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MODULE 5:
Integumentary System
PART 4 OF 7
Since childhood: “growing pains” in the feet at night (age 4–5). Adult: lacy purple mottling on the legs (livedo), dusky-red feet, shins that flush and swell after exercise. Filed under “poor circulation.”
Slide 1 Transcript
PATIENT CHART
STINA
Grad student · recurrent fevers, pain & swelling since childhood
THIS PART
Ages 3-35
PRESENTING WITH
Variable skinThe body’s largest organ, providing protection and regulation. conditions
ACTION TAKEN
Dermatological evaluation
DIAGNOSIS
Sweet Syndrome
CHART CLUES
COLLECTED AS YOU GO
Post-Streptococcal Guttate Psoriasis
Concurrent Eczema + Sterile Pustulosis
Sweet Syndrome — Acute Febrile Neutrophilic Dermatosis
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Put your money down: Mottled legs and red feet — poor circulation, or inflamed circulation?
Stina woke with aching feet as a child (‘growing pains’), and as an adult developed lacy purple mottling, dusky-red feet, and shins that flushed and swelled after a hard run. She was told ‘poor circulation.’ Two quick fact-checks on the skin’s blood supply; then the ask: is this sluggish circulation — or inflamed circulation?
Pick the answer you believe now. We’ll come back to it later!
Legs That Were Always a Little Odd
Stina’s legs had always been a little odd. As a small child she woke with aching feet her parents called growing pains. As an adult she developed a lacy, purplish net across her thighs and calves, dusky-red feet, and — most strangely — shins that turned hot, red, and swollen on the front after she pushed herself, like the middle-school day she ran the Presidential Fitness mile and came back with bright, tender pretibial skin. “Poor circulation,” she was told, and given compression socks.
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Single Choice: Where do the skin’s sensory receptorsProteins located on the surface or inside cells that bind specific molecules (e.g., neurotransmitter actually sit?
The Subpapillary Plexus
The superficialNear the surface of the body. network that feeds the epidermis — and mottles when it’s inflamed.
Slide 3 Transcript
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Drag the Words: Drop the facts about the subpapillary plexusA network of blood capillaries that vascularize the papillary layer of the dermis of skin. Loops ext.
The Skin’s Hidden Circulation
It wasn’t poor circulation; it was inflamed circulation. The dermis carries a rich vascular network, and when its small vessels are irritated by cytokines they constrict unevenly (livedo reticularis), pool dusky blood (acrocyanosis), and leak fluid when blood flow surges with exercise (the hot, swollen, erysipelas-like shins). The same IL-1β that inflamed her epidermis and called neutrophils into Sweet plaques also irritates the endotheliumThe innermost layer of blood vessels, composed of simple squamous epithelial cells, which reduces fr lining these dermal vessels. Even her childhood “growing pains” fit: nighttime inflammatory aching, not growthAn increase in size and number of cells.. Her legs were an early, ignored readout of a vascular bed under chronic inflammatory stress.
The Cutaneous Plexus
The deepAway from the surface of the body. network that keeps the dermis alive.
Slide 4 Transcript
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Fill in the Blanks: Fill in what the cutaneous plexusA network of blood capillaries that vascularizes the hypodermis/dermis border of skin. supplies.
Wound Healing
Stop the bleeding, clean up, then rebuild — a preview of Part 6.
Slide 5 Transcript
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Mark the Words: Mark the ordered steps of wound healing.
Not Poor Circulation — Inflamed Circulation
In Stina, that circulation wasn’t poor — it was inflamed. The same IL-1β that sped her epidermis and packed neutrophils into her Sweet plaques also irritates the endothelium lining these small dermal vessels. Inflamed endothelium constricts unevenly (her livedo), pools blood in her feet (her dusky red toes), and leaks fluid when flow surges during exercise (the hot, swollen, almost erysipelas-like shins after that mile). Even the childhood growing pains fit in hindsight: nighttime inflammatory aching, not the ache of growth. Her legs had been an early, honest readout of a vascular bed under chronic inflammatory stress — and everyone had been reading them as a plumbing problem.
Sebaceous Glands
Oil glands that ride along the hair — and when they plug, the epidermal (sebaceous) cysts Stina keeps forming.
Slide 6 Transcript
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Multiple Choice: What do sebaceous glandsOil-producing glands in the skin that secrete sebum. secrete, and what happens when one is blocked?
Sudoriferous Glands
Sweat glands for cooling — and a little immunity, the same neutrophil-rich defense that flares as neutrophilic dermatosis in her skin.
Slide 6 Transcript
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Flip Cards: Flip to check the sweat glands and their immune role.
Two Kinds of Sweat Gland
Eccrine for heat; apocrine for — we’re still learning.
Slide 6 Transcript
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Summary: Pick the true statement about eccrine vs apocrine glands.
Functions of Hair
More than decoration — four real jobs, from warmth to sensing.
Slide 6 Transcript
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Single Choice: Which of these is a genuine function of hair?
Hair
Terminal and vellus; growth in cycles, and shedding.
Slide 6 Transcript
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Drag the Words: Drop the hair facts into place.
Arrector Pili
The little muscles behind goosebumps — the rescue-cat fluff, in miniature.
Slide 6 Transcript
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Fill in the Blanks: Fill in what the arrector pili do.
Structure of a Nail
The lunuleThe white, crescent-shaped area at the base of the fingernail., the bed, and the cuticle — and in Stina, nailsHard, keratinized structures that protect the fingertips and enhance fine motor skills. turning brittle and no longer sealing at the cuticle.
Slide 6 Transcript
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Mark the Words: Mark the parts of the nail — and the signsObjective clinical findings observable by a provider (e.g., edema, fever). of a nail under inflammatory stress.
FINDING!
Inflammatory Cutaneous Vasculopathy
Concrete signs: lacy purple mottling (livedo reticularis), dusky-red feet (acrocyanosis), and hot, swollen, red shins on the front after exertion (erysipelas-like pretibial erythemaRedness of the skin due to increased blood flow, often caused by heat, infection, or inflammation.) — plus childhood nocturnal foot aching once called ‘growing pains.’ It isn’t poor circulation; it’s inflamed circulation: cytokine-irritated dermal vessels constrict unevenly, pool dusky blood, and leak when flow surges, all driven by the same IL-1β endothelial activation. Chart entry: inflammatory cutaneous vasculopathy, not occlusion — and the childhood aching was nighttime inflammation, not growth.
Confirm or refute your bet: Mottled legs and red feet — poor circulation, or inflamed circulation?
Having toured the dermal vascular network and its role in thermoregulation, return to the bet. It wasn’t poor circulation — it was inflamed circulation: cytokine-irritated vessels constrict unevenly (livedo), pool dusky blood (acrocyanosis), and leak when flow surges (the hot pretibial shins), and even the childhood ‘growing pains’ were nighttime inflammatory aching.
Slide 7 Transcript
NEXT PART
Two of Stina’s rashes look like opposites — one races, one leaks. Zoom into the epidermis and you can watch exactly where each one goes wrong, cell by cell.
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← Familial Mediterranean Fever — case home
All pages for Module 5 — The Integumentary System
5.0 Module Overview
5.1 The Rash Nobody Noticed
5.2 The Barrier Breaking Down
5.3 The Fever Rash
5.4 Red Feet & Mottled Shins
5.5 The Epidermal Conveyor Belt
5.6 Wounds That Won’t Heal
5.7 Inside the Skin’s Inflammation
5.8 Conclusion and Assessment
5.9 The evidence behind Stina’s skin
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
- epidermis
- receptors
- superficial
- subpapillary plexus
- endothelium
- growth
- deep
- cutaneous plexus
- sebaceous glands
- lunule
- nails
- signs
- erythema
- development