Diad ayayep, say utek, odino encephalon (Griego parad "diad ulo"), so sentro na kontrol na central nervous system. Diad maslak ya ayayep, say utek et walad ulo, a proprotektaan na balbas tan asingger ed primary sensory apparatus na pakanengneng, panagdengel, pakalikna tan pakaangob. Diad too, satan so sakey ya organ na kanonotan. Anggaman amin a bertebrado so walaan na utek, saray inbertibrado so walaan na sentralisadon utek odino koleksion na saray indibidual a ganglia. Saray utek et nayarin komplikado. Singa bilang, say utek na too et walaan na masulok ya 100 bilyon a neuron, ya kada neuron et mikonektaan ed 10,000 nin neuron.

Representation na MRI na utek