S&F Integumentary System Flashcards
0
Q
Weight of skin
A
4-5 kg (15% total body weight)
1
Q
Average surface area of skin
A
2 square meters
2
Q
Thickness of skin
A
0.5mm to 4mm depending on location
2mm on average
3
Q
Epidermis
A
Composed of stratified squamous epithelium with keritinocytes, melanocytes, langerhans cells, and Merkel cells
As cells move toward the surface they flatten, die, and lose their nuclei
More mitotically and metabolically active toward the basal surface
3-4 weeks from the bottom to the top
4
Q
Keratinocytes
A
90% of skin cells
4-5 layers
Have insoluble keratin proteins
Lamellar granules
5
Q
Melanocytes
A
8% of skin cells Ectodermal Produce melanin Long slender projections which extend between keratinocytes and transfer melanin toward the surface Susceptible to uv light
6
Q
Lngerhans cells
A
Endodermal Arise from red bone marrow and migrate to epidermis Few in number Important in immune response Susceptible to uv light Phagocytic
7
Q
Merkel cells
A
Very few
Lie in deepest layers
Associate with sensory neurons in light touch
Merkel’s disk
