Week 2 - Integumentary System Flashcards
What is the integumentary System
The skin and its accessory structures
What are the layers of the integumentary system
- epidermis
- dermis
- hypodermis
What are the cell types in the epidermis (4)
- keratinocytes
- melanocytes
- Merkel cells
- Langerhans cells
What are Keratinocyte cells
- The cell which manufactures and stores the protein keratin
- Produces the stratum Basale layer of cells which undergo continous cell division
- Keratinocyte on the surface of the skin is dead
What are melanocyte cells
- Spider shaped cells in the stratum Basale
- Synthesizes melanin which forms pigment shields to protect the nucleus from UV damage
- Provides hair and skin its colour
What are Merkel Cells
- located in the stratum Basale
- functions as a sensory receptor for touch
What are Langerhans cells
- Star shaped cells between keratinocytes
- they ingest foreign substances and activate immune system
- mostly in stratum spinosum
What is the acronym for the layers of the epidermis
Can Lemurs Get Some Bamboo
Come Lets Get Sun Burnt
What are the layers of the epidermis
- Corneum
- Lucidum*
- Grandulosum
- Spinosum
- Basale
What is the Stratum Corneum
- Outermost epidermal layer
- Dead cells
- essentially flat membranous sacs filled with keratin
- Protects from abrasion and biological and chemical assaults
- function - waterproofing and protection
What is the Stratum Lucidum
- Smooth seemingly translucent layer of the epidermis
- 2nd layer
- Only found in the thick skin of palms, soles and feet
- dead and flattened keratinocytes (cells)
function - extra stretch - packed with eleiden, a clear protein rich in lipids, derived from keratohyalin, which gives these cells their transparent (i.e., lucid) appearance
What is Stratum Grandulosum
- nuclei and other organelles disintegrate as the cells die leaving behind keratin (causing it to look grainy?)
- start of waterproofing and keratin production
- grainyappareance due to keratohyalin and lamellar granules (secrete water resistant glycolpids)
What is Structum spinosum
Function - tension resisting and start of keratin synthesis
Includes langerhands cells
Keratinocytes begin synthesis of keratin
What is Stratum Basale
- The deepest epidermal layer and attaches the epidermis to the basal lamina below which lies the dermis
- Consists of 1 layer of mitotic stem cells - where one daughter cell pushed into more superficial layers
- Cells are constantly going through mitosis to produce new cells
- Melanocytes and occasional Merkel cells at epidermal - dermal junction
What are the layers of the Dermis
- Papillary Dermis
- Reticular Dermis
- Hypodermis
What does the dermis contain
- Blood and lymph vessels
- Nerves
- Appendages, hair follicles, nails, glands
What is the papillary Dermis
- Thin sheet of areolar connective tissuewhich projects into the stratum Basale of the epidermis to form finger like dermal papillae
- Contains Meissner corpuscles which are free nerve endings and touch receptors
- Contains abundant small blood vessel
What is the Reticular Dermis
- Makes up of 80% of the dermis
- Made up of dense irregular connective tissue (elastin and collagen fibers)
- Rich sensory and sympathetic nerve supply
- Contains elastin fibres for elasticity of the skin enabling movement
- contains collagen fibres to provide structure and strength, collage also binds water to keep the skin hydrated
What is the hypodermis
- Above the connective tissue wrapping skeletal muscles - not a part of the skin
- well vascularized loose areolar connective tissue and adipose tissue
- Provides insulation and functions as fat storage(energy storage)*
- loosely anchors the skin to the underlying structures*
- where most of the body fat is stored
What are the skin appendages (glands) (3)
- Eccrine glands
- Apocrine glands
- Sebaceous glands
What are Eccrine glands
- Sweat Gland
- Found on the surface of the skin (mostly hands and feet)
- Duct opens in pores on skin’s surface
- Primary component of thermoregulation and thus helps maintain homeostasis
- Secretionis hypotonic (contains mostly water), some salt, antibodies, antimicrobial peptide
What are Apocrine Glands
- Associated with hair follicles in areas such as armpits and gential regions
- Ducts empty into hair follicles
- In addition to water and salts apocine sweat includes fatty acids and proteins (subject to bacterial decomposition and hence BO)
What are Sebaceous glands
- type of oil gland found everywhere except for palms and soles
- Produces sebum secreted into hair follicles
- Sebum helps lubricate and waterproof the skin and hair - prevents water loss from the skin
What makes the epidermis waterproof
Glycolipids
