Functions of integumentary system
Protection, excretion, maintain body temp, melanin production, keratin production, vitamin D3 synthesis, storage, detection
What is integumentary system made of?
Skin (epidermis, dermis, and hypodermic) hair, nails, sweat glands (sebaceous/ oil and sweat glands)
Epidermis
Provides a barrier against bacteria as well as chemical and mechanical injuries
dermis
between epidermis and hypodermic (subcutaneous)
Papillary Layer
Thin, areolar connective tissue. Cells wander and defend, lymph nodes, blood sensory neurons
dermal Papilla
increased surface area
dermatitis
bruises
recticular layer
thick, main layer, collagen and elastic fibres in dense irregular connective tissue. larger blood vessels, nerve fibres
collagen
provide strength and prevents too much stress, elastic fibres allow for more flexibilities
stretch marks
equal overstretched and wrinkles
tissues associated with integument system
Stratified squamous epithelium,
areolar connective tissue,
dense irregular connective tissue
Avascular stratified squamous epithelium (no blood vessels)
Not as thick as dermis, nutrition via diffusion
Basal surface more metabolic demands
Basal lamina separates from dermis
Keratinocytes
majority
Make keratin
Resist abrasion
Reduce H20 loss
Melanocytes
Produce melanin
Skin color, UV absorption
Transfer melanin granules to keratinocytes
Merkel (tactile) cells
associated with Merkel discs:
touch sensation
Langerhans (dendritic) cells
Immune response
stratum spinosum
The layer of the epidermis that contains several layers of living cells connected by abundant desmosomes
Superficial (oldest)
Stratum corneum
Stratum corneum
“horn layer”, the exposed surface of skin,
Thickest layer : 15 to 30 layers of dead keratinized cells, no organelles
NO CELL DIVISION
Water resistant
Shed and replaced every 2 weeks (Callouses)
Stratum lucidum
