Chapter 27, Lecture 2

Fill-in-the-blank flashcards covering daily water balance, sources of gain and loss, thirst regulation, and hormonal control by ADH, aldosterone, and ANP.

Average daily body water gain equals average loss at about __ per day.

≈2,500 mL (about 2.5 L)

Of the 2,500 mL daily water gain, metabolic water contributes only about __.

≈200 mL

Water obtained from ingested foods provides roughly __ per day.

≈700 mL

The greatest source of daily water gain is the __ we consume.

fluids (drinks)

Water loss via the lungs as water vapour averages about __ per day.

≈300 mL

Evaporation from the skin accounts for about __ of daily water loss.

≈600 mL

The organ responsible for the bulk of water loss is the __ via urine.

kidneys

The urge to drink is controlled by the __ center in the hypothalamus.

thirst

Increased blood osmolarity stimulates __ in the hypothalamus.

osmoreceptors

During dehydration, blood osmolarity __.

increases

Activation of osmoreceptors promotes release of __ to conserve water.

antidiuretic hormone (ADH/vasopressin)

ADH increases the insertion of __ channels in principal cells of the collecting duct.

aquaporin

Alcohol inhibits the secretion of __, leading to increased urine output.

ADH

Decreased blood pressure triggers kidneys to release __, initiating the RAAS pathway.

renin

Renin ultimately leads to production of __ II, which stimulates aldosterone.

angiotensin II

Aldosterone's main effect is to increase renal reabsorption of __ ions.

sodium (Na⁺)

Reabsorption of sodium by aldosterone is followed obligatorily by __ through osmosis.

water

Increased blood volume stretches the atria and stimulates release of __ peptide.

atrial natriuretic peptide (ANP)

ANP promotes __, the excretion of sodium in urine.

natriuresis

ANP causes production of __ urine with increased volume.

dilute

Salty snacks at bars raise blood __, thereby stimulating thirst.

osmolarity

Failure to drink when the thirst center is activated can lead to severe __.

dehydration