The kidney is an organ of amniotes most often located together in the abdomen, behind the peritoneum. The amniotes have two kidneys, arranged in a more or less symmetrical bilaterally. In humans, these two bodies are between the 11th thoracic and 3rd lumbar (to the left kidney) and the 12th and the space between the 3rd and 4th lumbar (for the right kidney). The kidney is the case for retroperitoneal. It ensures filtration and excretion of urine, fluid balance (homeostasis) of blood and body in general.
In humans, a single kidney (5% of individuals) is necessary for life and in this case it is most often the right kidney, unlike the better vascularized left and the presence of quadrilateral Rogie that promotes stasis venous and affects the genital level left. The bodies are flattened, ovoid. Their height is 12 cm, width is 6 cm, thickness is 3 cm. These dimensions are important to know because a malfunctioning kidney is atrophied, which facilitates the clinical examination and thus the diagnosis. The outer surface of the kidneys is convex. The kidney is vascularized by the renal arteries and veins and it is through an opening in the concave face that these vessels enter the kidney.
In the kidney, we can see the presence of a cavity (renal sinus) where branching renal artery. This vessel will then branch out into the kidney itself. Veins branch also in the renal sinus.
The hilum is the transit area of arteries, veins, excretory tract. The renal parenchyma is surrounded by a capsule hard, very resistant to protect it. The peripheral part of the cortex parenchyma, while the core is the medula. This medula is not continuous: it is suspended by extensions of the cortex that extend to the renal sinus.
The urine is secreted at papillae which are themselves the top of the pyramids.
The kidney also has an endocrine function (erythropoietin, renin-angiotensin-aldosterone).
The kidneys are covered by small gland called the adrenal. These consist of a cortex (cortico-adrenal) secrete mainly corticosteroids and a medulla (adrenal medulla), secreting adrenalin.
In the vernacular, often called the kidneys lumbar vertebrae. It is a misnomer and a mistake.
It is a thin tubule consisting of a cluster of capillaries called glomeruli, surrounded by a hollow bulb, the capsule of Bowman. Bowman's capsule leads to a long coiled tubule into 2 sections: the proximal convoluted tubule, loop of Henle, the distal convoluted tubule and collecting duct. The collecting ducts empty into the calyces via the papillae, calyces drain into the pan (also known as moiety), which is connected to the ureter. Each human kidney has about a million nephrons. The number of nephrons, fixed at birth, is a large variability. It depends on many factors including gestational age, delayed intrauterine growth, maternal nutritional status.
Blood supply to the nephron
The blood goes through several veins and arteries. In going there in order:
* Renal artery
* Segmental artery,
* Interlobar artery,
* Arcuate artery,
* Interlobular artery,
* Afferent arteriole,
* Arteriole glomerular
* Capsule glomerular
* Efferent arteriole,
* Peritubular capillaries and vasa recta,
* Interlobular vein,
* Vein arched
* Vein interlobar
* Renal vein,
* Vena cava.
Read also Kidney Stone