Kidney unit structure

The membrane-bound preparation from kidney is easily solubilized in non-ionic detergent and analytical ultracentrifugation shows that the preparation consists predominantly (80 85%) of soluble af units with 143000 [28]. The soluble a)S unit maintains full Na,K-ATPase activity, and can undergo the cation or nucleotide induced conformational transitions that are observed in the membrane-bound preparation. A cavity for occlusion of 2K or 3Na ions can be demonstrated within the structure of the soluble a)S unit [29], as an indication that the cation pathway is organized in a pore through the aji unit rather than in the interphase between subunits in an oligomer. 

The main functions of the human kidney are the formation and excretion of urine, and control of the composition of body fluids. Details of the structure and functions ofthe human kidney may be found in textbooks of physiology [1] or biomedical engineering [13]. Each ofthe two human kidneys contains approximately one million units of tubules (nephrons), each 20-30 pm in diameter, and with a total... 

Nephron The basic structural and functional unit of the kidney. The basic function of the nephron is to regulate water and soluble substances... 

The kidney tissue has a very intriguing structure. It is organized into several thousand structural and functional units. A single unit - a nephron (Figure 2.15b) - spans the better part of the entire distance between the organ periphery and the renal pelvis, which simply collects the final urine and feeds it into the ureters.. 

A striking example of the importance of the primary structure of polypeptides can be seen in the differences between oxytocin and vasopressin. Both of these molecules are nine-unit polypeptides that differ by only two amino acids (Fig. 22.19), yet they perform completely different functions in the human body. Oxytocin is a hormone that triggers contraction of the uterus and milk secretion. Vasopressin raises blood pressure levels and regulates kidney function. 

Figure 9.2 Structural overview of a nephron, the functional unit of the kidney. This figure was published in Anaesthesia and Intensive Care Medicine, Voi. 6, B.J. Pieunqr, Modes of drug eiimination, pp. 277-279, Copyright Eisevier 2005.

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