HE 35,36 Integument Flashcards
(35 cards)
Major function of the Integument and its two main divisions
protection, vitamin D production, immunologic, sensation though nerves and thermoregulation through sweat.
Integument: epidermins and dermis
Derivatives: hair follicles, sebacious glands, sweat, nails, mammary
Basement Membrane of integument
basil lamina (type IV) and retucular lamina (type III)
basal lamina aka lemina densa, light layer behind it is the lamina lucida
Epidermins and Dermis (General)
epi: dertinized stratified squamous epithelium
- rete riddes (epidermis dropping into dermis)
dermis: loose (close to epi) and Di CT
- papillae: dermis into epidermins
anchoring and adhering jxns between derm/epiderm
Dermatoglyphics
fingerprint ID
- integument grooves and ridges (Gross)
- each person genetically unique
(Much larger than dermal papillae and rete ridges)
Differences between thick and thin skin
refers to teh thickness of the epidermal layer
(thick-hairless palms and soles of feet)
epidermis stayes the same …karatinized layer is what changes
Layers of integument
strateum corneum 9with deam stratum lucidum and thick skin )
stratum granulosum
stratum spinosum (prickle cell layer)
stratum basale (stratum germinatium (germ layer))
Stratum Basale
Single cell layer adjacent to BL
cuboidal to low columnar
vit D productino
Stem cells (only mitotically active layer)
extensive cell jxns
- desmosomes
- hemidesmosomes (tether to BL)
Psoriasis
normal transit tiem from basal cell to desquamation is 50-60 days.
with psoriasis, rapid proliferation shortens to 7 days
stratum spinosum
prickle cell layer
severl layers thick
cuboidal to squamous at surface edge
vit D production
mitotically INACTIVE
cytoplasmic processes (spines) (pm looks like intracellular bridges) it is the desmosomes tethering together
desmosomes at light level, nodes of bizzozero
stratum granulosum
1-3 cells thick
squamous
nucleated
keratohyalin granules (small dark spots)
stratum corneum
variable thickness
squamous
ANUCLEATE
keratinized (PACKED)
-soft keratin made of IF;s
Dermis
papillary layer: loose CT
- more cellular
- lots of ground substance
- loosely arranged fibers
- thin collagen fibers (I, III) same as ret from BL
- thin elastic fibers
reticular layer
- DiCT
- less cellular
- closely packed fiber bundles
- thick collagen fibers
- thick elastic fibers
EVG stain collagen fibers RED elastic fibers BLACK
weigart elastic stain : see more in reticular layer
wound healing
collagen and elastic fibers oriented in parallel lines
LANGER LINES
surgical incisions parallel to langers lines heal faster
- stratum basale ramps up mitosis,
- micration of proliferating cells
- exfoliation (scab falls) of dead keratinocytes
- fibroblasts differenctiate into myofibroblasts
myofibroblasts also involved inclosure via actin/myosin contractile motion
cells of epidermis
keratinocyes
- keratinization
- accumulation of keratohyalin granules is characteristic histological feature that begins in stratum spinosuma nd collects in stratum granulosum
keratohyalin granules
release IF associated protiens liek Filaggrin to aggregate kerativ filaments (IF)
-become TONOfilaments and tono fibrils
stratum corneum just bags full of KG
Lamellar Bodies
Make water barrier by exuding contents via secretion (exocytosis)
-probarrier lipids, lipid processing enzymes, proteases all into intracellular space between SG and SC
cell envelop?
Structures of basal lamina and near
Hemidesmosomes use IF to teather cells to BL
reticular fibers within BL
-type VII collagen used for anchoring loops, attached BL to reticular lamina
focal adhesions function via actin
Cell Junctions
All layers connected by desmosomes
when fixed the stratum spinosum cells shrink and processes more visible
desmosomes tether keratinocytes together
cell jxns undergo proteolytic degredation in pH dependant manner with pH gradient to surface
more acidic activates desmosome degredation
exfoliation of deal cells: desquamation
Melanocytes
neural crest derived
stain electron lucent
migrate into stratum basale
pax 3 differentiates melanocytes (???)
-NO desmosomes
produce melanin granules (get darker as they get more mature)
-skin color differences due to differential maturation of melanin and degredation
(integument pigmenttation determined by melanin content of keratinocytes)
of melanocytes similar across humans
keratinocytes phagocytose melanin granules from extensions to uptake melanin
- leave melanocyte via kinesin
- enter keratinocyte via dynein
Cancers of epidermal origin
basal cell carcinoma, most comon least deadly
squamous cell carcinoma (less com, more dang)
malignant melanoma (least common most deadly)
ABCD rule assymetric border border of legion irregular color variation diameter greater than 6mm
langerhans cells
antigen presenting cells (presenting to t lympocytes)
- originate in bone marrow and migrate to stratum spinosum
- indented nuclei
- NO desmosomes
-rod shaped birbeck granules in cytoplasm ,
express the lectin langerin, inducing formation of birbeck granules , interlalize and degrade HIV?
cytoplasm stains clear, long cytoplasmic processes
Markel Cells
neural crest derived
located in stratum basale
most abundant in fingertipes
contained dense cored neurosecretory granules
-desmosome tetherd to deratinocytes
- synapse with psudounipolar neurons, fucntions for tactile sensation
- clear in tolouine bue
Nerve Types of the integument
Free Nerve Ending
-pain/tamperature/tactile
Pacinian Corpuscle
- deep pressure/vibration
- CT encapsulated Nerve endings
- upper circular (onion) (low in Dermis)
Ruffinis Corpuscle
-tactile
Merkels: only cell type involved
-tactile
Meissners Corpuscle (within dermal papilla)
- tactile
- surface
Derivatives - Hair Follicles
Sebacious glands
-errector pilli muscle associated
Apocrine gland: hair follicle associated
Eccrine gland: not physically part of the hair follicle
Epi Derived: Medulla, cortex (cuboidal cells), cuticle (squamous cells) (last two have most (hard) keratin), internal root sheathe, external root sheath
Dermally Derived: glassy membrane (separates two derivations), CT that extends into base as hair papilla, enclosed by bulb
hair color determined by melanin content and type
