CLT Skin Anatomy & Physiology 3

Question 1

What is the approximate pH range of healthy, intact skin surface?

Accepted Answer

4.5–5.5

Answer

Normal skin has a slightly acidic pH of 4.5–5.5, forming the 'acid mantle' that inhibits microbial growth and maintains barrier function.

Question 2

Melanin is synthesized from which amino acid precursor?

Accepted Answer

Tyrosine

Answer

Melanin biosynthesis begins with tyrosine, which is converted to DOPA and then dopaquinone by the enzyme tyrosinase in melanosomes.

Question 3

Which cells in the skin are responsible for the immunological surveillance and antigen presentation?

Accepted Answer

Langerhans cells

Answer

Langerhans cells are dendritic antigen-presenting cells in the epidermis that capture antigens and present them to T-lymphocytes, playing a key immune role.

Question 4

The stratum granulosum is named for the granules it contains, which are primarily:

Accepted Answer

Lamellar bodies and keratohyalin granules

Answer

The stratum granulosum contains keratohyalin granules (which form the keratin matrix) and lamellar bodies that release lipids to form the skin barrier.

Question 5

In laser treatments, post-inflammatory hyperpigmentation (PIH) is most likely to occur in patients with:

Accepted Answer

Fitzpatrick Type IV–VI skin

Answer

Darker Fitzpatrick skin types (IV–VI) have more active melanocytes that are prone to overproducing melanin in response to thermal injury, causing PIH.

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CLT Skin Anatomy & Physiology 3