Keratinocytes

Definition

Keratinocytes are the predominant cell type in the epidermis, the outermost layer of the skin. These cells are responsible for the production of keratin, a structural protein that provides strength and protection to the skin.

5 Must Know Facts For Your Next Test

1. Keratinocytes are the most abundant cell type in the epidermis, comprising approximately 90% of the epidermal cells.
2. As keratinocytes mature, they undergo a process called keratinization, where they produce large amounts of keratin and eventually lose their nuclei and organelles.
3. The keratin produced by keratinocytes forms a protective barrier that helps prevent water loss and protects the body from environmental stressors, such as UV radiation and pathogens.
4. Keratinocytes also play a role in the innate immune response by producing antimicrobial peptides and cytokines that help defend the skin against infection.
5. Disruption of the keratinocyte barrier function can lead to various skin conditions, such as atopic dermatitis and psoriasis.

Review Questions

• Explain the role of keratinocytes in the layers of the skin (5.1 Layers of the Skin)
  • Keratinocytes are the predominant cell type in the epidermis, the outermost layer of the skin. They are responsible for the production of keratin, a structural protein that provides strength, flexibility, and a protective barrier to the skin. As keratinocytes mature, they undergo a process called keratinization, where they produce large amounts of keratin and eventually lose their nuclei and organelles, forming the stratum corneum, the outermost layer of the epidermis. This keratin-rich stratum corneum is essential for preventing water loss and protecting the body from environmental stressors, such as UV radiation and pathogens.
• Describe the role of keratinocytes in the functions of the integumentary system (5.3 Functions of the Integumentary System)
  • Keratinocytes play a crucial role in the functions of the integumentary system, which includes the skin, hair, and nails. The keratin produced by keratinocytes is the primary structural component that gives the skin its strength, flexibility, and protective properties. Additionally, keratinocytes contribute to the skin's barrier function by forming the stratum corneum, which helps prevent water loss and protects the body from environmental threats. Furthermore, keratinocytes participate in the innate immune response by producing antimicrobial peptides and cytokines, which help defend the skin against infection, supporting the integumentary system's role in barrier defenses.
• Explain how keratinocytes contribute to the barrier defenses and innate immune response of the body (21.2 Barrier Defenses and the Innate Immune Response)
  • Keratinocytes, the predominant cell type in the epidermis, play a crucial role in the barrier defenses and innate immune response of the body. The keratin produced by keratinocytes forms the stratum corneum, the outermost layer of the epidermis, which provides an effective barrier against water loss and environmental threats, such as pathogens and UV radiation. Additionally, keratinocytes contribute to the innate immune response by producing antimicrobial peptides and cytokines, which help defend the skin against infection. This dual role of keratinocytes, in both barrier function and innate immunity, is essential for maintaining the skin's protective function and overall health of the integumentary system.

Related terms

Epidermis:

The outermost layer of the skin, consisting primarily of keratinocytes, which provide a protective barrier against the external environment.

Keratin:

A structural protein produced by keratinocytes that gives the skin its strength, flexibility, and protective properties.

Stratum Corneum:

The outermost layer of the epidermis, composed of flattened, dead keratinocytes that have undergone a process called cornification, providing an effective barrier against water loss and environmental threats.