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Module 5 · Anatomy & Physiology I
Her skinThe body’s largest organ, providing protection and regulation. turned into a map.
Paintbrush spots in first grade, ‘chicken pox twice’ in second, shins like the stove after the fitness-test mile, a lobster sunburn and two days of fever, a gym class that left her soaked, teardrops six weeks after strep at seventeen and again at thirty-seven, eczema and sterile pustules the summer she buried her mother — and in 2026 a dermatologist who typed ‘patient reports prior history of psoriasis’ and another who said ‘you must be so relieved’. This module builds the skin in anatomy’s own words — layers and tissues, strata and belt, dermisThe thick inner layer of the skin that contains blood vessels, nerves, and connective tissue. and plexuses, glands, hair and nailsHard, keratinized structures that protect the fingertips and enhance fine motor skills., melaninA brown-black pigment made by melanocytes in the stratum basal and given to keratinocytes as melanos and the solar panel — reads each rash as the structure that made it, and then lays the whole chart on one page: six names, one fire. Chart Clue #5.
The module’s question
The skin is the one organ a patient can see and a clinician can read without a test. When one patient collects six skin diagnoses over forty-five years, each on a fever’s schedule, which structure made each one — a belt, a barrier, a vessel, a gland, a thermostat — and what does it mean that every one of them was answering the same signal?
Module trailer · about 2 minutes
Six Names, One Organ — narrated, with captions and a full text description.
The module trailer. Watch it first.
Animation · in production · 2 min
Six Names, One Organ
Two minutes: nine pounds of organ in three tissues, a belt that takes a month, pus with nobody to fight, shins that were the opposite of poor circulation, a cardigan in September, a lobster and a loaded gun, two ways to break one belt — and a billboard on a highway with the business somewhere else.
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
1977 · 2
First fever after a sunburn · Clue #1
1981 · 6
Paintbrush spots · ‘eczema, or the soap’
1982 · 7
‘Chicken pox twice’ · the shore
1983 · 8
Dr. Gonzalez · the nail folds and the calendar
1985 · 10
The mile · shins like the stove
1992 · 17
Strep → teardrops → shingles · leaves school
2010 · 35
Eczema + sterile pustules · the cardigan
2026 · 50–51
‘Prior history’ · FMF named · ‘so relieved’ · Clue #5
Ochre = chart clue · Purple = diary entry.
The case this module reads
Six years old, red spots like a flicked paintbrush that itch and then burn, a cool wall to lean on, a fever by supper, ‘eczema or maybe the soap’. Seven, ‘chicken pox twice’ before Christmas, hidden from a mother in surgery; a sunburn at the shore and two days of fever. Eight, one doctor who pushed back her cuticles under a lamp, asked to see the spots, asked who else in the family got fevers, and wanted a calendar. Ten, the fitness-test mile and shins by supper hot like the stove with a dent that stayed — ‘some kids will do anything to get out of gym’. Eleven to fifteen, soaked and shaking after gym; heat she could not stand. Seventeen, strep in October, hundreds of red teardrops in December, shingles in January, forty-one days missed, a signature on a withdrawal form: ‘my skin turned into a map, and nobody once asked what kind of person gets all three in a row’. Thirty-five, teaching with ibuprofen on a schedule and a cardigan in September; the psoriasis fades and eczema and sterile pustules arrive; three creams. Thirty-seven, strep and the teardrops again; a contract not renewed. Fifty, ‘What makes you think that was psoriasis?’ Fifty-one, ‘You must be so relieved.’
The skin chart this module reads
Age 6
Recurrent red papules, abdomen and arms, itch → burn, with fevers · ‘eczema / soap’
Age 7
Pus-topped tender papules with fever, ×2 · ‘chicken pox twice’ · later biopsy: dense dermal neutrophils, no organisms
Age 7
Severe sunburn → 2 days fever and vomiting · ‘the sunburn’ (and the first fever at 2, Clue #1)
Age 10
Bilateral pretibial erythemaRedness of the skin due to increased blood flow, often caused by heat, infection, or inflammation., hot, pitting, after exertion, 48–72 h · ‘growing pains’ / later ‘cellulitis’, ‘poor circulation’
Ages 11–35
Heat intolerance, drenching sweats, fever hidden with ibuprofen and a cardigan
Ages 17, 37
Post-streptococcal guttate psoriasis, two episodes, six weeks after swab-positive strep
Age 35
Eczema (hands, flexures) + sterile pustules in a feverish week; psoriasis in remission
2026
‘Patient reports prior history of psoriasis’ · FMF named 11 May · ‘you must be so relieved’
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
5.1 The Paintbrush Spots
A rash is the one finding a patient can see for themselves and a clinician can read without a test. Before you can read Stina’s, you need the organ itself: its layers and tissues, its seven jobs, and why a sunburn, a soap and a fever can all write on the same page.
You decide: is a rash that burns and comes with a fever a skin disease, a soap, or the organ reporting?
4 animations · 1 slide · 5 things to explore · 10 quick checks · 1 verdict
2
5.2 October to February
The epidermisThe outermost layer of the skin, made of stratified squamous epithelium. is a conveyor belt: born in the stratum basaleThe deepest layer of the epidermis, where new skin cells are formed., dead and shed from the stratum corneumThe outermost layer of the epidermis, consisting of dead, keratinized cells. a month later. Before you can say what psoriasis is, you need the belt at normal speed — its layers, its cellsThe basic structural and functional units of life., where its cells die — so that “too fast” means something you can see.
You decide: were the teardrops the germ, the medicine, or an immune system taught something?
4 animations · 1 slide · 5 things to explore · 10 quick checks · 1 verdict
3
5.3 Chicken Pox Twice
Pus is the one finding everybody reads the same way: infection. Before you can say what a sterile pustule is, you need the dermis and its vessels, the neutrophil that climbs out of a vessel, and what pus actually is — so that “no organisms” on a pathology report becomes the loudest line on the page.
You decide: is pus with no germ an infection the lab missed, or neutrophils the body called?
5 animations · 1 slide · 6 things to explore · 12 quick checks · 1 verdict
4
5.4 Shins Like the Stove
The skin is the one organ whose blood supply you can read from across a room. Before you can say what a hot red shin after a run means, you need the dermal circulationThe vascularization of the dermis of skin. Two capillary plexuses vascularize the dermis: subpapilla, the three pigments that color it, the nerves that make it hurt — and the difference between a red shin with a germ in it and one without.
You decide: are hot red swollen shins poor circulation, an infection, or inflamed vessels?
4 animations · 1 slide · 5 things to explore · 10 quick checks · 1 verdict
5
5.5 Soaked and Shaking
Hair, nails and glands all grow from the same epithelial bud, and all of them report. Before you can read a sweat-soaked gym class, a cardigan in September, or a nail under a lamp, you need the two kinds of sweat gland and what runs them, the oil gland and what plugs it, the hair and its cycle, and the nail and the matrix that makes it.
You decide: was the sweat nerves, bad conditioning, or a thermostat set high?
4 animations · 1 slide · 5 things to explore · 10 quick checks · 1 verdict
6
5.6 The Lobster
Melanin is a shield and a shade at once: it keeps UV off the DNA and keeps UV off the molecule that makes vitamin D. Before you can say what a sunburn did to a seven-year-old, you need the melanocyte and what it hands upward, the three pigments, the cancers that follow UV, and the one hormone the skin starts and the liverA large organ that produces bile, detoxifies blood, and stores nutrients. and kidney finish.
You decide: did the sunburn make her sick, or pull a trigger?
5 animations · 0 slides · 5 things to explore · 10 quick checks · 1 verdict
7
5.7 Five Rashes, One Fire
Psoriasis and eczema look like opposites and are confused all the time, even by clinicians. Before you can say how one skin carries both, you need the barrier and the belt as two ways to break one conveyor, the phases of healing and the one that will not hand off — and then a lifetime of rashes read as one sentence.
You decide: six skin diseases, or one fire with six windows — Chart Clue #5?
4 animations · 1 slide · 5 things to explore · 10 quick checks · 1 verdict
5.8 · Conclusion and Assessment
The module verdict, then everything to practice
5.9 · The Evidence Behind the Case
Check our reasoning against the literature
Stina’s diary
The entries behind this module
Read the diary entries this module rests on — ‘First grade’, ‘Second grade’, ‘The shore’, ‘The doctor who looked’, ‘The fitness test’, ‘October to February’, ‘Nobody can tell’, ‘Teardrops’, ‘Prior history’, ‘The dermatologist’ — in Relief Is Not the Word.
The original lectures and histology
The original mini-lectures
Every scene links its mini-lecture: Introduction to the Integumentary System, Epidermal Layers, Epidermal Cells, The Dermis, Innervation and Vascularization, Skin Pigmentation, Sweat and Oil Glands, Hair and Nails, The Epidermal Conveyor Belt: Speed vs Quality, The Three Phases of Wound Healing, and Vitamin D3 Synthesis — plus the glossary, flash cards and the comparative-disease cases (Maya, Jordan, Sarah, Marcus, Alicia, Grace, David, Monica).
https://bettybroadbent.com/home/human-anatomy/integumentary-system/
By the end you can
- Name the layers of the cutaneous membrane and the tissue of each, and classify a burn by the layers it damages.
- Trace a keratinocyte from the stratum basale to the stratum corneum, name the four epidermal cells, and explain psoriasis as a speed defect of that belt.
- Describe the two layers of the dermis and its two vascular plexuses, and explain how a neutrophil leaves a vessel — and why pus can form with no germ.
- Read skin color back to its pigment or vessel change, and distinguish erysipelas-like erythema from infection and contact dermatitis.
- Compare eccrine, apocrine and sebaceous glandsOil-producing glands in the skin that secrete sebum., hair and nails, and name what controlsVariables that remain constant to ensure a fair test. sweating.
- Explain melanin’s double role, the three skin cancers and the ABCDEs, and the four steps from 7-dehydrocholesterol to calcitriolThe active form of vitamin D, promoting calcium absorption in the intestines..
- Contrast eczema and psoriasis as quality versus speed, order the phases of wound healing, and read a lifetime dermatology list as evidence of one systemic process.
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.
Hop to:
← Familial Mediterranean Fever — case home
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
- The Brain & the Blood–Brain Barrier
- The Autonomic Nervous System
- Special Senses (in developmentThe process of growth and differentiation.)
- The Endocrine System
- Blood
- The Heart
- Blood Vessels
- The Digestive System
- The Respiratory System
- The Urinary System
- Fluids, Electrolytes & Acid–Base Balance
- The Reproductive System
- The Immune System
List of terms
- skin
- dermis
- nails
- melanin
- erythema
- epidermis
- stratum basale
- stratum corneum
- cells
- dermal circulation
- liver
- sebaceous glands
- controls
- calcitriol
- development