Integument Histology Slides

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Integument Histology Slides
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DERMAL SYSTEM LABORATORYIMAGESThis laboratory is
concerned with the identification of the
histological features of the integumentary
system. It includes a study of the skin (thick
and thin varieties), hair, nails, glands (sweat
sebaceous), and specialized nerve endings.The
skin is an organ that provides an external
covering of the body. It consists of two major
layers, the epidermis and the dermis separated by
a basement membrane.The epidermis is a dry
stratified squamous epithelium with keratinized
superficial layers. The epidermis is specialized
depending upon the functional requirements placed
upon the area, and may be used to distinguish
between thick skin (palmer and plantar surfaces)
and thin skin (body skin). It is a non-vascular
layer. Nutrition is achieved by fluid
transudation from the dermis.The dermis
(corium) is the subjacent dense bed of vascular
connective tissue.A still deeper layer is the
hypodermis. While not part of the skin, it is
often described in association with it. This
layer contains large amounts of adipose tissue
and is referred to as 'superficial fascia' in
gross anatomy.
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1- Skin, Thick. This is a section through "thick"
skin as may be found covering the palm of the
hand or the sole of the foot. It is
characterized as having a very thick stratum
corneum (blue arrow). The dermis (black arrow)
lies deep to the epidermis and is classified as
a dense, irregular connective tissue. Dermal
papillae (green arrows) are projections of dermis
that pass into the deeper portion of the
epidermis.
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2- Skin, Thick. This is a higher magnification
from a section of the previous slide. Note the
thick stratum corneum, the s. lucidum, and the
granular s. granulosum. The cells of the s.
lucidum may contain nuclei, but they are usually
degenerating or absent from this layer.
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3- Skin, Thick. This section of thick skin was
processed with a stain different from the
previous slides. It shows a well-defined s.
granulosum (blue arrow) superficial to the s.
spinosum (yellow arrow).
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4- Skin, Thick. This is a higher magnification of
the previous micrograph to illustrate the extent
of the s. granulosum (yellow arrows). The two or
three layers of the s. lucidum is faintly
discernable between the s. corneum and the s.
granulosum. Deep to this latter layer is the s.
spinosum.
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5- Skin, Thick. In this high magnification of
thick skin, the black line outlines the
approximate boundary of the s. granulosum
(S.G.). The layers of the s. lucidum (S.L.) is
better illustrated in this micrograph. The lower
portion of the image contains the cells of the
s. spinosum (S.S.). Note the "spines"
interconnecting each of these latter cells.
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6- Skin, Thin. In this section of "thin" skin,
note the reduction of the number of epidermal
layers (especially the s. corneum) as compared
to "thick" skin. The red arrow in the left image
illustrates the extent of the epidermis and the
black arrow, the dermis. While dermal papillae
are present in thin skin, they are not as obvious
in this section. The right image is a higher
magnification of a portion of the left image
illustrating the papillary and reticular layers
of the dermis. Note that the papillary layer is
much more cellular than the reticular layer.
Also, the papillary layer does not tend to
contain collagen bundles giving it the
appearance of a loose connective tissue. Note the
dermal papillae in this image.
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6- Skin, Thin. In this section of "thin" skin,
note the reduction of the number of epidermal
layers (especially the s. corneum) as compared
to "thick" skin. The red arrow in the left image
illustrates the extent of the epidermis and the
black arrow, the dermis. While dermal papillae
are present in thin skin, they are not as obvious
in this section. The right image is a higher
magnification of a portion of the left image
illustrating the papillary and reticular layers
of the dermis. Note that the papillary layer is
much more cellular than the reticular layer.
Also, the papillary layer does not tend to
contain collagen bundles giving it the
appearance of a loose connective tissue. Note the
dermal papillae in this image.
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7- Dermis The dermis is classified as dense,
irregular connective tissue. It is divided into
two layers the papillary and the reticular
layers. This micrograph on the left illustrates
the division between the epidermis and the
papillary layer of the dermis (blue line) and
between this latter layer and the reticular layer
of the dermis (black line). The micrograph on the
right is a higher magnification of the that on
the left image illustrating the papillary and
reticular layers of the dermis. Note that the
papillary layer is much more cellular than the
reticular layer. Also, the papillary layer does
not tend to contain collagen bundles thus giving
it the appearance of a loose connective tissue.
Note the dermal papillae in this image.
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7- Dermis The dermis is classified as dense,
irregular connective tissue. It is divided into
two layers the papillary and the reticular
layers. This micrograph on the left illustrates
the division between the epidermis and the
papillary layer of the dermis (blue line) and
between this latter layer and the reticular layer
of the dermis (black line). The micrograph on the
right is a higher magnification of the that on
the left image illustrating the papillary and
reticular layers of the dermis. Note that the
papillary layer is much more cellular than the
reticular layer. Also, the papillary layer does
not tend to contain collagen bundles thus giving
it the appearance of a loose connective tissue.
Note the dermal papillae in this image.
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8- Sweat gland This is a section of the dermis
illustrating a portion of a sweat gland
(encircled in green). The sweat gland is
classified as simple, coiled tubular, thus a
section such as this will display several
portions of the same gland adjacent to each
other. The secretory portion of the gland (S) is
lighter-staining, is larger diameter, and has a
larger lumen than that of the excretory portion
(E). The lumen of each of the secretory portions
in this micrograph are continuous with each other
and with those of the excretory portions.
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9- Sweat gland This is a section through another
sweat gland illustrating a cut through a
secretory unit (S) and several cuts through the
excretory unit (E).
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10- Sweat gland This is a section through another
sweat gland. The secretory portion of the gland
is encircled in red and the excretory portion is
encircled in green.
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11- Sweat gland This tissue was prepared in
plastic and cut thin (1.5mµ). A single cut
through a secretory unit (as evidenced by the
lighter staining and larger diameter than the
excretory unit) is illustrated. Notice the area
of darker pink stain around the periphery of the
secretory unit. These represent the cytoplasmic
processes of myoepithelial cells, which, when
contracting, express the contents of the lumen
into the excretory portion (duct).
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12- Sweat gland The epidermal portion of a sweat
gland duct is illustrated in this micrograph..
The dermal portion of excretory units (ducts) of
sweat glands are lined by cuboidal cells (one or
two layers). As the duct passes through the
epidermis, it becomes lined by the cells of the
epidermis (yellow and green arrows).
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13- Hair. This micrograph is a cross section
through hair follicles located in the dermis.
Note the dense connective tissue sheath (CTS)
surrounding each follicle. This sheath is
referred to Connective Tissue Sheath or Dermal
Root Sheath. The External Root Sheath (ERS) lies
just deep to the CTS. The Inner Root Sheath (IRS)
is present in the follicle below the level of the
sebaceous gland duct The central portion of the
developing hair is known as the Medulla (ME) and
contains a scant amount of melanin. The Cortex
(CO) surrounds the medulla and contains a heavier
concentration of melanin. The Cuticle of the hair
is the outermost layer of the developing hair and
is adjacent to the cuticle of the inner root
sheath
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14- Hair. These micrographs are higher
magnifications of the previous image illustrating
a cross-section of a hair follicle. Note the
components of the follicle using the key from the
previous image (16). In this image, the
components of the inner root sheath (IRS) can be
identified and consists of an outer Henles layer
(single layer of cuboidal cells), a middle
Huxleys layer (one or two layers of cells, and
an inner cuticle (CU) consisting of flattened
squamous cells and usually transleucent. This
micrograph on the right is a higher magnification
of the central portion of a developing hair
follicle. In this image, the inner root sheath is
well defined. The arrow is directing your
attention to the cuticle of the hair (CU). The
cuticle of the inner root sheath can be seen
surrounding the cuticle of the hair.
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14- Hair. These micrographs are higher
magnifications of the previous image illustrating
a cross-section of a hair follicle. Note the
components of the follicle using the key from the
previous image (16). In this image, the
components of the inner root sheath (IRS) can be
identified and consists of an outer Henles layer
(single layer of cuboidal cells), a middle
Huxleys layer (one or two layers of cells, and
an inner cuticle (CU) consisting of flattened
squamous cells and usually transleucent. This
micrograph on the right is a higher magnification
of the central portion of a developing hair
follicle. In this image, the inner root sheath is
well defined. The arrow is directing your
attention to the cuticle of the hair (CU). The
cuticle of the inner root sheath can be seen
surrounding the cuticle of the hair.
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15- Hair. This micrograph is a longitudinal
section through a hair follicle. A sebaceous
gland (black arrow) is illustrated with its duct
(green arrow) opening into the hair follicle. A
portion of the arrector pili (red arrows) is
shown. DCTdense connective Tissue
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16- Hair. In this image of thin skin, a band of
smooth muscle (arrector pili) is illustrated
passing towards the papillary layer of the dermis
where it attaches. A cross-section of a hair
follicle is shown. The "free shaft" of the hair
(H) is missing.
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17- Hair. This is a scanning electron micrograph
of a hair shaft emerging from the skin. The
scaley cells of the stratum corneum is seen at
the base of the hair shaft. Note that the free
edge of the flattened cells of the cuticle
(arrows) are directed upward.
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18- Nail. This is a thin longitudinal section
(1.5mµ) of the proximal portion of a nail. Note
the component parts of the nail eponychium (an
extension of the stratum corneum), nail matrix
(black arrows), nail bed (green arrows), and nail
plate (N.P.).
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19- Nail. This is a thin longitudinal section
(1.5mµ) of the distal portion of a nail. Note the
nail plate and the hyponychium
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20- Meissners Corpuscle. The image on the left
is a high magnification micrograph of a section
through the papillary layer of the dermis.
Illustrated are two dermal papillae projecting
into the epidermis (arrows). The dermal papilla
on the right contains a Meissners corpuscle.
Meissners corpuscles are encapsulated
mechanoreceptors that respond to slight movements
of the epidermis. They contain one or two nerve
endings surrounded by a connective tissue sheath.
The image on the right is a higher magnification
through a dermal papilla illustrating a
Meissners Corpuscle (arrow).
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20- Meissners Corpuscle. The image on the left
is a high magnification micrograph of a section
through the papillary layer of the dermis.
Illustrated are two dermal papillae projecting
into the epidermis (arrows). The dermal papilla
on the right contains a Meissners corpuscle.
Meissners corpuscles are encapsulated
mechanoreceptors that respond to slight movements
of the epidermis. They contain one or two nerve
endings surrounded by a connective tissue sheath.
The image on the right is a higher magnification
through a dermal papilla illustrating a
Meissners Corpuscle (arrow).
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21- Meissners Corpuscle. (Thin 1.5mµ). This is a
low magnification of a section of thick skin
illustrating a Meissners Corpuscle located in
one of the dermal papillae (arrow). The image on
the right is a higher magnification of a
Meissners Corpuscle (arrow).
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21- Meissners Corpuscle. (Thin 1.5mµ). This is a
low magnification of a section of thick skin
illustrating a Meissners Corpuscle located in
one of the dermal papillae (arrow). The image on
the right is a higher magnification of a
Meissners Corpuscle (arrow).
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22- Pacinian Corpuscle. This is a high
magnification of a section through the dermis
illustrating a pacinian corpuscle which is an
example of an encapsulated mechanoreceptor.
Pacinian corpuscles respond to pressure and
vibrations. In section, these capsules have the
appearance of a cut onion. An axon is located in
the center (black arrow) and is surrounded by
several lamellae of connective tissue components
(green arrows). Each of the lamella are separated
from each other by a lymph-like fluid.
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23- Pacinian Corpuscle. This is a another example
of a Pacinian corpuscle. Refer to the previous
image for a description of this corpuscle.