Fruiting spike of a cereal plant especially corn; SYN. spike, capitulum.
Organ of hearing in animals. It responds to the vibrations that constitute sound, and these are translated into nerve signals and passed to the brain. A mammal’s ear consists of three parts: outer ear, middle ear, and inner ear. The outer ear is a funnel that collects sound, directing it down a tube to the ear drum (tympanic membrane), which separates the outer and middle ears. Sounds vibrate this membrane, the mechanical movement of which is transferred to a smaller membrane leading to the inner ear by three small bones, the auditory ossicles. Vibrations of the inner ear membrane move fluid contained in the snail-shaped cochlea, which vibrates hair cells that stimulate the auditory nerve connected to the brain. Three fluid-filled canals of the inner ear detect changes of position; this mechanism, with other sensory inputs, is responsible for the sense of balance.
When a loud noise occurs, muscles behind the eardrum contract automatically, suppressing the noise to enhance perception of sound and prevent injury.
1. The sense organ for hearing and equilibrium.
2. Good hearing.
3. Attention to what is said.
To form ears in growing