Skin Flashcards
Functions of skin
Barrier, regulation i.e. temp, immunity, enables movement and growth, excretion and endocrine function
Layers of skin
Epidermis –> dermis –> hypodermis –> blood vessels
What is it that makes skin thick?
Glabrous (non-hairy) - thin skin is hairy and has hair follicles
What layer of epidermis is not present in thin skin?
Stratum lucidum
Where is thick skin found?
Places of wear + tear: soles of feet, palms, back and buttocks
What are the layers of epidermis?
Bad (Stratum Basale), School (Stratum Spinosum), Girls (Stratum Granulosum), Like (Stratum Lucidum), Cocaine (Stratum Corneum)
Which layer is deepest?
Stratum Basale
Which layer has new cells being made?
Stratum Basale. New cells being made which migrate through other layers of skin.
What are the 3 types of non-epithelial cell in the epidermis?
- Melanocytes - protect from sunlight
- Langerhans cells - recognise antigens, role in immunity
- Merkel cells - mechanoreceptors for touch
Which layer does Basal Cell Carcinoma effect?
Stratum basale
Which layer does Squamous Cell Carcinoma effect?
Stratum corneum
Which layer does Malignant Melanoma effect?
Stratum granulosum. Melanocytes.
Least common carcinoma and most dangerous
What are warts?
Small lumps on hand/feet caused by HPV. Cause an XS amount of Keratin to be produced in epidermis.
How are blisters caused?
Forms between stratum basal and spinosum, or between epidermis and dermis. Moving over layers need frictional component which is not present in new shoes.
What are hair follicles?
Composed mainly of Keratin - central medulla surrounded by cortex with a surface cuticle. Hair bulb and papilla found together. Function = thermoregulation
What is a sebaceous gland?
Associated with hair follicles. Secrete lipids called sebum = waterproofing. Independent of hair follicles are areolae, vulva and eyelid where they open directly to skin or mucosal surface, Link to errecter pilli muscles. Look like bubble paintings + holey.
What are eccrine sweat glands?
Widespread throughout skin at junction between dermis and subcutis –> SWEAT. Look like hula hoops with spots on them.
What are apocrine glands?
Axillary + groin areas. Located dermis/subcutis. Scent production for territory marking and sexual attraction. Secrete into adj. hair follicles via duct.
What components are absent from thick skin?
Sebaceous glands
What components are absent from thin skin?
Dermal papillae
What components are involved in acne?
Sebaceous glands + hair follicles
Arrector pilli muscles + their link to sympathetic nervous supply…?
Arterioles are supplied by andronergic sympathetic fibres, which mediate vasoconstriction. Also supply myoepithelial cells + eccrine sweat glands.
What are the two layers of the dermis?
- Papillary dermis - fine interlacing collagen fibres and elastin. arterioles, capillary loops, venules, lympathics and Moistener’s corpuscles.
- Reticular dermis - large collagen + elastin bundles, blood vessels and nerves, skin appendages, lymphocytes, mast cells + macrophages (present but scarce)
What else does dermis contain?
Blood + nerve supply
What outgrowths are in epidermis?
Retes ridges, project downwards
What outgrowths are in dermis?
Dermal papillae
How do we get our individual fingerprint?
Retes ridge + dermal papillae
1 degree burn?
Pain + reddening of epidermis
2 degree burn?
Epidermis + dermis - pain, blistering, sore and red
3 degree burn?
Go through dermis and affect deeper tissue. Results in white or black charred skin which may be numb
What is a dermatome?
Localised area of skin that has sensation from one specific nerve
Efferent nervous system….?
Non-myelinated from sympathetic ANS. Blood vessels of skin + skin appendages - arrecter pills + eccrine sweat glands.
Types of afferent nervous system?
- Free Nerve Endings
a) Merkel-cell neurite complexes - Encapsulated endings
a) Meissener’s corpuscles
b) Pacinian corpuscles
c) Ruffini corpuscles
Free nerve endings
Nocioreceptors (pain), thermoreceptors (temp)
Merkel cell-neurite complex (mechanoreceptors)
- Dermal epidermal junction
- Slow speed of adaption
- Detect pressure
Meissener’s Corpuscles
- Papillary dermis
- Rapid acting mechanoreceptors
- Detect touch + sensation
Pacinian Corpuscles
- Subcutis
- Rapid acting
- Detect deep pressure + vibration
Ruffini endings
- Cutaneous tissue
- Slow acting
- Detect stretching + shearing
