Chapter 5 Flashcards
Integumentary system
- Epidermis; dermis
- Sweat glands, nails, oil glands, hairs
Integumentary system functions
- Protection
- Temperature maintenance
- Nutrient storage
- Vitam D3 synthesis
- Sensory detection
- Excretion; secretion
Epidermis
Superficial region
1. Epithelial tissue
2. Avascular
Dermis
underlies epidermis
1. Mostly fibrous connective tissue
2. Vascular
Hypodermis
Insulates and cushions
1. Subcutaneous layer deep to skin
2. Mostly adipose or areolar tissue
3. Anchors skin to underlying structures (muscles)
Thins as we age
Keratinocytes
Dead cells in the epidermis
Stratum granulosum
- Grainy layer
- Keratin and kertohyalin (granules)
Stratum lucidum
- Only in thick skin
- Transluscent layer
Stratum basale
- Innermost layero f the epidermis
- Attached by desmosomes
- Only layer which divides, giving rise to keratinocytes
Stratum spinosum
- 8-10 layers of cells attached by desmosomes
- Spiny layer
Keratinization
Keratinocytes undergo keratinization as they move towards the surface
1. Dead cells
2. Keratin is water repellant
Stratum corneum
- Outer layer of dead (keratinized cells)
- 15 to 30 layers
Melanin
Pigment produced by melanocytes; stimulated to produce more by sun exposure
Vitamin D
Needed for calcium absorption
Epidermal growth factor (EGF)
Helps the epidermis repair and heal; promotes:
1. Basal cell division
2. Production of keratin
3. Stimulates glands
4. Stimulates growth and repair
Two layers of the dermis
- Papillary
- Reticular
Papillary layer
- Dermal papillae
- Areolar tissue
- Blood vessels; sensory nerves
- Nourishes the epidermis
- Creates finger prints
Reticular layer
- Dense irregular connective tissue
- Colagen fibers
- Elastic fibers
- Gives the dermis durability
- Blood vessels
- Sensory neurons
Damage to the dermis
Wrinkles (aging)
Cutaneous sensory receptors
- Light touch
- Pressure
- Pain
- Temperature
Accessory structures
- Hair
- Sebaceous glands
- Sudoriferous glands
- Nails
Sebaceous glands
- Produces sebum
- Cause of acne
inhibits growth of bacteria, lubricates hair, and keeps skin soft
Sudoriferous glands
- Apocrine sweat glands - responsible for odor; stimulated by sex hormones
- Eccrine sweat glands - thermoregulation; all over the body
Hair
- Root hair plexus - sensory
- Arrector pili muscle - attached to hair follicle; contraction
Ceruminous glands
In ear, produce waxy cerumen
Nails
- Protection
- Keratinized epidermal cells
Injury and repair process
- Inflammation
- Migratory phase - basale cells migrating (scab formation)
- Proliferation Phase - dermis repairs self
- Scarring phase - inflexible fibrous tissue
