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Each Haversian canal generally contains one or two capillaries and many nerve fibres. The channels are formed by concentric layers called lamellae , which are approximately 50 μm in diameter . The Haversian canals surround blood vessels and nerve cells throughout bones and communicate with osteocytes (contained in spaces within the dense bone ...
The single canal found in hagfish appears to be secondarily derived. Additionally, the vestibular systems of lampreys and hagfish differ from those found in other vertebrates in that the otolithic organs of lampreys and hagfish are not segmented like the utricle and saccule found in humans, but rather form one continuous structure referred to ...
Each osteon consists of concentric layers, or lamellae, of compact bone tissue that surround a central canal, the Haversian canal. The Haversian canal contains the bone's blood supplies. The boundary of an osteon is the cement line. Each Haversian canal is surrounded by varying number (5-20) of concentrically arranged lamellae of bone matrix.
The ear canal of the outer ear is separated from the air-filled tympanic cavity of the middle ear by the eardrum. The middle ear contains the three small bones—the ossicles —involved in the transmission of sound, and is connected to the throat at the nasopharynx , via the pharyngeal opening of the Eustachian tube .
The outer ear funnels sound vibrations to the eardrum, increasing the sound pressure in the middle frequency range. The middle-ear ossicles further amplify the vibration pressure roughly 20 times. The base of the stapes couples vibrations into the cochlea via the oval window , which vibrates the perilymph liquid (present throughout the inner ...
Hearing loss is often secondary to absent, small or unusually formed ears and commonly results from malformations of the middle ear. Researchers have found that most patients with Treacher Collins syndrome have symmetric external ear canal abnormalities and symmetrically dysmorphic or absent ossicles in the middle ear space.
The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates , the inner ear is mainly responsible for sound detection and balance. [ 1 ] In mammals , it consists of the bony labyrinth , a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts: [ 2 ]
The stapes (stirrup) ossicle bone of the middle ear transmits vibrations to the fenestra ovalis (oval window) on the outside of the cochlea, which vibrates the perilymph in the vestibular duct (upper chamber of the cochlea). The ossicles are essential for efficient coupling of sound waves into the cochlea, since the cochlea environment is a ...