Fisiologia

Question 1

Baixo fluxo pela arteríola aferente

Answer 1

Leva a liberação de renina

Question 2

Angiotensina II

Answer 2

Potente vasoconstrictor
Retém na no túbulo proximal
Regula a tfg através da vasoconstrição da art eferente
Estimula a liberação da aldosterona

Vasconstricts afferent and efferent arterioles (efferent > afferent)
Systemic vasoconstriction
Stimulates thirst
Increases ADH, Cortisol, Epi, NE and Aldosterone

Question 3

variáveis que influenciam de forma significativa na taxa de filtração glomerular,

Answer 3

a pressão coloidosmótica dos capilares glomerulares, pressão hidrostática glomerular, resposta miogênica e feedback túbulo glomerular

Fatores que afetam a TFG

1) baixo fluxo na arteríola aferente leva a liberação de renina
2)fluxo tubular: feedback tubuloglomerular- baixo fluxo libera prostaglandina que dilatam a AA
Alto fluxo no túbulo distal causa vasoconstrição da AE pela adenosina

Question 4

Substâncias q aumentam a creat sem diminuir a tfg

Answer 4

Inibem ou competem com o transportador de cátion orgânicos
No sistema de transporte de cátions, os cátions ou bases orgânicas (p. ex., pramipexol e dofetilida) são secretados pelos túbulos renais; esse processo pode ser inibido por

cimetidina, trimetoprima, proclorperazina, megestrol ou cetoconazol

Question 5

Produção de urina maximamente concentrada depende

Answer 5

Presença de adh
Hipertonicidade da medula

Question 6

How is glomerular filtration rate (GFR) calculated?

Answer 6

How is glomerular filtration rate (GFR) calculated?
The GFR can be calculated using the following formula:
GFR= kfx x ( pg- pb-hg-hb)
where
Kf filtration coefficient, a constant
PG hydrostatic pressure in the glomerular capillaries PB hydrostatic pressure in Bowman’s capsule
Hg oncotic pressure in the glomerular capillaries
Hb oncotic pressure in Bowman’s capsule, typically 0

Question 7

fsr

Answer 7

Question 8

Site of erythropoietin (EPO) production

Answer 8

renal cortex peritubular cells produce most EPO in the human body

Question 9

Active form of Vitamin D

Answer 9

1,25 dihydrocholecalciferol (Calcitriol)
1st hydroxylation happens in the LIVER (via 25-alpha hydroxylase)
2nd hydroxylation happens in the KIDNEY (via 1-alpha hydroxylase)

Question 10

Juxtamedullary nephrons (less common than cortical nephrons)

Answer 10

Contains vasa recta, and has longer loops of Henle

Components of the Juxtaglomerular (JG) Apparatus

Macula densa (in the walls of the distal tubule; detects changes in BP
JG cells (in the walls of the afferent arteriole; secretes renin)

Question 12

Aldosterone

Answer 12

Site of aldosterone production

Zona Glomerulosa of the Adrenal Cortex

–

Aldosterone action

Increases Na+ reabsorption, K+ secretion, and H+ secretion

Question 13

ADH

Answer 13

ADH actions

Insertion of aquaporins/ water channels in the distal tubules and collecting ducts

Triggers for ADH secretion

Increased plasma osmolarity
Decreased blood volume

Decreased blood pressure

Question 15

2 types of acids produced by the human body

Answer 15

volatile (co2 —> HCO3)
non-volatile (fixed acids) H + SO4 + PO4

Question 16

What % of filtered bicarbonate is excreted in a normal kidney?

Answer 16

0% is secreted

Question 17

3 renal responses to metabolic acidosis

Answer 17

1. Decrease filtered load of bicarbonate (plasma bicarb low)
2. Increase H secretion
3. Increase NH3 production (from glutamine) to absorb H+ secreted

Question 18

Ammonium trapping is when NH3 leaves the DT and CD cells as NH3 and becomes NH4+ in the lumen. The charged particle can’t cross back. The NH3 in the cell is made from _______

Answer 18

GLUTAMINA

Question 19

Hydrogen ATPase is on the apical surface of the ___ and ___
Urine pH can drop to _____

Answer 19

DT and CD
4.5 (1000 fold greater from cell to lumen - it is why you need H-ATPase)

Question 20

________ cells of the DT regulates H+ excretion

Answer 20

Intercalated cells, some H ATPase facing lumen, some facing blood, depending on if blood is acidic or basic

Question 21

85% of bicarbonate reabsorption occurs in the ______ by ______ and _______ transporters and ______ enzyme

Answer 21

Proximal Tubule
Na/HCO3 symport

Question 22

The first thing to help buffer pH is _______, then ______, then ______

Answer 22

body proteins, respiratory CO2 changes (minutes), Renal HCO3 excretion (days)

Question 23

The urinary dipstick may be used to screen for proteinuria

Answer 23

Negative

●Trace – between 15 and 30 mg/dL

●1+ – between 30 and 100 mg/dL

●2+ – between 100 and 300 mg/dL

●3+ – between 300 and 1000 mg/dL

●4+ – >1000 mg/dL

A positive reaction (1+) for protein develops at the threshold concentration of 30 mg/dL, which crudely corresponds to a 24-hour urinary protein excretion of 300 mg/day, depending on urine volume.

Question 24

PTH acutely and chronically ______ Ca reabsorption
_________ on _________ surface of the _____
_____ on the _________ surface of the ______
PTH also causes a decrease in _____ reabsorption

Answer 24

increases
Ca-ATPase on basolateral surface of DT
Na/Ca exchange on the basolateral surface of DT
PTH causes a decrease in PO4 reabsorption

Answer 26