Final answer:
Kidney stones cause intermittent pain because ureters use peristalsis to move urine, and when stones cause obstruction, it leads to dilation and muscular spasms in the urinary tract, causing pain known as renal colic.
Step-by-step explanation:
The physiology that explains the intermittent nature of pain caused by a kidney stone is primarily because ureters use peristalsis and gravity to move urine. Ureters contract in a wave-like motion to transport urine from the kidneys to the bladder, and at the same time, stones can cause obstruction. The resulting obstruction leads to dilation or stretching of the upper ureter and renal pelvis as well as spasm of the ureteral muscle, which can cause severe episodic pain. This pain is most commonly felt in the flank, lower abdomen, and groin, and is known as renal colic. Renal colic can also be associated with nausea and vomiting, and hematuria may be present due to damage to the urinary tract lining.
Kidney stones are mineral crystals that form in the urine. They can cause a blockage if they become large enough, necessitating treatments like lithotripsy, stenting, or even surgery to ensure urine can flow from kidney to bladder. Smaller stones may pass with minimal or no symptoms, while larger stones can result in significant pain, obstruction, and potential damage to the kidneys.