10.2 Skin Flashcards
What are the layers of the epidermis? (5)
Superficial:
Stratum corneum- several layers of flattened keratinocytes
Stratum lucidum- only in thick hairless areas (sole of foot)
stratum granulosum- keratinocytes die and lose nucli
Stratum spinosum-langerhans cells are here
Stratum basale- contains stem cells, keratinocyte proliferation
Deepest:
Come, let’s get sun burned!
What type of cells do melanocytes form from?
What layer is it found in
Neural crest cells.
Found in stratum basale
Where are Langerhans cells located in the skin, and what do they do?
They are located in the stratum spinosum.
They are special macrophages that are capable of presenting antigens to T-cells in order to activate the immune system.
What are the layers of the dermis?
Upper layer: papillary layer: loose connective tissue
Lower Layer: Reticular layer: sweat glands, blood vessels, and hair follicles
What do the Merkel Cells do?
They are sensory cells at the epidermal-dermal junction.
Responsible for deep pressure and texture sensation within the skin.
What do Meissner’s Corpuscles do?
They are free nerve endings that respond to pain.
What do Ruffini endings do?
Respond to stretch
What do Pacinian corpuscles do?
They respond to deep pressure and vibration.
What does the hypodermis do?
It is a layer of connective tissue that connects the skin to the rest of the body.
Contains fat and tissue.
How does sweating work?
- Hypothalamus knows that temperature is too high.
- Postganglionic neurons use acetylcholine to innervate sweat glands and promote the secretion of water with certain ions into the skin.
- Heat is absorbed from the body as water molecules undergo phase change to evaporate.
What does the arrector pili do?
It contracts, causing piloerection, helping to trap a layer of heated hair near the skin.
How do blood vessels respond to cold and heat?
Cold: vasoconstriction
Hot: vasodilation
What is the predominant cell type in the dermis?
Keratinocytes
