295
2.2 Embryology and Early Development of the Auditory
System
Auditory structures, like other sensory systems, arise early during development
through a process closely linked with and infl uenced by the forming of the central
nervous system and mesoderm of the embryo (Fig. 2 ). The fi rst major event in the
development of the inner ear is the induction of the otic placode in the ectoderm of the
developing embryo. The otic placode then invaginates to form the otic pit and the subsequent closing of the otic pit forms the otocyst, which separates from the ectoderm.
The otocyst polarizes and differentiates into the various end organs of the auditory and
vestibular systems. Here we provide a brief review of these events in greater detail.
Fig. 2 Development of the brain and sensory organs in a fi sh embryo. NP—nasal placode, AP—
auditory (otic) placode, OC—optic cup, S—somites, OP—olfactory pit, F—forebrain, M—midbrain, H—hindbrain, L—lens, OtV—otic vesicle (redrawn from Berrill and Karp 1976 )
Development of Structure and Sensitivity of the Fish Inner Ear
2.2 Embryology and Early Development of the Auditory
System
Auditory structures, like other sensory systems, arise early during development
through a process closely linked with and infl uenced by the forming of the central
nervous system and mesoderm of the embryo (Fig. 2 ). The fi rst major event in the
development of the inner ear is the induction of the otic placode in the ectoderm of the
developing embryo. The otic placode then invaginates to form the otic pit and the subsequent closing of the otic pit forms the otocyst, which separates from the ectoderm.
The otocyst polarizes and differentiates into the various end organs of the auditory and
vestibular systems. Here we provide a brief review of these events in greater detail.
Fig. 2 Development of the brain and sensory organs in a fi sh embryo. NP—nasal placode, AP—
auditory (otic) placode, OC—optic cup, S—somites, OP—olfactory pit, F—forebrain, M—midbrain, H—hindbrain, L—lens, OtV—otic vesicle (redrawn from Berrill and Karp 1976 )
Development of Structure and Sensitivity of the Fish Inner Ear