3&4

Question 1

The kidneys maintain the osmolality and volume of body fluids within a narrow range by regulating the __________________.

Answer 1

Excretion of water and NaCl, respectively.

Question 2

Disorders in water balance are manifested by alterations in body fluid osmolality, whc are usually measured by changes in _______________.

Answer 2

plasma osmolality Posm

Question 3

The major determinant of Posm

Answer 3

Na+ (wt its anions Cl- and HCO3-)

Question 4

Acts on the kidneys to regulate the volume and osmolality of the urine.

Answer 4

AntiDiuretic Hormone/ Vasopressin

Question 5

Low plasma ADH levels = large vol of urine excreted; dilute urine

Answer 5

Diuresis

Question 6

High plasma ADH levels = small vol urine excreted; conc urine

Answer 6

Antidiuresis

Question 7

Hypoosmolality, shifts water _____________, and this results in cell _____________.

Answer 7

Water into the cells,

Swelling

Question 8

Symptoms of a rapid fall in Posm

Answer 8

Can alter neurological function = nausea, malaise, headache, confusion, lethargy, seizures, and coma

Question 9

Symptoms of an increase in Posm

Answer 9

Primarily neurological

• lethargy
• weakness
• seizures
• coma
• death

Question 10

Where is ADH synthesized?

Answer 10

In the neuroendocrine cells located wthn the supraoptic* and paraventricular nuclei of the hypothalamus

Question 11

Where is ADH stored?

Answer 11

Nerve terminals located in the hypophysis (post pit)

Question 12

Factors that influence secretion of ADH

Answer 12

Osmotic ctrl
Hemodynamic ctrl
Others

Question 13

Stimulates secretion of ADH

Answer 13

Nausea
Ang II
Nicotine

Question 14

Inhibits secretion of ADH

Answer 14

Atrial natriuretic peptide

Ethanol

Question 15

These cells termed ______________, appear to behave s osmometers and sense changes in body fluid osmolality by either shrinking or swelling.

Answer 15

Osmoreceptors

Question 16

When the effective osmolality of plasma increases, synth and secretion of ADH are ____________.
When the effective osmolality of plasma is reduced, secretion is ____________.

Answer 16

Stimulated,

Inhibited

Question 17

Because ADH is repidly degraded in plasma, circulating levels can be reduced to 0 in minutes aft secretion is inhibited.

Answer 17

As a result, the ADH system can respond rapidly to fluctuations in body fluid osmolality.

Question 18

A decrease in blood volume or pressure ____________ secretion of ADH.

Answer 18

Stimulates

Question 19

Location of receptors responsible for hemodynamic control

Answer 19

Low pressure (left atrium & large pulm vessels) & the high pressure (aortic arch & carotid sinus) sides of the circulatory system

Question 20

Bradykinin and histamine which _________ pressure thus ___________ ADH secretion.
NE, which __________ blood pressure, ____________ ADH secretion.

Answer 20

Lower, stimulate

Increases, inhibits

Question 21

The primary action of ADH on the kidneys

Answer 21

To increase the permeabiliy of the collecting duct to water.

In addtn, ADH increases the prmeability of themedullary portion of the collecting duct to urea.

Question 22

ADH stimulates reabsorption of NaCl where?

Answer 22

By the thick ascending loop of henle, distal tubule, and the collecting duct

Question 23

Actions of ADH on the kidneys

Answer 23

• (1*) increase permeability of the collecting duct to water
• increase permeability of the medullary portion of the collecting duct to urea
• stimulates reabsorption of NaCl in the TALH, distal tubule, and collecting duct

Question 24

ADH also ________ th permeability of the terminal portion of the inner medullary collecting duct to urea. This results in an __________ in reabsorption of urea and an ___________ in the osmolality of the medullary interstitial fluid.

Answer 24

Increase, increase, increase

Question 25

ADH, acting thru ____________, increases permeability of the apical membrane to urea.

Answer 25

cAMP/ PKA cascade

Question 26

Increasing __________ of the interstitial fluid of the renal medulla also increases the permeability of the collecting duct to urea. This effect is mediated by the ___________ & involves phosphorylation by PKC?

Answer 26

Osmolality

Phospholipase C pathway

Question 27

The increase in Na reabs by ADH is assoc wt increased abundance of key Na trasnporters:

Answer 27

1Na-1K-2Cl trasnporter (TALH)
Na-Cl transporter (distal tubule)
ENaC ( distal tubule, collecting duct)

Question 28

Stimulatin of NaCl transport by the TALH may help maintain the ____________, that is necessary for ______________ from the medullary portion of the collecting duct.

Answer 28

Hyperosmotic medullary interstitium, absorption of water

Question 29

Inad release of ADH results in the excretion of large volumes of dilute uirine.

Answer 29

Polyuria

Question 30

If the individual is deprived of water, the body fluids will become hyperosmotic. This condition is called __________________.

Answer 30

Central diabetes insipidus/

Pit diabetes insipidus

Question 31

Central Diabetes Insipidus

Answer 31

Hyperosmotic body fluids, conc urine, low ADH levels

Question 32

Syndrome of inapp ADH secretion

Answer 32

Hyperosmotic body fluids; dilute urine; high ADH levels

Question 33

Undetectable levels of ADH in the plasma

Mutations in the V2 receptor gene, thus receptor is constitutively activated, even in the absence of ADH

Answer 33

Nephrogenic syndrome of inappropriate anti diuresis

Question 34

When body fluid osmolality is ______________, or when blood volume or pressure is ____________, the individual perceives thirst.

Answer 34

Increased (2-3%)

Reduced (10-15%)

Question 35

Genetically determined threshold for ADH secretion

Answer 35

285 mOsm/H2O

Question 36

Genetically determined threshold for thirst

Answer 36

295mOsm/kg H2O

Question 37

Major site where solute and water are separated

Answer 37

The thick ascending loop of henle

Question 38

Reabsorption of solute w/o concomitant reabsorption of water occurs where?

Answer 38

Thick ascending loop of henle

Question 39

Intake exceeds loss

Answer 39

Positive water balance