Integumentary system
Skin
 the largest organ in the
body (16-20% of body
weight)
 thermal regulation,
protection from outside
environment, vapor
barrier, mechanical
barrier, excretion of
some waste products,
involved in vitamin D
synthesis, sensory
function (temperature
and touch)
 epidermis
 dermis
Epidermis
− Stratum basale
− Stratum spinosum
− Stratum granulosum
− thin skin (thick layer) – 1 (3-5) layer of cells
− two types of granules
− keratohyalin /large, without membrane,
proteins, LM/
− lamellar /smaller, with membrane, glycolipids,
only in EM, cells release contents of these
granules and fill the entire interstitial space/
− Stratum lucidum
− only in the thick skin
− Stratum corneum
− cells are completely filled with keratin filaments
which are embedded in a dense matrix of
proteins
− stratum disjunctum
Skin thick x thin
Skin as barrier
− Desmosomes, hemidesmosomes
− Intermediary cytokeratine fibers (tonofilaments, static),
traction network – anchored to dermis (collagen)
Profilaggrin – initiation of keratohyalin granules (s. granulosum)
Filaggrin – agreggation of cytokeratin filaments (s. corneum)
Keratin – from keratohyalin granules by action of filaggrin
Ceramids – Odland bodies in stratum granulosum
deposited extracellularly in stratum corneum
Other cells in epidermis
 Keratinocytes
 Melanocytes
 stratum basale
 pigment melanin in melanosomes
 1000-2000 / mm2
 Thin processes among other cells
 cytokrine secretion
 Langerhans cell
 2-8% of epidermal cells
 APC, thin processes between keratinocytes
 Antigen phagocytosis, migration to regional lymph
nodes
 Merkel cells
- mechanoreceptors
TNF-
ACTH
UV
Epidermis - cells
 Keratinocytes
 Melanocytes
 pigment melanin in
melanosomes
 1000-2000 / mm2
 send fine processes
between the other cells
 cytocrine secretion
 Langerhans cells
 2-8% of the cells
 M-M system, their fine
processes form a
network between the
cells of the epidermis and
phagocytose antigens
 can migrate to regional
lymph nodes
 Merkel cells
/mechanoreceptors/
Epidermis - melanocytes
Dermis
 papillary layer (dermal papillae)
- loose, comparatively cell-rich,
capillaries are frequent
 reticular layer appears denser
and contains fewer cells /coarse
collagen fibers and elastic fibers/
 Thick collagen fibres (5-10 µm)
often aggregate into bundles (up to
100 µm thick). The main orientation
of the fibres differs in skin
from different parts of the body their
main orientation will follow the
"lines of greatest tension" in the
skin (Kraissl lines) - surgical
importance.
 This layer contains also smooth
muscle cells /more – skin of areola
around nipple, tunica dartos
scroti../
Appandages of the skin
Gll. sudoriferae eccrinae
Eccrine sweat
glands
 the regulation of body
temperature
 the skin contains
2-3,000,000 sweat gland
which are found all over the
body - with the exception of
parts of the external
genitalia
 simple tubular glands
 secretory portion
 duct portion
 excretory duct
 intraepidermal duct
 the secretory tubulus and
the initial part of the
excretory duct are coiled
into a roughly spherical ball
Eccrine sweat glands
 The secretory part
 is cuboidal or low
columnar /two types of
cells - light and dark
type/
 a layer of
myoepithelial cells
 basement membrane
 The excretory part
 proper duct - a
stratified cuboidal
epithelium (two layers
of cells)
 intraepidermal
canaliculus
Eccrine sweat glands
intraepidermal canaliculus
Eccrine sweat glands
Apocrine sweat glands
 structure is similar to
that of merocrine sweat
glands
 the lumen of the
secretory tubulus is
much larger
 the secretory
epithelium consists of
only one major cell
type /cuboidal or
columnar/
 the excretory duct
empties the sweat into
the upper part of the
hair follicle
Gll. sudoriferae apocrinae
Apocrine sweat glands
 are much larger than
merocrine sweat glands
 only in some parts – gll.
sudoriferae axillares, gll.
areolares mammae
/Montgomery/, gll.
sudoriferae circumanales..
 they are stimulated by
sexual hormones
 apocrine sweat is a milky,
proteinaceous /also
steroids/ and odourless
secretion, the odour is a
result of bacterial
decomposition
Sebaceous glands
 empty product into the
upper parts of the hair
follicles x are also found in
some of the areas where no
hair is present (lips, eyelids,
external genitalia – labia
minora)
 exception: palmes and
soles
 branched alveolar glands
 alveoli full of cells, without
lumen
 holocrine secretion
 duct – short, s.s.epi
Hair
 The free part of each
hair is called the shaft.
 The root of each hair is
anchored in dermis and
usually partly also in
hypodermis.
 The deepest end of the
hair root forms an
enlargement, the bulb.
Cells in the bulb are
mitotically active. These
cells differentiates into
the cell types which form
the hair and the cells
that surround its root,
the root sheath.
Hair
 Scapus and radix pili
 Medulla
 Cortex
 Cuticula pili
 Folliculus pili
 Internal root sheath
 Cuticula vaginalis
 Huxley´s layer /1-3/
 Henle´s layer /1/
 External root sheath
/=epidermis/
 Connective tissue
sheath /dermal/
 Lamina vitrea
 Inner-circular
 Outer-longitudinal
Hair
vazivová
pochva
Huxley´s
layer
ORS
connective tissue
sheath /dermal/
bulbus pili
Huxley´s
layer
skin with hairs or skin from the axilla ?
skin with hairs or skin from the
axilla ?
Nails
 nail plate
 closely compacted, keratin enriched
with hard interfibrillar material, it is the
stratum corneum of the nail
 nail root
 stratum basale and spinosum of
epidermis are present here forming
nail matrix cells which synthesize the
nail plate
 nail bed
 epithelial : stratum basale and stratum
spinosum of nail, does not contribute
to nail synthesis
 dermal : corium /papillae – capillaries/
 eponychium: junction between skin
stratum corneum and base of nail
plate
 hyponychium: junction between the
skin stratum corneum and the tip of
the nail plate
Nail
longitudinal section
cross
section
Nail
Glandulae mammae
 are modified apocrine
sweat glands of the
skin
 branched tuboalveolar
glands, which consist of
15-25 lobes separated
by dense interlobar
connective tissue and fat
 each lobe contains an
individual gland with
the excretory duct of
each lobe, /lactiferous
duct/, has its own
opening on the nipple
Mamma non lactans
only ducts
Mamma non lactans
Mamma lactans
 Alveoli
 the basement membrane
 a layer of myoepithelial cells
 the epithelium
 Ducts
 Intralobular - small - cuboidal
cells, than columnar cells
 Lactiferous ducts – two
layered epithelium - basal cells
are cuboidal whereas the
superficial cells are columnar
 Beneath the nipple, the dilated
lactiferous duct forms a
lactiferous sinus, which
functions as a reservoir for the
milk /stratified squamous epi/
Mamma lactans
Mamma lactans
Skin - list of slides
 69. Skin from the tip of the
finger
 70. Skin from the axilla
 71. Skin with hairs
 72. Nail
 73. Mamma non lactans
 74. Mamma lactans