332A Hair Science and Structure 1 — Questions and Answers
Question 1: Which layer of the hair shaft is responsible for the hair's strength and elasticity?
- Medulla
- Cortex (Correct answer)
- Cuticle
- Dermal papilla
Correct answer: Cortex
The cortex makes up the majority of the hair shaft and contains the fibrous proteins (keratin) that give hair its strength, elasticity, and colour.
Question 2: What is the primary protein that makes up human hair?
- Collagen
- Elastin
- Keratin (Correct answer)
- Melanin
Correct answer: Keratin
Keratin is a tough, fibrous protein that is the primary structural component of hair, nails, and the outer layer of skin.
Question 3: Which type of melanin produces red and yellow hair colours?
- Eumelanin
- Pheomelanin (Correct answer)
- Trichosiderin
- Neuromelanin
Correct answer: Pheomelanin
Pheomelanin is the pigment responsible for red and yellow tones in hair. Eumelanin produces brown and black colours.
Question 4: What chemical bond in hair is broken by water and heat and reforms when hair dries or cools?
- Disulfide bond
- Hydrogen bond (Correct answer)
- Salt bond
- Peptide bond
Correct answer: Hydrogen bond
Hydrogen bonds are weak physical bonds that are easily broken by water and heat. They are responsible for temporary styling changes like blow-drying and curling.
Question 5: During which phase of the hair growth cycle does the hair actively grow?
- Catagen phase
- Telogen phase
- Anagen phase (Correct answer)
- Exogen phase
Correct answer: Anagen phase
The anagen phase is the active growth phase of hair follicles, lasting 2 to 7 years. Approximately 85-90% of scalp hairs are in this phase at any time.
Question 6: What is the function of the arrector pili muscle attached to the hair follicle?
- It produces sebum
- It causes goosebumps by contracting (Correct answer)
- It supplies blood to the papilla
- It anchors the cuticle layer
Correct answer: It causes goosebumps by contracting
The arrector pili muscle is a small involuntary muscle attached to the hair follicle. When it contracts, it causes the hair to stand upright, creating goosebumps.
332A Hair Science and Structure 1
Which layer of the hair shaft is responsible for the hair's strength and elasticity?