Pt 1. Integument and Barriers to Infection Flashcards
2 components of Integumentary System:
► 1) skin
► 2) epidermal derivatives ( nails, hair, sweat &
sebaceous glands and mammary glands)
3 layers of Integumentary System (skin)
Consists of 3 layers: epidermis (ectoderm),
dermis (mesoderm) & hypodermis
(subcutaneous layer=superficial fascia)
Skin categorized as thick and thin (what are the widths in mm?
(>5mm). (1-2mm).
5 General functions of Integumentary system:
◦ Protection – UV light, mechanical, chemical &
thermal insult
◦ Water barrier
◦ Thermoregulation – insulation via hair & SQ fat; heat
loss facilitated by sweating & dermal capillary
network
◦ Metabolic functions- synthesis of the precursors of
Vitamin D; energy stored as fat
◦ Sensation – largest sense organ in the body,
contains receptors for touch, pressure, pain &
temperature
Fingerprints are
produced by
____
and underlying
dermal papillae
and are
permanent
epidermal ridges
What is dermatoglyphics?
the study of ridge patterns of the skin
Tension lines, cleavage lines or Lines of Langer are due
to the arrangement of ____in the dermis
collagen fibers
An incision made ____ to the cleavage lines will result in less gaping, faster healing, and less scar tissue
parallel
Epidermis derived from
ectoderm
Epithelial barrier with the ability to regenerate
Epidermis
Epidermis is what kind of epithelium
stratified squamous keratinized epithelium
Dermis derived from
mesoderm
–mechanical strength
–reservoir of defensive elements
(skin layer)
dermis
connective tissue between superficial fascia and muscle
epimysium or periosteum
____ of the dermis is the subcutaneous layer
hypodermis (superficial fascia)
pertaining to skin
cutaneous
List the 5 layers of the epidermis of thick skin
Stratum Basale (germantivum)
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum (thick only)
Stratum Corneum
Primary epidermal ridge of epidermis interlocks with _____
ridge
subjacent dermal
Epidermal ____ and rete ridges interlock with the dermal ridge
interpapillary peg
Dermal papillae project upward into the _____
epidermal layer
cells of epidermis
keratinocytes
Variable thickness of epidermis
<1 mm to >5
–thick, highly keratinized layer
–restricted to valor (soles) and palmar surfaces
–lack hair (glabrous)
Thick Skin of epidermis
Epidermis supplied and nourished by _____
blood vessels in underlying (subjacent) dermis
Progressive damage to ____ fibers leads to loss of skin tone
elastic (aging–not good with repair)
______ connect the dermal layers with the epidermal layer and fit into pits of epidermal layer
Pegs or Papillae
Basal Keratinocytes of epidermis are anchored to ____ by ____
Basal Lamina. Hemidesmosomes.
Dermis of thick skin has 2 layers:
Papillary and Reticular Layer
Tissue types of Papillary Layer in Dermis
Dense Irregular CT.
Type I collagen/elastic fibers
Tissue types in Reticular Layer of Dermis
Collagen bundles and coarse reticular fibers for support
____ layer of dermis is thicker and contains less cells
Deep reticular layer
Layer of skin containing hair follicles, sweat, and sebaceous glands
Dermis
Dermis interdigitates with underlying ____
hypodermis
Thick collagen bundles and elastic fibers in reticular layer form _____
lines of tension, Langer’s Lines
Acute or chronic autoimmune skin disease, involving formation of blisters (bullae) at space between epidermis and dermis
Bullous Pemphigoid Antigens
Bullae are formed by immune reaction intiated by formation of ______
IgG autoantibodies
The bullae are formed by an immune
reaction, initiated by the formation of
IgG autoantibodies targeting
cytoskeleton linker protein dystonin
(Bullous Pemphigoid Antigen1)
and/or type XVII collagen, (also called
(Bullous Pemphigoid Antigen 2),which
is a component of ______
hemidesmosomes
Blood and lymphatic vessels course through the
___
dermis
Blood and lymphatic vessels course through the
dermis and function in
thermoregulation and nutrition of the skin
located at junction of papillary
& reticular layers
Subpapillary plexus
located at junction of reticular
layer & hypodermis
Cutaneous plexus
located deep within
hypodermis; largest of the three vascular plexi
Subcutaneous plexus
Vascular Plexi used in thermoregulation—in fingertips & ears,
associated with AV shunts containing ____
glomus bodies
glomus bodies reroute blood from ___ to ____ circulation
Bypass capillary bed, re-route blood from arterial
to venous circulation
–Thickened regions of smooth Mm in wall of arterioles, surrounded by connective tissue capsule.
Components of Stratum Basale
Keratinocytes (cuboidal or columnar), rest on basement membrane
–hemidesmosome
–mitotic figures
Components of Stratum Spinosum
Keratinocytes (flatterned polygons) with oval nucleis.
–Desmosomes
–spine-like cell processes (prickle cells)
Components of Stratum Granulosum
Keratinocytes (flatterned cells, flat nuclei)
–Basophilic Keratohyaline Granules (containing Involucin)
–inc tight junctions
Basophilic keratohyaline
granules contain a protein
_____ that interact with
cytokeratin tonofibrils to
produce that protein keratin
(involucin)
Keratinization initiated by release of _____ => rupture of keratohyaline granules &
polymerization of their contents
lysosomal
enzymes
What happens as keratinocytes mature?
Die and lose nuclei
Cells of granular layer contain membrane-bound,
lamellar structures called ____—contain
glycolipids, provide waterproofing coat for skin
cells
keratinosomes
Cells of _______ layer mature to form waterproof
layer of keratinized cells, with glycolipid coating on
surface of epidermis
granular
Components of Stratum Lucidum
–Keratinocytes with no nuclei
–intermediate layer between granulocytes and startum corneum
–forms barrier to water
–found in thick skin
Components of Stratum Corneum
Keratinocytes are flatterned, no nucleus (called squames)
–contain keratin filaments
–aids in a permeability barrier, prevents desication
–continuously exfoliated (dequamation)
dequamation
continuously exfoliated
Neuroectodermal (i.e., of
neural crest origin) dendritic
cells present in epidermis
Melanocytes
Melanocytes quantity and where present
Small # cells, restricted to basal layer
Responsible for production of melanin
melanocytes
Melanin released from melanocytes in organelles called _____
melanosomes
Melanin released from melanocytes in melanosomes and taken up by ____ cells
surrounding epidermal cells
_____occurs when skin cannot produce melanin quickly enough to prev UV injury to blood vessels
sun burn
Two types of melanin—
◦ eumelanin
◦ pheomelanin
eumelanin
dk brown, black pigment)—
present in dark haired individuals
pheomelanin
(red to yellow pigment)—
present in individuals with red or blond hair
lighter skinned individuals produce ____
pigment or digest pigment ____
less or faster
Autoimmune disease => destruction of
melanocytes => depigmentation
Vitiligo
Melanin synthesis under control of pituitary
hormone _____
melanocyte stimulating hormone (MSH)
To produce melanin, tyrosine precursor first oxidized to DOPA (3,4-
dihydroxyphenalalanine) by tyrosinase located in organelles called ____
premelanosomes
To produce melanin,_____ precursor first oxidized to DOPA (3,4-
dihydroxyphenalalanine) by ____ located in organelles called
premelanosomes
tyrosine. tyrosinase.
conversion of _____ to melanin occurs in melanosomes
DOPA
Albinos lack ___, so DOPA & melanin not formed;
tyrosinase
Albinos lack tyrosinase, so ____ & melanin not formed;
DOPA
___ can be used as a marker, to differentiate melanocytes
from keratinocytes containing phagocytosed melanin
Tyrosinase
Useful in distinguishing tumor types, e.g., melanoma vs. squamous
cell carcinoma
Melanin
Functions of Melanin: DNA subject to damage by UV; melanin functions as UV shield to
protect nucleus; inhibits _____
mutagenesis
___ necessary for normal neural development
Melanin
MITF (microphthalemia-
associated transcription
factor)
- regulates the
differentiation of
melanocytes
excess MITF associated
with
melanoma
Lack of MITF associated with
albinism type 1
Name the cell:
phagocytic, involved
in immune responses
◦ antigen-presenting
cells
◦ monitor foreign
antigens that contact
epidermis
Langerhans cells
(fixed tissue M)
Langerhans cells contain distinctive _____
Birbeck Granules (look like tennis rackets)
Langerhans Cells located within
Stratum Spinosum
►Involved in contact
allergic dermatitis
►Contain abundant
cytoplasmic
extentions
Langerhans Cells
Langerhan cells interact with T cells in the ____
lymphatic System
activated T cells then
travel back to the
epidermis through the
blood stream and release
pro-inflammatory
___ to neutralize
the antigen
cytokines
(cytokines amplify the immune response)
inflammatory skin
disorder
◦ initiated by Langerhans
cells
Psoriasis
What happens to the stratum corneum in psoriasis?
it thickens and forms plaques
What happens to the epidermal papillae in psoriasis?
they elongate
Inflam disorder resulting in excess proliferation of
epidermal keratinocytes
from stratum basale to
stratum corneum
Psoriasis
