Epidermis Layers
What is the deepest layer of the epidermis, containing stem cells?
Stratum basale
Which epidermal cell type produces keratin?
Keratinocytes
Which region of the dermis is just below the epidermis and makes up the outer 1/5?
Papillary region
What two main parts make up hair?
Shaft and root
Which function involves receptors for tactile, thermal, and pain sensations?
Sensation
Which layer is only found in thick skin?
Stratum lucidum
Which cells produce melanin?
Melanocytes
Which region makes up the deeper 4/5 of the dermis?
Reticular region
What muscle causes goosebumps by making hair stand on end?
Arrector pili muscle
Which function protects against abrasion, bacteria, dehydration, and UV radiation?
Protection
Which layer contains flattened cells that produce keratin precursors?
Stratum granulosum
Which epidermal cells are involved in the immune system?
Langerhans cells
What type of connective tissue is found in the papillary region?
Areolar connective tissue
What gland produces sebum that waterproofs the skin?
Sebaceous gland
Which epidermal cells phagocytize antigens as part of immunity?
Langerhans cells
Which phrase helps remember the strata: “Brilliant Studying Gives Loads of Confidence”? What does each word stand for?
Basale, Spinosum, Granulosum, Lucidum, Corneum
Which cells function as sensory receptors for touch?
Tactile discs (Merkel’s discs)
What type of connective tissue is found in the reticular region?
Dense irregular connective tissue
Which sweat glands are most numerous in palms and soles?
What vitamin is synthesized when UV light strikes the skin?
Vitamin D (calcitriol active form)
During epidermal growth, what happens to cells as they are pushed farther from the blood supply?
They die and become filled with keratin.
In the dermis, which cells produce fibers and ground substance?
Fibroblasts
What layer anchors the skin to deeper structures but is not part of the skin?
Hypodermis (subcutaneous layer)
Name the three main parts of the nail.
Nail body, free edge, nail root
About what percentage of total blood flow is found in the dermis at rest?
8–10%