To animate the development of the olfactory organ and nasal cavities, a 4-week-old embryo is shown in 3D and detailed with more than 15 legends. The olfactory placodes are shown at the frontonasal prominence. In the next sequence, the olfactory placodes reach the nasal pits through the nasal sacs. In order to animate the migration of the olfactory placodes as viewed in section, the head of a 4-week-old embryo is cut vertically at the level of the olfactory placode and horizontally at the level of the optic placode vesicle; the future vault of the skull is removed. The diagram shows the cut olfactive placode, the wall and cavity of the prosencephalon, as well as the lumen of the optic stalk. Then, the olfactive placode is framed, rotated toward the spectator, and somewhat magnified. The diagram details the olfactory placode with primary olfactory cells, stomodeum, mesenchyme, wall and cavity of the prosencephalon, and ectoderm. A 6-week-old embryo illustrates the proliferation of the mesenchyme surrounding the olfactory placode, which causes the placode to be depressed through the nasal sac up to the nasal pit. At the same time, the olfactory cells send axons toward the wall of the prosencephalon, where the primordium of the olfactory bulb forms. The formation of the primitive naris and the growth of the median nasal prominence are also animated. During the next week, in a 7-week-old embryo, the nasal sac and the nasal pit integrate into the primitive nasal cavity; the medial nasal prominence grows; and the oronasal membrane appears. At the same time, primordium of the lower lip and the primitive choana occur. During the course of the 8th week, the medial nasal prominence transforms into the primary palate, and the definitive nasal cavity and primordia of the three nasal conchae develop. The beginning of the fusion of the palatine shelves and the formation of the secondary palate are also animated. The olfactory bulb deepens toward the olfactory mucosa. The appearance of the cartilaginous lamina cribrosa is animated in an approximately 8-week-old fetus. The next sequence covers the period up to the 9th week, during which the mitral cells appear within the olfactory bulb. At the same time, the ethmoid and sphenoid cartilages and the hard and soft palate develop with the nasal conchae. The last diagram of the sequence details several other structures.

In order to follow the histogenesis of the olfactory epithelium, the olfactory placode of a 4-week-old embryo is illustrated. In the next sequence, the olfactory placode, together with the prosencephalic neuroepithelial layer, is cut out and observed under high magnification. The diagram shows the stratified squamous epithelium of the olfactory placode, the mesenchyme and, the wall of the prosencephalon. In a 5-week-old embryo, the placodal epithelium transforms into the pseudostratified olfactory epithelium, which is composed of neuroblasts, supporting cells, and basal cells. The precursors of the Schwann cell migrate in the region of the olfactory placode. At the beginning of the 6th week, the axons of the olfactory cells grow toward the prosencephalon, and their axons invaginate into the cytoplasm of the Schwann cells. In a 6-week-old embryo, each Schwann cell forms an olfactory nerve fibre with the axons of the olfactory cells in its cytoplasm. The penetration of the olfactory nerve fibres into the wall of the prosencephalon near the mitral cells is animated in a 7-week-old embryo. During the next 7 weeks, up to an approximately 14-week-old fetus synaptic contact is established between the olfactory axons and the dendrites of mitral cells (i.e. formation of the glomeruli). In addition, the development of the lamina cribrosa is shown. In an approximately 16-week-old fetus, the olfactory tract forms by the axons of the mitral cells, and the ventricle of the olfactory bulb is obliterated. The last sequence animates the use of the olfactory organ.

(This animation is essential for students of medicine, stomatology, veterinary medicine, and biology as well as for departments of anatomy, histology, embryology, physiology, and cell biology; it is also recommended for departments or clinics of otorhinolaryngology, neurology and neuroscience, and brain research institutes.)