Integument Flashcards
What are the characteristics of the epidermal ridges?
primary dermal ridge
secondary dermal ridge
interpapillary peg
dermal papillae
The primary and secondary ridges?
- primary dermal ridges form fingerprints and not found on forehead, ext ear, perineum, scrotum
- secondary dermal ridges occur in double rows, and thin collagenous, reticular and elastic fibers
What are the Dermal Papillae?
upward projections from the secondary dermal ridges.
What are the functions of the integument system? (list 6)
Protection
Prevent dessication
Bacterial protection
UV raditation protection
Thermoregulation and blood pressure
Synthesize provitamin D
List the layers of the skin from deepest to superficial.
Stratum basale (germinativum)
Stratum spinosum
Stratum granulosum (represented by few cells in thin skin)
Stratum lucidum ( not in thin skin)
Stratum corneum
Keratohyalin aggregates do what?
Fillagrin induce cross-linkage of keratin
No limiting membrane
What characteristics play a role in Stratum spinosum
Polyhedral shaped cells
Keratohyalin granules develop
Lamellar bodies: contain lipids, carbs, hydrolytic enzymes
Tonofibrils: form intercellular bridges.
What is the purpose and components of the Stratum basale (germinativum)
Columnar to high cuboidal keratinocytes
Single layer of cells held by desmosomes and hemidesmosomes to hold the basal lamina
Mitotic activity affected by chemotherapeutic and radiation treatments
Stratum lucidum
Flat keratinocytes lacking nuclei and organelles
Only in thick skin
Contains eleiden
Stratum Corneum
Enucleated, flattened, dead keratinocytes
Cytoplasm is replaced by keratin
Cytoplasm contains: keratin cross-linked with filaggrin to form the cornified cell envelope
What makes up the Cornified Cell Envelope?
Extracellular layer: multi-lamellar lipid covalently linked to involucrine
Intracellular layer: small proline rich proteins, loricrin, fillagrin/keratin complex, involucrine
What are characteristics of the Dermis?
Dense fibrous irregular CT under epidermis
From embryonic mesoderm
Induces development of epidermis and epidermal derivatives
- papillary layer is loose CT with network of elastic fiber and abundant capillaries
- reticular layer is dense irregular CT, with fibrocytes, macrophages, and adipocytes
What cells are contained within the Dermis?
Keratinocytes
Langerhans Cells
Merkel Cells
Melanocytes
What do the Merkel cells do, and where are they at?
Contain mechanoreceptors that can act as diffuse neuroendocrine cells
Within the stratum germinativum
Have catecholamine-like granules
What do the Langerhans Cells do?
Birbeck granules
Antigen-presenting cells. Primary in stratum spinosum
Migrate from epidermis to lymph nodes
What are characteristics/components of the Melanocytes?
Do not form desmosome attachments in epidermis
Inject melanin granules into keratinocytes
Pathway of the melanin formation
Tyrosine–> 3,4-dihydroxyphenylalanine (DOPA)–> dopaquinone–> melanin
Tyrosine is required
What are the embryonic derivative of the epidermis?
Periderm: sloughs off to form vernix caseosa
Inner cuboidal germinal layer: continue to proliferate to form adult layers of epidermis and derivatives
Fingernails form in 10 wks, and hair buds at 12 wks.
Describe the characteristics of stratum spinosum.
- polyhedral shape
- keratin 1 and 10
- lamellar bodies oflipid, carbohydrates, hydrolytic enzymes
- tonofibrils remain after staining process
What helps to make up the stratum basale?
- columnar keratinocytes
- keratin 5 and 14
- joined by desmosome and hemidesmosomes
- high mitotic activity
What layer of skin contain keratins 2 and 9, and what other things can you tell me about it?
- stratum granulosum
- flat nucelated keratinocytes
- fillagrin induces keratin cross-links
- have tonofilaments
What is in the stratum lucidum?
- flat keratinocytes. no nuclei or organelles
- contains eleiden
- only in thick skin
Stratum corneum contains what cells and is how many layers thick?
- 5–>50 layers
- enucleated, flattened, dead keratinocytes
- keratin replaces the cytoplasm
The extracellular cornified cell envelope consists of what?
-multi lamellar lipid covalently linked to involucrine
What is contained in the intracellular cornified cell envelope?
- involucrine
- proline rich proteins
- loricrin
- fillagrin and keratin.
Describe characteristics of the dermis.What type of CT, where is it derived from, and what are its functions?
- dense fibrous irrgeular CT
- derived from embryonic mesoderm, and forms epidermal derivatives
- its functions to support the epidermis
What tissue makes up the hypodermis, what other cells are contained in this layer?
- loose CT
- contain fat cells to form the panniculus adiposus
What are the two layers of the dermis?
- papillary layer
- reticular layer
What is used to make up the papillary layer?
- loose CT
- network of fine elastic fibers and abundant capillaries
What are involved in the reticular layer of skin? CT, and cell?
- dense irregular CT
- fibrocytes, macrophages, and adipocytes
Where do Langerhans cells come from and what is their primary purpose ?
- dendritic cells derived from monocytes
- they are antigen-presenting cells
- contained majorly in stratum spinosum and carry antigens to lymph nodes.
What are mechano receptors in stratum germinativum?
- merkel cells that contain catecholamine granules
- cause vasoconstriction?
What do not form desmosome attachments? (cell)
- melanocyte derived from melanoblasts
- produce melanin: tyrosine–> dopa–>dopaquinone–>melanin
tyrosinase
The ectodermal cell divide at week 6 or development to form what components?
- periderm: form vernix caseosa
- inner cuboidal germinal layer: proliferates to form adult layers
–fingernails at 10wks
–hair bud/tow nails at 12 wks
What type of gland are sebaceous glands?
- holocrine gland
- produce sebum released into the hair follicle. oily material
What is the real function of sebum?
-produce oil material to maintain flexibility of the hair strands
What type of gland are sudoriferous glands (sweat)?
-merocrine and apocrine
The merocrine sudoriferous glands look like what, and have what ending types?
- coiled, simple tubular secretory portion
- cholinergic endings.
secrete glycoproteins, water and electrolytes
Apocrine sudoriferous glands are found where, and have what types of cells?
- labia majora, areola, axillary and anal regions
- more viscous secretions
- adrenergic innervation
- ceruminous glands and glands of Moll
What makes up a hair follicle?
-root, free shaft, hair follicle
What components are associated with hair follicles?
- sebaceous glands, arrector pili muscle
- hair bulb which contains matrix and vascular dermal papilla
- this is the growing portion of hair
The down growth of the epidermis helps to form what in the hair follicle?
external root sheath
The internal root sheath is formed by what?
the bulb matrix
The hair shaft is formed by what layers?
- medulla
- cortex
- cuticle: free edges extend upwards to interlock with the cuticleof root sheaths to lock hair in place.
What is a significantly important feature of keratinocyte stem cells?
-reestablish erpidermis after a burn
What are the migration pathways of th keratinocyte stem cells?
- bulb epidermis stem cell pathway
- bulb sebaceous gland stem cell
- bulb hair stem cell pathway
What are the signaling pathways to perform teh repair mechanism of kertinocytes stem cell>
- Wnt
- Notch pathways
