10.2 Skin Flashcards
What are the 3 main layers of skin from out to in?
epidermis, dermis, subcutaneous/hypodermis
What are the sublayers/strata epidermis from out to in?
stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale
Name functions of each strata for epidermis
c: made up of flattened keratinocytes that form a barrier against pathogens and preventing loss of fluids and salts; l: only present in thick hairless skin like palms or soles; g: keratinocytes die and lose their nuclei; s: keratinocytes connect to each other & site of Langerhans cells; b: contains stem cells and site of proliferation of keratinocytes that produces keratin, site of melanocytes that produces melanin to protect against UV
How do calluses form?
Excessive keratin deposition in areas of repeated strain due to friction
What are Langerhan cells?
Macrophages residing in stratum spinosum
What are the sublayers and their functions of the dermis?
Papillary layer (right under epidermis) - loose connective tissue; reticular layer. Sweat glands, hair follicles and blood vessels originate in dermis
What are Merkel cells/discs?
sensory receptors at epidermal-dermal junction
What are Meissner’s corpuscles vs Ruffini endings vs Pacinian corpuscles vs free nerve endings?
sensory receptors responding to light touch vs stretch vs deep pressure and vibration vs pain and temp
What is the hypodermis?
Fat and fibrous connective tissue that connects skin to rest of the body
What part of the nervous system controls sweating?
Autonomic nervous system, mostly sympathetic
Why do hairs stand up when you’re cold?
Arrector pili muscles contract –> piloerection –> traps a layer of heated air near skin
What colored fats are found in humans?
We have white fat under skin for insulation; infants have brown fat which have less efficient ETC –> more heat energy is released
Where are mast cells found and mature?
Skin
Name 3 functions of skin
- Thermoregulation
- Innate immunity
- Production of inactive form of vitamin D
