Kidney Anatomy

Kidney Coverings

The kidneys are not free-floating.  They are located a little higher in the abdominal cavityThe body cavity containing the stomach, intestines, liver, and other digestive organs. than you probably think. They are retroperitoneal Referring to organs located behind the peritoneum, such as the kidneys and pancreas. like the pancreasA gland that produces digestive enzymes and hormones like insulin and glucagon. and duodenumThe first section of the small intestine where most digestion occurs; it receives chyme, bile, and p.  The most superficialNear the surface of the body. covering, called the renal fascia contains the kidney and the adrenal glandPaired endocrine glands above the kidneys producing stress-related hormones..

Beneath the renal fascia is the perinephric fatA layer of fat surrounding the kidney that provides cushioning and protection., which cushions the kidney, similar to how fat cushions the eyes. The fibrous capsuleThe outer protective layer of the kidney., a stocking-like covering, contains the kidney and its contents.  Collagen fibers extend from this deepAway from the surface of the body. covering through the adipose tissue. They also extend through the renal fascia to anchor the kidney to surrounding tissues.  These membranes are all attached at the hilum. This is the area where the renal arteryThe artery that supplies blood to the kidney., renal vein, and ureterThe tube that carries urine from the kidney to the bladder. enter the kidney. 

Kidney Gross Anatomy

We can divide the kidney into the cortex and the medulla.  However, the medulla for the kidney are these triangular shapes, which are really pyramids in 3D structure.  Most people have 7 pyramids, but it is not unusual to have more or less.  The cortex of the kidney runs along the outside border. It dips down between the pyramids in sections called cortical columns. 

This are where the ureter and blood vessel pierce the kidney is called the renal hilum.  This wide open area here is called the renal basin.  The renal basin can sometimes be called the renal pelvisThe central collecting region in the kidney where urine from the calyces enters before moving to the.  Students sometimes get confused by the term “pelvis” here. Therefore, I find that renal basin is a better term to use than renal pelvis.  In this area, urineThe liquid waste excreted by the kidneys. collects before descending into the ureter. 

The point of each medullary pyramid is called the renal papillaThe tip of a renal pyramid where urine drains into the minor calyx..  This is where urine weeps into these drainage areas which are called a minor calyxA small cavity in the kidney where urine from a renal pyramid collects before moving to the major ca.  Minor calices can then be grouped together into major calices, which all drain or lead to that renal basin.

Kidney Gross Anatomy

Most of the pictures we will view will be frontalForehead bone; forms the front part of the skull and roof of the orbits. Smooth and curved. sections of the kidney. An example is the one on the right.  This picture is a transverse section A cut or slice of the body or an organ for study. of the kidney.  This open area is the renal basin where the urine collects before descending the ureters.  These open spaces are the segmental arteriesBlood vessels that carry oxygenated blood away from the heart (except pulmonary arteries, which carr.  This central area is a renal pyramidA triangular structure in the kidney that contains nephrons and collecting ducts. representing the medulla of the kidney and the outer layer is the cortex.  The arcuate arteries run along the boundary of the cortex and the medullary pyramid.