Human olfactory system. Computer artwork of a section through a human head, showing the olfactory receptor cells (brush-like), and their location in the olfactory bulb (sausage-shape, upper centre-right) of the forebrain (brain, top right). These receptors are responsible for the sense of smell. The olfactory bulb contains many olfactory receptor cells that project through a layer of bone (beige) into the epithelial lining of the nasal cavity (red). They pick up smell information from molecules inhaled through the nose, and the olfactory bulb is responsible for transmitting these signals to the limbic area of the brain.