Integument- Lecture 10/7/21 Flashcards
Functions of the skin
- Protective (Keratin synth, hairs, sebum)
- Sensory (Specialized nerve endings)
- Thermoregulation (sweat glands, control of blood throw)
- Metabolic (Vitamin D synthesis, ion balance)
- Immunological (Langerhan’s cells, wandering lymphocytes)
Integument layers
1) Epidermis
2) Dermis
3) Hypodermis
Thick skin
Locates on palms/soles
- hairless
- Fingerprint grooves
- SSKE
Thin skin
- Everwhere else, usually hair and hair associated glands
- SSKE
Epidermis layers
1) Stratum corneum
2) Stratum Granulosum
3) Stratum spinosum
4) Strutum Basale
Stratum basale
Includes stem cells, melanocytes, and Merkel cells. Hemidesmosomes connect the basale to the basal lamina
Hemidesmosomes
Links keratin to basal lamina, transmembrane: Integrins, collagen XVII
- Peripheral proteins: Plectin, BP230
Bullous pamphigoid
Blistering disease involved with autoantibodies against collagen 17
Stratum spinosum
Prickle cell layer that get that appearance from abundant desmosomes
Desmosomes
Cell-cell connections using Cadherins, Desmogleins and desmocollin
Desmoglein and Desmocollin
Cadherins that span a desmosomes, holding the cells together
Pemphigus
Blistering disease involving autoantibody formation against desmoglein
Impetigo
Staph infection results in serine protease release
Stratum granulsum
Have granules containing filaggrin, loricrin, and trichohyaline
Tonofilaments
Microfilaments that are synthesized in the epidermis
Tonofibrils
In the granulosum, filagrin condenses the fibers
Lamellar granule
Contains lipid particles that serve as a waterproof barrier in the skin
Stratum corneum
Dead cells packed with keratin, has lipid layers and residual desmosomes
Melanocytes
Melanin pigment production, formed from a tyrosinase
Contributors to skin pigmentation
- Dermal capillary bed
- Ingested fat soluble pigments
- endogenous pigments (Bilirubin, hemosiderin)
- Stratum corneum thickness
- Eumelanin/Pheomelanin pigments
Melanocyte
- Neural crest derivative
- Lie superficial to BL
- Synthesize tyrosinase
Melanin cap
Protects the nucleus from UV rays, eumelanin is more effective than phaomelanin
Langerhan cell
Antigen presentation
No desmosomes
Marrow derivative
Merkel cell
Mechanoreceptors
Papillary dermis
Upfoldings into the epidermis
Hairs
Keratinized epithelial structures, can extend to the hypodermis
Characteristics of skin glands
- Simple, coiled tubular gland
- Thermoregulation
- Salt balance
- Has myothelial cells
- Ducts modify secretion
Eccrine sweat glands
Merocrine secretion of Na+
apocrine gland
Product is stored
Ducts do not modify secretion
Develop at puberty
Sebaceous gland
Acinar morphology
Holocrine secretion
Secrete oily sebum, usually associated with hairs
Free nerve endings
- Thermoreceptors
- Mechanorecepptors
- Nocireseptors
merkel endings
-Slow-adapting mechanoreceptors
Meissner’s corpsucle
-Rapidly adapting mechanoreceptors, dermal papilla
Pacinian corsucle
-rapidly adapting mechanoreceptors in the hypodermis