Table 1.
Description of the macroscopic and microscopic aspects of the temporal bone of Corriedale sheep (n=8)
| Element | Macroscopic aspects | Microscopic aspects |
|---|---|---|
| External ear canal epithelium | Skin | Keratinized stratified squamous cells |
| Middle ear epithelium | Mucosa | Simple squamous epithelium with mucous producing cells |
| Tympanic bulla epithelium | Mucosa in a broad and smooth cavity | Simple ciliated epithelium with mucous producing cells |
| Mastoid cells | Trabeculation | Filled up by fat and hematopoietic tissue |
| Type of ossicle classification and otic capsule | Compact bone | Endochondral bone tissue |
| Cochlea | Has a snail shape with 2.5 turns | Bone tissue in three slides |
| Scala vestibuli | Present in a triangular shape | Membranous bone tissue |
| Scala media (cochlear duct) | Triangular shape | Coated by the stria vascularis, organ of Corti and mesothelial cells |
| Reissner membrane | Tilted portion of the scala media | Membranous bone tissue coated with simple squamous cell epithelium |
| Basement membrane | Horizontal portion of the scala media | Layers of connective tissue and extracellular matrix |
| Tectorial membrane | Horizontal direction on the organ of Corti | Amorphous/jelly structure, similar to the macula |
| Scala tympani | Membranous bone tissue | |
| Round window/Round window membrane | Depression on the scala tympani at the level of the middle ear | Connective-epithelial membrane |
| Oval window/oval window niche/oval window membrane | Vestibuli depression | Connective-epithelial membrane |
| Pyramidal eminence | Hole in the posterior wall of the tympanic cavity | Endochondral bone tissue |
| Stapes muscle/stapes muscle tendon | Bony groove on the tympanic cavity posterior wall/muscle tendon | Skeletal muscle fibers/fibro-elastic connective tissue |
| Tensor tympani muscle/tensor tympani muscle tendon | From the cochleariform process to the malleus | Skeletal muscle fibers/fibro-elastic connective tissue |
| Annular ligament | Fibrous tissue separating the stapes footplate from the stapes on the oval window | Fibrous tissue of mesenchymal origin |
| Utriculus | In contact with the semicircular canals | Simple squamous cell epithelium with a thin layer of connective tissue |
| Saccule | In contact with the cochlear duct | Simple squamous cell epithelium with a thin layer of connective tissue |
| Organ of Corti | Standard shape | Deiter cells, Hensen cells, hair cells, internal and external sulcus cell, Claudius cells |
| Auditory tube (bony portion) | Long and narrow bony portion without relation with the internal carotid which opens up in the bulla | The mucosa coating its lumen is made up of low ciliated columnar epithelium |
| Auditory tube (cartilaginous portion) | Broad and extensive | Pseudo-stratified epithelium, columnar ciliated and more abundant globus cells |