Chapter 4 (page 20) Flashcards
Regulation of Water Intake is known as:
The Thirst Mechanism
_________ is the driving force of water intake.
Thirst
What happen if there is a decrease plasma volume?
It results in dry mouth and triggers the hypothalamic thirst centre.
The dry mouth occurs because the rise in plasma osmotic pressure causes less fluid to leave the blood stream. Because the salivary glands obtain water they require from the bloodstream, less saliva is produced.This motivates us to get a drink. True or False:
True
True regarding The Thirst Mechanism, except:
1.Thirst is quenched almost as soon as we begin drinking even though water has yet to be
absorbed into the blood.
2.The damping of thirst begins as the mucosa of the mouth and throat is moistened which
signal stretch receptors in the stomach and intestine to activate providing feedback
signals that inhibits the thirst centre.
3.This mechanism prevents us from drinking more fluid than needed and causing over
hydration.
4.Thirst is not always a reliably indicator - i.e. You may not feel thirsty even when you
need more fluid.
none
Regulation of water output is conducted by 4 organs in the body:
Kidneys
Lungs
Skin
Intestines
The _______ are the organs that affect the output of fluid the most.
Kidneys
What the kidneys does in regulation of water output?
They control fluid balance by changing the volume of urine excreted to match changes in the
volume of fluid intake. The more fluid we drink, the more urine one excretes.
Four major roles the kidneys have in the body:
- Excretion of nitrogen containing waste
- Maintaining water balance in blood
- Maintaining electrolyte balance of blood
- Ensuring proper pH balance in blood
how does the lungs contribute in regulation of water output?
Water exits the lungs in expired air
Organ that regulates the water output through perspiration:
Skin
Intestine regulates the water output through:
Feces
A condition that takes place when there is either Dehydration or Over hydration.
Fluid Imbalances
__________ - When interstitial fluid volume decreases, intracellular fluid and plasma
volumes decrease below normal levels. This can result form too little fluid intake or too
much fluid output.
Dehydration
What is Over hydration?
When total body fluid volume is larger than normal, the interstitial fluid volume increases, then the intracellular fluid increases and plasma volume increases.
