Fluid regulation

There is good evidence to suggest that oestrogens are involved in fluid regulation within the efferent ducts, especially in view of the fact that this is the site of highest ER expression. Curiously, it seems that under-exposure to... 

The nonapeptide vasopressin (AVP) is synthesized in the paraventricular nucleus of the hypothalamus (PVN) and the nucleus supraopticus. Besides its role in fluid regulation, AVP is also a key modulator of the HPA system, where it potentiates the effects of CRH on adrenocorticotropic hormone (ACTH) release. Extrahypothalamic AVP-containing neurons are localized in the medial amygdala and the bed nucleus of the stria terminalis. AVP applied intracere-broventricularly or to the lateral septum has been shown to affect cognition, social behavior, and anxiety-like behavior in rodents (Insel et al. 2001). 

The precise functions of the opioid receptor subtypes remain to be delineated. In many studies, it has been established that they modulate the functions of the dopaminergic system. For example, administration of morphine into the area 10 region results in a dopamine-dependent increase in locomotor activity. Electiophysiological studies of area 9 neurons suggest that p and k opioids have opposite effects on motor behaviors activation or sedation, respectively. The k and p agonists have also been found to exert opposite actions with respect to fluid regulation diuretic and... 

Actuators, such as valves or pumps, can be either integrated or external to the microfiuidic device and are needed to regulate the movement of fluids in the microchannels. Strict fluid regulation and control is important because the tasks... 

After the first trimester, the amnion and chorion layers become united together and remain fused until delivery. The AM is the true protective layer of the placenta. It inhibits activation of inflammatory cells, thus protecting the fetus against preterm labor. This unique function is unusual due to the lack of blood vessels, lymphatics, nerves, and muscles within the amnion construct. The amnion layer still retains the most important function of fluid regulation and maintenance of the fetal environment. 

How does intracellular fluid regulation dijferfrom extracellular fluid regulation 7... 

Which mechanisms of fluid regulation respond to high fluid volume in the... 

The major cation in extracellular fluid is sodium (Na+). Since sodium has a strong influence on osmotic pressure, it plays a major role in fluid regulation. As sodium is absorbed, water usually follows by osmosis. In fact, sodium levels are regulated more by fluid volume and the osmolality of body fluids than by the amount of sodium in the body. As stated earlier, ANH and aldosterone control fluid levels by directly influencing the reabsorption or excretion of sodium. 

Problems arise when there is a failure or a decrease in function in any of the fluid regulation mechanisms. For example, in aging, the thirst mechanism is suppressed. The elderly patient may not drink adequate fluids owing to a lack of the thirst drive, and hypovolemia could result. Problems also arise if the regulating mechanisms fail to excrete excess water from the body, such as might occur with renal failure, and fluid overload results. 

Cryogenic fluids, regulated under Article 80 and Article 75... 

In an adequately supplied adult male human subject, the total body selenium content is on the order of 30-60 mg, of which one-third is found in the skeleton and two-thirds in the soft tissues. A substantial fraction of kidney selenium is retained even when selenium at other sites is severely depleted during deficiency, and renal selenium is more constant between human populations than selenium in other tissues or body fluids. Regulation of selenoprotein synthesis at the transcription level appears to ensure a hierarchy of preservation of individual selenoproteins at critical sites. The cytosolic glutathione peroxidase (GPx I) and selenoprotein P can donate selenium to other sites whenever overall depletion occurs. Selenium crosses the placenta readily, and breast milk selenium concentration is responsive to changes in maternal selenium intake. In the United States, breast milk Se concentrations are generally in the range of 0.19-0.25 pmol/1, but colostrum has levels that are two or three times higher than those of mature breast milk. 

---