Final answer:
A renal stone would travel from the minor calyx to the renal pelvis, then through the ureter, urinary bladder, and finally be expelled via the urethra.
Step-by-step explanation:
If you were a renal stone at rest in a minor calyx of the left kidney of a 20-year-old man, your journey would begin by entering the renal pelvis from the calyx.
From there, you would travel through the ureter, a tube-like structure that leads to the urinary bladder. Along the way, you would traverse several types of tissues.
The innermost layer of the ureter is lined with transitional epithelium, a special type of epithelial tissue capable of expanding and stretching, which is essential as it allows the ureters to handle the fluctuating volume of urine without tearing.
Furthermore, the ureter walls consist of a layer of loose connective tissue that contains elastic fibers and blood vessels, followed by two layers of smooth muscle, which work to propel you forward through waves of peristalsis.
Upon reaching the urinary bladder, which is also lined by transitional epithelium, you would be stored until the bladder contracts, forcing you through the urethra.
The urethra is also lined with transitional epithelium at the proximal end, transitioning to a mucus-secreting epithelium at the distal end, which aids in protecting the tissues from corrosive urine.
The process that propels you forward through the upper urinary tract is the rhythmic contraction of the smooth muscle layers called peristalsis.
This is the primary means by which urine, or in this case, the renal stone, is pushed from the kidneys toward the bladder before being expelled from the body.