|
( Osmoregulation)
Osmoregulation is the active regulation of the osmotic pressure of bodily fluids to maintain the homeostasis of the body's water content; that is it keeps the body's fluids from becoming too dilute or too concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution the more water wants to go into the solution. Pressure must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water. Two major types of osmoregulation are osmoconformers and osmoregulators. Osmoconformers match their body osmolarity to their environment . It can either be active or passive. Most marine invertebrates are osmoconformers, although their ionic composition may be different from that of seawater. There are no specific osmoregulation organs in higher plants. Control of water intake and loss is by means of those internal and external factors which affect the rate of transpiration. Plants share with animals the problems of obtaining water and in disposing of the surplus. Certain plants develop methods of water conservation. Xerophytes are plants in dry habitats such as deserts which are able to withstand prolonged periods of water shortage. Succulent plants such as the cactus have water stored in large parenchyma tissues. Other plants have leaf modifications to reduce water loss, such as needle-shaped leaves, sunken stomata and thick, waxy cuticles as in the pine. The sand-dune marram grass has rolled leaves with stomata on the inner surface. Oncophyorans are also osmoregulators.
|
Osmoregulation Subcategories
Osmoregulation Articles
|
| 
