The pupillary sphincter muscles contain muscarinic cholinergic receptors that help the eyes to respond to parasympathetic tone. When this parasympathetic signal is blocked (antagonized) via atropine, you will observe a "sympathetic response" at the level of the pupil. In this scenario, you would observe the sympathetic response of pupil dilation. Hint: "aTROP'ine" and "seeing a TROPical setting" both cause your pupils to dilate nice and wide!

The parasympathetic nervous system conserves energy and is thus know as the "rest and digest" system. It slows heart rate, increases salivation, lacrimation, urination, deification, digestion, and sexual arousal. The nerves of the parasympathetic system arise in the CNS. Specific nerves include cranial nerves, including the oculomotor nerve, facial nerve, glossopharyngeal nerve, and vagus nerve.

In the sympathetic nervous system some sympathetic fibers pass through the paravertebral ganglia, and others synapse there.

The vagus nerve (CNX) provides the heart and digestive tract with parasympathetic ("rest and digest") control.

Cranial nerves with associated parasympathetic activity include CN III, VII, IX, and X. The sympathetic trunk and the white ramus communicans are associated with the sympathetic nervous system. 

The spinal cord has both ventral and dorsal horns. The dorsal horns contain afferent neurons that receive sensory input from the environment, while the ventral horns contain efferent motor neurons that send impulses to the effector.

Nerves are separate structures that branch out from the spinal cord and central nervous system into the periphery. Cerebrospinal fluid surrounds the components of the central nervous system and acts to protect the brain and spinal cord, as well as regulate the environment of the central nervous system.

The dorsal column medial lemniscal pathway is the sensory pathway of the neural system that transports vibration, proprioception, two-point discrimmination, and fine touch.

The lateral spinothalamic pathway is the sensory pathway that transports pain and temperature sensation.

The corticospinal pathway is the motor control pathway that travels from the brain—specifically the precentral gyrus—to the spinal cord.

The corticobulbar pathway is the motor control pathway that travels from the brain, to the brainstem and the cranial nerves.

The anterior spinothalamic pathway is sensory pathway for crude touch and pressure.

The correct order of CSF flow is as follows:

Lateral ventricals, foramen of Monro, third ventricle, cerebrel aqueduct of Sylvius, fourth ventricle, foramen of Magendie (medial) and foramen of Lushka (lateral), central canal and subarachnoid space, superior sagittal sinus

The lateral spinothalamic tract is a sensory tract that conveys pain and temperature information. Although the tectospinal tract is a motor tract, it coordinates reflexive head movements in response to visual stimuli. The rubrospinal tract is also a motor tract, but it regulates activity of the upper extremity flexors. The fasciculus gracilis is a sensory tract carries proprioception, vibration, and light touch information, from the lower extremities.

The spinal cord consists of 31 segments/pairs. The cervical contains 8, thoracic contains 12, lumbar contains 5, sacral contains 5, and coccygeal contains 1. 

The dorsal column track is an ascending system conveying somatic sensory information to the brain. The dorsal column tracts ascend in the fasiculus gracilis and fasiculus cuneatus. They synapse in the medulla so that signals from the left side of the body are transmitted to the right side, and vice versa. 

Preganglionic neurons of the parasympathetic nervous system originate in the nuclei of the craniosacral region (cranial nerves and in the spinal cord segments of S2-S4). Those of the sympathetic nervous system originate in the thoracolumbar region (spinal cord segments of T1-L3).