Info

FIGURE 8 Increase in plasma vasopressin (VP) in response to reduction in extracellular fluid volume. As the extracellular fluid volume decreases below the normal level of 15 L (for a typical 70-kg person), there is a progressive increase in plasma vasopressin, even if plasma osmolality is less than 280 mOsm/kg H2O.

Extraceliullar Fluid Volume

(liters)

FIGURE 8 Increase in plasma vasopressin (VP) in response to reduction in extracellular fluid volume. As the extracellular fluid volume decreases below the normal level of 15 L (for a typical 70-kg person), there is a progressive increase in plasma vasopressin, even if plasma osmolality is less than 280 mOsm/kg H2O.

Often, the presenting symptom of renal disease is a patient's complaint that he or she has to get up frequently during the night to urinate, a symptom referred to as nocturia. Nocturia often results when the kidneys are unable to concentrate the urine adequately and, thus, reduce its volume. However, nocturia and frequent voiding are symptoms of more common disorders such as urinary tract infection or inflammation, or prostate enlargement in the aging male.

The ability of the kidneys to dilute or concentrate the urine depends on the rate at which they excrete water in relation to solute. Therefore, to assess the efficacy of the kidney in producing dilute or concentrated urine, it is first necessary to quantify the rate of excretion of total solute. The parameter used for this purpose is referred to as the osmolal clearance (Cosm). The osmolal clearance is calculated in the same manner as the clearance of any substance (see Chapter 25), except that the concentrations of all solutes (which are reflected by the osmolality) are considered in the calculation. As shown in Eq. [2], the osmolal clearance is simply the product of the urine volume flow rate and the ratio of the urine osmolality to the plasma osmolality:

Osmolal clearance = Cosm =

Posm

The symbols in Eq. [2] have the same meaning as in Chapter 25. UF is the urine volume flow rate in mL/min; Posm is the plasma osmolality and Uosm is the urine osmolality, both in mOsm/kg H2O. The osmolal clearance is normally fairly constant in the range of 2 ± 0.5 mL/min because it represents the rate at which solutes are being removed from the plasma and excreted in the urine, and this depends in turn on the daily dietary intake, which is typically fairly constant. In effect, the osmolal clearance represents the rate of plasma flow from which solute is totally removed.

Get Rid of Gallstones Naturally

Get Rid of Gallstones Naturally

One of the main home remedies that you need to follow to prevent gallstones is a healthy lifestyle. You need to maintain a healthy body weight to prevent gallstones. The following are the best home remedies that will help you to treat and prevent gallstones.

Get My Free Ebook


Post a comment