Layers Flashcards
List the functions of the skin
Protection, sensation, thermoregulation, metabolic functions, endocrine function
Against what is the skin a mechanical barrier
Air (desiccation)
Water (bloating pruning)
Abrasions (uv, chemical, thermal)
Invasion (microbes immunological)
How does the skin thermoregulate
Hair and subcutaneous adipose tissue help reduce heat loss
Sweating increases heat loss
What are the metabolic functions of the skin
Synthesis of vitamin D
Store house of chloride
What are the two classifications of skin
Thick skin
Thin skin
How is thick skin distinguished
Areas of great friction
Thick epidermis ( thickest stratum corneum)
No hair, sebaceous glands or arector pili muscle
Has sweat glands
How is thin skin distinguished
Thin epidermis
Covers most of the body
No stratum lucidum (only 4 layers)
Has hair follicles, sebaceous glands and sweat glands
List the layers of the epidermis in order
Caroline Lina Gaan saam bella
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
List the layers of the dermis, and say which one is on top
Papillary dermis on top
Reticular dermis
What tipe of cells is the epidermis made of
Keratinized stratified squamous epithelium
What tipe of cells junctions are between epidermis cells
Desmosomes
What are the characteristics of the stratum basale
Single layer cuboidal cells
Cytokeratin filaments
Regenerates other layers
Function of stratum basale
Mitosis takes place here for renewal of epidermal cells
Characteristics of the stratum spinosum
Stratified cuboidal cells
Central nucleus and cytoplasmic extension
Bundles of cytokeratin filaments (tonofibrils)
Function of stratum spinosum
Synthesize cytokeratin filaments which become tonofibrils
Strength for recoil
Characteristics of stratum granulosum
Flattened polyhedral cells
Many tonofibrils and granules
Function of stratum granulosum
Synthesis keratinohyline granules
Function of keratinohyline granules
Form a matrix in which cytokeratin filaments embed which together form keratin
Build up causes nucleus and organelles to degenerate
Function of keratinosomes granules
Fuse with cell membrane to form coating of skin which makes it waterproof
Contain glycolipids which are release between epithelial cells to make epidermis waterproof
Characteristics of stratum corneum
Dead cells
Cells have no nucleus or organelles and cytoplasm is full of keratin
Functions of stratum corneum
Mechanical damage of surface cells are not permanent
Impermeable to water chemicals and micro-organisms
Name the non-keratinocytes in the epidermis
Melanocytes
Langerhans cells
Merkel cells
Characteristics of melanocytes
In stratum basale
Rounded cell bodies with long irregular cytoplasmic extensions
Functions of melanocytes
Manufacture pigment/ melanin granules
Protects dividing cells from uv light
Characteristics of Langerhans cells
In stratum spinosum
Star-shaped cells
Functions of Langerhans cells
Part of the monocyte macrophage system MMS
Uptake foreign material
Characteristics of Merkel cells
In stratum basale
Have nerve endings and vesicle which look like neuroendocrine granules
Functions of Merkel cells
Touch perception
Free nerve endings
Characteristics of papillary dermis
Form superficial dermal papillae
Areolar connective tissue
Many capillaries and temperature and mechano receptors
Have Meissner’s corpuscles
Characteristics of reticular dermis
Dense irregular connective tissue
Thicker larger collagen fibers
Characteristics of dermal papillae
Dermal extensions that project overlying epidermis
Contain capillary loops
Free nerve endings
Functions of dermal papillae
Help adhesion between dermal and epidermal layers
Provide large surface area to nourish epidermal layer
Epidermal ridges characteristics
Increase the contact area with dermis thus enhancing adhesion
Functions of hypodermis
Anchors skin to underlying structures
Stores fat
Shock absorber
Insulation
Pressure receptors
