HISTOLOGY REVIEW Eye and Ear Dr. Tim Ballard Department of Biology and Marine Biology

Structures of the eye Eyeball (anterior) – section – H&E – 4x objective conjunctiva posterior cavity ciliary body ciliary processes posterior chamber cornea iris anterior chamber lens The dashed lines indicate the locations of the suspensory ligaments connecting the ciliary processes to the capsule around the perimeter of the lens.

Structures of the eye Eyeball (anterior) – section – H&E – 4x objective conjunctiva iris cornea pupil lens anterior chamber The dashed line indicates the location of the pupil, located between the anterior-most margins of the iris.

Structures of the eye Eyeball (posterior) – section – H&E – 10x objective retina choroid sclera posterior cavity The brown-black pigments of the choroid are melanin granules. Go back to the previous two slides and follow this pigment into the iris.

Structures of the eye Retina – section – H&E – 40x objective pigmented epithelium choroid layer of rods and cones outer nuclear layer outer plexiform layer inner nuclear layer inner plexiform layer ganglion cell layer optic nerve fibers Plexiform layers are areas of synapses between adjacent neuronal types.

petrous portion of the temporal bone Structures of the ear Cochlea – longitudinal section – H&E – 4x objective petrous portion of the temporal bone bony cochlea modiolus vestibule The cochlea is a coiled structure, turning 2.75 times about a central axis (the modiolus). So, you see the same tube multiple times in the same structure.

Structures of the ear Cochlea – longitudinal section – H&E – 10x objective scala vestibuli scala media (cochlear duct) vestibular membrane spiral organ of Corti tectorial membrane (torn free) basilar membrane scala tympani spiral ganglion During histological processing the delicate tectorial membrane breaks free from its attachment and curls back on itself.

scala media (cochlear duct) Structures of the ear Cochlea – longitudinal section – H&E – 40x objective scala vestibuli scala media (cochlear duct) vestibular membrane spiral organ of Corti tectorial membrane basilar membrane scala tympani The spiral organ consists of hair cells, the stereocilia of which are embedded in the overlying tectorial membrane, and support cells. end