Lecture 3 (Revised) (Integument System) Flashcards
Integument?
Skin = Dermis + Epidermis
Skin is covered by?
Keratinized stratified squamous epithelium
(epithelium –> BM –> loose CT –> dense CT)
Layers of Epidermis?
-Stratum Corneum
-Stratum Lucidum
-Stratum Granulosum
-Stratum Spinosum
-Stratum Basale
Which layer is only for thick skin?
Stratum Lucidum
Mitotically active region?
Malphigian Layer = Spinosum + Basale
(Cutaneous Burns)
1st Degree Burns?
Can repair dermis
(damage stratum cornea + lucid + granulosum + spinous)
(stratum basale is unharmed)
(Cutaneous Burns)
2nd Degree Burns?
Patient can regenerate lost epidermis from dermis
(damage to all layers)
(sweat glands + hair follicles in dermis can regenerate epidermis)
(Cutaneous Burns)
3rd Degree Burns?
Patient has complete loss of epidermis + dermis
(only skin graft)
(most dangerous because loss of H2O barrier)
Epidermis Cells?
-Keratinocytes (most abundant)
-Langerhans Cells
-Melanocytes
-Merkel Cells
(Epithelial Skin Cancers)
Basal Cell Carcinoma?
Occurs in thin skin only (where sebaceous glands are located)
(affects keratinocytes in stratum basale excess basal cells in area they shouldn’t be (dermis))
(Epithelial Skin Cancers)
Squamous Cell Carcinoma?
Loss of normal (squamous) epithelium appearance of cuboidal or columnar cells
(affects keratinocytes all throughout epithelial layers)
(Epithelial Skin Cancers)
Malignant Melanoma?
Most dangerous form of skin cancer
(affects melanocytes in stratum basal –> migrate into dermis –> invade blood and lymph vessels to spread cancer)
(Epidermis Cells)
Keratinocytes?
(most abundant)
-Produced in stratum basale (move to spinosum and proliferate)
-Cells mature and accumulate keratin filaments
-Start to die in stratum granulosum (move to corneum)
(Epidermis Cells)
Langerhans Cells?
-Found in stratum spinosum
-Derived from mesoderm
-Act as immune cell (migrate into dermis then lymph)
(Epidermis Cells)
Melanocytes?
-Found in stratum basale (germinative) with hemisdesmosomes
-Derived from neural crest cells which allow for migration
-Contain tyrosinase –> produces melanin –> gives skin color
(Epidermis Cells)
Merkel Cells?
-Found in stratum basale of only thick skin
-Specialized keratinocytes (mechanoreceptor cells)
Dermis consists of?
Loose + Dense CT underlying epithelium
(Dermis Layers)
Upper Loose CT Layer?
Papillary Layer
(cells > fibers)
(fibroblasts, mast cells, macrophages)
(part of dermal papillae)
(Dermis Layers)
Lower Dense CT Layer?
Reticular Layer
(fibers > cells)
(type 1 collagen)
(sweat glands, sebaceous glands (thin), nerve fibers, arrector muscle (thin))
Dermis in Thin Skin is same as?
Thick Skin (except thin skin has sebaceous glands and arrestor muscle (for hair))
Structures in Dermis come from?
Epidermis
Hair Follicles are found in the?
Dermis of only thin skin
(down growth of epidermis into dermis)
(usually near oil glands of dermis)
(Hair Follicles)
External + Internal Root Sheaths?
Basal Cells
(surrounded by dense CT within dermis)
Dermal Papillae?
Hair bulb surrounded by root sheath
(located at bottom of hair follicle)
(contains vasculature that nourishes hair)
Hair itself in follicle has 2 layers?
Cortex + Medulla
Eccrine Sweat Glands?
-Most common (watery, non-viscous secretion)
-Derived from epidermal cells invading down into dermis
-Simple cuboidal epithelium
Apocrine Sweat Glands?
-Less common (axillary, areolar, anal regions) (pheromones)
(protein-rich, viscous, odorless)
(glands secrete fluid)
(mammary glands)
Sebaceous (Oil) Glands?
-Located only in thin skin because they develop with hair follicles
-Secrete sebaceous (oil) via holocrine secretion more active after puberty
-Basal cells (from epidermis)
Nails?
Plates of keratinized epithelial cells (dead skin cells)
Nail Layers?
1) Nail Plate (keratinized epithelial cells)
2) Nail Bed (epithelial cells of stratum spinous + basale) (malphigian layer)
3) Nail Matrix (generates cells of nail bed)
Free Nerve Endings?
Unmyelinated axons (nerve tissue) in dermis penetrate up into malphigian layer of epidermis
Meissner’s Corpuscles?
-Present in thick skin (most abundant) + thin skin (identify in upper (papillary) layer of dermis)
(discriminative touch/edge detection)
Discriminative Touch/Edge Detection?
Meissner’s Corpuscles
Pacinian Corpuscles?
-Present in thick skin + thin skin
(identify in lower (reticular) layer of dermis)
(deep pressure + vibration)
Deep Pressure and Vibration?
Pacinian Corpuscles
