Burns and wound healing
How the depth of a burn decides which parts of the skin survive, why large burns leak fluid into the tissues and cause shock, and how wounds heal through inflammation, new tissue and remodelling, sometimes with thick scars and contractures.
By the end, you can
- Describe the layers and appendages of the skin and its barrier functions.
- Relate superficial, partial-thickness and full-thickness burns to the layers they destroy.
- Explain the zones of a burn and the fluid shifts that cause burn shock.
- Describe the phases of wound healing and why skin appendages matter for regrowth.
- Explain hypertrophic scarring, contractures and the consequences of losing the barrier.
- Recognise burn depth, the zones of Jackson and the rule of nines, and explain how cooling, fluid resuscitation, escharotomy, excision and grafting act on the mechanism.
What it is
A burn is injury to the skin or deeper tissues from heat, electricity, chemicals, friction or radiation. Its severity depends on its depth and the total body surface area (TBSA) affected. Wound healing is the overlapping sequence of haemostasis, inflammation, proliferation and remodelling by which damaged tissue is repaired, with regeneration of epidermis and, in the dermis, repair by scar.
3 types to tell apart
- Superficial (epidermal)
- Epidermis only: red, painful, no blisters; heals in days without a scar.
- Partial thickness
- Superficial: into the papillary dermis; blistered, moist, very painful; heals in about two weeks. Deep: into the reticular dermis; blotchy, less painful; heals slowly with scarring.
- Full thickness
- Through the whole dermis: white, brown or leathery, painless, dry; cannot heal from within except at the edges.
US spelling: haemostasis → hemostasis.
Normal function
Skin as a living barrier
The skin has an outer epidermis, a vascular dermis (thin and thicker layers) and . The dermis carries , and the deep roots of and .
Skin keeps water in, keeps microbes out, regulates temperature through sweating and blood flow, and senses touch, pain and heat.
The appendages matter for healing. Hair follicles and sweat glands are lined by epithelium that extends deep into the dermis; if the surface is lost, these islands of living epithelial cells can regrow the epidermis.
Underlying change · Step 1 of 4
Depth decides what survives
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 2 of 4
Large burns leak fluid and cause shock
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 3 of 4
How wounds heal
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 4 of 4
Scars, contractures and other consequences
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Exam detail
Exam detail
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Treatment
How treatment works
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .