A sample of cerebrospinal fluid might be taken to see if cancerous cells have entered the CNS, or chemotherapy might be administrated to prevent or combat CNS involvement. The Sensory Systems A receptor or sense organ picks up stimulus and converts it into a nerve impulse. This impulse is then conducted along a neural pathway to the brain, where the signal is converted into a sensation. The skin contains specialist receptors for touch, pressure, vibration, hot, cold, and pain. Integrative sensations are not well defined but include memory, sleep, emotions etc.
Olfactory neurons have dendrites that are connected to fine hairs in the nose that react to odours.
Taste buds contain gustatory cells which contain sensitive hair like processes. The retina of the eye converts light into nerve impulses which are transmitted to the optic nerve. Retinoblastoma is a rare tumour in the cells of the retina. Sound waves cause fine hairs in the inner ear to vibrate generating nerve impulses. The nerves of the ANS activate the involuntary smooth muscles, cardiac muscles, and some glands.