A&P Exam 2 (Chapter 5) Flashcards

Questions and Answers

Describe the two basic layers of the skin.

Epidermis; the outermost layer, which provides a waterproof barrier and gives the skin tone. Dermis; layer beneath the epidermis, contains the tough connective tissue, hair follicles and sweat glands.

Identify each layer of the epidermis from superficial to deepest.

Stratum Corneum, Stratum Lucidum, Stratum Granulosum, Stratum Spinosum, Stratum Basale.

Describe each layer of the epidermis in detail.

Stratum Corneum; composed of 15-20 layers of flattened cells with no nuclei. Stratum Lucidum; a thin, clear layer of dead skin cells. Stratum Granulosum; keratinocytes become granular cells. Stratum Spinosum; composed of polyhedral keratinocytes. Stratum Basale; the deepest layer, a continuous layer of cells.

List each type of cell found in the epidermis.

Keratinocytes, melanocytes, Langerhans cells, Merkel cells. Signup and view all the answers

What are the functions of the cells of the epidermis?

Keratinocytes; produce keratin and form a barrier against environmental damage. Melanocytes; produce melanin for skin color. Langerhans cells; protect against infections. Merkel cells; associated with the sense of touch. Signup and view all the answers

List the functions of the epidermis.

Provides a barrier to infection and regulates water loss. Signup and view all the answers

Identify the components of the integumentary system.

Cutaneous membrane and accessory structures (skin, hair, nails, exocrine glands). Signup and view all the answers

Describe the two divisions of the dermis.

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Describe the blood supply of the dermis.

The cutaneous and papillary plexi are blood vessels supplying the dermis, providing circulation and nourishment. Signup and view all the answers

Describe the role of keratinocytes.

Keratinocytes are the predominant cell type in the epidermis, forming a barrier and being key to skin structure. Signup and view all the answers

Identify common disorders of the skin.

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Describe UV light in the production of Vitamin D.

Vitamin D is produced when UVB rays react with 7-dehydrocholesterol in the skin. Signup and view all the answers

Study Notes

Skin Structure Overview

Skin comprises two main layers: epidermis (outer layer) and dermis (beneath the epidermis).
The epidermis serves as a waterproof barrier and influences skin tone.
The dermis contains connective tissue, hair follicles, and sweat glands.

Epidermis Layers

Stratum Corneum: Outermost layer with 15-20 flattened dead cells lacking nuclei. Contains ceramides, cholesterol, and fatty acids to protect against dehydration and stress.
Stratum Lucidum: Clear, thin layer visible in thick skin areas (palms, soles). Composed of dead keratinocytes.
Stratum Granulosum: Contains keratinocytes that transform into granular cells.
Stratum Spinosum: Between the stratum granulosum and basale, with polyhedral keratinocytes.
Stratum Basale: Deepest layer, continuous with active cell division; also known as stratum germinativum.

Epidermal Cell Types

Keratinocytes: Major cell (90%) producing keratin; provides a barrier against environmental damage.
Melanocytes: Pigment-producing cells located in the stratum basale responsible for skin color.
Langerhans Cells: Dendritic immune cells found in most epidermis layers, except the stratum corneum; protect against infections.
Merkel Cells: Receptor cells linked to touch sensation; can develop into Merkel cell carcinoma.

Functions of the Epidermis

Acts as a barrier against infection and regulates water loss through transepidermal water loss (TEWL).
Contributes to skin hydration and color.

Integumentary System Components

Comprises cutaneous membrane (skin) and accessory structures (hair, nails, glands).
Skin, although a few millimeters thick, is the largest organ in the body.

Dermis Divisions

The dermis has two parts: papillary (upper, loose connective tissue) and reticular (deeper, dense irregular connective tissue).

Dermis Blood Supply

Blood vessels from the papillary region are present in the dermis.
Dermis provides cushioning from stress and strain and supplies nutrients to the epidermis.

Keratinocyte Role

Predominantly found in the epidermis, keratinocytes constitute 90% of the epidermal cells, with basal keratinocytes in the stratum basale.

Common Skin Disorders

Melanoma: A serious type of skin cancer.
Basal Cell Carcinoma: The most common skin cancer, usually treatable.
Vitiligo: Loss of skin pigment resulting in white patches.
Dermatitis: Inflammation of the skin.
Psoriasis: Chronic skin condition causing rapid skin cell production, leading to scaling.

Vitamin D Production via UV Light

Vitamin D synthesis occurs when UVB rays react with 7-dehydrocholesterol in the skin.
Optimal UV wavelengths for synthesis range between 270-300 nm; effective when UV index exceeds 3.

Description

Test your knowledge of skin anatomy with these flashcards focused on Chapter 5 of Anatomy and Physiology. The quiz covers the basic layers of the skin and the different strata of the epidermis. Perfect for students preparing for an A&P exam.