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ENT
Ear Applied Anatomy and Physiology
Built from Behrbohm — Ear, Nose and Throat Diseases with Head and Neck Surgery
What’s inside
17 sections · 99 slides
Overview
- What this deck will teach you
How the Ear Forms
Embryology explains why parts belong together
- Three tissue origins build one organ
- Where the three tiny hearing bones come from
- Development of the external ear from six hillocks
- How the ear canal, middle ear and labyrinth develop
- Why the embryology matters clinically
The Layout of the Ear
One peripheral sensor, one central pathway
- Two big divisions: peripheral and central
- Overview: the three sections of the ear
The External Ear
Collecting and channelling sound safely
- The auricle: an elastic-cartilage funnel
- Surface landmarks of the auricle
- The ear canal: a curved, self-cleaning tunnel
- Nerves and neighbours of the canal
The Middle Ear
An air-filled bridge that boosts sound
- The eustachian tube: the pressure-equalising valve
- The three floors of the middle ear cavity
- The three levels of the middle ear cavity
- The tympanic membrane: a tuned drumskin
- The normal eardrum and its four quadrants
- Microscopic layers of the eardrum
- The ossicular chain: three bones, one lever
- Medial view of the ossicular chain and facial nerve
- How the ossicular chain pivots
- The mucosa lining: a thin, reactive skin
- Blood, veins and referred pain
- Danger relationships around the middle ear
The Mastoid Air-Cell System
Why aeration decides ear health
- The mastoid: a honeycomb of air cells
- Pneumatisation as a health readout
- The pneumatic air-cell system of the temporal bone
- Two mastoids, two risk patterns
The Inner Ear (Labyrinth)
Two sensors sharing one fluid maze
- Two sensors in one bony maze
- Two fluids that must not mix: perilymph vs endolymph
- The membranous labyrinth and vestibular apparatus
The Balance Organ
Detecting straight-line and turning motion
- Two motion detectors: maculae and cristae
- The static macula and its otolith crystals
- The cupula: a swinging door for spinning
- The receptor inside a semicircular canal
- The ampulla of a semicircular canal
- How head rotation deflects the cupula
The Cochlea
A spiral piano that sorts sound by pitch
- Three fluid canals coiled in a spiral
- Cross-section through the coiled cochlea
- The organ of Corti: where sound becomes signal
- The cochlear duct and organ of Corti
- Rows of hair cells under the microscope
- Tonotopy: a place for every pitch
How Hearing Works
From air waves to a nerve impulse
- Four jobs, four parts
- Impedance matching: why the middle ear amplifies
- Stimulus transport: matching air to fluid
- Two routes for sound: air and bone
- Stimulus distribution: the travelling wave
- The travelling wave along the basilar membrane
- The tonotopic map of the basilar membrane
- Transduction: opening ion gates by pulling strings
- Hair-cell transduction and the cochlear amplifier
- Transformation and otoacoustic emissions
The Hearing Pathway to the Brain
Coding sound and carrying it up
- From cochlea to cortex
- The afferent auditory pathway
- How the brain codes loudness and pitch
- Coding cues for directional hearing
The Balance Pathway to the Brain
Wiring for posture, gaze and orientation
- The vestibular nerve and its central reach
- Central vestibular connections in the brainstem
The Facial Nerve
A close and vulnerable neighbour in the temporal bone
- What the facial nerve carries
- Its winding path and two bends (genu)
- The course of the facial nerve fibres
- Why the surgeon respects its sheath
When Hearing Fails
Three levels of loss, three signatures
- Conductive vs sensorineural loss
- Central disorders: hearing without understanding
- Recruitment: a fingerprint of cochlear damage
How Balance Works
Three senses fused into one sense of position
- Balance is a team of three senses
- Inputs and outputs of the vestibular nuclei
- The resting discharge: one cell, both directions
- Vestibular hair-cell response to cilia bending
- Otolith organ: sensing straight-line motion
- Semicircular canals and the vestibulo-ocular reflex
When Balance Fails
Vertigo, imbalance, and how the brain heals
- How vestibular disorders show themselves
- Why a sensor mismatch causes dizziness
- How orientation and balance break down
- Central compensation: the brain's self-repair
- The oculomotor control system
Putting It All Together
The whole ear in one view
- The hearing story in one slide
- The balance story in one slide
- Why is bone conduction better than air conduction in conductive hearing loss?
- What makes recruitment a sign of a cochlear (not retrocochlear) lesion?
- Ear, Nose, and Throat Diseases: With Head and Neck Surgery