Histology of Integumentary System Flashcards
integument
aka skin = cutaneous membrane
derma
skin
Integumentary System
organ because takes on more than one type of tissue
- largest in the body
includes: skin and derivatives (hair, nails, and glands)
Fans of Integumentary System
- protection (keeps stuff out, abrasion, toxins (if substance is fat soluble then it can move across skin)
- Hydroregulation- prevention in water loss
- temperature regulation- sweat glands and blood vessels
- vitamin D synthesis
- immune response
- sensory reception
- excretion (glands, lose sweat)
Two tissue layers
Epidermis and Dermis
Dermis
hypodermis aka subcutaneous layer
-mostly fat and areolar CT
Subcutaneous layer
connects skin to muscle
Epidermis (general)
- cells are keratinized squamous epithelium
- thickness varies 4-5 recognizable layers
- most cells are dead:deepest are alive (stratum basale)
- hairs and glands arise from epidermis that extends into dermis
Epidermal Layers (deepest to most shallow)
Stratum Basale Stratum Spinosim Stratum granulosum Stratum lucidum Stratum corneum (outermost)
Stratum Basale
- one layer of cuboidal cells on basement membrane
- main cell typesKeratinocytes- alive and produce keratin (constantly divides) -stem cells—-cells die as keratin accumulates (they end up in all cell layers)Melanocytes: produce pigment melanin; protects vs UVR (single cell pigment)Tactile Cells (merkel cells)- close contact with nerve ending
Stratum Spinosim
Some cell division- immune response cells (dendritic cells)
Stratum granulosum
keratinization begins here, and cells begin to die (immune response)
Stratum lucidum
in thick skin only not necessarily a callus
Stratum Corneum (outermost)
Cornfield cells (dried and flattened keratinized cells); are dead 20-30 layers of cells
- especially thick on palms of hands and soles of feet
- forms calluses and nail
Dermis (general)
Irregular dense CT- made of collagen fibers and some areolar CT
- Deeper and thicker layer than epidermis
- Dermal papillae interface with epidermal ridges
- Fingerprints and toe prints are caused by friction ridges
-CONTAINS: blood vessels, nerves, glands, hair follicles, and arrestor pili muscles
