Each kidney is about 11 cm long and about 5 cm thick, weighing 150 grams in the human adult.
The basic anatomy of the kidney
On the medial aspect of each kidney is an opening, called the hilus, which admits the renal artery, the renal vein, nerves, and the ureter. Within the kidney is a cavity named the renal sinus. Within the renal sinus are the filtration organs called nephrons (containing the filtering unit (glomerulus), its tubule and duct), of which there are more than a million within each kidney. At the top of each kidney is an adrenal gland (also called suprarenal gland).
renal capsule - The membranous covering of the kidney.
cortex - The outer layer over the internal medulla. It contains blood vessels, glomeruli (which are the kidneys' "filters") and urine tubes and is supported by a fibrous matrix.
hilus - The opening in the middle of the concave medial border for nerves and blood vessels to pass into the renal sinus.
renal column - The structures which support the cortex. They consist of lines of blood vessels and urinary tubes and a fibrous material.
renal sinus - The cavity which houses the renal pyramid.
pyramids - The conical segments within the internal medulla. They contain the secreting apparatus and tubules and are also called malphighian pyramids.
renal artery - Two renal arteries come from the aorta, each connecting to a kidney. The artery divides into five branches, each of which leads to a ball of capillaries. The arteries supplie (unfiltered) blood to the kidneys. The left kidney receives about 60% of the renal bloodflow.
renal pelvis - Basically just a funnel, the renal pelvis accepts the urine and channels it out of the hilus into the ureter.