Integumentary system Flashcards
What components are included in the integumentary system?
skin + accessory structures (sweat and oil glands, hair and nails)
What are the 3 layers of skin?
- epidermis
- dermis
- hypodermis (superficial fascia)
What is the epidermis made of and explain keratinization?
superficial epithelial region: layered - thick keratinized stratified squamous epithelium
Keratinization: keratin in epithelium cells which died and provide a tough surface for protection
What is the dermis made of and what is the purpose of vascularization?
dense connective tissue
- blood vessels for blood regulation and nutrition
What is the hypodermis made of and what is its purpose?
adipose tissue and not considered a part of the skin, hence considered subcutaneous
- anchors skin
What are the 4 types of epidermal cells?
- keratinocytes
- melanocytes
- dendritic (Langerhans) cells
- tactile (Merkel) cells
What is the main function and lifespan of keratinocytes?
- produces keratin (protein for strength, flexibility and waterproof)
- 30 days
Where is the stem cell that produces keratinocytes and what is the growth factor?
- in the basal layer
- stimulate growth of keratinocytes and other skin cells
What is the function of melanocytes and where are they located?
- produce melanin which is packed into melanosomes
- deepest layer of epidermis which branches into adjacent cells
Why is melanin important and how does it contribute to different colour skins and tanning?
absorbs and disperses UV rays and protects cells from damage
- to produce melanin which gives colour
Where is the dendritic cells located and how does macrophages contribute to the body?
epidermal dendritic cells (star-shaped); migrates from bone marrow to epidermis
- contains macrophages that activate immune system (capture antigens for T cells)
Where are tactile (Merkel) cells located and what is their role?
the junction between the epidermis and dermis
- sensory nerve endings for touch sensation (texture and shape)
What is the different between thick and thin skin when it comes to layers of the epidermis?
Thick - all 5 layers
Thin - 4 layers
What are the 5 layers of the epidermis?
- Stratum corneum
- Stratum lucidum (only in thick skin)
- Stratum granulosum
- Stratum spinosum
- Stratum basale
What are the cells and fibers that are included in the dermis?
- fibroblasts (production of CT)
- macrophages (immune)
- Mast cells
- WBC
- collagen, elastin, and reticular
What type of innervation and accessories are in the dermis?
nerves, blood vessels, and lymphatic vessels, epidermal hair follicles, oil glands, and sweat glands
What are the layers of the dermis?
- Papillary layers
- dermal papillae - Reticular layers
What makes up the papillary layer and the subcategory?
areolar CT fibers with blood vessels
- Dermal papillae: superficial region of dermis that indents the overlying epidermis
What makes up the dermal papillae?
- capillary loops
- free nerve endings
- touch receptors (Meissner’s corpuscles - sensitivity to light touch)
What important functions do the dermis provides?
- increased SA for O2, nutrition and waste product exchange
- are finger prints
Where are friction ridges located and what are their functions?
on palms and fingers, soles of feet, dermal papillae lie on top of dermal ridges
- enhances gripping ability (friction)
- contributes to sense of touch (SA fir sensory nerves)
- sweat pores in ridges leave unique fingerprints
How are friction ridges unique?
- developed fully before birth
- permanent
- unique pattern
What is the reticular layer of the dermis made of, what is it a source of and when functions does it provide?
thick dense irregular CT (thick collagen fibers in different directions)
- langer’s lines
- strength and resiliency and maintain skin hydration; elastic fibers provide stretch-recoil
What is the hypodermis made of and what functions does it provide?
areolar CT + blood vessels (more supply than in the dermis) and adipose tissue
- anchors skin to underlying structure
- shock absorbers and insulation
- stores fat
