"Blood solutes affect the water potential of the blood, and thus the water potential gradient between the blood and the tissue fluid. The size of this water potential gradient is largely due to sodium ions and plasma proteins. The blood solute level regulates the movement of water between blood and tissues."

 

Above is the description from my bio book.

 

What does it mean by:

 

1. Water potential

 

2. tissue fluid, is it plasma?

 

 

What do the sodium ions and plasma proteins affect the gradient?

 

Does the whole description mean that the water moves by osmosis to balance the concentration between tissue and blood solute? does "regulate" mean "move"?

 

Albert

What does it mean by:

 

1. Water potential

 

2. tissue fluid' date=' is it plasma?[/quote']

Water Potential and Living Plant Cells

 

&

 

tissue fluids are just the liquids which happen to be contained in certain cells (and those certain cells make up certain tissues). kinda what the name suggests!

to 5614, it is not blood, but plant...

 

any way, maybe "potential" means "concentration"? so water potential means water concentration?

 

Albert

oohhhhhhhhhhh soz, i was thinking plants:

 

water potential in blood (2nd para) (its the same for plants as it for blood)

 

and tissue fluids remains the same answer.

thx 5614, now I know what does it mean by water potential, it is a tendency that water move from a higher concentration to lower concentration.....

 

but for the last thing, what does it mean by "regulate"? it does not explain in ur site...

 

Albert

regulate: Control, govern, or direct by rule or regulations; subject to guidance or restrictions; adapt to circumstances or surroundings.

dictionary definition

 

basically it means that it is controlled.

ok, not a specific bio term,... just means "control",,,, need to improve my English...

 

thx you very much , 5614

 

Albert

Above is the description from my bio book.

 

What does it mean by:

 

1. Water potential

It means the osmotic gradient between blood and interstitial fluid

 

2. tissue fluid' date=' is it plasma?[/quote']

Tissue fluid (interstitial fluid) is plasma filtrate. It is plasma without the large anionic proteins (albumin) and other solutes contained in plasma.

 

 

What do the sodium ions and plasma proteins affect the gradient?

I'm guessing you mean "How do....etc." Water will always try to 'equalize' across a semipermiable membrane (like capillary walls). If the water on one side contains a higher concentration of solutes than water on the other, then per unit volume, there is less water on the high concentration side. This forms an osmotic gradient. Water will try to move from the low concentration side to the high concentation side, to equalize the amount of water on each side.

 

Does the whole description mean that the water moves by osmosis to balance the concentration between tissue and blood solute?

Put simply, yes.

 

does "regulate" mean "move"?

No. 'Regulate' means 'control'. For example, you use a tap (faucet) to regulate the flow of water, not to move the water. Mains pressure moves the water.

To Glider, I ask how do the sodium ions and plasma proteins affect the gradient, not water........

 

any way, what I really want to know is: what are sodium ions and plasma proteins in Biology? what roles do they play?

 

Albert

To albertlee, I answer that these are the solutes that determine the concentration gradient that drives osmosis.

 

Plasma proteins are proteins found in plasma (mainly albumin). Sodium ions are sodium ions. If you want to know the role of sodium ions in biology, the answers would fill books. They have a role in just about everything. Cardiac function, neural & nerve function, muscle function, renal function etc., etc.

 

You need to define your questions more clearly.

thx Glider, so what are plasma proteins used for?

 

Albert

They are responsible for about 15% of buffering in the blood (keeping acids and bases regulated). They are also responsible for the thyroid transportation. Their most important role is probably in the exchange of fluids across capillaries

Yep, what he said.