Renal Phys 2

Front 1

What is the osm of isotonic urine and what is its rate of production?

Back 1

300 mOsm
1ml/min

Front 2

What is the osm of hypotonic urine, what condition will cause its production, and what is its rate of production?

Back 2

100 mOsm

over-hydration

25ml/min

Front 3

What is the osm of hypertonic urine, what condition will cause its production, and what is its rate of production?

Back 3

1200 mOsm

dehydration

0.3 ml/min

Front 4

What does Obligatory Water Loss
mean?

Back 4

Body must lose a certain amount of water regardless of level of hydration.

Front 5

What happens when the renal threshold [] is exceeded?

Back 5

Solute will be excreted into urine

Front 6

Na+ reabsorption in the ALofH:

Back 6

None

Front 7

What reabsorption occurs in the ALofH and how is it transported?

Back 7

K+ and Cl-

Brought through via facilitated diffusion (active process)

Front 8

Na+ reabsorption in the DT and its symporter:

Back 8

Na actively pumped out; Cl-

Front 9

Na+ reabsorption in the CD:

Back 9

Na moves in passively; Na is pumped out

Front 10

What determines passive Na+ channels in DT & avail of symporters in DT?

Back 10

Presence of Aldosterone

Front 11

Na+ follows H20 or H2O follows Na+?

Back 11

H2O follows Na+

Front 12

What creates the osm gradient for H20 passive reabsorption?

Back 12

Movement of Na+

Front 13

What's the driving force for H2O?

Back 13

Osm gradient

Front 14

What is the paracellular route for Na+ Coupled Passive Water Reabsorption and what allows the Na+ in?

Back 14

In between "leaky" epith cell junctions

ATPase pumps on the lateral spaces

Front 15

How much H2O is reabsorped in the proximal tubule and the loop of henle?

Back 15

80 %

Front 16

What allows H2O to reasbsorp transcellularly, where are they found, and what is limiting factor?

Back 16

The presence of ADH creates aquaporins

Found basolaterally

Amount of aquaporins and hence levels of ADH

Front 17

What regulates [plasma] of PO43- and Ca2+?

Back 17

Renal threshold absorption

Front 18

What is the only waste product that's reabsorped?

Back 18

urea

Front 19

How much Na+ & Cl- and H2O are reabsorped in LoH?

Back 19

25% and 15%

Front 20

What important substances are secreted?

Back 20

Hydrogen ions, potassium ions,
and organic cations and anions (usually foreign to the body)

Front 21

What role does H+ secretion play and where does it prim. occur?

Back 21

Helps with pH balance and in the PT and CD

Front 22

How is H+ secretion accomplished in PT?

Back 22

Na+/H+ antiporter

Front 23

How is H+ secretion accomplished in CD & LoH?

Back 23

Facilitated diffusion

Front 24

K+ is actively secreted where?

What is the mechanism?

How is the level determined?

Back 24

DT & CD

K+ secretion is coupled to Na+ reabsorption

(levels determined by aldosterone)

Front 25

Which is regulated, K+ reabsorption or secretion?

Back 25

Secretion

Front 26

If plasma [K] is low – secretion is __________

Back 26

minimal

Front 27

K+ is reabsorbed via passive diffusion where?

Back 27

PT

Front 28

Where are K+ channels located on the luminal membrane and what does that mean?

Back 28

In the DT and CD

It means it can enter tubular lumen

Front 29

What effect does aldosterone have on Na+ reabsorption and K+ secretion?

Back 29

opens luminal Na+ Channels (fast effect)

increases Na+/K+ ATPase expression (slow effect)

Front 30

What are the two reasons for a pathway for Organic Anion and Cation Secretion?

Back 30

Some of these ions can be bound to plasma proteins
and are never filtered by the glomeruli

2) Increase the speed of elimination

Front 31

What does the medullary osmotic gradient do and what anatomical arrangement creates it??

Back 31

plays a key role in the kidneys ability
to produce urine of varied concentrations

Medullary Countercurrent System

Front 32

What makes up the Medullary Countercurrent System and which sets osmotic gradient?

Back 32

LoH, DT, & CD

LoH

Front 33

What structure prevents dissipation of osmotic pressure and how does it work?

Back 33

Vasa recta

reduces surface area available for exchange between HGb and IS fluid

Front 34

DLoH is Permeable to ____ and Impermeable
to ____

Back 34

H2O; Na+

Front 35

ALoH is Permeable to ____ and Impermeable
to ____

Back 35

Na+; H20

Front 36

Difference in permeability of ALoH and DLoH causes _______ creating _______; this is called _______

Back 36

countercurrent multiplication

osmotic gradient

countercurrent flow

Front 37

ADH affects H2O permeability in _______ & ________

Back 37

DT & CD

Front 38

ADH is synthesized in the _______

Back 38

hypothalamus

Front 39

Vasopressin works by binding to receptors on the _______ increasing ______ and creating ______

Back 39

basolateral membrane

cAMP

aquaporins

Front 40

Regulation of ECF _______ helps maintain ___________ and therefore tissue perfusion.

Back 40

volume

BP

Front 41

Regulation of ECF __________ helps maintain cell ________

Back 41

osmolarity

volume

Front 42

How does the body regulate ECF volume?

Back 42

by regulating total-body salt content

Front 43

What's the main osmotic constituent of ECF volume?

Back 43

Na+

Front 44

Is the relationship between Na+ & H2O gain/loss inverse or linear?

Back 44

linear

Front 45

What are the two mechanisms for NaCl loss?

Back 45

Renal excretion

Nonrenal loss (sweat and feces)

Front 46

How is Na+ gained?

Back 46

Through ingestion

Front 47

How does the body monitor ECF volume? What kind of receptors are involved in this? What are they?

Back 47

Through changes in BP that have a direct effect on plasma volume

Aortic Arch baroreceptors
Carotid Sinus baroreceptors
Renal baroreceptors

Front 48

What act as renal barorecptors?

Back 48

Granular cells

Front 49

What is the sequence of events when the JGA baroreceptors sense a drop in blood pressure?

Back 49

The liver produces Angiotensiogen, which is converted by renin released from the kidneys, which converts

Front 50

How is total-body osmolarity defined?

Back 50

the ratio of total-body osmoles
to total-body water

Front 51

How is total-body osmoles determined?

Back 51

ECF Na+ content

Front 52

What are two sources for water gain?

Back 52

consumed

liberated from metabolic processes

Front 53

What are three sources for water loss?

Back 53

Urine (MAIN ROUTE)

feces

sweat

Front 54

What elements control osmolarity?

Back 54

the kidneys control of water excretion

the thirst mechanism that controls oral intake of water

Front 55

Are the mechanisms that control osmolarity a negative or positive feedback loop? Where do they originate?

Back 55

Negative

Hypothalamus

Front 56

What is the name for the two central osmoreceptors collectively? What are they individually?

Back 56

Circumventricular Organs (CVOs)

Subfornical Organ (SFO)& Organum vasculosum of the lamina terminalis (OVLT)

Front 57

Where are the CVOs?

Back 57

Outside the blood-brain barrier

Front 58

What happens when the CVOs detect high osmolarity?

Back 58

Increase firing rate, stimulate neurosecretory cells in teh SON & PVN, signal to the posterior pituatary which then releases ADH

Front 59

What is the plasma osmolarity in healthy individuals? What is the threshold for AVP release?

Back 59

290 mOsm

280 mOsm

Front 60

What happens when mOsm drops below threshold? What is the relationship between ADH levels and osmolarity?

Back 60

CVOs stop secreting ADH (over-hydration)

Linear

Front 61

Where does ADH act?

Back 61

On the DT & CD to increase H2O reabsorption

Front 62

Baroreceptors will also cause activation of the _________ resulting in ________

Back 62

hypothalamus neurosecretory cells; thirst

Front 63

What effect does EtOH have on plasma [ADH}?

Back 63

Decreases it