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A Handbook of Biology
Utricle & Saccule have a projecting ridge called macula.
Crista and Macula are specific receptors in vestibular apparatus. They
contain sensory hair cells. They are responsible equilibrium & posture of body.
MËÇHÅÑÏSM ØF HËÅRÏÑG
Pinna collects sound waves ® waves pass through ear ® relayed to
the tympanic membrane ® tympanic membrane vibrates ® vibrations
transmit to ear ossicles & oval window ® perilymph in the vestibular
canal vibrates ® vibrations reach the scala tympani and force the
basilar membrane to vibrate ® hair endings of sensory hair cells press
against tectorial membrane ® sensory hair cells are excited ® auditory
nerve carries impulses to auditory centre of the brain ® Hearing.
ÑØSË
01
Organ of smell (olfaction).
Bowman’s gland are the mucus glands that are
found below the olfactory membrane which
secretes mucus.
02
It contains mucus-coated receptors (olfactory
receptors) made up of olfactory epithelium. They
receive sense of smell. It contains 3 kinds of cells.
03
The neurons of olfactory epithelium extend from the
outside environment directly into a pair of broad
bean-sized organs, called olfactory bulb.
04
These are extensions of the brain’s limbic system.
05