P1 Structure List - Integumentary System Flashcards
organs of the integumentary system
include the skin and its accessory structures including hair, nails, and glands, as well as blood vessels, muscles and nerves.
function of the integumentary system
- Maintains the body’s integrity
- Maintains temperature
- Converts inactive vitamin D to its active form
- Provides sensory information
- Maintains homeostasis
3 major layers of the skin (cutaneous membrane)
- epidermis
- outer layer
- avascular
- epitheal tissue
- dermis
- inner layer
- vascular
- subcutaneous (aka hypodermis)
- areolar & adipose tissue
- contain nerve endings
epidermis
Contains four major types of cells:
- Keratinocytes (90%): 4-5 layers
- produce keratin (tough, protects), and lamellar granules (release water repellant sealant)
- Melanocytes
- produce melanin (pigment that contributes to skin color and absorb UV light)
- Intraepidermal macrophages
- AKA Langerhans cells
- participate in immune responses by helping immune system recognize invading microbes and destroy them
- Tactile epithelial cells
- AKA Merkel Cells
- detect touch sensations
stratum corneum
- on average 25-30 layers of flattened, dead keratinocytes
- constant friction stimulates callus (abnormal thickening of stratum corneum)
- SHEDDING
stratum lucidum
- ONLY in THICK skin (finger tips, palms, soles)
- flattened, clear, dead keratinoctyes
- provides extra toughness
(think transparent)
stratum granulosum
contains flattened keratinocytes undergoing apoptosis, contains granules (keratohyalin (stains dark), lamellar granules (produce water resistant sealant)
stratum spinosum
8-10 layers of keratinocytes, flatten toward top, intraepidermal macrophages and melanoctyes present here
stratum basale / stratum germinativum
- deepest layer
- contain single row of cuboidal or columnar keratinocytes,
- rapidly dividing
- AKA stratum germinativum (always forming new cells)
dermis
- composed of connective tissue containing collagen and elastic fibers
- dense irregular connective tissue: containing elastic fibers and collagen
- It contains two regions
- The papillary region lies just below the epidermis
- contains thin collagen and fine elastic fibers, dermal papillae (increases surface area)
- All dermal papillae contain capillary loops
- Meissner corpuscles (sensitive to touch) are found here
- contains thin collagen and fine elastic fibers, dermal papillae (increases surface area)
- The reticular region consists of dense irregular connective tissue
- The papillary region lies just below the epidermis
dermal papilae
sudoriferous (sweat) glands
hair follicle
- below the level of the skin
- epithelial root sheath
external + internal root sheath
dermal root sheath
hair papila
sebaceous gland
are connected to hair follicles
another word for oil