Basic structure and growth cycle of hair MCQs With Answer

Introduction: The basic structure and growth cycle of hair cover essential concepts for B.Pharm students, including hair shaft anatomy, follicle organization, bulb and dermal papilla function, keratinization, and pigmentation by melanocytes. Key phases—anagen (growth), catagen (involution), telogen (resting) and exogen (shedding)—determine growth rate and hair density. Understanding follicular compartments (inner and outer root sheaths, matrix, bulge stem cells), influence of hormones (androgens, thyroid), nutritional factors, and pharmacologic modulators (minoxidil, finasteride) links basic science to clinical alopecia management. Mastery of these topics supports rational drug therapy and counseling in pharmacy practice. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What are the three main structural layers of the hair shaft?

• Cuticle, cortex, medulla
• Inner root sheath, outer root sheath, bulb
• Follicle, papilla, matrix
• Shaft, root, bulb

Correct Answer: Cuticle, cortex, medulla

Q2. Which structure contains rapidly dividing cells that generate the hair shaft?

• Dermal papilla
• Hair matrix
• Arrector pili
• Sweat gland

Correct Answer: Hair matrix

Q3. Which component of the hair follicle provides vascular supply and key growth signals?

• Inner root sheath
• Dermal papilla
• Sebaceous gland
• Cuticle

Correct Answer: Dermal papilla

Q4. Which layers compose the inner root sheath (IRS)?

• Henle’s layer, Huxley’s layer, cuticle of IRS
• Cuticle, cortex, medulla
• Outer root sheath, connective tissue sheath, bulge
• Bulb, matrix, papilla

Correct Answer: Henle’s layer, Huxley’s layer, cuticle of IRS

Q5. Trichilemmal (pilar) keratinization is characteristic of which follicular region?

• Hair bulb matrix
• Follicular isthmus / outer root sheath
• Inner root sheath at the infundibulum
• Sebaceous gland acinus

Correct Answer: Follicular isthmus / outer root sheath

Q6. Which phase of the hair cycle is the active growth phase?

• Catagen
• Telogen
• Anagen
• Exogen

Correct Answer: Anagen

Q7. What best describes the catagen phase?

• Active cell proliferation producing shaft
• Transitional involution with apoptosis and shortened follicle
• Resting phase with fully formed club hair
• Shedding of the hair shaft

Correct Answer: Transitional involution with apoptosis and shortened follicle

Q8. Exogen refers to which event in the hair cycle?

• Initiation of anagen growth
• Shedding of the hair shaft from the follicle
• Programmed cell death in catagen
• Permanent follicle destruction

Correct Answer: Shedding of the hair shaft from the follicle

Q9. Approximately what percentage of scalp hairs are in anagen at any time?

• 5–10%
• 15–30%
• 80–90%
• 100%

Correct Answer: 80–90%

Q10. Average scalp hair growth rate in adults is closest to:

• 0.1 mm per month
• 1 mm per month
• 1 cm per month
• 1 inch per week

Correct Answer: 1 cm per month

Q11. Hair pigmentation is produced by which cells in the follicle?

• Keratocytes in the cortex
• Melanocytes in the hair bulb transferring melanosomes
• Sebocytes in the sebaceous gland
• Fibroblasts in the dermal papilla

Correct Answer: Melanocytes in the hair bulb transferring melanosomes

Q12. The primary structural protein of hair is:

• Collagen type I
• Elastin
• Alpha-keratin rich in cysteine residues
• Actin

Correct Answer: Alpha-keratin rich in cysteine residues

Q13. Which anatomical site harbors follicular stem cells essential for regeneration?

• Arrector pili insertion
• Bulge region of the outer root sheath
• Sebaceous gland duct
• Medulla of the shaft

Correct Answer: Bulge region of the outer root sheath

Q14. Which gland is typically associated with the hair follicle and contributes lipids to the hair surface?

• Eccrine sweat gland
• Apocrine sweat gland
• Sebaceous gland
• Meibomian gland

Correct Answer: Sebaceous gland

Q15. Dihydrotestosterone (DHT) contributes to androgenic alopecia primarily by:

• Stimulating sebaceous secretion only
• Causing autoimmune destruction of follicles
• Miniaturizing susceptible hair follicles and shortening anagen
• Increasing melanin production in follicles

Correct Answer: Miniaturizing susceptible hair follicles and shortening anagen

Q16. Minoxidil’s main therapeutic effect on hair is to:

• Block 5-alpha reductase
• Increase anagen duration and promote follicular blood flow
• Destroy hair matrix cells
• Inhibit melanocyte activity

Correct Answer: Increase anagen duration and promote follicular blood flow

Q17. Finasteride treats male pattern hair loss by inhibiting:

• Aromatase enzyme
• 5-alpha reductase type II, reducing DHT formation
• Thyroid peroxidase
• Sodium channels in follicular cells

Correct Answer: 5-alpha reductase type II, reducing DHT formation

Q18. Which histological layer of the hair shaft provides tensile strength and pigment incorporation?

• Cuticle
• Cortex
• Medulla
• Inner root sheath

Correct Answer: Cortex

Q19. Telogen effluvium is most often associated with which immediate pathophysiology?

• Permanent follicle scarring
• Acute synchronized shift of follicles into telogen causing diffuse shedding
• Localized fungal invasion of follicles
• Excessive melanin deposition

Correct Answer: Acute synchronized shift of follicles into telogen causing diffuse shedding

Q20. Which of the following micronutrient deficiencies is commonly linked to impaired hair growth?

• Vitamin C excess
• Iron deficiency
• Excess vitamin A only
• High dietary zinc only

Correct Answer: Iron deficiency

Q21. The arrector pili muscle connects which structures?

• Dermal papilla to hair matrix
• Outer root sheath connective tissue to the epidermis at the follicular infundibulum
• Hair bulb to sebaceous gland
• Shaft cuticle to cortex

Correct Answer: Outer root sheath connective tissue to the epidermis at the follicular infundibulum

Q22. Which phase duration is shortest in the human hair cycle?

• Anagen (scalp long phase)
• Catagen (transitional phase)
• Telogen (resting phase)
• Exogen (shedding, variable)

Correct Answer: Catagen (transitional phase)

Q23. Vellus hairs differ from terminal hairs mainly by:

• Presence of medulla in vellus only
• Greater diameter, pigmentation and longer anagen in terminal hairs
• Attachment to sebaceous glands only in vellus
• Origin from different germ layers

Correct Answer: Greater diameter, pigmentation and longer anagen in terminal hairs

Q24. Which follicular structure protects and shapes the emerging hair shaft by overlapping scales?

• Medulla
• Cortex
• Cuticle of the shaft
• Dermal papilla

Correct Answer: Cuticle of the shaft

Q25. The hair bulb is typically located in which skin layer for scalp hair?

• Stratum corneum
• Superficial dermis
• Deep dermis or superficial subcutis
• Epidermal basal layer

Correct Answer: Deep dermis or superficial subcutis

Q26. Which investigative parameter is most useful to assess active hair growth in a clinical study?

• Hair shaft melanin concentration
• Proportion of hairs in anagen (anagen/telogen ratio)
• Sebum lipid composition
• Scalp temperature only

Correct Answer: Proportion of hairs in anagen (anagen/telogen ratio)

Q27. Which endocrine disorder commonly alters the hair growth cycle and can cause diffuse hair thinning?

• Hypothyroidism and hyperthyroidism (both affect cycle)
• Hyperparathyroidism only
• Pancreatic insufficiency only
• Osteoporosis

Correct Answer: Hypothyroidism and hyperthyroidism (both affect cycle)

Q28. The medulla of the hair shaft is best described as:

• A continuous thick cortical layer with pigment
• A central, often discontinuous core of loosely packed cells or air spaces
• The outermost protective overlapping layer
• The secretory portion of the follicle

Correct Answer: A central, often discontinuous core of loosely packed cells or air spaces

Q29. Which process explains why hair straightening or perming alters shaft mechanical properties?

• Reversible ionic bond formation only
• Disruption and reformation of disulfide bonds in keratin
• Removal of melanocytes from the bulb
• Loss of dermal papilla blood supply

Correct Answer: Disruption and reformation of disulfide bonds in keratin

Q30. In pharmacology, targeting follicular stem cells in the bulge would most directly affect which outcome?

• Sebum production rate only
• Long-term follicle regeneration and cycling capacity
• Immediate pigment synthesis without growth change
• Arrector pili contraction strength

Correct Answer: Long-term follicle regeneration and cycling capacity

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