Osmosis based questions HELP!!!! Please!

Hey guys would really appreciate it if you could help me with some of the questions. I need some good answers which have relevant A-level terminology. The topic is mainly around Osmosis and water potential :smile:

-How does salt increase blood pressure?

-What does 'no net movement' actually mean?

(edited 11 years ago)

Reply 1

Turkishee

Original post by Doctor.

-How does salt increase blood pressure?

-What does 'no net movement' actually mean?

Not sure if this will extend beyond the scope of your work but here it goes:

Na is maintained via the Angiotensin-Renin-Aldosterone mechanism, for normal conditions when BP is low renin is stimulated and does various things (I dont want to get into the mechanics) but it stimulates the production of Angiotensin II which acts as a vasoconstrictor and aldosterone which stimulates water retention. This increases blood pressure. However, when one ingests Salt (NaCl) the water concentration also rises to compensate for the sodium...
As for how Salt helps to increase blood pressure:

Think of it like this; 10grams of Sodium dissolved in 100ml of water - if you take out a scoop you take even distributions so nothing changes - though if you add 10ml of water you've gotta add 1gram of sodium, similarly if you add 10grams of water you gotta add 100ml of water (More water = more pressure).

As for no net movement; think of it like this;

If an inside of and an outside of a cell have equal osmotic gradients there will be no net gain - there will still be movement across the gradients but one will not have more than the other - we also use the word equilibrium to represent this behaviour.

Hope that helps.

Reply 2

Doctor.

Original post by Turkishee

Woah thanks for that, they were a little bit too good a answer for me :tongue:

. Although I have simplified it :biggrin:

So thank you so much for that. It's pretty hard to find the answer via Google :angry:

got one more question:
(it's a silly how science works que but I would appreciate your vast undergraduate knowledge to help me out :colondollar:

)

-Are results still reliable even with an outlier? :coma:

Reply 3

Turkishee

Original post by Doctor.

Woah thanks for that, they were a little bit too good a answer for me :tongue:

. Although I have simplified it :biggrin:

So thank you so much for that. It's pretty hard to find the answer via Google :angry:

got one more question:
(it's a silly how science works que but I would appreciate your vast undergraduate knowledge to help me out :colondollar:

)

-Are results still reliable even with an outlier? :coma:

I'm assuming you're referring to ingested salt content? Well generally speaking the kidneys work by removing unnecessary Sodium ions, in fact they're very good at that, but a combination of factors contribute to high blood pressure, Sodium acts as one factor. Obesity, LDL factor, diabetes lipidus etc etc all contribute to it.

Reply 4

Elwyn

Original post by Doctor.

-Are results still reliable even with an outlier? :coma:

It would depend on how many reading you took. For example if you took 100 readings, 99 of them demonstrated strong correlation where as 1 was an outlier (or an anomaly) then you could safely say that this result was just an anomaly and the results are still reliable. If however you only took 5 readings and 1 was an anomaly then you should be more careful about describing the reliabilty.

If you are referring to coursework or something similar there would be nothing wrong with saying you think your results are reliable however this anomaly doesn't fit with them and that if you had the opportunity you would repeat the experiment more times to improve that reliability.