Anatomy & Physiology Fundamentals Flashcards

Which layer of the hair follicle wall is immediately adjacent to the hair shaft and is derived from the outer root sheath?

Answer: Cuticle of the inner root sheath

The cuticle of the inner root sheath directly surrounds the hair shaft and interlocks with the hair shaft cuticle to anchor it in place.

What is the primary function of the dermal papilla at the base of the hair follicle?

Answer: Supply nutrients and growth signals to matrix cells

The dermal papilla contains blood vessels and fibroblasts that deliver nutrients and signaling molecules to the matrix cells in the hair bulb to sustain hair growth.

In the context of electrolysis, which structure must be permanently damaged to prevent hair regrowth?

Answer: Dermal papilla and germinal matrix

Permanent hair removal requires destruction of the dermal papilla and germinal matrix cells, which are responsible for producing new hair shaft cells.

The catagen phase of the hair cycle is best described as:

Answer: A transitional regression phase where the follicle shrinks

Catagen is a short transitional phase (2–3 weeks) during which the hair follicle regresses and the lower follicle undergoes apoptosis.

Which autonomic nervous system division controls the contraction of arrector pili muscles, causing goosebumps?

Answer: Sympathetic nervous system

The sympathetic nervous system releases norepinephrine to stimulate smooth muscle contraction in the arrector pili, erecting the hair.

Which of the following accurately describes the epidermis?

Answer: It is avascular and receives nutrients by diffusion from the dermis

The epidermis is avascular and lacks blood vessels; it receives oxygen and nutrients by diffusion from capillaries in the underlying dermis.

Langerhans cells in the epidermis serve primarily as:

Answer: Antigen-presenting immune cells

Langerhans cells are dendritic immune cells in the epidermis that capture antigens and present them to T lymphocytes to initiate immune responses.