BALANCE
1. SEMI-CIRCULAR CANALS:
- sensitive to movement of head
- lie in three planes (90 degrees to each other) enables them to record movement in
any direction
- cristae: groups of sensory hairs —> occur in ampulla at base of canals
- hairs embedded in jelly substance called cupula
- sudden head movements cause endolymph to flow around semicircular canals and
cause capula to bend
- sensory hairs in ampulla stimulated
- stimulus changed to nerve impulse and carried to cerebellum via auditory nerve
2. SACCULUS AND UTRICULUS
- react according to head position relative to gravity
- maculae: groups of sensory hairs embedded in jelly substance that occur in sacculus
and utriculus
- jelly substance: contains calcium carbonate granules called otoliths which rest on hairs
- pressure that otoliths exert on sensory hairs due to gravity’s force is effected by
changes in head position
- change in pressure cause hair cells to be stimulated
- stimulus changed to nerve impulse and carried to cerebellum via auditory nerve
1. SEMI-CIRCULAR CANALS:
- sensitive to movement of head
- lie in three planes (90 degrees to each other) enables them to record movement in
any direction
- cristae: groups of sensory hairs —> occur in ampulla at base of canals
- hairs embedded in jelly substance called cupula
- sudden head movements cause endolymph to flow around semicircular canals and
cause capula to bend
- sensory hairs in ampulla stimulated
- stimulus changed to nerve impulse and carried to cerebellum via auditory nerve
2. SACCULUS AND UTRICULUS
- react according to head position relative to gravity
- maculae: groups of sensory hairs embedded in jelly substance that occur in sacculus
and utriculus
- jelly substance: contains calcium carbonate granules called otoliths which rest on hairs
- pressure that otoliths exert on sensory hairs due to gravity’s force is effected by
changes in head position
- change in pressure cause hair cells to be stimulated
- stimulus changed to nerve impulse and carried to cerebellum via auditory nerve
