Integumentary System Flashcards
Integumentary System
Consists of the skin and accessory structures
Functions:
- Protection,
- Sensation
- Temperature Regulation
- Vitamin D Production
- Excretion
The skin
Epidermis,
Dermis,
Hypodermis
Epidermis Cell Types
- Keratinocytes
- Merkel,
- Langerhans
- Melanocytes
Stratum basal
Deepest layer of epidermis,
Attached to underlying dermis
Cells actively divide
Mitosis occurs to form keratinocytes which form more superficial layers of epidermis
Contain Merkel and Melanocytes
Stratum Spinosum
“Spiny” appearance caused by artifacts of histological preparation
Some mitosis seen
Contains Langerhans cells
Stratum Granulosum
Consists of keratinocytes with deep staining granules
Two types of granules
- Keratohyaline granuales - help form keratin
- Lamellated granules - contain a waterproofing glycolipid
Stratum Lucidum
Seen only in thick skin (hands and soles)
Composed od a few rows of flat, dead keratinocytes
Stratum corneum
Thick layer of dead keratinocytes and thickened plasma membrane
Protects skin against dehydration, abrasion and penetration by microbes
Dermis
Richly suppllied with blood vessels and nerves
Has two layers:
- Papillary and reticular
It also has blood vessels, sweat, oil glands, and deep pressure receptors called lamellar corpuscles.
Papillary Layer
- Made of areolar CT, has dermal papillae
Reticular Layer
- 80% of thickness of dermis, dense irregular CT
Hypodermis
Deep to skin
Contains areolar and adipose connect tissue
Anchors skin to underlying structures
Helps insulate the body
Acts as shock absorber
Accessory Skin Structures
Hair
Glands
Nails
Hair
Flexible type of dead, ketanised epithelial structure.
Root and shaft
Three concentric layers of keratinised cells:
- Medulla,
- Cortex
- Cuticle
Sebaceous Glands (oil)
Occur over entire body - except palms and soles
Exocrine glands
Secrete sebum
Most are associated with hair follicle
Function of sebum: softens and lubricates hair and skin
