Conversely, when renin levels are low, angiotensin II and aldosterone levels decrease, contracting the extracellular fluid compartment, and decreasing blood pressure. Glucose formation
The kidney in humans is capable of producing glucose from lactate, glycerol and glutamine. The kidney is responsible for about half of the total gluconeogenesis in fasting humans. The regulation of glucose production in the kidney is achieved by action of insulin, catecholamines and other hormones. Renal gluconeogenesis takes place in the renal cortex. The renal medulla is incapable of producing glucose due to absence of necessary enzymes. Measurement of renal function

A simple means of estimating renal function is to measure pH, blood urea nitrogen, creatinine, and basic electrolytes (including sodium, potassium, chloride, and bicarbonate). As the kidney is the most important organ in controlling these values, any derangement in these values could suggest renal impairment. There are several more formal tests and ratios involved in estimating renal function:


== References ==
Keratomalacia is an eye disorder that results from vitamin A deficiency. Vitamin A is required to maintain specialized epithelia (such as in the cornea and conjunctiva). The precise mechanism is still not known, but vitamin A is necessary for the maintenance of the specialized epithelial surfaces of the body. A lack of vitamin A leads to atrophic changes in the normal mucosal surface, with loss of goblet cells, and replacement of the normal epithelium by an inappropriate keratinized stratified squamous epithelium. In addition, the substantia propria of the cornea breaks down and liquefies, resulting in keratomalacia.The resulting cornea becomes totally opaque, which is one of the most common reasons for blindness around the world, particularly in developing countries. See also
Acute promyelocytic leukemia
Keratoconjunctivitis sicca
Xerophthalmia

References
External links

patient.co.uk