Skin Flashcards
What are the three layers of skin and what are they primarily made of?
Epidermis(stratified squamous epithelium), dermis(dense irregular connective, hypo dermis(loose connective tissue)
What are the four main cell types in epidermis and what do they do?
Keratinocytes-waterproofing and friction
Melanocytes-UV protection
Langerhans cells- immune
Merkel cells- sensation
What are the four layers of the epidermis in to out?What do they do?
Basale-stem cells attached to hemidesmosomes. Flex.
Spinosum-make lamellar bodies, stiff.
Granulosum-darker, make trichohyalin and fillagrin.
Corneum- dead cells
How does skin become waterproof?
Ceramides released by lamellar bodies when cells die
How does melanin form and work?
UV hits keratinocyte, releases aMSH, stims melanocytes to make melanosomes which are eaten by keratinocytes
What is rate limiting step in melanin production?
Tyrosinase
What three main things does the dermis have?
Sweat glands, sebaceous glands, and hair follicles.
How do sweat glands work?
Eccrine, sweat squeezed to surface through duct by myoepithelial cells. Merocrine secretion
How do sebaceous glands work?
Holocrine secretion, lubricates hair
What makes goosebumps?
Erector pili muscles
How is hair length regulated?
By length of hair growth cycle
What do the dermal papilla contain?
Vessels and nerves
Where is the stem cell bulge in skin?
In the root sheath
What layer of skin is most affected in aging?
Dermis
Where are pacinian corpuscles?
In hypodermis. Fatty layer
