Vascular-tubular relationships in the mammalian kidney
overview - introduction - technique - back to index
General comment
In this "chapter", I have presented pictures that illustrate the basic organization of the mammalian kidney, based on the unpapillary kidney of the rabbit and the rat, two species widely used in renal physiology (before the era of transgenic animals which put the mouse on the front of the scene).
Another chapter, to come, will be devoted to the special characteristics of the mouse kidney and another one to the adaptations observed in rodents adapted to arid or desert habitat.
It is important to underline that the complexity of structure of the mammalian kidney is largely linked to the adaptations allowing the production of urine of higher osmotic pressure than the body fluids and thus to the ability to save water for the excretion of soluble waste. Among mammals, and especially among rodents, wide quantitatives, but also sometimes qualitative differences are observed, in relation to adaptations of various degrees to higher capacity to concentrate urine. The diet (herbivorous, omnivorous, or carnivorous) is also associated with different types of renal adaptations. These aspects will be addressed in subsequent chapters.
Important features of the organization of the mammalian kidney,
illustrated in this chapter :
1. Hairpin shape of the loops of Henle and of the medullary vessels, favoring counter current exchanges of water and solutes.
2. Compartmentalization of the vascular environment of the different parts of the nephron allowing isolation of some zones from others.
2.a. Vertical compartmentalization (along the axis of the nephrons): cortex and different zones and subzones of the medulla (see pictures 1 to 9).
2.b. Horizontal compartmentalization resulting, in the cortex, from the alternance of medullary rays and labyrynthic zones (pictures 14 to 17), and in the inner stripe of the outer medulla, from the alternance between vascular bundles and interbundle capillary plexuses (pictures 21 to 27).
