Which of the following nerve innervation is present on ureters which aids in ureteric peristalsis for passage of urine?
**Core Concept**
The ureters are muscular tubes that transport urine from the kidneys to the bladder. The ureteric peristalsis is a crucial mechanism that aids in the passage of urine. This process is primarily facilitated by the intrinsic smooth muscle of the ureters, but it also receives extrinsic innervation from the autonomic nervous system.
**Why the Correct Answer is Right**
The correct answer is sympathetic innervation. The sympathetic nerves release norepinephrine, which stimulates the alpha-adrenergic receptors on the smooth muscle cells of the ureters. This stimulation leads to contraction of the smooth muscle cells, which aids in the ureteric peristalsis. The sympathetic innervation is responsible for the initial contraction of the ureters, which helps to propel the urine towards the bladder.
**Why Each Wrong Option is Incorrect**
**Option A:** Parasympathetic innervation is primarily involved in the relaxation of the smooth muscle cells of the ureters, which would hinder the ureteric peristalsis.
**Option B:** Preganglionic fibers of the parasympathetic nervous system are responsible for the stimulation of the smooth muscle cells, but the preganglionic fibers of the parasympathetic nervous system are not the primary source of innervation for the ureters.
**Option D:** The enteric nervous system is responsible for the intrinsic control of the gastrointestinal tract, but it is not primarily involved in the innervation of the ureters.
**Clinical Pearl / High-Yield Fact**
The sympathetic innervation of the ureters is primarily responsible for the initial contraction of the smooth muscle cells, which helps to propel the urine towards the bladder. This is an example of the autonomic nervous system's role in the regulation of the gastrointestinal tract and the urinary system.
**Correct Answer: C. Sympathetic innervation.**