The Kidneys in humans are located in Abdominal Cavity and to be specific they lie at Retroperitoneal (Potential space in Abdominal Cavity) position at a slightly tilted angle. There are two kidneys; one at each side of the spine. The asymmetry caused by the Liver in abdominal cavity result in the slight tilt of right kidney in respect to the left. The left kidney is located at Vertebral level T12 to L3 and the right one lies slightly lower. The right kidney lies below the Diaphragm and posterior to liver. On each kidney rests an Adrenal Gland. The upper parts of kidneys are protected by eleventh and twelfth ribs and each kidney is surrounded by layers of fat (Perirenal and Pararenal ) and Renal Fascia.
Branching from Abdominal Aorta the kidneys are supplied with left and right Renal Arteries. Kidneys receive 20% of cardiac output (blood pumped by heart). These Renal arteries divide into segmental arteries which further branch into Interlobar Arteries (vessels of renal circulation supplying Renal Lobes). These Interlobar Arteries penetrate the Renal Capsule while extending through Renal Columns. Blood is supplied to Arcuate arteries through these Interlobar arteries which pass through the boundaries of Medulla and Cortex.
Interstitium (core substance of a non hollow organ) is a functioning space in kidneys which are enriched with blood vessels. Interstitium collects fluids recovered from urine. Various conditions lead to Scarring of this area causing kidney dysfunction and failure.
Renal Plexus whose fibers run through renal arteries to each kidney result in the communication of Kidneys and Nervous System. Sympathetic Nervous System activates Vasoconstriction (narrowing of blood vessels) resulting in the reduction of Renal Blood Flow. It also receives input from Parasympathetic Nervous System but the function of it is still unclear.
Kidney serves in the Homeostasis of whole body. These homeostatic functions are as follows.
Regulating Acid-Base balance
Concentration of Electrolytes
Extracellular fluid volumes
Blood pressure regulation
These Homeostasis function are performed by kidneys independently or in concert with other organs of Endocrine System. Taking place in Nephron many of the kidney’s functions are simple mechanisms of Filtration, Reabsorption, and Secretion.
Kidneys have several diseases which may be Acquired or Congenital which are as follows.
Hydronephrosis (enlargement of one or both kidneys)
Renal or Kidney Failure
Congenital obstruction of Urinary Tract