Module 5 - Integumentary Flashcards
Identify the three layers of the skin in order
Epidermis, dermis, hypodermis
Identify the five layers of the epidermis
- stratum corneum - outer most layer
- stratum lucidum - second layer
- stratum granulosm - third layer
- stratum spinosum - white nuclei
- stratum basale - bottom layer
Tip: “Come Lets Get Sun Burnt”
Describe the stratum corneum
- outer most layer of epidermis
- composed of corneocytes
- these cells serve as protective barrier against environmental factors
- continually sheds dead cells, replacing them with new cells from lower layers
Describe the Stratum lucidum
- second layer of epidermis
- translucent
- found in thick skin of palms and soles
- composed of keratinocytes
Describe Stratum granulosum
- third layer of epidermis
- contains proteins that help form keratin
- plays role in dehydration and hardening of keratinocytes
Describe stratum spinosum
- composed of layers of keratinocytes which are connected by desmosomes
- desmosomes provide mechanical strength to epidermis
- this layer also contains dendritic cells which are involved in immune response
Describe stratum Basale
- Deepest layer of epidermis
- in direct contact with underlying dermis
- contains single layer of cuboidal stem cells which divide to produce new keratinocytes
- responsible for skin regeneration + repair
Identify the four major cell types in the epidermis
- keratinocytes
- Melanocytes
- Intraepidermal macrophages (langerhan’s cell)
4.Tactile epithelial cells (Merkel cells)
Describe keratinocytes
*Develop in basal layer and move up to top layer
*protection to stop pathogens and UV and physical injuries
*Keratin production for strength and flexibility of skin
*Waterproofing – produces lipids to prevent water loss
Describe Melanocytes
*Important for protection as they protect DNA within keratinocytes from UV damage
Describe Intraepidermal Macrophages (Langerhans Cells):
- type of immune cell
- they capture microbes/allergens that come into contact with the skin
- They serve as a crucial component of the skin’s defense against pathogens and play a role in allergic responses.
Describe Tactile Epithelial Cells (Merkel Cells):
- located in the stratum basale
- They are involved in the sensation of touch.
- Merkel cells form synapses (connections) with sensory nerve endings in the skin and play a role in detecting pressure, texture, and shapes.
- These cells are particularly abundant in areas of the body where fine touch discrimination is important, such as the fingertips.
Identify conditions that arise when there is a disruption in homeostasis of the major cells in the epidermis
- Albinism – little or no melanin production (one impacts hair skin and eyes and one impacts only eyes)
- Vitiligo – patches of skin lose their pigment (cow look) ; autoimmune response, genetic factors, oxidative stress, neural
- Skin cancer – basal cell carcinoma, squamous cell carcinoma, malignant melanoma
Describe the sensory function of the skin
1.Mechanoreceptors – respond to physical changes
2.Thermoreceptors – temperature (cold 25-30, warm 30-46)
3.Nociceptors – pain – only signal at tissue damage
Identify the 6 mechanoreceptors of the skin
- Hair follicles
- Meissner corpuscles – indentation and slipping
- Pacinian corpsucles – vibration
- Merkel complexes – texture understanding
- Ruffini corpuscles – stretch
- Tactile epithelial cells – sensitive to touch areas like fingertips, lips, base of hair follicles