Block IV Lecture 41 Renal Water Balance

The input of water must ____ the output to maintain homeostasis.

In a normally inactive state, most water is lost through ____.

When we have prolonged exercise, we lose most of the water through _____. There is decreased loss of water through _____. Since so much water is lost, we need to maintain balance by increasing water ____.

match; urine; sweat; urine; intake

____ is urine flow above the usual levels.

______ is the low rate of water excretion as hyperosmotic urine.

The normal urine flow is ____ mL/min.

An example of an antiduretic hormone is arginine _____ which helps with water ____.

diuresis; antidiuresis; 1; vasopressin; reabsorption

The kidneys need to excrete the _____ load which is about 600 mosmol/d.

The kidneys can control H20 excretion ______ of NA and K.

Kidneys have the critical ability to ___ relative proportions of ____ and water excreted in urine to achieve homeostasis.

solute; independently; vary; solute

Water is permeable and travels in the proximal tubule through _____ which is always ____ and present in the membranes.

There is also paracellular movement via the ____ ____.

AQP1; open; tight junctions

In the ABSENCE of ADH:

Water is permeable in the _____ tubule and in the ____ ____ limb of Henle.

Water is impermeable in the ____ _____ limb of Henle, the ____ tubule, and the ____ duct.

proximal; thin descending; thick ascending; distal; collecting

In the PRESENCE of ADH:

Water is permeable in the ____ tubule, the _____ ____ limb of Henle, and the _____ duct.

Water is impermeable in the ___ tubule, and the ____ ____ limb of Henle.

proximal; thin descending; collecting; distal; thick ascending

In _____ urine there are less than 300 solutes, meaning that the urine is more ____.

In ______ there is more than 300 solutes, meaning the urine is more ____.

These terms are relative to ____ osmolarity.

hypoosmotic; diluted; hyperosmotic; concentrated; plasma

Kidneys maintain plasma osmolarity at ____ mOsm.

They do this by using the _____ mechanism in which fluid in 1 tube flows in the _____ direction of the 2nd tube.

This greatly increases opportunity for ____ of H2O and solutes.

300; countercurrent; opposite; exchange

The countercurrent system is going to occur in the tubules of the Loop of ____ as well as in the ____ _____ capillaries.

They have ____ loops.

Henle; vasa recta; hairpin

In regards to the countercurrent system:

In the Loop of Henle, the thin descending tubule is only permeable to _____. The thick ascending is only permeable to _____.

The descending/ascending segments of the vasa recta capillaries are permeable to ____ and ions and passive exchange is based on ____ ____ and diffusion.

The hypertonic medullary ____ serves as the osmotic equilibrating device.

The ______ hormone like vasopressin control the number of _______ channels (AQP2) which leads to ____ reabsorption of water.

water; solutes; water; osmotic gradients; interstitium; antidiuretic; aquaporin; passive

When there is a hypertonic interstitial fluid, this means we need more water _____.

This causes the water permeable tube of the _____ _____ to go to the capillaries. This is done via _____.

This produces a _____ urine.

reabsorption; collecting duct; osmosis; concentrated

Urine becomes _____ as it moves through the ascending limb since Na is reabsorbed and H2O is ______,

To make concentrated urine, vasopressin uses cAMP to cause _____ insertions into the ___ membrnae of the principle cells of the ____ duct. This causes water to flow out of the ____ fluid into the renal _______.

The maximum concentration of urine is 1200 mOsm.

diluted; impermeable; AQP2; luminal; collecting; tubular; capillaries

The stimulus for ADH release is:

1. Increase of _____ in the plasma which are detected by _____.

2. Sensing of lower pressure by _____ meaning there is less plasma volume. There are ____ pressure receptors in the LT atrium, large pulmonary and ____ pressure receptors in the aortic arch and carotid sinus.

osmolarity; osmoreceptors; baroreceptors; low; high

In the collecting duct, _____ is always regulated by ADH, while AQP3 and AQP4 are always ____ and present in the membrane.

When vasopressin binds to its receptor on the _____ membrane, it triggers _____ which ends up creating AQP2 channels on the ____ membrane to allow ____ of water.

AQP2; open; basolateral cAMP; apical; osmosis

When we have water restriction or severe ____, it is going to trigger the release of an ____.

This leads to increased water _____.

sweating; ADH; reabsorption

When there is decreased plasma volume, there is going to be a decrease in venous, atrial, and arterial _____.

This will then be detected by the ____ which will cause the posterior pituitary to release ______.

They will bind to their receptors on the basolateral membrane of the ____ _____ which will increase tubular _____ by creating AQP2 channels.

This will cause increased H2O ______ and thus a small volume of _____ urine.

pressure; baroreceptors; vasopressin; collecting duct; permeability; reabsorption; concentrated

When you have high water intake, you end up needing ____, meaning there are ___ plasma levels of ADH, which leads to ____ water reabsorption.

diuresis; low; decreased

When there is excess H2O ingested, the body fluid osmolarity ______.

This activates and increases hiring of the _______ which _____ the secretion of vasopressin by the posterior pituitary

This will lead to decrease tubular ______ .

This ____ H2O reabsorption and creates a large volume of _____ urine.

decreases; osmolarity; decreases; permeability; decreases; diluted

When you have severe sweating, there is a loss of _____ salt solution.

This causes a _____ in plasma volume which decreases glomerular _____ rate, meaning less ___ is excreted. Since plasma volume is low, there is going to be an increase in plasma ____ to help with retaining of water.

It also causes ____ plasma osmolarity. This leads to increase of plasma ______ which increases water reabsorption.

hypoosmotic; decrease; filtration; Na; aldosterone; increased; vasopressin

The most important stimular for thirst under most physiological conditions is the activation of the ______.

Inputs controlling thirst include:

1. Low plasma volume will activate the _____ which will ____ thirst.

2. Increases plasma _____ will activate the osmoreceptors which will ___ thirst.

3. A dry mouth or ____ will increase thirst.

4. Metering of water intake by ___ tract will ____ thirst.

osmoreceptors; baroreceptors; increase; osmolarity; increase; throat; GI; decrease