Internal senses cant be ignored, it detect changes taking place inside our body. They signal things like hunger, thirst, fatigue, internal pain, and the need to breathe or to go to the toilet. In cooperation with our biological clock, internal sensors make us feel tired at day's end and jet-lagged if we have flown across time zones. In fact, because we can consciously "sense" the flow of time, it has been suggested that time awareness be added to the catalog of senses