Podcast
Questions and Answers
Which layer of the epidermis contains cells that participate in the immune response?
Which layer of the epidermis contains cells that participate in the immune response?
- Stratum basale
- Stratum spinosum (correct)
- Stratum lucidum
- Stratum granulosum
Which layer of the epidermis is responsible for the formation of protective, superficial layers of cells filled with keratin?
Which layer of the epidermis is responsible for the formation of protective, superficial layers of cells filled with keratin?
- Stratum lucidum
- Stratum granulosum
- Stratum basale
- Stratum corneum (correct)
What is the basic structural component of hair and nails in humans?
What is the basic structural component of hair and nails in humans?
- Keratin (correct)
- Collagen
- Elastin
- Melanin
Which layer of the epidermis is only present in thick skin?
Which layer of the epidermis is only present in thick skin?
Which layer of the epidermis forms epidermal ridges that extend into the dermis?
Which layer of the epidermis forms epidermal ridges that extend into the dermis?
Which cells dominate the epidermis and form several layers?
Which cells dominate the epidermis and form several layers?
What is the main function of the epidermis?
What is the main function of the epidermis?
Which layer of the epidermis is responsible for the synthesis of pigment by melanocytes?
Which layer of the epidermis is responsible for the synthesis of pigment by melanocytes?
What is the process of the formation of protective, superficial layers of cells filled with keratin called?
What is the process of the formation of protective, superficial layers of cells filled with keratin called?
Which layer of the epidermis is responsible for insensible perspiration?
Which layer of the epidermis is responsible for insensible perspiration?
Which layer of the epidermis is avascular and relies on the diffusion of nutrients and oxygen from capillaries within the dermis?
Which layer of the epidermis is avascular and relies on the diffusion of nutrients and oxygen from capillaries within the dermis?
Which layer of the epidermis contains the body's most abundant epithelial cells?
Which layer of the epidermis contains the body's most abundant epithelial cells?
Which layer of the epidermis is responsible for the synthesis of pigment by melanocytes?
Which layer of the epidermis is responsible for the synthesis of pigment by melanocytes?
Which layer of the epidermis forms epidermal ridges that extend into the dermis?
Which layer of the epidermis forms epidermal ridges that extend into the dermis?
Which layer of the epidermis contains cells that participate in the immune response?
Which layer of the epidermis contains cells that participate in the immune response?
Which layer of the epidermis is only present in thick skin?
Which layer of the epidermis is only present in thick skin?
What is the process of the formation of protective, superficial layers of cells filled with keratin called?
What is the process of the formation of protective, superficial layers of cells filled with keratin called?
Which layer of the epidermis is responsible for insensible perspiration?
Which layer of the epidermis is responsible for insensible perspiration?
Which layer of the epidermis contains tactile (Merkel) cells?
Which layer of the epidermis contains tactile (Merkel) cells?
What is the basic structural component of hair and nails in humans?
What is the basic structural component of hair and nails in humans?
What is the main function of the epidermis?
What is the main function of the epidermis?
What is the name of the protein that is a tough, fibrous protein and the basic structural component of hair and nails in humans?
What is the name of the protein that is a tough, fibrous protein and the basic structural component of hair and nails in humans?
What is the name of the protein made by keratinocytes in the stratum granulosum that promotes dehydration of the cell as well as aggregation and cross-linking of the keratin fibers?
What is the name of the protein made by keratinocytes in the stratum granulosum that promotes dehydration of the cell as well as aggregation and cross-linking of the keratin fibers?
What is the name of the growth factor that promotes the divisions of basal cells in the stratum basale and stratum spinosum, as well as accelerates the production of keratin in differentiating keratinocytes?
What is the name of the growth factor that promotes the divisions of basal cells in the stratum basale and stratum spinosum, as well as accelerates the production of keratin in differentiating keratinocytes?
Explain the process of keratinization and its role in the formation of protective layers in the epidermis.
Explain the process of keratinization and its role in the formation of protective layers in the epidermis.
Describe the role of epidermal growth factor (EGF) in the epidermis and its source of production.
Describe the role of epidermal growth factor (EGF) in the epidermis and its source of production.
Discuss the characteristics and functions of the stratum lucidum in the epidermis.
Discuss the characteristics and functions of the stratum lucidum in the epidermis.
Study Notes
Epidermis
- The epidermis is a stratified squamous epithelium that provides physical protection, prevents water loss, and keeps microorganisms out of the body.
Characteristics of Epidermis
- Avascular, relying on diffusion of nutrients and oxygen from dermal capillaries
- Epidermal cells with high metabolic demands are found close to the basement membrane
- Superficial cells are dead
Cells of the Epidermis
- Keratinocytes dominate the epidermis, forming multiple layers and containing keratin
- Keratin is a tough, fibrous protein also found in hair and nails
Layers of the Epidermis
- Thin skin has 4 layers, covering most of the body
- Thick skin has 5 layers, covering palms of hands and soles of feet
Stratum Basale
- The deepest layer of the epidermis
- Dominated by basal cells (stem cells) that divide to replace superficial keratinocytes
- Contains melanocytes that synthesize pigment, tactile (Merkel) cells, and hemidesmosomes that attach to the basement membrane
Stratum Spinosum
- Keratinocytes bound together by desmosomes
- Contains dendritic cells (Langerhans cells) that stimulate defense against microorganisms and superficial skin cancer
Stratum Granulosum
- Cells stop dividing and start making large amounts of keratin
- Cells grow thinner, flatter, and their plasma membranes thicken and become less permeable
- Keratohyalin promotes dehydration and aggregation of keratin fibers
Stratum Lucidum
- Only found in thick skin
- A glassy, clear layer with flattened, densely packed cells filled with keratin
Stratum Corneum
- The exposed surface of both thick and thin skin
- Contains 15-30 layers of keratinized cells
- Dead cells remain tightly interconnected by desmosomes
- Cells are shed in large groups or sheets rather than individually
Epidermal Growth Factor (EGF)
- Produced by salivary glands and duodenal glands
- Promotes divisions of basal cells, accelerates keratin production, and stimulates epidermal development and repair after injury
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Description
Test your knowledge of the epidermis with this quiz. Explore the functions and characteristics of the epidermal layer, including its role in providing protection, preventing water loss, and maintaining a barrier against microorganisms.
