Functions of the integumentary system
- protection (Form barrier, immune responce, prevent water loss)
- thermoregulation(Sweat cools: Fat insulates)
- Sensation ( touch, pressure, pain, temperature)
- Storage ( lipids and adipocytes)
- Vitamin D Synthesis (Uv light stimulates Sun thesis)
- Excecreation ( water, urea, salts)
Three layers of the integument
- Epidermis (skin)
- dermis (skin)
- hypodermis (fat layer)
What tissue does the epidermidis consist of
Stratified squamous epithelial
3 main cell types of the integument
Keratinocytes: Produce protein keratin,Most superficial cells are dead
Melanocytes: Produce pigment melanin,UV radiation stimulates melanin production, tan
Products against UV radiation
Dendritic Cells: Immune function (macrophages that patrol the skin), Protect against pathogens/cancer
LAYERS OF THE EPIDERMIS
COME LETS GET SUNBURNED
Stratum corneum, stratum lucidium, stratum granulosum, stratum spinosum
Stratum Corneum
“Horny” layer
- Up to 30 layers of dead keratinocytes
- Cells filled with protein keratin
- Protective (cells continually shed)
Stratum Lucidum
Clear layer
- Few layers of thin, flat
- Found only in thick skin (plantar, Palmer Regions)
which layer of the epidermis is only found in thick skin?
Lucidum Eg. Plantar, soles of feet
Stratum Granulosum
- Keratinization begins here
- Keratin fibres bound tightly together by keratohyallin granules
- Gylcolipid granules secreted
Stratum Spinosum
“Spiny” layer
- 8-10 layers tightly joined-living keratinocytes
- Intracellular junctions = desmosomes (form tight barrier)
- Dendritic cells here (immune defence)
Stratum Basale
Bottom layer
- Single layer of living keratinocytes and melanocytes
- vitamin
Facts about the Dermis
- 2nd layer of skin
- Blood vessels/nerves here
- Thick layer off CT
- Various sensory detectors
What are the layers of the dermis?
Papillary (top 20%)
- Tissue= loose areolar CT
- Folds (papillae) form ebidermal ridges
- Tactile corpuscle - sensory receptors detect light touch
reticular (bottom 80%)
- Tissue = dense irregular CT
- Thick network of collagen/elastic fibres
- Lamellated corpuscles - sensory receptors detect pressure and vibration
Hypodermis
Below the skin
Not a layer of the skin (subcutaneous) of the integument
- Tissue=adipose+areolar
FUNCTIONS: Insulation/lipid storage ,Flexible
Sebaceous Glands
- Produce sebum (oily secretion)
- Soften/lubricants hair and skin
- Associated with hair follicles
- Most active during puberty/fetal development
- Functional classification-Holocrine
Sweat Glands (sudoriferous)
- Structural classification=simple tuqabular
- Functional classifications=merocrine
2 types of sweat glands
Eccrine:
- Abundant over body surface, especially in palmer/plantar areas
- cools body
Apporcine:
- Associated with hair follicles in axillary /anogenital areas
- Secretion is viscous/yellowish (contain fat/proteins)
Modified apporcine sweat glands:
Cerminal gland — Secrete ear wax/earumen
Mammary gland — Secretes milk
