Characteristics and functions of the kidneys

The kidneys are two very important organs for our body since they help us to carry out the purification of the body. In this article we will explain the characteristics of the kidneys, how they are, their physiological characteristics, what role they play in our body and everything completed with impressive images about the kidneys .

Anatomical characteristics of the kidney

The kidneys are two bean-shaped organs, 12 cm long. high, 6 cms. of width and 3 cms. of thickness. Arranged in the frontal plane, its medial, concave edge presents the hilum of the organ through which the renal artery and nerves enter, and the renal vein and renal pelvis emerge. The major axis of the kidneys converges cephalad, so that their upper poles are closer to the midline than their lower poles. In both kidneys, the upper pole is in contact with the suprarenal gland.

Where are the kidneys

The kidneys are located retroperitoneally, in the upper part of the abdominal wall, resting on the diaphragm and the psoas major muscle. The medial border of the right kidney is related to the inferior vena cava, the left kidney does to the abdominal aorta. These relationships produce differences in the length of the renal vessels that pass transversally to each hilum. The left renal vein is considerably longer than the right; conversely, the right renal artery is longer than the left. The right kidney is 3 cm. lower than the left, due to the relationship it presents with the liver. The kidneys are surrounded by a fibrous layer, the renal fascia, which forms a pocket, the renal cell, which contains the kidney, adrenal gland and perirenal fat. This fat is an important element in the support of the kidney in normal position. The kidney has a cavity in its interior, the renal sinus, which opens towards the hilum; The breast contains the branches of the artery, the vein, the renal calyces and the renal pelvis. Intimately attached to the surface of the kidney is a thin fibrous lamina, the renal capsule, which is inserted through the hilum and covers the walls of the renal sinus. This kidney capsule separates the kidney from perirenal fat. When cut, the renal tissue has two sectors: the renal medulla, arranged in conical portions called renal pyramids; and the renal cortex, located peripherally but with central projections, the renal columns, which are arranged between the renal pyramids.

Structure of the kidney

The structural unit of the kidney is the nephron. Each kidney has about one million of them. The nephron is constituted by the renal corpuscle (glomerulus + glomerular capsule or Bowman), the proximal convoluted tubule, the loop of Henle and the distal convoluted tubule, which ends in the collecting tube. The collecting tubes open at the apex of the renal pyramids, an area that is called the renal papilla.

The kidney, despite its size, consumes 25% of cardiac output, there being a particular distribution of the arterial system known as admirable network. The renal artery is divided into five segmental branches (apical, superior, middle, inferior and posterior). These segmental branches pass through the renal sinus, and are divided into interlobar branches that are to be located in the renal columns. At the base level of the renal pyramid, the interlobar arteries are divided into arcuate or arcuate arteries. These outline the base of the pyramids and give rise to the interlobular arteries. The interlobular arteries are arranged in a radiated form in the renal cortex and give origin to the afferent arterioles. These short afferent arterioles are going to capillary forming the renal glomerulus; then the efferent arteriole of the glomerulus is formed, which will capillary, forming the peritubular plexus, in relation to the contiguous tubules. From here the interlobular venous territory will follow, then arcuate veins, interlobular, and finally the renal vein. As you can see, in the kidney there are two networks of capillaries (the glomerulus and the plexoperitube) connected by the efferent arteriole, this is an admirable network.

How the kidney works

The urine filtered by the nephrons will be collected, at the level of the renal papilla, by the lesser calyces. These smaller chalices are funnel-shaped conduits, consisting of a mucosa and a layer of smooth muscle. At the level of the renal sinus, two or three smaller chalices converge to form a greater calyx (structurally similar to the lesser calyces); and three or four major chalices will form the renal pelvis. The kidney pelvis, funnel-shaped, is located in the renal sinus, crosses the hilum of the kidney and continues with the ureter. Structurally, it is constituted, like the ureter, by a mucosa, a smooth muscular tunic arranged in a circular inner layer and a longitudinal external layer, and an adventitia.