Skin and Glands Flashcards
Functions and Characteristics of Skin
Protection
Homeostasis
Sensation
Excretory function
Photoconversion of precursors to active molecules (vitamin D)
Importance in clinical diagnosis and treatment
Importance in criminology
Attachment of epidermis to the dermis
Hemi desmosomes send projecting proteins down into the layer
Desmosomes hold cells together
Layers of epidermis
Stratum Cornetum Stratum Lucidum Stratum Germinitivum Stratum Spinosum Stratum Basale
lamellar bodies
Lipids inside cell and then release contents: coats cells w/ water proof fatty material
Thick Skin v. Thin Skin
Thick skin is only found on palms of hand an soles of feet
Everything else is thin skin
Thin has hair thick does not
Thin skin has stratum lucidum thick doesn’t
Changes in pH (more acidic) in the extracellular
environment
permit the activation of proteases (kallikrein-like)
that degrade the desmosomes
allowing the outer layer of cells to be sloughed off
Layers of the dermis
Papillary layer
fingerlike projections into overlying epidermis layer
Reticular layer
Thick bundles of collagen
Langerhan’s cells (dendritic cells)
Antigen presenting cells
Endocytose antigens and transport them to the lymph nodes
Initiate the immune response
Located w/in keratinocytes
protect against environmental concerns
Natural sunscreen
Radiant heating
Evaporative cooling
Pigment in the hair and skin
Melanocytes
processes interacting with keratinocytes
Dark skinned people:
Melanosomes are larger and more resistant to degradation.
Temperature control
Capillaries extend into papillae and warm or cool skin as needed
Sweat gland:
Gland: protein free primary secretion
Duct: absorption of Na+ and Cl-
Normally eccrine
Some Apocrine: more protein: in armpits and groin
Merkel’s cells
Located in stratum basale
Associated with neuron terminal
Abundant in the fingertips
sense of light touch discrimination of shapes and textures
Pacinian corpuscle
- vibration
- rapid changes in state of tissues
- Detects rough v. smooth surfaces
- Histologically looks like an onion
Meissner’s corpuscle
- movement and low frequency vibration
- sensitivity to light touch
- Histologically look like cocoons
