General anatomy
The
kidneys (left and right) are found
dorsal to the
peritoneum, adjacent to the body wall. The
kidneys are protected dorsally by the 11th and 12th ribs. The size of the right lobe of the
liver pushes the right
kidney so that it sits slightly more
inferior than the left
kidney.
The
superior aspect of each
kidney is covered by an
adrenal gland. At the
medial portion of the
kidney, called the
renal hilum, several
structures connect to the
kidney. The
renal artery and
renal vein attach to the
kidney at the hilum as well as the
ureter. The
ureters then extend down
inferiorly to the
bladder, which connects to the
external opening of the
urinary system by the
urethra.
The bladder and urethra
The
bladder is a hollow
organ in the pelvic region. It stores the
urine until
excretion of the
urine by
micturition.
The two
ureters descend from the
kidneys to two
ureteral openings on the
inferior surface of the
bladder. The ureteral openings and the opening to the
urethra form a triangular section of smooth
tissue called the
trigone.
The
internal urethral sphincter is controlled involuntarily with
smooth muscle. It is connected to the
external urethral sphincter (controlled voluntarily with
skeletal muscle) by the
urethra, a hollow tube that connects the
bladder to the external urethral opening. The
external urethral opening is the opening of the
urethra to the outside of the body.
Click here for a digital activity on the anatomy of the urinary system
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1 - Anatomy and Physiology Basics