Skin Principles Flashcards
What are the three layers of the skin
Epidermis, Dermis, subcutis
The epidermis has
Keratinising stratified epithelium, natural openings for hair follicles
The four layers of the epidermis
Horn cell layer, granular cell layer, prickle cell layer, basal cell layer
What are keratinocytes held together by and anchored by
They are held together by desmosomes and anchored to the basement membrane by hemidesmosomes
Where are Melanocytes located
In the basal layer
Where did melanocytes originate from
The dendritic cells originated from the neural crest
What do you melanocytes do
Produce melanin And protect against UV, they also help determine skin colour
What does the basement membrane do
Joins epidermis to dermis
What is the basement membrane made out of
A type of IV collagen
What is special about the basement membrane
It Is resistant to shearing forces
What does the basement membrane provide
Structure and controls the interaction of the epithelial mesenchymal
What is the dermis made of
Collagen and elastic fibres, they also have fibroblasts and histocytes
What does the dermis do
Supports the epidermis
Fibroblasts
They are spindle shape cells in the extracellular matrix and collagen, they are used in wound healings
Histocytes/ Macrophages
Eat debris to get rid of stuff, bean shaped nuclei and they are fully differentiated
What type of epidermal appendages are there
Hair, Sebaceous glands, arrector pili muscles
Hair
 is made of keratin and the colour is due to the type of melanin
Sebaceous gland formation and function
It is formed from sebocytes and the fluid drains into the follicle
Types of sweat glands
Eccrine (all over the body)
Apocrine (in sweaty parts- armpit)
Types of skin mecanoreceptors receptors
Paccinian corpuscle, meissners corpuscle, Ruffinu endings, merkel cell discs
Meissners corpuscle
Common in hands and feet and formed from stacked Schwann cells
Paccinian corpuscle
It is ovoid and has a lamellar structure. It senses deep pressure vibrations
Types of scars
Hypertrophic and keloid
Hypertrophic scar
Tissue doesn’t extend past wound
Keloid scar
Extends beyond margin due to thick rope bundle of collagen
What is haemangrioma
Benign tumour of blood vessel
Skin functions
To cover, protection, antimicrobial defence, thermoregulation, sensing, attraction, waterproofing, secretion and absorption, vitamin d metabolism
Homoeotherms
Humans are homoeothermic as they maintain their temperature above ambient temperature
How do we control our temperature (thermoregulation)
Behaviour, cutaneous bloodflow (vasoconstriction and vasodilation), sweating, pilo erection, counter currents and hypothalamus
What is cancer
An abnormal growth of cells which are not under control
Three primary skin cancers are
Squamous cell sarcoma (from squamous cells), basal cell sarcoma (from basal cells) and melanoma (formed from melanocytes)
Secondary skin cancer is
Cutaneous metasis
How do you basal cells appear under a microscope 
Blue cells in the dermis
What is skin cancer caused by
Mainly UV radiation
Ruffini endings stimulus, location and ending
They detect stretch and warmth, There in the deep dermis and encapsulated
Merkel cells Stimulus, location and ending
They detect light touch as they are in the base of the epidermis and they are non-encapsulated
