Hair follicles, sebaceous and sweat glands, nails !
- Organ
Hair, oil glands, sweat glands and nails grow down from the epidermis into the dermis and help with protection and temperature.
Updated 2026-11-01
See it in 3D: Skin
What it is
Skin appendages are epidermal structures that grow down into the dermis. The hair follicle, with its sebaceous gland and arrector pili muscle, forms the pilosebaceous unit. Eccrine sweat glands cool the body all over the skin, apocrine glands open into follicles in the axilla and groin, and nails are plates of hard keratin made by the nail matrix.
Structure
- Eccrine gland: coiled secretory tubule in deep dermis with clear and dark cells and myoepithelial cells; the duct has two layers of cuboidal cells.
- Apocrine gland: wider lumen lined by cells with eosinophilic cytoplasm.
- Sebaceous gland: lobules of pale foamy cells that fill with lipid toward the centre.
- Hair: medulla, cortex and cuticle, surrounded by inner and outer root sheaths and a glassy membrane.
Function
- Sweating removes heat; eccrine glands receive sympathetic fibres that use acetylcholine.
- Sebum softens hair and the corneum and limits water loss.
- Stem cells in the hair follicle bulge help re-epithelialise wounds.
Clinical notes
- Acne starts in the pilosebaceous unit: plugged follicle, more sebum, bacteria and inflammation.
- Wounds that keep their appendages heal from islands of epithelium inside them; full-thickness loss does not.
- Fungal infection of the nail (onychomycosis) is common in warm, humid climates.
Test yourself
Think of the answer, then tap the question to see it.
What are the parts of the pilosebaceous unit?
The hair follicle with its hair, the sebaceous gland that empties into it and the arrector pili muscle attached to it.
How do sebaceous glands release their product?
By holocrine secretion: the cells fill with lipid and break down entirely to become sebum.
How do eccrine and apocrine sweat glands differ in location?
Eccrine glands are spread over most of the skin and open on the surface; apocrine glands are in the axilla and groin and open into follicles.
Why can a partial-thickness wound heal without a graft?
Epithelial cells from surviving hair follicles and sweat ducts in the dermis grow out and cover the surface.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Skin: epidermis layers, dermis, hypodermis
- Keratinocytes, melanocytes, Langerhans and Merkel cells
- Glands: exocrine vs endocrine, secretion types
- Wound healing: phases and scar
Educational content on normal microscopic structure and its clinical relevance; no substitute for studying slides or for a health professional's advice.
Sources: 5.2 Accessory Structures of the Skin - Anatomy and Physiology 2e | OpenStax (OpenStax, Rice University, 2022); Anatomy of the Skin (National Cancer Institute, SEER Training Modules, 2024).
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Representative model, for educational purposes only.