Skin Flashcards
What are the functions of the skin?
Protection Moisture control Metabolic function Sensation Thermoregulation
What are the three layers of the skin?
Epidermis
Dermis
Hypodermis
What is the epidermis?
The outer epithelial layer
What is the function of the epidermis?
Protection - basal layers folded into dermal papillae
What is the dermis?
Underlying layer of connective tissue
What is the function of the dermis?
Sensation, protection, thermal regulation, nerves, blood supply - apical layers form dermal papillae
What is the hypodermis?
Loose connective tissue deep to the dermis - adipose tissue considered to be part of the skin
How is skin classified?
Classified as thin or thick - according to the thickness of epidermis
What type of skin has hair follicles?
Thin skin
What type of skin is glabrous (non hairy)?
Thick skin
Where is thick skin located?
In areas of abrasion - palm, sole of feet, fingertips
what makes up the epidermis?
Keratinised, stratified squamous epithelium
Which layer of skin is made up of Keratinised, stratified squamous epithelium?
Epidermis
How many layers are there in thick skin?
5
What are the 5 layers of thick skin
Stratum basal Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum
What is stratum basal?
A layer of thick skin responsible for constant regeneration of the other layers of epidermis.
Which layer do cells divide in?
Stratum basal
What is stratum spinosum?
Cells have lots of desmosomes which anchor the cells to each other and contain thick tufts of intermediate filament (keratin)
Which layer do cells start to lose their nuclei and cytoplasmic organelles and begin to turn into keratinised squares of the next layer?
Stratum Granulosum
What is the function of stratum granulosum?
The granules contain lipid rich secretions which act as water sealant
What is stratum lucidum?
Thin transparent layer - sometimes absent from thin skin
What is stratum corneum?
Keratinised squares layer - layer of dead cells reduced to flattened squares filled with densely packed keratin
Which layer is sometimes absent from thin skin?
Stratum lucidem
What are the three types of non epithelial cells present in the epidermis?
Melanocytes
Merkel cells
Langerhans cells
What type of non-epithelial cell gives the pigment in skin?
Melanocytes
What type of non-epithelial cell has an immunological role?
Langerhans cells
Which type of non-epithelial cell acts as a mechanoreceptor?
Merkel cells
Which layer is squamous cell carcinoma in?
Granular/keratin layer
Which layer is a basal cell carcinoma in?
Basal layer
Which layer is a malignant melanoma in?
basal later - melanocytes within the basal layer (least common but most dangerous)
What is the name for a small rough lump that develops on hands and feet?
Wart
What causes warts?
HPV infection - causes excess keratin production in the epidermis
What type of skin are hair, sebaceous glands and sweat glands absent from?
Thick skin
What is the function of an eccrine sweat gland?
Synthesis of thin water liquid (sweat) which passes along eccrine ducts and deposits onto skin surface for thermoregulation
What is the function of sebaceous glands?
Secrete sebum into hair follicles - provides waterproofing
What is the function of hair follicles?
Produce long thin cylindrical structures composing of mainly keratin and arranged in an organised manner for thermoregulation
How is acne developed?
By sebaceous glands producing excess sebum
What is the function of arrector pills muscles?
contraction causes hair to stand on end - provides insulation through trapping air
What type of nerve supply do arrestor pills muscles and eccrine sweat glands have?
Sympathetic nerve supply
What is the dermis made up of?
Connective tissue - containing irregular bundles of collagen and elastic fibres
How many layers are there in the dermis?
2 - superficial loosely woven papillary layer
- Deep thicker denser reticular layer
Which layer contains blood and nerve supply of the skin?:
The dermis
\which layer is damaged in 1st degree burn?
epidermis
Which degree burn damages the epidermis and dermis?
second
Which layers are damaged in a third degree burn?
Epidermis, Dermis, Hypodermis
What is the name for an area of skin supplied by a single spinal nerve?
Dermatome - each nerve relays sensation from a particular region of the skin to the brain
What type of receptor is in the basal cell epidermis and detects sustained touch and pressure?
Merkel cell - neurite complex - slow speed of adaptation
What is the function of pascinian corpuscle?
Detects deep pressure and rapid vibration
Deep in hypodermis of soles of feet
Rapid speed of adaptation
What type of receptor resides in the dermal papillae of skin, fingertips, eyelids and nipples?
Reissner’s corpuscle
- rapid speed of adaptation
- Detects changes in texture, pressure and vibration
What are ruffini endings receptors
The reside in the dermis layer
Detect stretching, shearing
Slow speed of adaptation
Which receptors have slow speed of adaptation?
Ruffini endings and Merkel cell - neurite complex
Which receptors have fast speed of adaptation?
Pascinian corpuscle and Meissner’s corpuscle
