CPE Anatomy & Physiology of Hair Growth 5

Question 1

Which enzyme converts testosterone to dihydrotestosterone (DHT) within the hair follicle?

Accepted Answer

5-alpha reductase

Answer

5-alpha reductase, present in follicle dermal papilla cells, converts testosterone to the more potent DHT locally within the follicle.

Question 2

The cuticle of the hair shaft is best described as:

Accepted Answer

Overlapping flattened keratinized scales pointing toward the hair tip

Answer

The hair cuticle consists of overlapping, scale-like keratinized cells angled toward the distal tip, forming a protective outer layer.

Question 3

Which phase immediately follows catagen in the hair cycle?

Accepted Answer

Telogen

Answer

After catagen's regression phase concludes, the follicle enters telogen, a resting period during which the club hair is retained before eventual shedding.

Question 4

Hair follicles first appear in the human fetus at approximately:

Accepted Answer

9–12 weeks gestation on the face

Answer

Hair follicle development begins around 9–12 weeks of gestation, first appearing on the face (lips, eyebrows) before progressing over the rest of the body.

Question 5

What is the function of the companion layer within the hair follicle?

Accepted Answer

It separates the outer root sheath from the inner root sheath and allows them to move independently

Answer

The companion layer acts as a sliding plane between the inner and outer root sheaths, allowing the inner sheath and hair shaft to move upward while the outer sheath remains relatively stationary.

(CPE) Certified Professional Electrologist Practice Test

(CPE) Certified Professional Electrologist Practice Test

CPE Anatomy & Physiology of Hair Growth 5