Touch is associated with sensory papillae (A-iii) which are the receptors involved in the sensation of touch. Smell is detected by receptors in the nasal epithelium (B-i). The cranial nerves are part of the peripheral nervous system (C-iv) since they transmit sensory and motor information to and from the central nervous system. The medulla oblongata, through which the spinal cord passes, is connected to the foramen magnum (D-ii) as it is the opening in the skull through which the spinal cord enters and exits.