Questions and Answers
What organs form the integumentary system?
The skin and its derivatives (sweat and oil glands, hairs, and nails).
What are the two distinct layers that compose the skin?
The epidermis and dermis.
What is the epidermis?
The outermost protective shield of the body composed mostly of epithelial cells.
What is the dermis?
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What is the hypodermis?
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The epidermis is a keratinized stratified squamous epithelium.
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What are the four distinct cell types found in the epidermis?
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What is the chief role of keratinocytes?
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Where are melanocytes found and what do they synthesize?
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What do dendritic cells in the epidermis do?
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What is the function of tactile cells?
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What determines if skin is thick or thin?
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What is the stratum basale?
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What is the stratum spinosum known for?
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What happens in the stratum granulosum?
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What is the stratum corneum?
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Study Notes
Integumentary System Overview
- Comprises the skin and its derivatives, including sweat and oil glands, hairs, and nails.
- Functions mainly include protection, sensation, and regulation of body temperature.
Skin Structure
- Divided into two distinct layers: the epidermis (outer layer) and the dermis (inner layer).
Epidermis
- Formed primarily of epithelial cells.
- Acts as the body's outermost protective shield.
- Contains four distinct cell types: keratinocytes, melanocytes, dendritic cells, and tactile cells.
- Responsible for constant renewal, with a complete new epidermis formed every 25-45 days.
Keratinocytes
- The most abundant cells in the epidermis, primarily producing keratin.
- Keratin provides protective properties; millions of dead keratinocytes are shed daily.
- Cell production is enhanced in areas with frequent friction, like hands and feet.
Melanocytes
- Located in the deepest epidermal layer, these cells produce melanin, the pigment responsible for skin color.
- Play a key role in protecting against harmful UV radiation.
Dendritic Cells
- Also known as Langerhans cells, these originate from bone marrow.
- Serve as immune system activators by ingesting foreign substances.
Tactile Cells
- Present at the junction of the epidermis and dermis; linked with sensory nerve endings.
- Function as a sensory receptor for touch.
Layers of the Epidermis
- Thick skin contains five layers: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.
- Thin skin lacks the stratum lucidum and has thinner strata.
- Thick skin is found in areas prone to abrasion like palms and soles.
Stratum Basale (Basal Layer)
- Deepest epidermal layer, firmly attached to the dermis.
- Known as the "germinating layer," where basal cells divide to produce new keratinocytes.
Stratum Spinosum (Prickly Layer)
- Comprises several layers of cells with intermediate filaments that connect to desmosomes.
- Contains melanin granules and a high density of dendritic cells.
Stratum Granulosum (Granular Layer)
- Thin layer containing one to five cells, where keratinization begins, altering keratinocyte appearance.
Stratum Lucidum (Clear Layer)
- Typically found only in thick skin; provides an extra layer of protection.
Stratum Corneum (Horny Layer)
- The outermost layer made up of 20 to 30 cell layers; accounts for most of the epidermal thickness.
- Composed of keratinized cells that provide the primary barrier to environmental damage.
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Description
Test your knowledge about the integumentary system with these flashcards. Discover the organs that comprise this system, including the skin, hair, and nails. Learn about the different layers of the skin and their functions in protection.
