diffusion –> through the membrane ?

i don’t know if there is any least affected system, since all are highly regulated by receptors.

Water diffusing passively across a membrane is not a receptor mediated process. So i would guess diffusion would not be affected by a damaged/non-functional receptor.

Homeostatis would be affected because … the molecular mechanisms necessary to maintain homeostatsis encompass many different signal transduction pathways molecules and receptors.

Muscle activity is also quite a broad topic … and (although I can’t think of any recptor mediated muscular activity) i’m almost 100% confident that muscles have many types of receptors .. that respond to external stimuli.

(I’m sure some of the science wiz-kids on this web-site can name off a couple receptors … of the top of their head … Kudos to these smart people!! Cuz, i’m not a physiology person).

Anyways, take a peek at this .. http://en.wikipedia.org/wiki/Cell_receptor Hope this is a hint for helping you with your research!

buena suerte!
– KIM

and what about the carrier mediated transport ?

agreed

muscles are activated by somatic motorneurons which release Ach and other substances that deploarise the sarcolemma. Thus highly dependant on receptors (including the internal receptors on the sarcoplasmic reticulum which releases Ca(2+) into the sarcoplasm)

I am only reffering to passive transport (ie. simple diffusion ….) which is not a receptor mediated process.

Of course, actively transported water and carrier mediated transport … both requiring energy CAN BE a receptor mediated processes. (which I thought was not called "diffusion"??? but I could be wrong?)

I appologize intentionally leaving out details .. which i did in the name of simplicity.

Anyways, good luck with your research!
– KIM

it’s a form of diffusion because it needs a concentration gradient (except the active transport which can go against the concentration gradient)

an example of receptor that are important in diffusion are the ligand-gated ionchannels.

yes … you’re right …! (

Water isn’t transported by carrier proteins. The only two ways water can enter the cell is either through simple diffusion or through special channels (similar to ion chanells) called aquaporines. Not only water can pass through simple diffusion, but also small, nonpolar molecules like NO, CO and hydrophobic substances such as steroids. I have to agree with LilKim that simple diffusion would be the least affected mechanism, just because it doesn’t require receptors or transporters.

yes, i think so… 🙂