Skin Anatomy and Fitzpatrick Scale Flashcards
6 cards from real CLS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Skin Anatomy and Fitzpatrick Scale flashcards as text
The epidermis is divided into five layers. Which layer is directly responsible for producing new skin cells through mitosis?
Answer: Stratum basale
The stratum basale (basal layer) is the deepest epidermal layer and contains mitotically active keratinocytes and melanocytes. New keratinocytes produced here migrate upward through the other layers, maturing and eventually becoming the anucleate corneocytes of the stratum corneum.
What is the primary function of melanin in skin?
Answer: Absorbing and dissipating UV radiation to protect underlying cells from DNA damage
Melanin is produced by melanocytes in the stratum basale and transferred to surrounding keratinocytes. It forms a supranuclear 'cap' over the nucleus, absorbing UV radiation and converting it to heat, thereby protecting cellular DNA from UV-induced mutagenic damage.
Which Fitzpatrick skin type is characterized by skin that 'always burns, never tans' and is associated with the highest risk of UV-induced damage?
Answer: Type I
Fitzpatrick Type I describes very fair skin, often with red or blonde hair and blue or green eyes, that always burns upon sun exposure and never develops a protective tan. This type has minimal melanin and the highest susceptibility to UV-induced erythema and photodamage.
Where are hair follicles located anatomically, and why does this matter for laser hair removal?
Answer: Rooted in the dermis (bulb in the deep dermis, bulge in the mid-dermis); laser must penetrate to dermal depth to destroy the follicle
Terminal hair follicles are rooted in the dermis, with the bulb at depths of 2–7 mm. The follicle bulge (stem cell niche) is located at approximately 1–1.5 mm depth. Effective laser hair removal requires sufficient fluence at these dermal depths, which depends on wavelength selection (longer wavelengths penetrate deeper) and adequate energy delivery.
Which statement correctly describes the difference between eumelanin and pheomelanin?
Answer: Eumelanin is brown-black and absorbs laser energy efficiently; pheomelanin is yellow-red, found in red and blonde hair, and absorbs laser energy less efficiently
Eumelanin is the dark brown-to-black pigment that strongly and broadly absorbs laser wavelengths, making it an effective chromophore for laser hair removal and pigmentation treatments. Pheomelanin is the red-to-yellow pigment in red and blonde hair and lighter skin tones, with lower and less broad laser absorption, explaining why light hair is poorly targeted.
A patient is Fitzpatrick type IV. What clinical characteristics define this skin type?
Answer: Light brown skin, sometimes burns, tans easily and darkens significantly
Fitzpatrick Type IV describes olive to light brown skin (often Mediterranean, Middle Eastern, or East Asian heritage) that sometimes burns with prolonged sun exposure but tans easily and significantly. This type has moderate epidermal melanin and is at intermediate risk for post-inflammatory hyperpigmentation from laser treatments.