332A Hair Science and Structure 2 — Questions and Answers
Question 1: What is the outermost layer of the hair shaft called?
- Cortex
- Medulla
- Cuticle (Correct answer)
- Matrix
Correct answer: Cuticle
The cuticle is the outermost protective layer of the hair shaft, consisting of overlapping scales that protect the inner cortex from damage.
Question 2: Which bond in the hair is the strongest and can only be broken by chemical treatments?
- Hydrogen bond
- Salt bond
- Disulfide bond (Correct answer)
- Van der Waals bond
Correct answer: Disulfide bond
Disulfide bonds are strong covalent bonds formed between sulfur atoms of cysteine amino acids. They can only be broken by chemical processes such as perming or relaxing.
Question 3: What does the pH scale measure?
- Temperature of a solution
- Acidity or alkalinity of a solution (Correct answer)
- Viscosity of a product
- Concentration of keratin
Correct answer: Acidity or alkalinity of a solution
The pH scale measures the acidity or alkalinity of a solution on a scale from 0 to 14, with 7 being neutral. Hair and skin have a natural pH of approximately 4.5 to 5.5.
Question 4: What is the approximate natural pH of healthy hair and skin?
- 7.0
- 2.0 to 3.0
- 4.5 to 5.5 (Correct answer)
- 8.0 to 9.0
Correct answer: 4.5 to 5.5
Healthy hair and skin have a natural pH of approximately 4.5 to 5.5, which is slightly acidic. This is often referred to as the acid mantle.
Question 5: The telogen phase of the hair growth cycle is best described as what?
- The active growth phase
- The transition phase
- The resting and shedding phase (Correct answer)
- The regeneration phase
Correct answer: The resting and shedding phase
The telogen phase is the resting phase lasting about 3 to 4 months, during which the hair follicle is at rest and the old hair is eventually shed to make room for new growth.
Question 6: What structure at the base of the hair follicle provides nourishment for hair growth?
- Sebaceous gland
- Dermal papilla (Correct answer)
- Arrector pili muscle
- Hair bulge
Correct answer: Dermal papilla
The dermal papilla is a small, cone-shaped structure at the base of the follicle that contains blood vessels and nerves. It supplies nutrients essential for hair growth.
332A Hair Science and Structure 2
What is the outermost layer of the hair shaft called?