Biomaterial Database

The efferent innervation of the avian cochlea. 1983

W Firbas, and G Müller

The efferent auditory innervation of the budgerigar (Melopsittacus undulatus) was investigated by means of acetylcholinesterase staining. The course of the efferent fibres is described: the single terminal fibre regularly branches out to innervate several hair cells. Three types of efferent, axosomatic synapses could be distinguished: small outer hair cells bear large cup-like efferent synapses, intermediate hair cells with cone-shaped synapses, and tall inner hair cells with small, knob-like synapses. In the basal part of the cochlea the small hair cells with heavy efferent endings predominate, while in the apex only tall inner hair cells with small efferent terminals exist. There are more intermediate hair cells in the apical area than in the basal area.

UI	MeSH Term	Description	Entries
D009411	Nerve Endings	Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.	Ending, Nerve,Endings, Nerve,Nerve Ending
D009412	Nerve Fibers	Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.	Cerebellar Mossy Fibers,Mossy Fibers, Cerebellar,Cerebellar Mossy Fiber,Mossy Fiber, Cerebellar,Nerve Fiber
D009476	Neurons, Efferent	Neurons which send impulses peripherally to activate muscles or secretory cells.	Efferent Neurons,Efferent Neuron,Neuron, Efferent
D003051	Cochlea	The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.	Cochleas
D006198	Hair Cells, Auditory	Sensory cells in the organ of Corti, characterized by their apical stereocilia (hair-like projections). The inner and outer hair cells, as defined by their proximity to the core of spongy bone (the modiolus), change morphologically along the COCHLEA. Towards the cochlear apex, the length of hair cell bodies and their apical STEREOCILIA increase, allowing differential responses to various frequencies of sound.	Auditory Hair Cells,Cochlear Hair Cells,Auditory Hair Cell,Cell, Cochlear Hair,Cells, Cochlear Hair,Cochlear Hair Cell,Hair Cell, Auditory,Hair Cell, Cochlear,Hair Cells, Cochlear
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001717	Birds	Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.	Aves,Bird
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse