Skin Flashcards
What are the cells in the epidermis called?
Keratinocytes
What do keratinocytes make?
Keratin
What is the function of the epidermis?
- Prevents water loss
- Separates internal and external environment
What is the function of the dermis?
- Maintains epidermis with blood flow
- Allows cooling
- Immune surveillance
- UV protection
- Sensory info
- Structural strength
What is the hypodermis?
?Adipose tissue below dermis
What is the function of the hypodermis
Anchoring the skin to underlying tissue
What are the 4 cell types found in the epidermis?
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells
What is the function of melanocytes?
Pigment formation
What is the function of langerhans cells
Immune surveillance
What are merkel cells?
- Touch receptors
- Essentially nerve endings
What are the 5 layers of the epidermis?
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
What is the cell arrangement of the stratum basale?
- Tall columnar cells
- Interspaced melanocytes and merkel cells
How are cells in the stratum basale bound to the basement membrane?
Hemidesmosomes
How are cels in the stratum basale linked to each other?
Desmosomes
What is the relationship between the papillary layer of the dermis and the stratum basale like?
- Papillary layer projects into the SB in some areas and a lot less in others
What cells are in the stratum basale?
Pre-keratinocyte stem cells
Where does the stratum spinosum start?
After cell death
Why is it called “spinosum”
Cells have spines
How do the cells of the stratum spinosum form spines?
- Cell shrinks after death but desmosomes stay attached
What does the stratum granulosum contain?
Granules of keratohyalin
Where is keratohyalin converted into keratin?
Stratum corneum
Which skin layer varies in thickness?
Stratum corneum
Where is thick skin?
- Hands
- Feet
Where is thin skin?
Abdomen
What are the two layers of the dermis?
- Papillary layer
- Reticular layer
What type of connective tissue is the papillary layer?
Loose connective
What type of tissue is the reticular layer?
Dense irregular connective
What are the blood vessels in the dermis responsible for?
- Thermoregulation
- Supplying the dermis and stratum basale with oxygen
What is the name of the structural protein found in the reticular layer
Collagen
What does the dermis lose with age?
Elasticity
What glands are found in the reticular layer?
- Sebaceous gland
- Sweat glands
What other structures are found in the reticular layer?
- Receptors
- Nails
- Vessels
How do cells develop waterproofing?
- Form keratin
- Have glycolipid in between cells
What protects the skin from UV?
Melanin
What muscle causes piloerection?
Erector pili
What is secreted by sebaceous glands?
Sweat
