332A Hair Science and Structure 3 — Questions and Answers
Question 1: How many layers does the hair shaft consist of?
- Two
- Three (Correct answer)
- Four
- Five
Correct answer: Three
The hair shaft consists of three layers: the cuticle (outer), cortex (middle), and medulla (inner core, which may be absent in fine hair).
Question 2: What type of hair has no medulla?
- Coarse hair
- Medium-textured hair
- Very fine or vellus hair (Correct answer)
- Grey hair
Correct answer: Very fine or vellus hair
Very fine hair and vellus hair often lack a medulla entirely. The medulla is more commonly present in coarse or thick hair types.
Question 3: Which gland attached to the hair follicle produces sebum?
- Sweat gland
- Sebaceous gland (Correct answer)
- Thyroid gland
- Pituitary gland
Correct answer: Sebaceous gland
The sebaceous gland is attached to the hair follicle and produces sebum, a natural oil that lubricates the hair and skin, keeping them moisturized.
Question 4: What is the catagen phase of the hair growth cycle?
- The active growth phase
- The resting phase
- The short transition phase between growth and rest (Correct answer)
- The shedding phase
Correct answer: The short transition phase between growth and rest
The catagen phase is a brief transitional phase lasting about 2 to 3 weeks, during which the hair follicle shrinks and detaches from the dermal papilla.
Question 5: What determines the natural colour of a person's hair?
- The cuticle thickness
- The ratio and type of melanin in the cortex (Correct answer)
- The diameter of the medulla
- The number of disulfide bonds
Correct answer: The ratio and type of melanin in the cortex
Natural hair colour is determined by the type, amount, and distribution of melanin pigments (eumelanin and pheomelanin) within the cortex of the hair shaft.
Question 6: What happens to the cuticle layer when hair is exposed to alkaline solutions?
- It tightens and contracts
- It swells and opens up (Correct answer)
- It dissolves completely
- It becomes more acidic
Correct answer: It swells and opens up
Alkaline solutions (pH above 7) cause the cuticle scales to swell, lift, and open. This allows chemicals to penetrate into the cortex but also makes hair more vulnerable to damage.
332A Hair Science and Structure 3
How many layers does the hair shaft consist of?