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Module 12 · Anatomy & Physiology I
Two cranial nervesNerves that arise from the brain and control head and neck functions., a cochlea and an eye under the same tide.
An eye she could not see out of at 34 — “her pressureThe force exerted by gases in the respiratory system, affecting airflow and gas exchange. is 75” — given a name and filed, and the same eye again at 39. Cold air on one side of her face at 38, and a neurologist with a name inside ten minutes. Restaurants where she can hear that people are talking and cannot catch the words, 2018. Two folders in a stack of ten — a neurologist’s and an audiologist’s — and neither doctor knew the other existed. Everything the course has sensed so far was general: a receptorA structure that detects stimuli. you could describe in a sentence, anywhere on the body. This module builds the five senses that need an organ of their own — taste, smell, vision, hearing, balance — and the twelve nerves that leave the brain without touching the cord, teaches each one properly, and then does the thing no one did in 2018: lays an eye, a face nerve, a cochlea and ten spared cables on one page beside the dates her markers were high.
The module’s question
Each special sense is a purpose-built organ, a dedicated receptor cell, a private cranial nerve and a named patch of cortex. When a patient has an eye whose drain keeps inflaming under a label, one sensory cranial nerve reporting a breeze as lightning and another losing its top octave, and ten others — including the one made of brain itself — documented normal, what does the pattern of what was spared tell you about the process that did the damage? And what does it mean that both findings arrived in the two years her CRP was up on every draw?
Module trailer · about 2 minutes
Two Nerves, One Neighborhood — narrated, with captions and a full text description.
The module trailer. Watch it first.
Animation · in production · 2 min
Two Nerves, One Neighborhood
Two minutes: an eye at 34, a face at 38, a restaurant at 43; twelve cables in a known order from known places; a flask of cellsThe basic structural and functional units of life. with a pore; a sense that skips the thalamusThe brain’s relay center, sending sensory information to the cerebral cortex.; a window, a lens and a shutter that is not yours; a retina wired backwards; five translations from air to nerve and the one tissue that keeps its damage; two sacs, three rings and a quiet half of a nerve — and a chart with ten normal lines, which is the only kind that can show you a change.
How every chapter works
- Animation (dark teal) — a short animated explainer, one idea each
- Slide (dark teal) — a still to study: a micrograph, a diagram or a map
- Explore (purple) — something to push on while you watch
- Game (purple) — a quick challenge
- Think (gold) — reason it out, then spot-check yourself with a few true/false questions; not graded
- Check (gold) — a quick H5P that scores itself
Read the chart and make a private prediction → the story → the scenes → sort your evidence → build your verdict → the finding. Nothing is graded, nothing is recorded, nothing is locked.
Where this module sits in Stina’s life
2009 · 34
“The Eye”: left eye, pressure 75; six drops; a week; named Posner-Schlossman and filed
Dec 2011 · 36
The Accident — the hinge the diary hangs the next five years on
2013 · 38
Cold air on one side of her face and it fires; a scarf, and the scarf sets it off too · trigeminal neuralgia, named in ten minutes
2014 · 39
“The Eye,” second attack — nine days, and the first time she says at work that something is wrong
Nov 2016 · 41
Fever of unknown origin: CRP and ESR up on every draw; gastro, oncology, infectious disease clear
2016–19 · 41–44
“Ten folders”: neurologist, audiologist, ENT among them
2018 · 43
Consonants gone in restaurants; birdsong gone · audiogram: early high-frequency sensorineural loss; ENT, “nothing to fix”
2020 · 45
Reading glasses, on schedule · MRI: white-matter spots, “more than expected for age” (The Brain)
2025 · 50
A posterior subcapsular cataract, left eye — the cost of sixteen years of attacks and steroid drops; the lens replaced
Mar 2026 · 50
The statin: “legs, headaches, eyes, dehydration” — stopped
Jun 2026 · 51
Dr. Y, cranial nerves I–XII: ten normal, V and the cochlear half of VIII not · Clue #12
Ochre = chart clue · Purple = diary entry.
The case this module reads
A left eye whose pressure reached 75 at 34, treated with six drops and given a name — Posner-Schlossman — that nobody ever put beside the fevers; it came back, years apart, and at 50 the lens pays for it. A face that reports a breeze as lightning since 2017, quieted by a drug that is not a painkiller. An audiogram at 43 that an audiologist called young for its shape. A ringing in quiet rooms. Both filed under two specialties and two kinds of bad luck, in the same two years a fever of unknown origin put her CRP up on every draw. And — examined in 2026 by someone who went through all twelve — smell, sight, taste, balance, facial movementA fundamental property of life involving motion of the body or its parts., the shrug and the tongue, all normal. Two sensory cranial nerves leaving the brainstemThe lower part of the brain that connects to the spinal cord and controls vital functions. at the edge of the ponsA part of the brainstem that connects the cerebrum to the cerebellum and helps regulate breathing., a finger’s width apart; ten left alone; and a calendar that matches the markers. This module teaches the organs well enough to say exactly what was spared, and exactly why neighbors is a finding.
Patient chart · Stina · Chart Clue #12
Nov 2016 · 41
FUO workup: CRP and ESR raised on every draw; the specialties begin to multiply
2013 · 38
Trigeminal neuralgia: paroxysmal, unilateral, electric, touch-triggered; exam normal between attacks; analgesics useless; carbamazepine effective
2018 · 43
Sensorineural hearing loss: symmetric high-frequency dip, air better than bone, drums intact; tinnitus; “earlier than age explains”
2009 · 34
The Eye: left eye, pressure 75, open angle, six drops; Posner-Schlossman; recurrent, treated attack by attack; the eye doctor’s label stays idiopathic
~2020 · 45
Presbyopia: reading glasses, the lens stiffening on everyone’s schedule
2020 · 45
MRI: periventricular and subcortical white-matter spots; nothing reported on the optic nerves, chiasm or trigeminal root (The Brain, 10.1)
Standing
IL-1β and IL-6 raised between attacks; no imaging of the cochlea or the trigeminal root ever; no cytokine ever measured in her inner ear
Jun 2026 · 51
Dr. Y, cranial nerves I–XII: I, II, III, IV, VI, VII, IX, X, XI, XII and the vestibular division of VIII normal; V abnormal by history; VIII cochlear division abnormal — Chart Clue #12 logged
Seven chapters, seven decisions
Each chapter opens on the chart and ends with a verdict you build from evidence. Work them in order — later chapters assume the cards you collected earlier.
1
12.1 Two Nerves, One Neighborhood
A face that reports a breeze as lightning and an ear that loses the consonants first are filed under two specialties and two kinds of bad luck. Before you can read them together you need what makes a special sense special — a purpose-built organ, a dedicated receptor cell, a private cable, a named patch of cortex — and the one habit this module insists on: a chart that writes down what is still normal, because that is the only chart that can ever show you a change.
You decide: two unlucky organs, or two neighbors?
5 animations · 0 slides · 5 things to explore · 10 quick checks · 1 verdict
2
12.2 Twelve Private Cables
Before Stina’s two nerves can be read as neighbors, you need all twelve: their order, where each emerges, whether it carries sensation, motor fibers or both, and which special sense rides which cable. Then the trigeminal in detail — three territories, a sensory ganglionA cluster of neuron cell bodies located in the peripheral nervous system (PNS). inside the skull, a root entry zone where myelin changes hands — and the physiologyThe study of how the body functions. of a nerve that starts to scream: allodynia, a demyelinated root, an excitable membrane, and a drug that works because it is not a painkiller.
You decide: a painkiller too weak, or a fault that is electrical?
4 animations · 1 slide · 5 things to explore · 10 quick checks · 1 verdict
3
12.3 The Chemical Senses
Five qualities on the tongue and thousands of odors behind the nose, assembled quietly into flavor. For each chemical sense you need the four items — receptor, nerve, route, cortex — and then the two places the textbooks are usually wrong: there is no tongue map, and the cells that taste are not neuronsThe functional cells of the nervous system that transmit signals.. Then the one sense with a private road into the limbic systemA group of brain structures responsible for emotions and memory., and what a normal line on her exam buys the reading of the two that are not.
You decide: nothing to record, or two senses whose normal is a finding?
4 animations · 1 slide · 5 things to explore · 10 quick checks · 1 verdict
4
12.4 The Eye
Light has to cross a cornea, a watery humor, a lens and a gel before it reaches anything that can see it, and the sphere only holds its shape because a fluid is made and drained at the same rate. What is in the orbit and what aims the eye; what the three layers of the wall are; where the aqueous humor comes from, where it leaves, and what happens to the optic nerve when it cannot; why a lens rounds on command at 20, stiffens at 45 and clouds at 50; and why six eye drops in one bottle bag are a tour of the receptor table from Module 11 — and of the heart, the airways and the blood pressure they can reach on their way out through the nose.
You decide: a drain that clogged, a syndrome with a name — or a label that stopped the question?
4 animations · 1 slide · 5 things to explore · 10 quick checks · 1 verdict
5
12.5 The Retina
To read a visual pathway you need the retina in layers — which cell is where and why the arrangement is inverted — rods against cones in numbers, place and pigment, the molecular trick that turns a photon into less transmitter rather than more, the relay from photoreceptor to the ganglion cell that owns the first spike, and then the optic nerve to chiasm to tract to thalamus to occipital lobeThe brain region responsible for visual processing., with the one rule that decides which half of the world lands on which side of the brain.
You decide: vision spared by luck, or a process that works elsewhere?
5 animations · 0 slides · 5 things to explore · 10 quick checks · 1 verdict
6
12.6 Sound Becomes Signal
Build the chain first and then break it. The outer and middle ear and the trick the ossicles do with pressure; the cochlea past the oval window, its three ducts and the membrane that sorts sound by place; the hair cell and the stereocilia that open channelsProtein passages in the cell membrane that allow specific molecules to pass through. when they bend; the road up the brainstem to the temporal lobeThe brain region responsible for processing sound and memory.. Then the audiogram: conductive against sensorineural, why the high notes go first, why hair cells are a one-way door, and what a slow inflammatory disease can and cannot be said to do in an inner ear.
You decide: a blocked ear, or hair cells at the baseA substance that accepts hydrogen ions (H⁺) or releases hydroxide ions (OH⁻). that do not come back?
5 animations · 0 slides · 5 things to explore · 10 quick checks · 1 verdict
7
12.7 Balance, and Chart Clue #12
The vestibular apparatus: maculae with otoliths for linear acceleration and tilt, cristae in ampullae with cupulae for rotation, and a nerve whose traffic goes mostly to the cerebellumThe brain region responsible for balance, coordination, and fine motor control. and the eye-movement nucleiClusters of neurons in the CNS responsible for processing information. rather than to the cortex. Then the clue: what it means that the vestibular half of VIII is intact beside a failing cochlear half, what it means that ten nerves and three senses are spared, and what a face pain that rises and falls with a lab value, and a hearing loss that arrived in the years the lab value was high, are telling you about which story they belong to.
You decide: two coincidences, or two cranial nerves, a cochlea and an eye under the same tide?
5 animations · 0 slides · 5 things to explore · 10 quick checks · 1 verdict
12.8 · Conclusion and Assessment
The module verdict, then everything to practice
12.9 · The Evidence Behind the Case
Check our reasoning against the literature
Stina’s diary
The entries behind this module
“Fever of unknown origin” (41) · “Ten folders” (41–44) · “The statin” (50) · “Every page” (51)
The original lectures and histology
Three decks, one evidence page, the cranial-nerve glossary
The three Module 11 senses decks on bettybroadbent.com — The Special Senses and Cranial Nerves, The Fading Sound (sensorineural hearing loss) and A Stab in the Face (trigeminal neuralgia) — move here with their slides and transcripts (their speaker notes, with the rotation fixed, are the voice of this module), as do the live 11.4–11.6 pages, Activities 06–12 and the 11.9 validity note. This module has no mini-lecture videos of its own: the textbook A&P 2e §14.1, §14.2, §13.4 and §16.3 are the authority for values, and anything added beyond them is marked where it appears. The Nervous Tissue glossary and flashcard sets (12137; 8884) carry the sensory-receptor terms; the Brain hub’s Pons and Medulla pages carry the cranial-nerve nuclei.
By the end you can
- Distinguish the general from the special senses, classify receptorsProteins located on the surface or inside cells that bind specific molecules (e.g., neurotransmitter by location, cell type and stimulus, and for each of the five special senses name the receptor, the cranial nerve, the route and the cortex — the four-item grid.
- List the twelve cranial nerves in order with their origins (forebrain, midbrainThe upper portion of the brainstem involved in visual and auditory processing., pons, medulla), sort them as sensory, motor or mixed, and map the trigeminal’s three divisions, its ganglion and its root entry zone — then explain trigeminal neuralgia as a use-dependent sodium-channel problem rather than a tissue problem.
- Describe taste buds and papillae, the two transduction mechanisms for five qualities, the three taste nerves and the gustatory pathway to the insulaA deep brain region involved in taste, emotions, and visceral functions.; describe the olfactory epithelium, the cribriform plateHorizontal part of ethmoid with many tiny holes for olfactory nerves; beside crista galli., bulb and tract, why smell bypasses the thalamus, why olfactory neurons regrow, and why flavor is mostly smell.
- Identify the accessory structures of the eye, the six extraocular muscles and their three nerves (LR6SO4) and the three tunics; trace the aqueous humor from the ciliary processes through the trabecular meshwork and explain intraocular pressure, glaucoma and a Posner-Schlossman attack as a drain inflaming; explain accommodation, presbyopia and a steroid/inflammatory cataract; and read six eye drops off the autonomic receptor table — including the heart, airway and blood-pressure effects they reach through the nasolacrimal duct.
- Describe the inverted retina, rods against cones in number, place, pigment and wiring, photoisomerization and why photoreceptors are depolarized in the dark, the three-cell relay, the optic chiasm rule and the visual pathway to the occipitalPosterior and base of the skull; curves under to form the back of the head. lobe, with the field defects each lesion predicts.
- Trace sound from auricle to auditory cortex: ossicles and impedance matching, the three scalae, the basilar membrane’s tonotopy (20 kHz at the base, 20 Hz at the apex), hair-cell mechanotransduction, the central auditory pathway, and conductive against sensorineural loss on an audiogram with the Rinne and Weber tests.
- Explain the maculae with otoliths (tilt, linear acceleration) and the ampullae with cupulae (rotation), the vestibular nuclei’s four outputs and the vestibulo-ocular reflex — and read Chart Clue #12: two specific addresses a slow inflammation can reach, ten nerves spared, a calendar that matches the markers, and an evidence page that says which parts are measured and which are read.
Reliable information on rare diseases
NORD · NIH GARD · Orphanet · MedlinePlus Genetics: FMF · FMF & AID Global Association · Autoinflammatory Alliance · Global Genes · Amyloidosis Foundation
Stina has one rare disease. In the United States, about 1 in 10 people live with one of the more than 7,000 known rare diseases. These organizations are where patients, families and clinicians go for trustworthy information.
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All Modules
- Anatomical Language, Membranes & Homeostasis
- Just Enough Chemistry
- The Cell & Its Transport
- Making Cells & Proteins
- The Integumentary System
- The Skeletal System
- The Muscular System
- Nervous Tissue & the Senses
- The Spinal Cord
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- The Autonomic Nervous System
- The Special Senses
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- Fluids, Electrolytes & Acid–Base Balance
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List of terms
- cranial nerves
- pressure
- receptor
- cells
- thalamus
- movement
- brainstem
- pons
- ganglion
- physiology
- neurons
- limbic system
- occipital lobe
- channels
- temporal lobe
- base
- cerebellum
- nuclei
- receptors
- midbrain
- insula
- cribriform plate
- occipital