Which of the following structures receives parasympathetic innervation from the vagus nerve (cranial nerve X)?
Solution
Correct Answer: Option A
The correct answer is Heart and gastrointestinal tract up to the splenic flexure.
- The vagus nerve (cranial nerve X) provides parasympathetic innervation to many thoracic and abdominal organs.
- It plays a crucial role in modulating the autonomic control of these structures.
Important points:
- The vagus nerve supplies parasympathetic fibers to the heart, helping to decrease heart rate and promote relaxation.
- Parasympathetic innervation extends along the gastrointestinal tract from the esophagus to the splenic flexure of the colon. This includes the stomach, small intestine, and proximal large intestine up to the splenic flexure.
- Structures distal to the splenic flexure, such as the distal colon and rectum, receive parasympathetic innervation from the pelvic splanchnic nerves (S2-S4), not the vagus nerve.
- The kidneys, distal ureter, and bladder are primarily innervated by sympathetic fibers and receive parasympathetic input from the pelvic splanchnic nerves as well, not from the vagus nerve.
Thus, the parasympathetic innervation pattern is divided roughly at the splenic flexure, with the vagus nerve supplying parasympathetic fibers proximally and pelvic splanchnic nerves distally.
Reference: Gray's Anatomy, 42nd Edition, Nervous System, Parasympathetic Nervous System / Pages 1004-1006
- The vagus nerve (cranial nerve X) provides parasympathetic innervation to many thoracic and abdominal organs.
- It plays a crucial role in modulating the autonomic control of these structures.
Important points:
- The vagus nerve supplies parasympathetic fibers to the heart, helping to decrease heart rate and promote relaxation.
- Parasympathetic innervation extends along the gastrointestinal tract from the esophagus to the splenic flexure of the colon. This includes the stomach, small intestine, and proximal large intestine up to the splenic flexure.
- Structures distal to the splenic flexure, such as the distal colon and rectum, receive parasympathetic innervation from the pelvic splanchnic nerves (S2-S4), not the vagus nerve.
- The kidneys, distal ureter, and bladder are primarily innervated by sympathetic fibers and receive parasympathetic input from the pelvic splanchnic nerves as well, not from the vagus nerve.
Thus, the parasympathetic innervation pattern is divided roughly at the splenic flexure, with the vagus nerve supplying parasympathetic fibers proximally and pelvic splanchnic nerves distally.
Reference: Gray's Anatomy, 42nd Edition, Nervous System, Parasympathetic Nervous System / Pages 1004-1006
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