Ureteric peristalsis is due to intact supply of?
**Core Concept**
Ureteric peristalsis is a crucial mechanism for the propulsion of urine from the kidneys to the bladder, involving the coordinated contraction and relaxation of **smooth muscle** cells in the ureteral wall. This process is regulated by the **autonomic nervous system**, specifically the **sympathetic** and **parasympathetic** divisions. The intact supply of a specific component is essential for this peristalsis to occur.
**Why the Correct Answer is Right**
The correct answer is related to the **nervous supply** that controls ureteric peristalsis. The **ureter** receives its innervation from the **renal** and **hypogastric plexuses**, which are part of the **sympathetic nervous system**. However, the primary driver of peristalsis is the intrinsic **muscularis** layer of the ureter, which can function independently due to the presence of **pacemaker cells**. The intact supply of these cells and their coordination are crucial for peristalsis.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because while **sympathetic innervation** plays a role, it is not the primary factor for initiating peristalsis.
**Option B:** Incorrect as **parasympathetic** influence is more related to the lower urinary tract.
**Option C:** Incorrect because **sensory innervation** is not directly responsible for the initiation of peristalsis.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that ureteric peristalsis can occur even in the absence of external nervous stimulation due to the intrinsic properties of the ureteral smooth muscle. Understanding this can help in diagnosing and managing conditions affecting the ureters.
**Correct Answer:** D.