Intergumatory Sytsem Flashcards
What are the three layers of the skin?
Epidermis
Dermis
Hypodermis (sub-cutaneous tissue)
What is found in the epidermis?
Keratinocytes (secrete impermeable keratin)
Melanocytes (release melanosomes with melanin)
Langerhan cells (DC’s which present Antigens to T-cells)
Merkel cells (Mechanoreceptors - sense pressure)
Dermal papillae (Protect against abrasion)
What is found in the dermis?
Sebaceous glands (secrete sebum) Sweat glands (apocrine - with hair follicle, eccrine - without hair follicle) Network of fibres (collagen, keratin, elastin)
What is found in the sub-cutaneous tissue?
Adipose tissue (Unilocular adipocytes - layer of insulation)
Macrophages
Network of fibres (collagen, keratin, elastin)
Network of blood vessels and lymphatics
What are the functions of the skin?
1) Barrier
2) Sensation
3) Thermoregulation
4) Excretion/Secretion
5) Immunity
6) Endocrine
7) Growth
How does the skin act as a barrier?
With impermeable keratin and the strong flexible collagen can protect against:
physical stress, UV radiation, pathogens, chemicals, water (dehydration)
How does the skin allow sensation?
With merkel cells and other receptors: heat, pressure, light, chemicals
How does the skin contribute to thermoregulation?
Efferently with: capillaries, adipose tissue, and sweat glands
Afferently with: thermoreceptors
How does the skin contribute to excretion and secretion?
With sebaceous and sweat glands
How does the skin contribute to the immune response?
With langerhans cells and macrophages
Physical barrier preventing pathogen entry
How does the skin contribute to endocrine control?
With production of Vitamin D from photolysis (VitaminD is stored as calcidol in the kidneys
How does the skin contribute to growth?
With elastic fibres; allows the expansion of the tissue for normal growth and scar tissue
