30 Questions
Which of the following is NOT a function of the integumentary system?
Regulates blood sugar levels
What is the main component of the integumentary system besides the skin layers?
Accessory structures like hair, skin glands, and nails
Which layer of the epidermis is rich in dead and flattened keratinocytes packed with eleiden?
Stratum lucidum
Where is an additional layer of skin present between the stratum corneum and stratum granulosum?
Palms and soles
Which cell type is responsible for synthesizing keratin in the epidermis?
Keratinocytes
Which part of the body has the thickest skin?
Fingertips
What is the function of the water-repelling glycolipid released by keratinocytes in the stratum spinosum?
Prevent water loss from the body
What type of cells located in the basal layer are responsible for regenerating the epidermis?
Stem cells
Which epidermal layer is replaced entirely approximately every 4 weeks?
Stratum corneum
Which function of the integumentary system involves the detection of heat, cold, and other sensations?
Detects heat, cold, and other sensations and regulates body temperature
Which protein-lipid complex gives cells in the stratum lucidum their transparent appearance?
Eleiden
Which type of epidermal cell makes up approximately 90% of all epidermal cells?
Keratinocytes
What is the main function of elastin fibers in the deep reticular dermis?
Providing elasticity
Which layer of the dermis contains finger-like projections called dermal papillae?
Superficial papillary dermis
What is the main function of collagen fibers in the deep reticular dermis?
Providing structure and tensile strength
Which type of cells in the dermis are responsible for immune responses?
Dendritic Cells
Where does the hypodermis lie in relation to the skin layers?
Between the dermis and underlying organs
What is the primary function of mast cells in the dermis?
Initiating immune responses
What is the main function of keratin in the skin?
Support the structure of the skin and protect underlying tissues
Which type of cells in the epidermis are responsible for producing melanin?
Melanocytes
What is the role of Langerhans macrophages in the skin?
Protect skin from infection and stimulate allergic reactions
What is the primary function of epidermal ridges in thick skin?
Decrease friction when in contact with smooth surfaces
Which layer of the skin contains Merkel cells?
Deepest layer of the epidermis
Which type of cell forms the ridges on fingers that result in the formation of fingerprints?
Basal cells
What do melanocytes protect the skin from?
Sun damage and burns
What is the composition of the stratum spinosum?
8-10 layers of keratinocytes
What is a key feature of the dermis in relation to nerve endings?
Rich supply of nerve endings for touch perception
From where do cells of the epidermis derive their nutrition?
Underlying dermis
Which cell type is a precursor of keratinocytes in the epidermis?
Basal cells
What is the role of Langerhans cells within the epidermis?
Interspersed among the keratinocytes in the stratum spinosum
Study Notes
Integumentary System
- Made up of two main components: skin layers (cutaneous membrane) and accessory structures (hair, skin glands, nails)
- Functions: physical barrier, excretes sebum and sweat, synthesizes vitamin D, protects from UV rays, helps heal injuries, detects heat and cold, regulates body temperature
Epidermis
- Composed of 4-5 strata (layers)
- Cells are called keratinocytes (except in stratum basale)
- Devoid of blood supply, derives nutrition from underlying dermis
- Regenerates from stem cells in basal layer
Epidermal Strata
- Stratum basale: single layer of cuboidal-shaped stem cells (basal cells) with melanocytes and Merkel cells
- Stratum spinosum: 8-10 layers of keratinocytes with Langerhans cells
- Stratum granulosum: 3-5 layers of flat, thick keratinocytes with large amounts of keratin
- Stratum lucidum: smooth, seemingly translucent layer of dead and flattened keratinocytes
- Stratum corneum: most superficial layer, exposed to outside environment, helps prevent microbial penetration and dehydration
Epidermal Cells
- Keratinocytes: 90% of epidermal cells, produce keratin, lamellar granules, and release a water-repellent sealant
- Melanocytes: produce melanin, contributes to skin, hair, and eye color, absorbs UV light, protects from sun damage
- Langerhans cells: present in all epidermal layers, role in immune response, protect skin from infection and stimulate allergic reactions
- Merkel cells: found in deepest layer, function as touch receptors, stimulate sensory nerves
Dermis
- Subdivided into two layers: reticular dermis and papillary dermis
- Reticular dermis: dense connective tissue, elastin and collagen fibers, well-vascularized, rich sensory and sympathetic nerve supply
- Papillary dermis: loose connective tissue, fibroblasts, fat cells, small blood vessels, phagocytes, defensive cells, lymphatic capillaries, nerve fibers, and touch receptors
- Contains different types of cells: fibroblasts, dendritic cells, mast cells
Hypodermis
- Lies between dermis and underlying organs
- Contains adipose tissue (trauma absorber)
Test your knowledge on the different layers of the epidermis, including stratum spinosum, stratum granulosum, and stratum lucidum. Learn about the functions and characteristics of each layer.
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