Integument System Flashcards
What are the layers of the integument system?
Epidermis
Dermis
Hypodermis
What are the accessory structures of the skin?
- hair
- nail
Summarize the epidermis of the skin
Epidermis- epithelial tissue
5 layers
4 cells typed
Summarize the dermis
Dermis- connective tissue
2 regions
-nerve corpuscles
What is the hypodermis?
A subcutaneous layer
- NOT part of the skin
- adipose tissue
- connective tissue
- highly vascularized
- nerve endings
Describe the epidermis in detailed
5 layer
-stratified squamous keratinized epithelium
4 cell types:
-Kerwtinicytes, approx. 90%, produce protective protein keratin, water-repellant sealant
Melanocytes- 8% produce melanin determine skin color and absorbs uv light
-malignant melanoma
- Langherhans- macrophages
- Merkel- touch sensor
Give the layers of the epidermis from top to bottom
- Corneum
- Luciderm
- granulosum
- spinosum
- Basale(germinativum)
Describe the Corneum
25-30 layers flag dead cells- corneocytes/shames
Desquamation or shredding is continuous: 4-6 weeks
Keratin- protect underlying layers
Describe the luciderm
4-6 layers of dead cells
Contain large amounts of keratin
Describe the granulosum
3-5 layers of cells
Organelles begin to die- apoptosis
Keratohyalin protein assembles filaments into keratin
Lamellar granules-releases water repellent material between cells
Describe the spinosum
8-10 Layers of rounded cells
Keratinocytes contain coarser filament
Upper layer flatter in shape
Deepest layer highly active
“Spines” are appearent
Describe the basale
Actively dividing cuboidal- columnar cells
Stem cells produce new keratinocytes
Contain filaments which attach to desmosomes
Desmosomes anchor cells to each other.
Hemidesmosomes anchor cell to basement membrane
What is the papillary dermis?
- interdigitates with epidermis - anchor, increased surface area - dermal papillae
- thin collagen and elastic fibers - strength and elasticity
- capillaries
- nerves - free endings, Meissner’s corpuscles (touch receptors)
What is Resticular Dermis?
- Bundles of collagen fibers, thick elastic fibers- strength, elasticity
- cells- fibroblasts, macrophages
- glands, hair follicles
- nerves, blood vessels
What is the function of hair?
-protects from sunlight , frictions, heat loss, foreign particles
What is hair?
Extension of keratinized epithelium of Skin
Shaft- extends above the skin
Root- below the skin penetrating into the dermis
-Surrounded by hair follicle - two epithelial sheaths
Explain the structure of the root and shaft
- Inner concentric layer: medulla-irregular cells and pigment granules, air spaces
- Middle concentric layers: cortex-elongated cells with pigment granules and air spaces
- Outer concentric layers: cuticle-single layer of thin flat keratinized cells
- Inner sheath- produced by hair matrix (germinal layer of cells)
- Outer sheath- downward continuation of the epidermis-at the base contains only the stratum basale layer
- Dermal root sheath- surrounds the hair follicle
Describe hair papilla
- loose connective tissue with capillary loop
- located in the bulb
What are the functions of the stratum basale of the hair?
Gives rise to the hair matrix
- responsible for the growth
- replacement of hair after shredding
- produced the internal root sheath
What are nails?
Tightly packed keratinized epidermal cells
Explain the parts of the nail
Stratum corneum
-Body (plate) - hardened keratin
- Hyponychium (nail bed) -anchors nail to the fingertip
- Eponychium(cuticle)
- Lunula -white crescent shaped
Stratum basale
- Matrix-deep to nail root, highly mitotic
Root-proximal part of the nail
Free edge
Describe sebaceous glands
Sebaceous gland- simple, branched acinar
Absent on soles and palms
Sac like base
Lumen filled with cells
Mostly empties at neck of hair follicle
Describe the sudoriferous sweat gland
Sudoriferous -sweat gland
Eccrine/Merocrine
-simple coiled tubular
Abundant on forehead, palms, soles
Excretory
Describe the apocrine sweat gland
Simple coiled tubular
Axilla, aerola
Adolescents
