Skin Anatomy 1 Flashcards
Outline melanin production function of skin
Produces melanin, which protects underlying tissue from ultraviolet radiation
Outline keratin production role of skin
Produces keratin, which protects against abrasion and serves as a water repellent
Outline skin lipid storage role
Stores lipids in adipocytes in the dermis and in adipose tissues in the subcutaneous layer
Outline detection function of skin
Detect touch, pressure, pain, and temperature stimuli, and relay that information to the nervous system
What tissue types is skin made up of
All 4 tissue types.
Epithelial, connective, muscle, and nervous tissues
What are the 3 primary layers of skin
Epidermis - outer skin
Dermis - skin
Hypodermis - bellow skin
3 features of epidermis
Stratified barrier
Mostly keratinocytes (protein cells)
No blood circulation - a vascular
2 features of Dermis
Protein fibres for strength (collagen and elastin)
Vascular (nourishes epidermis)
Feature of Hypodermis
Adipose tissue
What tissue dominates in the epidermis
Epithelial tissue
Simple vs Stratified tissues
Simple - single layer of tissue cells
Stratified = stacked layers of tissue cells
3 types of epithelia
Squamous - squashed/scales
Cuboidal
Columnar
4 layers of epidermis, from superficial to deep
Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale
Stratum corneum cell types
Dead, dried out hard cells without nuclei
Stratum granulosum cell types
Contains granules that promote cell dehydration. cross linking of keratin fibre (dead cells cannot attach to eachother). Waxy material secreted into the intercellular spaces
Stratum spinosum cell type
Intercellular bridges (desmosomes) link cells together within epidermis
Cells become increasingly flattened as the move upward
Stratum basale cell type
Columnar regenerative stem cells. As basal cell decides, a daughter cell migrates upwards to replenish the layer above
Desmosomes vs Hemidesmosomes
Desmosomes - anchor adjacent/neighbouring cells within the epidermis
Hemidesmosomes - anchor stratum basale to the dermis
Outline thin skin
4 layers
“Come get some burgers”
Top layer is dead (stratum corneum)
Outline thick skin
5 layers
“Come lets get some hand burgers”
Found of palms of hands and feet
No hair
Extra epidermal layer - stratum lucidum
Outer 2 layers are dead (stratum corneum and stratum lucidum)
Outline the dermis
Situated below the epidermis and anchors via Hemidesmosomes
Is not shed
Divided into two layers - papillary layer and reticular layer
Both layers contain blood vessels, lymphatics, sensory nerve fibres, and accessory structures
Papillary layer vs reticular layer
Papillary layer - consists of highly vascularised tissues (for nourishment)
Reticular layer - mesh like structure of collagen and elastin fibres (for strength)
Two plexuses of the dermis
Cutaneous plexus
Subpapilliary plexus
Cutaneous plexus
Network of blood vessels present at the junction of dermis/hypodermis.
Supplies the hypodermis, deeper dermis, including the capillaries for hair follicles and sweat glands
Subpapillary plexus
Branches from the cutaneous plexus
Lies deep to the papillary layer of the dermis
Network of blood vessels providing O2 and nutrients to the upper dermis and epidermis
Define plexus
Plexus refers to a network of blood vessels or nerves
Outline the hypodermis
The “subcutaneous” layer
Classical anatomy does not consider as a part of skin (hubs192 does)
Dominated by adipocytes that produce subcutaneous fat
The subcutaneous fat stores energy and provides insulation
Common site of injections using hypodermic needles
What fat is consumed during fasting
Subcutaneous fat stores are consumed during fasting
Outline first degree burns
Superficial only - only involve outer layers of the epidermis
Red/pink, dry, painful
Usually no blisters
Skin remains a water and pathogenic barrier
Usually heals within 3-10 days
Outline a normal second degree burn
Epidermis + varying amounts of dermis
Painful, moist, red, and blistered
Usually heals in approx 1-2 weeks (needs good dressing)
Outline a deeper second degree burn
May include whiteish, waxy looking areas
Hair follicles, sweat glands may remain intact
Usually heal in one month
May have some loss of sensation and scaring
Outline a third degree burn
full thickness burn - extends into subcutaneous tissue, may involve muscle/bone.
Varied colour from waxy white through to deep red or black
Hard, dry and leathery skin
No pain in these areas as sensory nerve endings are destroyed
May require skin draft
Weeks to regenerate + scaring
