21-00
Skin
and
its Accessories
21-00 Skin and its Accessories

21 Skin and its Accessories
Menu 1/2
21-00.

Skin and its Accessories

21-15.

Duct of sweat gland 1. Transverse section. Human， H-E stain， x 160.

21-001. Skin

21-16.

Duct of sweat gland 2. Passing through the epidermis 1. Human， H-E stain， x 100.

21-01.

Skin of the palm 1. General view. Human， H-E stain， x 3.3.

21-17.

Duct of sweat gland 3. Passing through the epidermis 2. Human， H-E stain， x 160.

21-02.

Skin of the palm 2. Human， H-E stain， x 25.

21-18.

Dermal papilla， containing a Meissner’s corpuscle. Human， H-E stain， x 160.

21-03.

Skin of the palm 3. Dermis. Human， H-E stain， x 64.

21-19.

Meissner’s corpuscle. Silver impregnation. Human， x 100.

21-04.

Skin of thumb tip 1. Human， H-E stain， x 1.7.

21-20.

Pacinian corpuscle 1. Transverse section. Human， H-E stain， x 25.

21-05.

Skin of thumb tip 2. Human， H-E stain， x 5.0.

21-21.

Pacinian corpuscle 2. Longitudinal section， Human，H-E stsin，x 25.

21-06.

Skin of thumb tip 3. Stratum spinosum. Human， H-E stain， x 400.

21-22.

Organ of Hoyer-Grosser 1. Human， H-E stain， x 66.

21-07.

Skin of the thumb tip 4. Stratum germinativum and melanocytes. Human， H-E stain， x 160.

21-23.

Organ of Hoyer-Grosser 2. Human， H-E stain， x 160.

21-08.

Skin of auricula. Melanocytes and Langerhans cells. Human， H-E stain， x 250.

21-24.

Skin of abdomen 1. Human， H-E stain， x 25.

21-09.

Sweat gland 1. General view. Human， H-E stain， x 10.

21-25.

Skin of abdomen 2. Human， H-E stain， x 160.

21-10.

Sweat gland 2. Secretory portions and ducts. Human， H-E stain， x 64.

21-26.

Skin of axilla 1. Human， H-E stain， x 10.

21-11.

Sweat gland 3. Secretory portion and duct， longitudinal section 1. Human， H-E stain， x 130.

21-27.

Apocrine sweat gland 1. Human axilla， H-E stain， x 66.

21-12.

Sweat gland 4. Secretory portion and duct， longitudinal section 2. Human， H-E stain， x 100.

21-28.

Apocrine sweat gland 2. Gl. cerminosa. Human， H-E stain， x 64.

21-13.

Sweat gland 5. Secretory portion and duct， longitudinal section 3. Human，H-E stain， x 160.

21-002. Scalp

21-14.

Sweat gland 6. Transverse section of acinus and duct. Human， H-E stain， x 250.

21-29.

Scalp. Vertical section. Human， H-E stain， x 3.0.

21-30.

Hair follicle. Longitudinal section. Human， H-E stsin， x 25.

21 Skin and its Accessories
Menu 2/2
Longitudinal section of hair and hair follicle. Human， H-E stain， x 160.

21-003. Nail

21-32.

Glandullae sebaceae and arrector pili muscle 1. Human， H-E stain， x 25.

21-48.

Longitudinal section of nail. Human， H-E stain， x 1.6.

21-33.

Glandullae sebaceae and arrector pili muscle 2. Human， H-E stain， x 30.

21-49.

Transverse section of nail 1. Human， H-E stain， x 2.75.

21-34.

Tangential section of scalp 1. Level of the sebaceous glands. Human， H-E stain x 25.

21-50.

Transverse section of nail 2. Human， H-E stain， x 10.

21-35.

Tangential section of scalp 2. Level of the sweat glands. Human， H-E stain， x 25.

21-51.

Transverse section of nail 3. Human， H-E stain， x 25.

21-36.

Tangential section of scalp 3. Level of the deeper portion of hair follicle. Human， H-E
stain x 25.

21-004. Mammary Gland
21-52.

Nipple and mammary gland. General view. Human， H-E stain， x 0.7.

21-37.

Tangential section of scalp 4. Level of the hair papilla. Human， H-E stain， x 25.

21-53.

Nipple. Longitudinal section. Human， H-E stain， x 4.0.

21-38.

Transverse section of hair follicle 1. Human， x 64.

21-54.

Mammary gland on resting stage. Human， H-E stain， x 25.

21-39.

Transverse section of hair follicle 2. Human， x 64.

21-55.

Mammary gland at term， 1. Human， H-E stain， x 2.5.

21-40.

Transverse section of hair follicle 3. Human， x 64.

21-56.

Mammary gland at term， 2. Human， H-E stain， x 25.

21-41.

Transverse section of hair follicle 4. Human， x 64.

21-57.

Mammary gland at term， 3. Human， H-E stain， x 100.

21-42.

Tangential section of scalp 2-1. Human， H-E stain， x 3.0.

21-43.

Tangential section of scalp 2-2. Human， H-E stain， x 3.0.

21-44.

Tangential section of scalp 2-3. Human， H-E stain， x 3.0.

21-45.

Tangential section of scalp 2-4. Human， H-E stain， x 3.0.

21-46.

Tangential section of scalp 2-5. Human， H-E stain， x 3.0.

21-47.

Tangential section of scalp 2-6. Human， H-E stain， x 3.0.

21-31.

21-001Skin
21-001 Skin①②③
Adipose tissue

Retinaculum cutis
21-01 Skin of the palm 1. General view. Human， H-E
stain， x 3.3.

Opening of sweat gland duct

Stratum corneum

Str. lucidumStr. granulosum
Str. germinativum

Dermis21-02 Skin of the palm 2. Human， H-E stain， x 25.

Str. spinosum

①

①

①

①

Str. basale
Str. reticulare(Dermis)21-03 Skin of the palm 3. Dermis. Human， H-E stain， x 64.

①

Epidermis
DermisSubcutaneous tissue21-04 Skin of thumb tip 1. Human， H-E stain， x 1.7.

Sweat glands
Pacinian
corpuscles

21-05 Skin of thumb tip 2. Human， H-E stain， x 5.0.

Pacinian
corpuscles

Intercellular bridges

Intercellular space

21-06 Skin of thumb tip 3. Stratum spinosum. Human，
H-E stain， x 400.

Stratum spinosum

Stratum basale

21-07 Skin of the thumb tip 4. Stratum germinativum
and melanocytes. Human， H-E stain， x 160.

Stratum basale21-08 Skin of auricula. Melanocytes and Langerhans
cells. Human， H-E stain， x 250.

Epidermis

Dermis

Duct

Duct

AdiposetissueAcinus21-09 Sweat gland 1. General view. Human， H-E stain，
x 10.

Duct

AcinusAcinusDuct21-10 Sweat gland 2. Secretory portions and ducts.
Human， H-E stain， x 64.

Duct
Duct
Lumen of acinus

Lumen of duct
Myoepithelium
21-11 Sweat gland 3. Secretory portion and duct，
longitudinal section 1. Human， H-E stain， x 130.

Myoepithelium

Acinar cells
Myoepithelium
Lumen of duct21-12 Sweat gland 4. Secretory portion and duct，
longitudinal section 2. Human， H-E stain， x 100.

21-13 Sweat gland 5. Secretory portion and duct，
longitudinal section 3. Human，H-E stain， x 160.

21-14 Sweat gland 6. Transverse section of acinus andduct. Human， H-E stain， x 250.

21-15 Duct of sweat gland 1. Transverse section.
Human， H-E stain， x 160.

Duct in str. corneum

Stratum lucidum
Stratum granulosum

Stratum spinosum

Duct in str. spinosum

21-16 Duct of sweat gland 2. Passing through theepidermis 1. Human， H-E stain， x 100.

Stratum granulosum

Stratum spinosum

Duct21-17 Duct of sweat gland 3. Passing through theepidermis 2. Human， H-E stain， x 160.

cap

M

cap

21-18 Dermal papilla， containing a Meissner’s
corpuscle. Human， H-E stain， x 160.

21-19 Meissner’s corpuscle. Silver impregnation.
Human， x 100.

21-20 Pacinian corpuscle 1. Transverse section. Human，
H-E stain， x 25.

21-21 Pacinian corpuscle 2. Longitudinal section，
Human，H-E stsin， x 25.

V

A
V

An
Nerve

Nerve
An

An

21-22 Organ of Hoyer-Grosser 1. Human， H-E stain， x 66.

Epitheloid cells

V

Lumen of anastomosis

21-23 Organ of Hoyer-Grosser 2. Human， H-E stain，
x 160.

DermisSweat gland

21-24 Skin of abdomen 1. Human， H-E stain， x 25.

21-25 Skin of abdomen 2. Human， H-E stain， x 160.

21-26 Skin of axilla 1. Human， H-E stain， x 10.

Duct

Nerve

21-27 Apocrine sweat gland 1. Human axilla， H-E
stain， x 66.

21-28 Apocrine sweat gland 2. Gl. cerminosa. Human，
H-E stain， x 64.

21-002
Scalp
21-002 Scalp

Adipose tissue

Retinaculum cutis

Galea
aponeurotica
21-29 Scalp. Vertical section. Human， H-E stain， x 3.0.

21-3821-39

Connective tissue sheath
Glassy membrane
Outer root sheath
Inner root sheath
Cortex
Medulla21-40
Retinaculum cutis

21-41

Hair papilla21-30 Hair follicle. Longitudinal section. Human， H-E
stsin， x 25.

Connective tissue sheath
Glassy membrane
Stratum cylindricum
Stratum spinosum
Henle’s layer
Huxley’s layer

Cuticle of innerroot sheath

Cuticle of hair

Cortex of hair

21-31 Longitudinal section of hair and hair follicle.
Human， H-E stain， x 160.

Outer root
sheathInner root shathDuct of sweat gland

Sebaceous glands

Sweat glandArrector pili muscle
21-32 Glandullae sebaceae and arrector pili muscle 1.
Human， H-E stain， x 25.

21-33 Glandullae sebaceae and arrector pili muscle 2.
Human， H-E stain， x 30.

Sebaceous gland
21-34 Tangential section of scalp 1. Level of thesebaceous glands. Human， H-E stain x 25.

M

Sweat gland

21-35 Tangential section of scalp 2. Level of the sweat
glands. Human， H-E stain， x 25.

21-36 Tangential section of scalp 3. Level of the
deeper portion of hair follicle. Human， H-E stain x 25.

21-37 Tangential section of scalp 4. Level of the hairpapilla. Human， H-E stain， x 25.

⑤

③

⑥

②
①

④

⑦

⑧

21-38 Transverse section of hair follicle 1. Human， x 64.

⑤
③

②

⑥
④

⑦
⑧

①

21-39 Transverse section of hair follicle 2. Human， x 64.

③
②

⑤
④

⑥

①
⑦
⑧

21-40 Transverse section of hair follicle 3. Human， x 64.

③
②

④
⑤
⑥

①
⑦

⑧

21-41 Transverse section of hair follicle 4. Human， x 64.

21-42 Tangential section of scalp 2-1. Human， H-E
stain， x 3.0.

21-43 Tangential section of scalp 2-2. Human， H-E
stain， x 3.0.

21-44 Tangential section of scalp 2-3. Human， H-E
stain， x 3.0.

21-45 Tangential section of scalp 2-4. Human， H-E
stain， x 3.0.

21-46 Tangential section of scalp 2-5. Human， H-E
stain， x 3.0.

21-47 Tangential section of scalp 2-6. Human， H-E
stain， x 3.0.

21-003
Nail
21-003 Nail

Nail plate

Eponychium

Proximal nail fold

Nail bed

Nail matrix
Nail root

21-48 Longitudinal section of nail. Human， H-E stain，
x 1.6.

Nail plate
Lateral nailgroove21-49 Transverse section of nail 1. Human， H-E stain，
x 2.75.

Nail plate

PapillaDermis21-50 Transverse section of nail 2. Human， H-E stain，
x 10.

Nail bed

Nail plate

PapillaDermisNail bed

21-51 Transverse section of nail 3. Human， H-E stain，
x 25.

21-004
Mammary Gland
21-004 Mammary GlandNippleLactiferous duct

Glandular lobe
21-52 Nipple and mammary gland. General view. Human，
H-E stain， x 0.7.

Lactiferous sinus

Smooth muscle
fiber bundles

21-53 Nipple. Longitudinal section. Human， H-E stain，
x 4.0.

21-54 Mammary gland on resting stage. Human， H-E
stain， x 25.

21-55 Mammary gland at term， 1. Human， H-E stain，
x 2.5.

21-56 Mammary gland at term， 2. Human， H-E stain，
x 25.

21-57 Mammary gland at term， 3. Human， H-E stain，
x 100.

21-00 Skin and its Accessories

•

•

•

The skin is the organ， which covers the whole surface of the body and accounts for some
16% of the body weight. The skin consists of ectodermal epithelium， epidermis， andunderlying mesodermal dense connective tissue， dermis. Beneath it follows very loose
connective tissue， hypodermis or subcutaneous tissue， which connects the skin looselywith the deeper structures， namely， fascia， peritendineum， and periosteum. In many
places the subcutaneous tissue contains a lot of fat cells ( adipose tissue )， which protect
the interior from the influence of the mechanical power and thermal change of theenvironment. In the skin distribute a number of nerve fibers and many terminal apparatuses ofvarious senses， tactile， pain， temperature， etc. In this meaning， the skin is one of theimportant sense organs.
The epidermis forms an uninterrupted investment over the entire surface of the body and islocally specialized for the production of the skin appendages， hair and nails. It gives rise to
two kinds of glands， namely， sweat glands and sebaceous glands.
The interface between the epidermis and dermis is highly irregular. An intricate pattern of
ridges and grooves on the under side of the epidermis fits into a conforming pattern ofgrooves and ridges on the underlying dermis. The projections of the dermis are called dermal
papillae.

21-001 Skin

21-01 Skin of the palm 1. General view. Human， H-E stain， x 3.3.

••

This is a section of the palm， perpendicular to the surface. Here the skin is very thick and consists of epidermis ( ① )， dermis (② )， and subcutaneous tissue ( ③ ). The epidermis is a thick stratified squamous epithelium， which shows keratinization typically ( see 21-02 ). Into its basal layer project a number of finger-shaped papillae from the dermis. The substance of the dermis
consists of thick collagen fiber bundles running mostly parallel to the skin surface and tightly woven with each other. Beneath thedermis follows a very loose connective tissue， called hypodermis or subcutaneous tissue， containing a lot of fat cells ( adipose
tissue ). From the lower surface of the dermis a number of thin strings of the collagen fiber bundles connecting the skin with the
deeper structures as fascia and peritoneum. They are called retinaculum cutis. In the superficial area of the subcutaneous tissue
there are numerous sweat glands. An arrow indicates the opening of a duct of the sweat gland.
In the dermis and subcutaneous tissue there are numerous blood vessels of larger and smaller calibers.

21-02 Skin of the palm 2. Human，H-E stain，x 25. (1/2)

•
•

•

•

•

Higher magnification of 21-01.
The epidermis consists of following cell layers from the base to the surface: ① Stratum basale，② Stratum spinosum， ③ Stratum granulosum， ④ Stratum lucidum， and ⑤ Stratum corneum.
① and ② are called stratum germinativum， ③ and ④， stratum intermedium.
The cells of the epidermis are continually renewed by mitosis of the cells in the basal layer， andas new cells are formed they are slowly displaced toward the surface of the epithelium by the
proliferation of the cells in the basal layer. In their transit， they differentiate， enlarging andaccumulating increasing amounts of keratin filaments in their cytoplasm. As they approach thesurface， they die and their flake-like lifeless cell bodies are continually shed. Their transit timefrom the base of the epithelium to the surface is 20 to 30 days. Their changing appearance at
different levels in the epithelium makes it possible to distinguish above described zones inhistological sections， perpendicular to the skin surface.
Stratum basale is the undermost layer of the epidermis and consists of a single layer ofcylindrical or cuboidal cells supported by a typical basal membrane. These cells are densely
arranged with each other and perpendicular to the junction line between the epidermis anddermis. Their cytoplasm is intensely basophilic. Mitotic figures are common in this layer.
Stratum spinosum. The cells of this layer are polyhedral of flat polyhedral and have basophilic
cytoplasm. They radiate a number of tiny projections ( spines ) from the surface that unite
tightly with those of the neighboring cells with the desmosome at about the middle portion of
the intercellular spaces ( see 21-06 ). They were called the intercellular bridges in the lightmicroscopic histology. The thickness of this layer varies largely according to the place of the
body. The dermal papillae invade deeply into this layer.

21-02 Skin of the palm 2. Human，H-E stain，x 25. (2/2)

•

•

•

•

Stratum granulosum consists of three to five layers of cells that are somewhat more flattened
than those of the stratum spinosum. The most distinguishing feature of the cells is thepresence of the coarse granules， deeply dark blue stained， in the cytoplasm; they are called
keratohyalin granules. They are believed to be precursors of the keratin. The keratohyalin
granules are more numerously and densely packed， as the cells go upward.
Stratum lucidum is a layer of thin， lightly staining， refractile cells locating between thestratum granulosum and stratum corneum in thick skin， but this is not identifiable in thethinner skin. This layer consists of 4 to 6 rows of very flat cells. The nuclei are usually not
identified. The keratin filaments in the cytoplasm are closely arranged and very flattenedcytoplasm is densely layered parallel to the skin surface.
Stratum corneum consists of many layers of very flat， heavily keratinized cells con- taining no
nucleus or cytoplasmic organelles. As is here seen， stratum corneum is very thick at the palmand sole and occupies more than three fourths of the epidermis. The cells of the lower layersof the stratum corneum are still closely adherent with each other， but in the outer layers， thefully keratinized， lifeless cells loosen and ultimately desquamate. In this figure a duct of sweat
gland penetrates the stratum corneum with a spiral course.
Beneath the epidermis is the dermis， from which numerous dermal papillae deeply invade into
the stratum germinativum.

21-03 Skin of the palm 3. Dermis. Human， H-E stain， x 64.

•

Higher magnification of 20-02. The upper half of this figure consists of epidermis (②， stratum basale and stratum spinosum )and the lower half， the dermis， which is composed of mostly thick collagen fiber bundles running parallel to the skin surface andbeing densely woven with each other. This layer is called stratum reticulare of dermis. The dermis sends numerous finger-likeprojections deep into the stratum germina- tivum; they are called dermal papillae ( ① ). The papillae consist of thinner collagenfibers， running perpendicular to the skin surface and contain the roops of blood capillaries. The dermal papillae are called as awhole statum papillare of dermis. The dermal papillae are the base from which the nutrients of epidermis are supplied.

21-04 Skin of thumb tip 1. Human， H-E stain， x 1.7.

•

This is a transverse section of the thumb tip. The skin of the thumb tip is similar to that of the palm， consisting of thick
epidermis， also thick dermis and very loose subcutaneous tissue， rich in adipose tissue.

21-05 Skin of thumb tip 2. Human， H-E stain， x 5.0.

•

Higher magnification of 21-04. General histological features of the thumb tip are well identified. The epidermis is thick and thebasophilia of the stratum germinativum is evident. The dermis is also thick consisting of densely woven collagen fiber bundles，
which projects numerous finger-shape papillae deeply into the stratum germinativum of epidermis. In the deeper area of thedermis there are several Pachinian corpuscles， the terminal apparatuses of the sense of pressure. In the uppermost area of thesub- cutaneous tissue numerous sweat glands are distributed， whose ducts penetrating the dermis are encountered here andthere.

21-06 Skin of thumb tip 3. Stratum spinosum. Human， H-E stain， x 400.

••

The cells constituting the stratum spinosum are polyhedral in shape and arranged with a narrow intercellular space apposing to
one another. Each cell projects a number of tiny processes from the cell surface， which unite tightly with those of theneighboring cells at about the middle of the intercellular space with desmosomes. They are called， as a whole， intercellularbridges. The nutrients， exuded from the capillary loops in the dermal papillae， go through the intercellular spaces toward thesurface， feeding the epithelial cells， and finally evaporate from the skin surface.
Here， the intercellular spaces and intercellular bridges are evident.

21-07 Skin of the thumb tip 4. Stratum germinativum and melanocytes.
Human， H-E stain， x 160.
•

This is the stratum germinativum surrounded by dermis and dermal papillae. On its surface line columnar or cylindrical cells， thestratum basale. Surrounded by them， polyhedral cells are densely packed， the stratum spinosum. The cells of stratum basalecontain melanin granules in the apical cytoplasm. Among these cells intermingle several large lucent cells with a large nucleus( indicated with arrows ). They are the melanocytes， but they contain no melanin granules. They synthesize the melanin granules
and give them to the cells of the stratum basale. They may appear in the dermis a little apart from the stratum basale.

21-08 Skin of auricula. Melanocytes and Langerhans cells. Human， H-E
stain， x 250.
•

The skin of the auricula is thin; although the stratum germinativum is well iden- tified; stratum granulosum and stratum corneum
are both very thin and no stratum lucidum is perceived. Among the cylindrical cells of stratum basale intermingle threemelanocytes ( upward arrows ). The melanin granules in the apical cytoplasm of the cells of stratum basale are here conspicuous.
Among the cells of the stratum spinosum two Langerhans cells are perceived ( downward arrows ).

21-09 Sweat gland 1. General view. Human， H-E stain， x 10.

•

The whole view of a sweat gland is shown， namely， the secretory portion in the subcutaneous adipose tissue， spiral course of
the duct in the dermis and epidermis are seen.

21-10 Sweat gland 2. Secretory portions and ducts. Human， H-E stain， x64.
•Groups of the secretory portions ( acini ) and ducts of the sweat gland are shown. The wall of ducts with narrow lumen consistsof two layers of cuboidal cells whose cytoplasm stains dark reddish violet. The acinus consists of two layers of cells; the inner，surroundding a relatively large lumen， have a round nucleus and lightly violet staining cytoplasm; the outer， long slender deep
red staining cells containing a long spindle shaped nucleus， the myoepithelium， Both acini and ducts wind up and make balls，
and are densely surrounded by the capillary network. In the middle of this figure an acinus continuing with a duct is seen ( see21-11 ).

21-11 Sweat gland 3. Secretory portion and duct， longitudinal section 1.
Human， H-E stain， x 130.
•

Higher magnification of 21-10. In the lower half of this figure a secretory portion and a duct are continuously observed. The ductconsists of two layers of epithelial cells; the inner cells are cuboidal in shape and contain a round nucleus and their apicalcytoplasm stains dark red， called cuticle; the outer cells are low cuboidal and contain an elliptic nucleus. At the transition fromthe duct to the acinus， the inner cells of the duct become the secretory cells， having the lightly violet stained cytoplasm and around nucleus; and the outer cells of the duct change into the myoepithelium ( indicated by an arrow ). Around the acini andducts very dense capillary networks are developed. Along the upper edge of this figure traverses a longitudinal section of an
acinus.

21-12 Sweat gland 4. Secretory portion and duct， longitudinal section 2.
Human， H-E stain， x 100.
•

This is also a longitudinal section of an acinus and excretory duct of the sweat gland. Of the duct the cuticle encircling the lumen
is evident. In the acinus the acinar cells sur- rounding a narrow lumen have lightly violet stained cytoplasm and a round nucleus.
The myoepithelium consisting of thin long smooth muscle fibers wraps the acinus longi- tudinally ( spirally ). The transition fromthe duct to the acinus is indicated by an arrow.

21-13 Sweat gland 5. Secretory portion and duct， longitudinal section 3.
Human，H-E stain， x 160.
•

This figure shows also the transition from the duct to the acinus of the sweat gland. The transition is indicated by two longarrows. The acinus is sectioned obliquely， so that the arrangement of the smooth muscle fibers ( myoepithelium ) is very
conspicuous ( arrow heads ).

21-14 Sweat gland 6. Transverse section of acinus and duct. Human， H-E
stain， x 250.
••

The histological features of the acinus and duct are evident in this figure. In the acinus light violet stained cytoplasm and roundnucleus， and intercellular secretory canaliculi are clearly observed. The smooth muscle fibers of myoepithelium are cuttransversely and their nucleus are fit into the base of the acinar cells. In the duct the dense apical cytoplasm ( cuticle )of theinner cells encircling the lumen is conspicuous.
dct: duct; my: myoepithelium; ves: blood capillaries;

21-15 Duct of sweat gland 1. Transverse section. Human， H-E stain， x 160.

•

This is a transversely sectioned duct， in the dermis just beneath the epidermis. Approaching the epidermis the duct of thesweat gland is encircled by the cells of the epidermis extending downward， so that it consists of several layers of the epithelial
cells.

21-16 Duct of sweat gland 2. Passing through the epidermis 1. Human， H-E
stain， x 100.
•

Entering into the epidermis the duct of the sweat gland is encircled by the cells of the stratum spinosum and penetrates it withhighly spiral course， and nearing the stratum granulosum cells containing the keratohyalin granules extend downward andencircle the duct. Entering into the stratum corneum the duct loses the structure as a duct and as a highly tortuous spiral gap
extends to the skin surface ( see 21-02 ).

21-17 Duct of sweat gland 3. Passing through the epidermis 2. Human， H-E
stain， x 160.
•

At bottom center of this figure a duct enters into the stratum germinativum. Above it two sections of the duct showing theconcentric arrangement of the cells around the lumen， that shift to the cells of stratun spinosum without any boundary. Further
above is a part of longitudinally sectioned duct， which is enveloped by keratohyalin granule containing cells.

21-18 Dermal papilla， containing a Meissner’s corpuscle. Human， H-E stain，
x 160.
••The dermal papillae are finger shaped projections of dermis extending deeply into the stratum germinativum of the epidermis，
consisting of fine collagen fibers running mostly perpendicular to the skin surface. They contain loops of blood capillaries. Someof them contain moreover the terminal apparatus of tactile sense， Meissner’s corpuscle， They are called the papillae nervosaeand others， papillae vasculares. In this figure there is a papilla containing capillary loop ( left side， cap ) and a Meissner’s
corpuscle ( right side， M ).
The Meissner’s corpuscles are long elliptic structures， about 150μm in length， locating in dermal papillae of palms， soles
nipples， lips， and external genitalia， perpendicular to the skin surface and consisting of numerous cells with elliptic nuclei
arranged parallel to one another and perpendicular to the long axis of the corpuscles. The corpuscle has a moderately thickcapsule. Myelinated nerve fibers reach the lower pole of the corpuscle and enter into it as non-myelinated fibers. They proceedwithin it to the upper extremity with a course of many bendings， among flattened cells that are probably modified Schwann cells( see 21-19 ). The Meissner’s corpuscles are believed as mechanoreceptors.

21-19 Meissner’s corpuscle. Silver impregnation. Human， x 100.

•In this specimen nerve fibers are demonstrated by the silver impregnation. The course of the axons of many bendings isevident. . .

21-20 Pacinian corpuscle 1. Transverse section. Human， H-E stain， x 25.

••

As they are seen in 21-05， the Pacinian corpuscles are large ovoid structures up to one mm in diameter. They are found in thedermis and hypodermis of the skin， in the periosteum of bone， and connective tissue stroma of some organs. A myelinatednerve enters one pole， loses the myelin sheath， and its axon continues in the core of the corpuscle ending as a somewhat
thickened club， which is surrounded by 20 to 60 concentric lamellae consisting of very thin flat cells separated by narrow space
filled with gel-like material of low viscosity. The nerve and its surrounding lamellae are enclosed in a thin connective tissue
capsule.
This figure shows a transverse section of a Pcinian corpuscle， in the thumb tip skin.

21-21 Pacinian corpuscle 2. Longitudinal section， Human，H-E stsin， x 25.

•

This is a longitudinal section of a Pacinian corpuscle， also in the thumb tip skin.

21-22 Organ of Hoyer-Grosser 1. Human， H-E stain， x 66.

•

This is an arterio-venous anastomosis， seen in the dermis of the thumb tip skin， called the organ of Hoyer-Grosser. In thedermis of palms， soles， and finger tips， there are numerous such arterio-venous anastomosis. Under certain circumstances，
these open， shunting blood directly from arteries to veins without an intervening capillary meshwork. Thus， they play animportant role in the thermoregulation. The organ of Hoyer-Grosser consists of arteries， veins and connecting anastomoses，
that are composed of densely concentrically arranged thin and small cells， surrounding a very narrow lumen. These cells are
modified smooth muscle cells， called the epitheloid cells. Artery ( A )， veins ( V ) and anastomoses ( An ) are enclosed together
by the connective tissue capsule， in which several small nerves are observed.

21-23 Organ of Hoyer-Grosser 2. Human， H-E stain，
x 160.
•

This shows the opening from an anastomose into a vein ( V ). The lumen of the anastomose is very narrow and lined by theendothelium. Around it surround the epitheloid cells very densely.

21-24 Skin of abdomen 1. Human， H-E stain， x 25.

•

The skin of abdomen consists of thin epidermis and thick dermis. The epidermis is very thin and so that the dermal papillae are
not conspicuous ( see 21-25 )， but the dermis is thick consisting of dense collagen fiber bundles. Beneath the dermis follows
the subcutaneous adipose tissue， in which some sweat glands are recognized.

21-25 Skin of abdomen 2. Human， H-E stain， x 160.

•

Here， in the epidermis， stratum basale is well identified as a layer of cylindrical cells; stratum spinosum consists of only threeor four layers of polyhedral cells; stratum granullosum is very poor and only three flat cells are perceived at upper left corner.
Stratum lucidum is not identified and stratum corneum is also very thin. Beneath the stratum basale follows loose connective
tissue of fine collagen fibers， among that numerous blood vessels are seen. This layer corresponds to the stratum papillare in
the thick skin.

21-26 Skin of axilla 1. Human， H-E stain， x 10.

•

The skin of axilla consists of thin epidermis and thick dermis. In the epidermis stratum germinativum is well identified whereas
stratum granulosum is poorly developed and stratum corneum is thin and loosely constituted. Beneath the epidermis follow theloose connective tissue and then dermis consisting of densely woven thick collagen fiber bundles. In the deeper region of dermis
and in the subcutaneous adipose tissue there are apocrine sweat glands， glandullae axillares， and also eccrine sweat glands. At
the top center of this figure there is a deep hollow， which is the opening of the follicle of an axillary hair.

21-27 Apocrine sweat gland 1. Human axilla， H-E stain， x 66.

•

Higher magnification of 21-26. At center two sections of the acinus show the typical secretory process of apocrine secretion.
The apocrine gland has a large lumen surrounded by a layer of cuboidal cells. During the secretion， numerous secretory droplets，enveloped by plasma membrane， protrude into the lumen from the apical surface of the acinar cells， then leave from the cellsurface and drop into the lumen as secretory substance. The other sections of acini， consisting of low cuboidal acinar cells，
have no secretory droplets， that means， just after the secretion. At the lower left corner there is a longitudinally sectioned
duct and a nerve fiber bundle.

21-28 Apocrine sweat gland 2. Gl. cerminosa. Human， H-E stain， x 64.

•

The Gl. cerminosa in the outer acoustic meatus is also the apocrine sweat gland. At the lower left corner apocrine droplets
protruding from the apical surface of the acinar cells are evident. In this figure the myoepithelial cells spirally wrapping the acini
are evident.

21-002 Scalp•

The scalp is the skin of the head， from which grow numberless thick hairs. The scalp consists of relatively thin epidermis， thickdermis， and thick subcutaneous adipose tissue. In the dermis there are a number of sebaceous glands attaching to the hairfollicles. In the superficial area of the subcutaneous tissue sweat glands are distri- buted numerously， whose ducts open
independently on the scalp surface. From the inferior surface of the dermis extend numerous thin collagen fiber bundles，
retinaculum cutis， uniting the scalp with the galea aponeurotica.

21-29 Scalp. Vertical section. Human， H-E stain， x 3.0.

•

The general view of the scalp is well demonstrated. Numerous hairs and hair follicles deeply extend obliquely from the surface tothe subcutaneous adipose tissue. In the thick dermis M. arrector pili， attaching obliquely to the hair follicle is recognized， here
and there. Sebaceous gland and sweat gland are evident. From the inferior surface of the dermis extends the retinaculum cutis，
uniting the dermis with galea aponeurotica.

21-30 Hair follicle. Longitudinal section. Human， H-E stsin， x 25.
•

•

•

•
•

The hairs are slender keratinous filaments that develop from the matrix cells of folli- cularinvaginations of the epidermal epithelium. Each hair arises in a tubular invagi- nation of theepidermis， the hair follicle， which extends down into the dermis where it is surrounded byconnective tissue ( see 21-29 ). The follicle has a bulbous terminal with a concavity in its
bottom occupied by a connective tissue papilla. The papilla is covered by epithelial matrix cellsof hair and root sheath. The cells of dome of the convexity form the hair root which develops
into the hair shaft. The free end of the shaft protrudes beyond the surface of the skin.
The epithelial cells around the papilla ( the matrix ) differentiate into several types. (1) The
central matrix cells on the top of the convexity of the papilla develop into the medulla of thehair shaft. The cells are large and vacuolated and eventually keratinize. (2)The next concentric
layer of matrix cells keratinizes and develops into the cortex of the hair， the main constituentof the shaft. Its cells are heavily keratinized and tightly compacted， and they carry most of thepigment of the hair. (3) Peripheral to the matrix cells of the cortex lie those of the cuticle ofthe hair. These cells of the outermost layer are the most heavily keratinized.
The more peripheral concentric rows of matrix cells produce the internal root sheath， atransient structure surrounding the hair shaft below the level of the sebaceous glands. It
consists of three layers. The cuticle of the internal root sheath， like the cuticle of the hair，
consists of overlapping thin scales with their free margins directed toward the bottom of thefollicle. Huxley’s layer consists of one to three layers of cornified cells. Henle’s layer is asingle layer of elongated cells closely adherent to the external sheath.
The outermost layer of the follicle， the external root sheath， is basically similar to theunspecialized epidermal epithelium and is continuous with it above.
This figure shows a longitudinal section of a hair passing through the medulla， so that theconcentric arrangement of the cells constituting the hair and hair follicle is evidently
recognized. The transverse sections indicated by 21-38 ～ 21-41 are shown in the respective
figures.

21-31 Longitudinal section of hair and hair follicle. Human， H-E stain， x
160.
•

Higher magnification of 21-30. The concentric arrangement of the cells constituting the hair and hair follicle is evidently
recognized. Here the outer root sheath consists of stratum cylindricum and stratum spinosum， the same as the stratum
germinativum of the epidermis.

21-32 Glandullae sebaceae and arrector pili muscle 1. Human， H-E stain， x
25.
•

Along the left edge of this figure runs a hair shaft with its follicle obliquely from bottom upward. Right to it there are three lobesof the sebaceous gland that are limited right side by an arrector pili muscle. The ducts of the sebaceous glands unite together
and open into the gap between the hair shaft and outer root sheath. At lower right corner there is a group of sweat glands. The
arrector pili muscle is a thick bundle of smooth muscle fibers which originates at the middle portion of hair follicle and terminates
at the superficial portion of the dermis. Its contraction pulls up the hair and makes it perpendicular to the skin surface.

21-33 Glandullae sebaceae and arrector pili muscle 2. Human， H-E stain， x
30.
•

Four lobes of sebaceous gland occupy the figure， uniting their ducts at right edge of the figure. In each lobule， the process ofthe holocrine secretion is evidently observed. At the lower left corner runs a thick bundle of the arrector pili muscle ( M )obliquely.

21-34 Tangential section of scalp 1. Level of the sebaceous glands. Human，
H-E stain x 25.
••

Figures 21-34 to 21-37 are tangential sections passing through the plane roughly perpendicular to the slant of the hairs，
arranged from superficial level to downward. . Magnification of them is x 25.
21-34 is the section through the most superficial level passing through the sebaceous glands. In the scalp hairs and sebaceous
glands are grouped and loosely encircled by loose connective tissue. Here three thick hairs and one thin hair ( long arrow ) andsurrounding eight lobes of sebaceous gland are grouped. At the upper periphery two ducts of sweat gland are recognized ( shortarrows ).

21-35 Tangential section of scalp 2. Level of the sweat glands. Human， H-E
stain， x 25.
•

This section passes through the level of the sweat glands. Two thick hair follicles and two thin hair follicles are grouped，
together with the sweat gland. They are encircled loosely by collagen fiber bundles. The originating portion of arrector pili muscle( M ) is encountered. Around the thick hair， the external root sheath is very thick and surrounded by connective tissue follicle. A
narrow gap between the hair and internal root sheath is conspicuous. Follicles of thin hairs show the bottom level figures.

21-36 Tangential section of scalp 3. Level of the deeper portion of hairfollicle. Human， H-E stain x 25.
•

This section shows most beautifully the concentric arrangement of cells of hairs and hair follicles. In the upper three follicles
concentric arrangement of the cells is evidently shown， namely， medulla and cortex of hair， hair cuticle and internal sheath
cuticles， Huxley’s layer， Henle’s layer， stratum spinosum and stratum cylindricum， glassy membrane， and connective tissue
follicle are all definitely demonstrated. Around and in the connective tissue follicle there are numerous blood vessels. The lower
left one is a section at deeper level， a little above the top of the papilla. As the outer epithelial root sheath only one layer ofcylindrical cells is recognized and no internal root sheath is perceivable.

21-37 Tangential section of scalp 4. Level of the hair papilla. Human， H-E
stain， x 25.
•

This is a section at the deepest level of the hair follicle. At lower center is a section passing through the hair papilla; around thepapilla heavily melanin loaded matrix cells are densely packed. Around the matrix cellular elements of the hair cuticle and Henle’s
layer are recognized. Other four hair follicles in this figure are sectioned at a little higher level. Each follicle is surrounded bynumerous blood vessels.

21-38 Transverse section of hair follicle 1. Human， x 64.

••

From 21-38 to 21-41 are transverse sections of hair follicle at different levels， arranged from upper to downward. These levels
are shown in 21-30.
21-38 is a section at the level， where the external root sheath is the thickest. Concentric arrangement of layers are as follows:① is the connective tissue root sheath， in which numerous blood vessels are distributed. ② is the glassy membrane. ③ is thestratum cylindricum of the external root sheath. ④ is the stratum spinosum of the external root sheath. ③ and ④ correspondto the respective layers of dermis. ⑤ is the Henle’s layer， already cornified. ⑥ is the Huxley’s layer. ⑦ is the gap between theinternal root sheath and the hair. ⑧ is the hair.

21-39 Transverse section of hair follicle 2. Human， x 64.

•

The level of this section is indicated in 21-30. ①～⑥ are the same as in 21-38. ⑦ indicates the united root sheath cuticle andhair cuticle. ⑧ is the hair.

21-40 Transverse section of hair follicle 3. Human， x 64.

•

The level of this section is indicated in 21-30. ①～⑤ are the same as in 21-39. ⑦ is the inner root sheath cuticle， ⑧， the haircuticle， and ⑨ cortex and ⑩ medulla of hair.

21-41 Transverse section of hair follicle 4. Human， x 64.

•

The level of this section is indicated in 21-30. ① and ② are the same as in 21-40. ③ is the external root sheath， ④ theHenle’ s layer， ⑤ the cuticle of inner root sheath and ⑥ cuticle of hair. ⑦ is the hair matrix and ⑧ is the hair papilla.

21-42 Tangential section of scalp 2-1. Human， H-E stain， x 3.0.

••

21-42 ～ 21-47 are transverse sections of human scalp at different levels， shown with very low magnification. They arearranged from upper to downward. To understand these figures， it is necessary to refer to the figure 21-29.
21-42 is the section of the most superficial level， namely the level of the dermis. In this section hairs are left off. Three to five
hair follicles are grouped and each group is separated one another by collagen fiber bundles， running mostly parallel to the skinsurface， and densely woven around the hair groups.

21-43 Tangential section of scalp 2-2. Human， H-E stain， x 3.0.

•

This is the section of the level of sebaceous glands. In this section hairs are also fallen out. Hair follicles are grouped together
with sebaceous glands. Collagen fiber bundles separating these groups are woven somewhat looser than those in 21-42.

21-44 Tangential section of scalp 2-3. Human， H-E stain， x 3.0.

•

This is the section of the level of the sweat glands， that means the level of the uppermost area of subcutaneous adipose tissue.
Each follicle shows the thick external root sheath.

21-45 Tangential section of scalp 2-4. Human， H-E stain， x 3.0.

•

This is the level of deeper portion of the hair follicles. Hair follicles are in the subcutaneous adipose tissue. The epithelial root
sheath is here the thickest. Thick collagen fiber bundles separating the groups of the hair follicles are the retinaculum cutis.

21-46 Tangential section of scalp 2-5. Human， H-E stain， x 3.0.

•

This is the level of the hair papilla.

21-47 Tangential section of scalp 2-6. Human， H-E stain， x 3.0.

•

This is the level of the bottom of the hair follicles.

21-003 Nail

21-48 Longitudinal section of nail. Human， H-E stain，
x 1.6.
•••The nails are plates of closely compacted hard corneous substance covering the dorsal surface of the finger tip as well as toe
tip. The exposed portion of the nail is called nail plate and its proximal portion embedded in the epidermis， proximal nail fold， isnamed the nail root. The epidermis of the proximal nail fold covers the dorsal surface of the nail root and turns inward enclosing
its proximal end of the nail root， and continues with the epithelial cell layer of the inferior surface of the nail plate， the nail bed.
The epidermis enclosing the nail root is called the nail matrix.
The nail plate is formed by proliferation and keratinization of epithelial cells in the nail matrix. The stratum corneum of theepidermis of the proximal nail fold extends for a short distance onto the upper surface of the nail， forming a thin covering of its
proximal 0.5 to 1.0 mm， that is called the eponychium.
The nail bed consists only of the stratum germinativum adhering to the inferior surface of the nail plate， but it has no function
to form the nail plate. Distal end of the nail bed continues with the thick epidermis attaching to the inferior surface of the distal
end of the nail plate， that is epidermis of the finger tip.

21-49 Transverse section of nail 1. Human， H-E stain， x 2.75.

•

The nail plate is limited laterally by the lateral nail grooves where the nail plate continues with the epidermis of the lateral nailfolds. Here the epidermis of the lateral nail fold loses its stratum corneum and continues beneath the body of the nail plate as
the nail bed. There the epidermis consists only of the stratum germinativum. Growth of the nail is occurred by the cellproliferation in the nail matrix and the nail slides over the thin epidermis of the nail bed which makes no contribution to its
formation.

21-50 Transverse section of nail 2. Human， H-E stain，
x 10.
•
•

Higher magnification of 21-49.
The thick nail plate is underlain by the nail bed consisting only of the stratum germinativum. The dermis of the nail bed is highly
vascular and this is reflected in the pale pink color transmitted through the translucent nail.

21-51 Transverse section of nail 3. Human， H-E stain， x 25.

••

Higher magnification of 21-50.
Dermis sends numerous narrow papillae deeply into the stratum germinativum， oriented parallel to the long axis of finger， thatgive comb-teeth like appearance to the nail bed of the transverse section.

21-004 Mammary Gland••

The mammary glands are specialized accessory glands， to provide for the nourish- ment of the offspring. In the human there arepaired mammary glands on the thorax. The mammary glands undergo extensive structural changes associated with puberty，pregnancy and menopause.
The mammary glands are large spherical in form and with a nipple on their top. Around the base of nipple there is a circularpigmented area of the skin， called areola. Fifteen to twenty lactiferous ducts ( ductus lactiferi ) penetrate through the nipple andopen onto its tip， that are excretory ducts of the separate lobes of the mammary gland.

21-52 Nipple and mammary gland. General view. Human， H-E stain， x 0.7.

••

The mammary gland is a compound tubuloalveolar gland consisting of 15 to 20 lobes drained by the same number of lactiferous
ducts that open on the tip of the nipple. The lobes are separated by connective tissue and adipose tissue. The lactiferous duct ofeach lobe goes through several orders of branching， to drain multiple small lobules， each consisting of a group of alveoli around
one of the terminal branches of that lactiferous duct. The mammary gland does not have a capsule. Interlobular connective tissue
septa extend inward from the subcutaneous tissue surrounding the gland.
This is a longitudinal section of a human nipple and mammary glands on resting stage. Several lactiferous ducts penetrate
through the nipple， that extend deeply inward and attain to the glandular lobes. At the level of the base of the nipple，
lactiferous ducts are slightly dilated to form lactiferous sinus. As this specimen was on resting stage， the glandular lobes are
small and poorly developed.

21-53 Nipple. Longitudinal section. Human， H-E stain， x 4.0.

•

In this figure， several lactiferous ducts are seen penetrating the nipple; around each of them encircle a number of smoothmuscle fiber bundles.

21-54 Mammary gland on resting stage. Human， H-E stain， x 25.

•

On the resting stage there are no secretory portions at the distal end of the lactiferous duct. This is a lobule of tortuous tubule
consisting of two layered cuboidal epithelial cells.

21-55 Mammary gland at term， 1. Human， H-E stain，
x 2.5.
••

In pregnancy， the elevated levels of circulating estrogens and progesterone bring about major changes in the mammary glands.
There is a rapid growth in length and branching of the duct system and proliferation of alveoli， caused by the vigorous cell
divisions at their distal ends. The paired mammary glands protrude massively on the thorax at the expense of the adipose tissue
among the alveoli. The acini develop highly and have the wide lumen， but until the delivery no secretion is observed in the lumen.
This specimen shows the mammary gland at term， consisting of numerous alveoli， but no adipose tissue among them..

21-56 Mammary gland at term， 2. Human， H-E stain，
x 25.
•

This figure is throughout filled by the aveoli consisting of one layer of cuboidal epithelial cells encircling a wide lumen.
Interalveolar stroma is densely filled by capillaries containing a lot of erythrocytes.

21-57 Mammary gland at term， 3. Human， H-E stain，
x 100.
•

Higher magnification of 21-56. The epithelial cells encircling the alveolar lumen are tall cuboidal and have basophilic cytoplasm.
The wide lumen is empty and contains still no secretion. Around the alveoli encircles a capillary network very densely.