

PAH Clearance

Answer 15

Freely filtered, complete clearance

C pah = RPF = CV/P

True RPF = C pah/0.9

(90% truly cleared) - 5 vasa recta, 5 fat

Question 16

Glucose Clearance

Answer 16

Completely reabsorbed

E = F-R = 0

Question 17

Loop diuretics

Answer 17

Inhibit Na/K/Cl symporter in Thick ALOH

Question 18

K Sparing Diuretics

Answer 18

Block Na+ or Aldosterone receptor to indirectly inhibit K+ secretion and excretion in the CT

Question 19

Principle cells controlled by

Answer 19

Hormone aldosterone (Na+ reabsorption)

Question 20

Na+ excretion depends on

Answer 20

Effective circulating volume (ECV), not [Na plasma]

Question 21

Renin release stimulated by:

Answer 21

Less AA stretch (low BP)
Less Na+/Cl delivery to macula densa
Sympathetic system
Decreased ANP/BNP

Question 22

Angiotensin II effects

Answer 22

Vasoconstriction of peripheral vessels (increase BP)
Thirst and salt intake desire
ADH secretion via anterior pituitary
Aldosterone release
Increase Na/K anti porter in PCT & TAL
Contracts AA & EA
Contract intraglomerular mensangial cells to decrease GFR

Question 23

Actions of Aldosterone

Answer 23

Increase Na reab. (Via principle cells luminal channels = Na, activates basolateral=Na/K)

Increase K secretion (via principle cells, luminal K channels)

Stimulate H ATPase of alpha-intercalated cells

Question 24

Sympathetic effects on Na+ Reab.

Answer 24

Renin release = Beta-1 receptor

AA & EA vasoconstriction via alpha-1

Na reab. At PCT via alpha-1

Question 25

Conn's Syndrone

Answer 25

Hyperaldosterone = hypertension Increased Na reabsorption at CT Increased K secretion = hypokalemia Increased H ATPase activity (increased H secretion, HCO reab.) = metabolic alkalosis

Question 26

Water diuresis

Answer 26

Increase in urine excretion caused by absence of ADH = hypotonic urine

Question 27

Anti diuresis

Answer 27

High ADH levels causing high water reabsorption In CT causing hypertonic urine

Question 28

What stimulates H+ secretion

Answer 28

Increased PCO2 Decreased pH Increased Aldosterone Increased Angiotensin II (which acts on Na/H on luminal side) K+ wasting diuretics

Question 29

K+ Sparing Diuretics act on

Answer 29

Blocks Principle cell Na+ channels - making lumen more positive therefore excreting H+ Blocks aldosterone receptors

Question 30

Problems with respiratory acidosis

Answer 30

Sleep apnea | opiates

Question 31

Problems with respiratory alkalosis

Answer 31

Respiratory diseases | Pneumonia

Question 32

Problems associated with metabolic acidosis

Answer 32

Diarrhea Lactic acidosis Ketoacidosis

Question 33

Problems associated with metabolic alkalosis

Answer 33

``` Antacid ingestion Low vascular volume High aldosterone Vomiting Loop/thiazide diuretics ```

Question 34

Intracellular buffers and extracellular buffers

Answer 34

Intra - proteins Extra - phosphate and bicarbonate

Question 35

Anion Gap

Answer 35

(Na+) - ( HCO - Cl ) Cations - Anions 9-14 normal

Question 36

Renal response pH equation

Answer 36

pH = 6.1 + log [HCO]/[CO2]

Question 37

Hypotonic expansion

Answer 37

1. H2o 2. D5W 3. SIADH