Final answer:
The cranial nerves with parasympathetic fibers are the oculomotor, facial, glossopharyngeal, and vagus nerves. They regulate functions like pupillary constriction, salivation, tear secretion, and organ function in the thoracic and abdominal cavities.
Step-by-step explanation:
The cranial nerves that contain parasympathetic fibers include the oculomotor nerve (cranial nerve III), the facial nerve (cranial nerve VII), the glossopharyngeal nerve (cranial nerve IX), and the vagus nerve (cranial nerve X). These nerves play pivotal roles in the autonomic control of various bodily functions.
- The oculomotor nerve's parasympathetic fibers control pupillary constriction through the ciliary ganglion, affecting the smooth muscles of the iris.
- The facial nerve facilitates tear and salivary gland secretion.
- The glossopharyngeal nerve also contributes to salivation through innervation of certain salivary glands.
- The vagus nerve exerts parasympathetic influence on the heart, bronchi, esophagus, as well as on multiple organs in the abdominal cavity like the stomach, liver, pancreas, gall bladder, and small intestine.
The autonomic functions of these cranial nerves are crucial for maintaining homeostasis within the body.