Histología del Oído

General Overview of the Ear's Histology

• The ear, responsible for hearing and equilibrium, is composed of three primary sections: the outer ear, middle ear, and inner ear.
• Each section exhibits distinct histological characteristics tailored to its respective function.

Histology of the Outer Ear

• The auricle (pinna) is composed of elastic cartilage covered by skin.
• The skin contains hair follicles, sebaceous glands, and sweat glands.
• The cartilage provides structural support and flexibility to the pinna.
• The external auditory canal possesses skin with hairs and ceruminous glands (produce earwax).
• The skin transitions from thicker, hairy skin to thinner, non-hairy skin deeper within the canal.
• The deeper portion of the canal has a significant layer of glands that produce cerumen.

Histology of the Middle Ear

• The middle ear cavity is lined with a simple cuboidal epithelium.
• The tympanic membrane (eardrum) is composed of three layers:
  • Outer layer: Stratified squamous epithelium.
  • Middle layer: Loose connective tissue containing collagen and elastic fibers.
  • Inner layer: Simple cuboidal epithelium lining the middle ear cavity.
• The ossicles (malleus, incus, and stapes) are composed of compact bone, a dense structure for sound transmission.
• Tiny muscles (stapedius and tensor tympani) act to dampen sound intensity. These muscles are mostly skeletal muscle with supporting connective tissue.

Histology of the Inner Ear

• The inner ear, which contains the cochlea and vestibular apparatus, is a complex structure.
• The cochlea houses the spiral organ of Corti, responsible for hearing.
• The spiral organ consists of hair cells, supporting cells, and the basilar membrane.
• The hair cells contain stereocilia, which are essential for transducing sound vibrations into neural impulses.
• The vestibular system, comprising the semicircular canals, utricle, and saccule, is responsible for balance.
• The vestibular system is lined with special sensory epithelial cells (hair cells) embedded in the sensory maculae of the utricle and saccule.
• These hair cells are critical for detecting head position and movement, providing information for balance.
• The supporting cells in the inner ear maintain the structure and function of the sensory epithelium, acting like a framework.
• The walls of the inner ear are made of dense connective tissue, and the perilymph and endolymph fluids that fill the spaces within the cochlea and vestibular system are crucial for proper transmission of vibrations related to both hearing and balance.
• The membranous labyrinth is composed of a delicate structure of epithelial cells, providing protection and support for the intricate sensory receptors.

Sensory Epithelia

• Specialized sensory epithelial cells, such as hair cells of the cochlea and vestibular apparatus, convert mechanical stimuli (sound waves, head movements) into electrical signals.
• These specialized cells are crucial for the transduction of sensory information.

Neurovascular Tissue

• The ear also contains supporting blood vessels and nerves to nourish and innervate the various structures.
• Blood vessels deliver oxygen and nutrients, while nerves transmit signals from the sensory receptors to the brain.
• These components contribute to maintaining a functional and healthy auditory and vestibular system.