Synonyms
Renal calyx, renal pole, renal pelvis, renal hilus, wandering kidney, cortex, renal medulla, nephron, primary urine, inflammation of renal pelvis Medical: Ren
Anatomy of the kidney
The kidney, of which each person normally has two, is approximately bean-shaped. Each kidney weighs about 120-200 g, with the right kidney generally being smaller and lighter than the left. To orientate the kidney, the physician describes an upper and a lower renal pole (upper and lower end of the kidney), an anterior and a posterior surface of the kidney, and a medial (i.e. facing the middle of the body) and a lateral (outer) edge.
At the medial (inner) edge of the kidney there is an indentation, the so-called renal hilius. This is where blood vessels reach and leave the kidney. The renal pelvis is also located here, from where the urine enters the bladder via the ureter.
The kidney is covered by a tough capsule of connective tissue (capsula fibrosa). Underneath it is a layer of fat, the capsula adiposa, which serves to protect the kidney by absorbing shocks and vibrations. In cases of severe emaciation (such as anorexia), this layer of fat may be completely absent, which causes the kidney to change its position due to lack of support (so-called wandering kidney).
The position of the kidney changes with the position of the body and during breathing: when standing, the kidneys are therefore lower than when lying down and when breathing in they are lower than when breathing out. Due to the space occupied by the liver (hepar), the right kidney is positioned slightly lower than the left. Each kidney has its own artery (A. renalis), which originates from the aorta, and a vein (V. renalis), which carries the blood to the lower vena cava.
The renal arteries also supply the adrenal gland, ureter and fat capsule with nutrients and oxygen. Before entering the renal hilus, each renal artery divides into 2 – 3 branches. It is not unusual to find additional renal vessels, but these have no disease value.
Nevertheless, knowledge of such unusual blood flow conditions, e.g. during operations, can be important.
- Kidney Marrow
- Cortex of the kidney
- Renal artery
- Renal Vein
- Ureter (Ureter)
- Kidney capsule
- Renal calyx
- Renal pelvis
The kidney is divided into: They are clearly distinguishable in color and structure. 1. renal medulla (medulla renalis): The renal medulla consists of approx.
12 – 15 conical pyramids, the base of which points towards the surface of the kidney, while the tip (papilla) projects into the calices of the renal pelvis. There are several openings in the papilla through which the urine enters the renal pelvis. 2. renal cortex (Cortex renalis): The cortex of the kidney extends over the base of the pith pyramids.
On longitudinal sections the surface appears columnar (so-called Bertini’s columns). A medullary pyramid with an associated cortical layer forms a renal lobe, which is approximately wedge-shaped. The basic unit of the kidney is the nephron.
It consists of: which can be divided into different sections of the kidney. In total, each person has about 2 million nephrons! 1. renal corpuscle (glomerulus) The renal corpuscle is a ball of the smallest blood vessels (capillaries), with one inflowing and one outgoing vessel (vascular pole).
It is surrounded by a capsule (Bowman capsule), which consists of two leaves. A protein-free filtrate of the blood (primary urine) is released into the interstitial space, which is fed into a canal system at the urinary pole (opposite the vascular pole). The walls of the capillaries in the ball have large pores through which the blood can be filtered into the capsule.
The passage of protein is prevented by foot cells (podocytes), which cover the pores with their feet like a kind of sieve and prevent the passage of too large particles. At the vascular pole there is a point of contact with the urinary tract, the macula densa. This is where the saline concentration of the urine is measured and, depending on the result, the blood flow and thus the filtering capacity of the glomerulum is altered.
2. renal tubules The renal tubules can be divided into different sections. From the collection tubes, the so-called secondary urine (approx. 1.5 – 2 l per day) reaches the renal pelvis and then further via the ureters into the bladder.
- Renal cortex and
- Renal medulla.
- Renal corpuscles and
- Renal tubules,
- Proximal tubule (main piece) with twisted and stretched partThe cells lining this canal have a strongly folded surface (brush border).It is home to various enzymes, which have channels and pores for the reabsorption of water, sugar (glucose), amino acids, sodium, potassium, chloride, phosphate and uric acid. However, the exchange of substances can also take place past the cells through interstitial spaces.
- Intermediate tubule (transition piece) with descending and ascending part (Henle loop)The lining cells are flat and have no brush border. Here water is reabsorbed and urine is concentrated.
This is achieved by an accumulation of common salt in the surrounding tissue, resulting in an outflow of water from the tubule.
- Distal tubule (middle section) with elongated and tortuous sectionIt moves upwards into the cortex, where it makes contact with the macula densa at the vascular pole (see above). This is where common salt is reabsorbed, which favors the escape of water, and potassium is released. These processes are controlled by a hormone from the adrenal gland (aldosterone).
- Tubulus reuniens (connecting tubulus)This is the last section of the nephron.
It is tortuous and can accommodate several distal tubules. Several tubules then end in a collection tube. All winding tubule sections lie in the cortical labyrinth, all straight ones in the medulla.
- Collection tubeThe kidney collection tube is used to reabsorb water according to need and to concentrate the urine under the control of the hormone ADH (antidiuretic hormone).
- Abdominal artery (aorta abdominalis)
- Upper intestinal artery (Arteria mesenterica superior)
- Kidney
- Renal artery (Ateria renalis)
- Ovarian veinTesticle vein (ovaricatesticular vein)
- Ovarian arteryTesticular artery (Arteria ovaricatesticularis)
- Renal vein (Vena renalis)
- Inferior vena cava (vena cava)
Almost all renal tumors are so-called renal cell carcinomas.
These malignant tumors (malignancies) are relatively insensitive to chemotherapy and can take a very different course. Kidney cancer is usually a tumor of the elderly patient (usually between 60 and 80 years). Acute renal failure (ANV) can have various causes, e.g.
acute glomerulonephritis, damage to the blood vessels of the kidneys (e.g. vasculitis), toxins, etc. It often develops after serious injuries, operations, shock or sepsis. In the context of multi-organ failure it has a particularly bad prognosis. If an artery (thrombosis or embolism) or its branch is blocked, e.g. by a blood clot, a renal infarction (tissue loss) occurs in the area of supply, which means that the tissue of the kidney no longer supplied with blood dies.
