L22. Skin Flashcards
Name characteristics of the skin
- largest organ in the body
- waterproof and protective
- regulates body temperature
- sensory receptors for pain, pressure and touch
What are the 2 layers of the skin
- epidermis
2. dermis
Describe the epidermis
- stratified squamous keratinized epithelium
- contains specialized cell types
- Merkel cell
- Langerhan cells
- melanocytes - gives rise to specialized skin appendages
- sebacous and sweat glands
- hair follicles
Where is the epidermis derived from ( which germ layer)
ectoderm
Which germ layer is the dermis derived from
mesoderm
Describe the dermis
- underlying layer of dense irregular connective tissue
- blood vessels
- sensory nerves
- temperature, pain, touch ( Meisner’s corpuscles)
- deep pressure sensors ( Pacinian corpuscles)
What are Pacininan Corpuscles , and where are they found
deep, reticular layer of the dermis
What are the Meisner corpuscles, where are they located
pain, temperature and touch receptors, located at dermal ridges which are the papillae
What is the hypodermis
loose Connective tissue and adipose tissue
What is the function of the hypodermis
connects skin to underlying tissue and organs
Identify all structures on page 3 of L21. ( draw the stratum corneum , stratum spinosum and stratum basale)
pg 3 L 21
Identify all features of the epidermis
pg 4 L 21
What are the 5 layers of the epidermis ( name from outer to inner)
- stratum coneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
Describe the stratum basale
- stem cells that are undifferentiated
- high mitotic activity
- cell-cell adhesions with desomosomes
- cubodial to low columnar epithelial cells/keratinocytes
- hemidesmosomes at cell-basement membrane interface of the stem cell phenotype
- as the basal keratinocytes move up the stratum layer they begin to differentiate
- contains melanocytes and merkel cells
Why are hemisdesmosomes important in the stratum basale
- needed for attachment of epidermis to dermis layer
2. maintain stem cell phenotype