Lecture 1 Flashcards
What does the Integumentary system include?
Skin and accessory structures
What are the 3 primary layers of skin?
Epidermis and Dermis (Cutaneous) and Hypodermis (Subcutaneous)
Features of epidermis
Stratified (stacked) layer, Mostly keratinocytes, Avascular, Constantly replenishes (shedding)
Features of Dermis
Protein fibres (collagen + elastin) for strength, Vascular (nourishes epidermis)
Features of Hypodermis
Adipose tissue
Types of Epithelia with descriptions
Simple and Stratified: Squamous (flat like scales), Cuboidal, Columnar
What is the predominant cell type in the epidermis?
Keratinocytes
Stratified squamous epithelium
Describe the Stratum corneum
Spiky layer- made of dead, dried out cells without nuclei
Describe the Stratum granulosum
Granular layer- contains granules that promote dehydration of the cell and cross linking of keratin fibre, Waxy material is secreted into the intracellular spaces to make watertight barrier
Describe the Stratum spinosum
Spinous or prickly cell layer- Desmosomes link the cells together, Cells become increasingly flattened as they move upward, Contains dendritic cells
Describe the Stratum basale
Basal layer- Columnar regenerative cells, As the basal cell divides, daughter cell migrates upwards to replenish above layer
What is the name of the layer found only in thick skin?
Stratum lucidum
Difference between Desmosomes and Hemidesmosomes
Desmosomes anchor adjacent/neighbouring cells in ALL of epidermis. Hemidesmosomes anchor stratum basale to the dermis
Acronyms for Thick and Thin skin
Thin- Come Get Some Maccas (4 layers)
Thick- Come Lets Get Some Maccas (5 layers)
Characteristics of thick skin
Palms of hands and soles of feet, No hair and contains an extra ependymal layer
Dermis layers
PR- Papillary layer and Reticular layer
Dermis characteristics
Below the epidermis and anchored by hemidesmosomes, Not shed
Papillary layer
Consists of highly vascularised tissues (for nourishment)
Reticular layer
Mesh-like structure of collagen and elastic fibres (for strength)
What is common between Reticular and Papillary layer
Both contain blood vessels, lymphatics, sensory nerve fibres and accessory structures
What is a plexus
A network of blood vessels OR nerves
Describe the Cutaneous Plexus
Network of blood vessels present at the dermis/hypodermis junction and Supplies the hypodermis and deeper dermis including capillaries for sweat glands and hair follicles
Describe the Subpapillary Plexus
Branches from the cutaneous plexus and is deep to the papillary layer of the dermis, Network of blood vessels that provide O2 and nutrients to the upper dermis and epidermis
Hypodermis Characteristics
Subcutaneous layer so is not part of the skin, Is dominated by adipocytes that produce subcutaneous fat which stores energy and provides insulation , is a common site for injections using hypodermic needles
What layer of the skin is affected by 1st degree burns?
Outer layers of the epidermis (superficial)
Characteristics of a 1st degree burn?
Red/pink colour, dry, painful, usually no blistering, water and bacterial barrier intact
How long does it take for 1st degree burns to heal approximately?
3-10 days
What layer of the skin is affected by 2nd degree burns?
Epidermis and varying amounts of the dermis
Characteristics of 2nd degree burns
Painful, moist, red, blistered
How long does it take for 2nd degree burns to heal approximately?
1-2 weeks
What are the characteristics of deeper 2nd degree burns?
May include white, waxy areas. Some loss of sensation and scarring
How long do deeper 2nd degree burns take to heal?
1 month
What layer of the skin is affected by 3rd degree burns?
Full thickness burns so epidermis, dermis, hypodermis and can even extend down into the bone
What is the appearance of 3rd degree burns?
Varied colour - waxy white to red to black
Characteristics of 3rd degree burns
Hard, dry and leathery skin. No pain because sensory nerve endings have been destroyed
Treatment and healing of 3rd degree burns
May require skin grafting and can take weeks to months to regenerate- will result in permanent scarring
