March 3, 20 1 year14 is 19 National Safety Education Day for Primary and Secondary School Students. "Obey traffic rules and travel safely and civilized" means that primary and secondary school students stay away from traffic accidents. (1) The formation process of vision: the light reflected by external objects passes through the cornea and aqueous humor, enters the eyeball from the pupil, and is refracted by the lens and vitreous body to form an inverted object image. Photosensitive cells on the retina are stimulated by the image of the object to produce nerve impulses, and then reach the visual center of the cerebral cortex through the optic nerve to form vision.

(2) The formation process of hearing is: external sound waves reach the eardrum through the external auditory canal, causing the eardrum to vibrate; Vibration is transmitted to the inner ear through the ossicle, which stimulates the auditory receptors in the cochlea and produces nerve impulses; Hearing is formed when nerve impulses are transmitted to auditory pathways in cerebral cortex through nerves related to hearing.

(3) The spinal cord consists of gray matter and white matter. Gray matter is the gathering place of neurons, which has the function of reflection, while white matter is composed of nerve fibers and has the function of conduction. Nerve impulses are generated by the nerve centers related to the cerebral cortex, and are transmitted to the corresponding nerve centers in the spinal cord along the descending conduction bundles (nerve fibers) in the white matter, and then transmitted to the corresponding muscles through the efferent nerves to generate exercise.

(4) One end of the eustachian tube is connected with the tympanic cavity, and the other end is connected with the pharynx, so the tympanic cavity communicates with the oral cavity through the eustachian tube. Bacteria in the mouth or respiratory tract can enter the middle ear from the pharynx through the eustachian tube, causing inflammation. Therefore, when people suffer from respiratory diseases such as colds, otitis media sometimes occurs.

So the answer is: (1)② lens; ④ retina; III visual center; (2)6 cochlea; I auditory pathway; (3) a white matter; Efferent nerve; (4)5 eustachian tubes.