Renal Slides (Post Quiz 1)

Question 1

Reabsorption

Answer 1

Water and Na- about ~99% (an avg)
Glucose- 100%
Urea- 40

Question 2

Rapid excretion of wastes

Answer 2

Large quantities excreted, therefore large amount of filtered amounts

Question 3

Plasma components undergo almost complete reabsorption

Answer 3

Small fractions of filtered amounts

Question 4

Because glucose is 100% reabsorbed

Answer 4

The kidneys do NOT reg the plasma glucose concentration

Question 5

Plasma water reabsorption

Answer 5

Subjected to physiological control and is controlled by kidneys

Question 6

Paracellular path

Answer 6

Goes between/alongside cells; (into and out of tubule lumen) through tight junctions and thus between cells- occurs via diffusion

Question 7

Transcellular path

Answer 7

(into and out of tubule lumen thru brush borders) Across cell via active transport or diffusion

Question 8

Pathway of reabsorption

Answer 8

Filtrate –> Tubular cells (thru basolateral membrane)–> basement membrane –> interstitial fluid –> peritubular capillary

Question 9

Pathway of excretion

Answer 9

Filtrate –> lumen (filtrate) –> excretion

Question 10

Three ways to cross tubular cell (basolateral membrane)?

Answer 10

1. Passive diffusion of solutes
2. Active transport via ATP
3. Osmosis for water

Question 11

How does fluid enter peritubular capillary

Answer 11

Bulk flow

Question 12

Luminal membrane?

Answer 12

Brush border (luminal membrane)

Question 13

Intercellular space

Answer 13

Contains renal interstitial fluid

Question 14

Tight junctions

Answer 14

Between brush borders of luminal borders

Question 15

From renal intersititial fluid into peritubular capillary plasma

Answer 15

Combo of diffusion and bulk flow

Question 16

Notes from reabsorption

Answer 16

Across membranes- one being ACTIVE TRANSPORT

Question 17

Types of reabsorption

Answer 17

Diffusion or carrier-mediated transport

Question 18

Carrier-mediated

Answer 18

Glucose is reabsorbed by SECONDARY ACTIVE TRANSPORT (Na cotransport) and uses energy and occur against glucose concentration gradient

Question 19

From tubular lumen into tubular cells

Answer 19

Na-glucose cotransporter

SGLT memb protein carriers Glucose and Na- no atp

Question 20

Tubuler cells into interstitial fluid

Answer 20

1. Na-K Pump causes concentration gradient (Na out, K in)

2. Glucose transporter via GLUT (no ATP but concentration gradient)

Question 21

Diabetes Mellitus

Answer 21

When carrier protein (SGLT) is involved, a very high glucose concentration in blood (and therefore in initial filtrate) can exceed the capacity- (TRANSPORT MAXIMUM/ Tm) of carrier and in result glucose will be within the urine

Question 22

Diffusino: Urea

–> The first portion of tubule (proximal)

Answer 22

Is equal to its concentration in the interstitial fluid and peritubular cap plasma

Question 23

Urea reabsorption

Answer 23

Accidentally reabsorbed bc it follows H2O

• Needs concentration gradient
• Does not need carrier bc of lipid soluble

Question 24

High creatine

Answer 24

Indicator of a low GFR (hallmark of kidney disease)

Question 25

Na and H20 doe not undergo tubular secretion so

Answer 25

Amount excreted= amount filtered - amount reabsorbed

Question 26

Na reabsorption

Answer 26

Active transport

Question 27

Water reabsorpt

Answer 27

Diffusion and coupled to Na

Question 28

Na gets into luminal membrane by:

Answer 28

1. Cotransport with glucose or AA 2. By countertransport with H+ 3. Diffusion through Na channels