Ear
- Introduction
• The ear is the sensory organ responsible for hearing and balance.
• It is anatomically divided into three parts: outer ear, middle ear, and inner ear.
• Converts sound waves into electrical signals and helps maintain equilibrium. - Structure of the Ear
A. Outer Ear (External Ear)
• Pinna (Auricle): visible part made of cartilage covered by skin; collects sound waves.
• External Auditory Canal: curved tube running from pinna to the tympanic membrane; contains ceruminous glands producing earwax to trap dust and protect ear.
• Tympanic Membrane (Eardrum): thin membrane vibrating in response to sound waves; separates outer and middle ear.
B. Middle Ear
• Air-filled cavity located in the temporal bone.
• Contains three tiny bones (ossicles) that amplify sound:
• Malleus (Hammer): attached to the tympanic membrane.
• Incus (Anvil): connects malleus and stapes.
• Stapes (Stirrup): smallest bone, attached to the oval window of the cochlea.
• Eustachian Tube: connects middle ear to the throat (nasopharynx); equalizes air pressure on both sides of tympanic membrane for proper hearing.
C. Inner Ear
• Contains the bony labyrinth, consisting of:
• Cochlea: spiral-shaped organ responsible for hearing.
• Vestibule: central part involved in balance.
• Semicircular Canals: three loops oriented in different planes to detect head rotation and maintain equilibrium.
• The membranous labyrinth lies within the bony labyrinth, containing fluid (endolymph and perilymph).
• The cochlea converts vibrations into nerve impulses carried to the brain by the auditory nerve. - Functions of the Ear
• Hearing: Sound waves collected by pinna travel through auditory canal, vibrate tympanic membrane, transmitted by ossicles to cochlea where hair cells convert vibrations to electrical signals.
• Balance: Vestibular apparatus (vestibule and semicircular canals) detects head movement and position to maintain posture and balance.
• Pressure Regulation: Eustachian tube equalizes pressure in middle ear, preventing damage to ear structures. - Common Ear Disorders
• Otitis Media: middle ear infection causing pain and hearing loss.
• Tinnitus: ringing or buzzing in the ears.
• Hearing Loss: may be conductive (outer/middle ear) or sensorineural (inner ear damage).
• Vertigo: sensation of spinning/dizziness due to inner ear balance problems.
• Earwax Impaction: excessive buildup blocking ear canal. - Nursing Care and Considerations
• Assess hearing and balance regularly.
• Assist with cleaning and protection of ear (avoid inserting objects).
• Educate on preventing infections (keep ears dry, manage upper respiratory infections).
• Support patients with hearing aids or therapy.
• Monitor post-operative care for ear surgeries.
• Recognize signs of ear infections and complications. - Summary for Quick Review
The ear is divided into outer (collects sound), middle (amplifies sound), and inner ear (hearing and balance). Sound waves move through the outer ear and eardrum, transmitted by ossicles to cochlea, where signals are sent to the brain. The vestibular organs in the inner ear maintain balance. Nursing care involves assessment, education, and infection prevention.