Renin-Angiotensin-Aldosterone System. 1  Specialized cells in the distal tubule called the macula densa sense the concentration of sodium and chloride. 2  If blood pressure falls there is a reduction in concentration of sodium and chloride in the distal tubule which is sensed by the macula densa. The macula densa releases prostaglandins which act on the juxtaglomerular apparatus which releases renin into the bloodstream. The drop in blood pressure is also detected by baroreceptors in the aortic arch, carotid sinus and the afferent renal arteriole which stimulates renin release by the juxtaglomerular apparatus. Renin cleaves angiotensinogen into angiotensin 1 which in turn is cleaved by Angiotensin Converting Enzyme into angiotensin 2.
Many people are surprised to learn that the source of their dizziness may be because of an inner ear or vestibular problem. Dizziness due to a vestibular dysfunction are reported in about 9 percent of the population who are 65 years of age or older.
Causes of Dizziness. The reasons of a dizzy spell can usually be identified on the basis of the sensation experienced by the individual. So, the cause will depend on whether you are feeling faint, experiencing vertigo, or feeling a loss of balance.