Kidney anatomy

The kidneys are created as an instrument to cleanse the blood of excess moist essence, which is initially necessary, as we have already explained. This necessity disappears when the blood matures and becomes capable of passing through the body; you already know about this too. Since this moist essence is very abundant, an instrument had to be created that cleanses it and draws it in, either in the form of one large organ or two paired organs. If it were one large organ, it would certainly constrict and squeeze neighboring organs; therefore, instead of one, two kidneys were created. There is already a well-known usefulness in the doubling of this organ, which is also manifested in the creation of organs in pairs, dicotyledons or having several lobes, more than one: if damage occurs in one of the two lobes, then the other carries out partially or completely the action of the entire organ.

Doubling and compacting the substance of the kidneys has several benefits: firstly, the multiplication should compensate for the small volume of each kidney, secondly, the density of the substance does not allow it to draw in and absorb matter other than liquid, thirdly, an organ with a dense substance is not easily affected constantly filling it with spicy liquid, which in most cases is accompanied by spicy juices. Since the kidneys are created in this way, the vein located next to the kidneys easily passes between them, and the space for the insides located there is quite spacious. The right kidney is located above the left in order to be closer to the liver and extract as much juice as possible from it; it almost touches the liver, or rather touches the process adjacent to it. The left kidney is lowered lower because it is pushed aside on the left side by the spleen, and also so that the seeping moisture does not wander between two organs that are at the same level, but is first attracted to the nearest kidney and then to the more distant one.

The kidneys face each other with their concave parts, and their convex parts are adjacent to the bone of the spine. Inside each kidney there is a cavity into which the watery part of the blood is drawn from the “rising” vessel leading to it, and this vessel is short. Then, from inside the kidney, the waste separated from the moisture gradually seeps through the ureter into the bladder after the kidney has cleared this moisture to the fullest extent possible from the blood waste that accompanies it; the kidney feeds on what has been purified and expels waste. The fact is that the watery part of the blood does not enter the kidney completely purified and separated from the blood; on the contrary, it comes there with a trace of bloodiness and looks like slop from carefully washed fresh meat. If the kidneys weaken, they also do not cleanse, and the moisture leaves, accompanied by residue. In the same way, if the liver is weak, it does not separate the aqueous humor from the bloody humor to the proper extent and sends to the kidneys, along with the aqueous humor, more bloody humor than needs to be sent there; then the bloody matter accompanying the aqueous humor exceeds the proper amount needed by the kidney for nutrition, and, excreted in the urine, also has the appearance of meat slop, similar to the slop-like urine that is excreted when the kidneys are too weak to nourish.

A small nerve approaches the kidneys, from which their membrane is formed; from the side of the “gate” of the liver a vein approaches them. An artery of quite significant size also approaches them, branching off from the artery that goes to the liver.