Module title = Tutorial: Derm Morphology

Lesson title = Normal Skin

This is lesson 1 of 18 in this module

This lesson will cover normal skin.

Objectives

• Review normal skin anatomy
• Identifying locations of pathology based on morphology

 
Introduction

• There are three major subdivisions of skin:

1. Epidermis –the most superficial layer of skin
   • Thickness varies depending on location i.e., it is thinner on your eyelids and thickest on your palms and soles
   • The epidermis is where new keratinocytes (cells that make up the majority of the epidermis) are made
   • The epidermis contains melanocytes which produce melanin and provide the pigmentation to skin
   • The epidermis plays a major role in barrier function and immune protection

 

2. Dermis –the second layer of skin below the epidermis, contains the blood vessels and other skin appendages
   • This is where sweat glands reside and where sweat is produced
   • Sensation is derived from the nerves in the dermis
   • The root of hair is found in the dermis

 

3. Subcutaneous fat – third layer of skin; fatty tissue below the dermis
   • This layer attaches the dermis to the structures underlying the skin (ie, muscles and bones)
   • Also contains blood vessels and nerves that feed into the dermis
   • Important for thermoregulation (maintaining body temperature)

**In the image below the three main layers of skin are labelled. The stratum corneum is part of the epidermis and is a layer of dead keratinocytes (the cells making up the majority of the epidermis)
 
 
 
Using skin anatomy to determine location of pathology

• In the next theory module the concept of “Morphology” will be discussed
• Morphology is important because it is a way of conveying where in the skin the pathology is likely originating.
• For instance disease in the epidermis will likely be flat and non-palpable; whereas, when disease is in the dermis or subcutaneous tissue it tends to be raised and palpable
  • Understanding where the disease is likely originating or targeting can help narrow your differential diagnosis