A high rate of urine flow is called diuresis and there are two main types; water
diuresis and osmotic diuresis. Water diuresis occurs when there are inadequate
amounts of ADH in the blood. Osmotic diuresis is caused by an increase in the rate of
solute excretion. An increase in solute excretion causes an increase in the amount of
water that is excreted with the urine.
228. ENDOCRINE CONTROL
a. Antidiuretic Hormone. The effect of ADH on the permeability of water
through the tubules is very rapid, and changes in the ADH concentration in the blood
are only 10 to 15 minutes behind the change in the solute concentration.
b. Renin and Aldosterone. When the sodium concentration in the blood falls to
a very low point or when the blood pressure falls (for example, in hemorrhage), special
cells in the nephron release a hormone called renin which acts upon a plasma protein
(angiotensinogen) to form angiotensin2. Angiotensin2, in turn, acts upon the cortex of
the adrenal gland to produce aldosterone. Aldosterone increases Na+ reabsorption and
thus increases water reabsorption. This increases the plasma volume and the blood
Section V. THE ANATOMY AND PHYSIOLOGY OF RESPIRATION
229. THE ANATOMY OF THE RESPIRATORY SYSTEM (Figure 213)
a. Nasal Cavity.
(1) Structure. The nose contains the nasal cavity, which is divided by the
nasal septum. The nasal cavity is separated from the mouth by the palate. The part of
the nasal cavity just within the nostril is called the vestibule. The vestibule is lined with
skin and coarse hair. The interior of the nose is lined with a highly vascular mucous
membrane and very fine cilia.
(a) Filtering. The hair and cilia covering the nasal mucosa aid in
removing dust and other solid particles from the air in its passage to the lungs. Air
breathed through the mouth is not filtered as well.