Skin 1 Flashcards
What is the largest, most visible organ of the body?
Skin
What is the main function of the skin?
Protection of internal organs from external environment
What does the skin excrete? think about when you’re sweating - what is released when sweating?
Salts, water and organic waste
What does the skin produce to protect underlying tissue from UV radiation? It is also responsible for pigmentation.
Melanin
What does the skin produce to protect against abrasion and serves as a water repellent?
Keratin/sebum
What tissues make up the skin?
Epithelial, nervous, connective and muscle tissue (composite organ)
What are the 3 primary layers of the skin?
Epidermis
Dermis
Hypodermis
This layer is a stratified, avascular barrier that is made mostly made of keratinocytes.
Epidermis
This is a vascular layer made of protein fibres that provide nourishment and strength to the skin.
Dermis
This is a layer made of adipose tissue and adipocytes (main cell types)
Hypodermis
What are the two layers that make up the cutaneous skin?
Dermis and epidermis
What is the layer that makes up the subcutaneous skin?
Hypodermis
What are the 2 layers of the dermis?
Papillary and reticular layer
What tissue type dominates in the epidermis?
Epithelial tissue
What are the 2 types of epithelia in the epidermis?
Simple and stratified epithelia.
What’s the difference between simple and stratified epithelia?
Simple = only 1 layer of epithelial cells
Stratified = a stacked layer of epithelial cells
What are the 3 shapes of epithelia?
Squamous, cuboidal and columnar
What kind of epithelia makes up the epidermis?
Stratified squamous epithelia
What are the layers of the epidermis of thin skin?
Stratum corneum, granulosum, spinosum, basale
This is the layer of the epidermis that contains dead, dried out hard cells without nuclei. Mostly made of stratified squamous cells that exist to protect internal organs from external environment.
Stratum corneum (spiky layer - hence why it flakes off more easily)
This layer of the epidermis contains granules that promote dehydration of the cell and crosslinking of keratin fibre. Waxy material is secreted into intercellular spaces.
Stratum granulosum (granular layer)
This layer of the epidermis has intercellular bridges that link the cells together.
Stratum spinosum (spinous layer)
These anchor adjacent/neighbouring cells in epidermis
Desmosomes
These anchors stratum basale to the dermis (so anchors epidermis to dermis)
Hemidesmosomes
This is a layer of the epidermis that contains mostly columnar, tall regenerative stem cells that actively divide. It is the nearest to the dermis and receives the most nourishment from the subpapillary plexus.
Stratum basale (basal layer)
What are the layers of the epidermis in thick skin?
Stratum corneum, lucidum, granulosum, spinosum, basale
This layer of skin is situated underneath the epidermis and is anchored via hemidesmosomes. This layer does not shed.
Dermis
This is a layer of the dermis that contains highly vascularised tissues (for nourishment)
Papillary layer
This is a layer of the dermis that contains a mesh-like structure of collagen and elastin fibres (for strength)
Reticular layer
What do the papillary and reticular layers have in common?
Blood vessels, lymphatics, sensory nerve fibres and accessory structures
What are the 2 plexuses of the dermis?
Cutaneous and subpapillary plexus
This term refers to a network of blood vessels or nerves
Plexus
This is a network of blood vessels present at the junction of dermis/hypodermis. It supplies nourishment to hypodermis including capillaries for hair follicles and sweat glands.
Cutaneous plexus
This is a network of blood vessels providing O2 and nutrients to the upper dermis and epidermis. It lies deep to the papillary layer of the dermis.
Subpapillary plexus
This is characterised by red/pink, dry, painful skin and usually no blisters. The skin maintains its function.
First degree burns
This is characterised by painful, moist, red and blistered skin. It affects the epidermis and varying amounts of dermis and takes a longer time to heal. Skin maintains some function.
Normal 2nd degree burns
This is characterised by painful, moist, red and blistered skin but may include whiteish waxy looking areas (pus). May have some loss of sensation and scarring but hair follicles and sweat glands remain intact.
Deeper 2nd degree burns
This is characterised by deep muscle and bone and skin damage. Varied color from waxy white through to deep red or black and results in hard/dry/leathery skin. Usually no pain in these areas as sensory nerve endings/skin receptors are destroyed.
3rd degree burns
