INTEGUMENT
Dr. Larry Johnson
Objectives
• Distinguish between the 5 layers of epidermal cells in
thick skin and the differences in these found in thin skin.
• Describe the organization of the two layers comprising the
dermis.
• Detail the structure of the sebaceous gland, eccrine sweat
gland, and aprocrine sweat gland.
• Recognize melanin and its functional significance.
From: Douglas P. Dohrman and TAMHSC Faculty 2012 Structure and
Function of Human Organ Systems, Histology Laboratory Manual
BINARY ORIGIN
OF SKIN
EPIDERMIS –
ECTODERM
31
BINARY ORIGIN
OF SKIN
EPIDERMIS –
ECTODERM
DERMIS MESODERM
31
Functions of skin
PROTECTS AGAINST INJURY AND DESICCATION
MAINTENANCE OF WATER BALANCE
Functions of skin
PROTECTS AGAINST INJURY AND DESICCATION
MAINTENANCE OF WATER BALANCE
EXCRETES VARIOUS SUBSTANCES
Functions of skin
PROTECTS AGAINST INJURY AND DESICCATION
MAINTENANCE OF WATER BALANCE
EXCRETES VARIOUS SUBSTANCES
THERMOREGULATION
Functions of skin
PROTECTS AGAINST INJURY AND DESICCATION
MAINTENANCE OF WATER BALANCE
EXCRETES VARIOUS SUBSTANCES
THERMOREGULATION
RECEIVES STIMULI
• TEMPERATURE
• PAIN
• PRESSURE
Functions of skin
PROTECTS AGAINST INJURY AND DESICCATION
MAINTENANCE OF WATER BALANCE
EXCRETES VARIOUS SUBSTANCES
THERMOREGULATION
RECEIVES STIMULI
• TEMPERATURE
• PAIN
• PRESSURE
BASIS OF RECOGNITION AND YIELDS
CLUES TO ONE’S WELL BEING
Functions of skin
PROTECTS AGAINST INJURY AND DESICCATION
MAINTENANCE OF WATER BALANCE
EXCRETES VARIOUS SUBSTANCES
THERMOREGULATION
RECEIVES STIMULI
• TEMPERATURE
• PAIN
• PRESSURE
BASIS OF RECOGNITION AND YIELDS
CLUES TO ONE’S WELL BEING
FAT METABOLISM IN THE
SUBCUTANEOUS LAYER
Integument
CHARACTERISTIC
THICK SKIN
THIN SKIN
Surface Texture
Alternating ridges and
grooves
Smooth
Epidermis/Dermis
Interface
Interdigitating ridges
Less prominent ridges
Epidermal Strata
•
•
•
•
•
• Same as thick skin,
except: no S. Lucideum.
• The corneum,
granulosum, and
spinosum layers are
reduced in thickness.
Hairs and Sebaceous
Glands
None
Regionally variable
Sweat Glands
Abundant
Moderate
S. Basale
S. Spinosum
S. Granulosum
S. Lucidum
S. Corneum
REGIONAL VARIATION OF THE
EPIDERMIS
THICK SKIN - SOLE OF FOOT (1.4 mm
THICK)
THIN SKIN - EYELID AND MOST OF BODY
(0.07 TO 0.12 mm)
CORNEA OF EYE - TRANSPARENT
APPENDAGES - HAIR FOLLICLES
NAILS
GLANDS
REGIONAL VARIATION OF THE
EPIDERMIS
Slide 29: Thick Skin (ventral surface of
finger)
Epidermis
)
Adipocytes
Copyright McGraw-Hill Companies
Dermis
Hypodermis
Slide 29: Thick Skin (ventral surface of
finger)
Epidermis
Copyright McGraw-Hill Companies
Papillary
layer
Dermal papillae
Epidermal peg
Dermis
Reticular layer
Dermal side
of the Epidermal – dermal interface
Slide 29: Thick Skin (ventral surface of
Meissner’s corpuscles
finger)
in dermal papillae
Epidermis
Epidermal peg
Dermal papillae
Dermis
Meissner’s
corpuscle is a
mechanoreceptor
Epidermis
nerve
ending for
sensitivity to light
touch; you would
find more on your
fingers because
they are more
sensitive to touch
than your elbow.
109
Skin hand monkey
Hypodermis
Papillary layer
Dermal
papillae
Epidermal peg
109
Skin hand monkey
Eccrine sweat glands
Adipocytes
Hypodermis
Pacinian corpuscles
Papillary layer
Dermal
papillae
Epidermal peg
Obesity is
characteristic
of having a
thickened
subcutaneous
layer
LAYERS OF THE EPIDERMIS: PALMS
AND SOLES OF FEET
STRATUM CORNEUM
• KERATINIZED
FLATTENED,
DENUCLEATED, DEAD
CELLS
LAYERS OF THE EPIDERMIS: PALMS
AND SOLES OF FEET
STRATUM CORNEUM
• KERATINIZED
FLATTENED,
DENUCLEATED, DEAD
CELLS
STRATUM GRANULOSUM
• KERATOHYALIN
GRANULES
LAYERS OF THE EPIDERMIS: PALMS
AND SOLES OF FEET
STRATUM CORNEUM
• KERATINIZED
FLATTENED,
DENUCLEATED, DEAD
CELLS
STRATUM GRANULOSUM
• KERATOHYALIN
GRANULES
STRATUM SPINOSUM
• TONOFIBRILS DESMOSOMES
LAYERS OF THE EPIDERMIS: PALMS
AND SOLES OF FEET
STRATUM CORNEUM
• KERATINIZED
FLATTENED,
DENUCLEATED, DEAD
CELLS
STRATUM GRANULOSUM
• KERATOHYALIN
GRANULES
STRATUM SPINOSUM
• TONOFIBRILS DESMOSOMES
STRATUM BASALE
• CONTINUAL RENEWAL OF
EPIDERMIS
Slide 29: Thick Skin (ventral surface of
finger) cont.
Keratohyalin granules
Desmosomes
Hemidesmosomes
1
2
3
2
3
4
5
4
1. Stratum corneum
2. Stratum lucidum
3. Stratum granulosum
4. Stratum spinosum
5. Stratum basale
5
Slide 29: Thick Skin on finger cont.
Keratohyalin granules
S. granulosum: flattened
cells undergoing
Stratum
the terminal
granulosum
differentiation
process of
keratinization –
.
forming the skin’s
barrier against water
loss when sealed with
contents of membrane
coating granules.
Desmosomes
Hemidesmosomes
Stratum lucidum
1
Stratum
spinosum
Stratum basale
Slide 29: Thick Skin on finger cont.
The epidermis of
thick skin is
subject to
continuous
friction and
pressure so the
abundant
desmosomes
(and tonofibrils)
withstand this and
hold the cell
layers together.
Keratohyalin granules
Desmosomes
Hemidesmosomes
1
Epidermis
Stratum
spinosum
Dermis
Stratum basale
STRATUM
CORNEUM
STRATUM
GRANULOSUM
STRATUM
SPINOSUM
STRATUM
BASALE
STRATUM
BASALE
STRATUM SPINOSUM
STRATUM SPINOSUM
STRATUM SPINOSUM
STRATUM SPINOSUM
STRATUM SPINOSUM
EM 8g of skin: Note the different
layers and the cellular contents
of each
1. Stratum corneum
2. Startum granulosum
3. Stratum spinosum
STRATUM CORNEUM
STRATUM GRANULOSUM
STRATUM CORNEUM
STRATUM CORNEUM
Cells in EPIDERMIS
STRATIFIED SQUAMOUS CELL TYPES INCLUDE:
KERATINOCYTES - MAIN CELL
TYPE – ECTODERM
MELANOCYTES PIGMENTATION - NEURAL
CREST
LANGERHANS CELL IMMUNOLOGIC ROLE
MERKEL CELLS ASSOCIATED WITH NERVE
ENDINGS
MELANOCYTE –
PIGMENT SYNTHESIS
The embryonic origin
of melanocytes is the
neural crest derivatives
NEURAL CREST ORIGIN (EYE & CNS) that migrate into the
embryonic epidermis’
stratum basale.
111
107
111
107
111
107
MELANOCYTE - PIGMENT SYNTHESIS
MELANOGENESIS
CYTOCRINE SECRETION - PASS MELANIN GRANULES
TO KERATINOCYTES
CYTOCRINE SECRETION - PASS MELANIN GRANULES
FROM MELANOCYTES TO KERATINOCYTES
MELANOCYTE - PIGMENT SYNTHESIS
LOCATED IN THE STRATUM BASALE
CLEAR CELL - NO DESMOSOMAL CONNECTION
Slide 31: Thin Skin (scalp)
Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale
Slide 31: Thin Skin (scalp)
Sun from
NASA
Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale
Melanin
capping
of nuclei
Slide 31: Thin Skin (scalp)
Sun from
NASA
Stratum corneum
Stratum granulosum
Stratum spinosum
4
Stratum basale
Melanin
capping
of nuclei
Melanin granule accumulate over
the nuclei of mitotic cells of the
stratum basale to protect nuclear
DNA from UV damage.
Melanocytes
respond to
melanocyte
stimulating
hormone
secreted by
the pars
intermedia.
107
MELANOCYTE - PIGMENT SYNTHESIS
SUSCEPTIBLE TO HORMONES AND PHYSICAL
FACTORS
• SUN-TANNING
• SEX DIFFERENCES
• PREGNANCY
MELANOCYTE
DENSITY SIMILAR IN ALL
HUMANS
MELANOCYTE DENSITY - SIMILAR IN ALL HUMANS
MELANOCYTE - PIGMENT SYNTHESIS
FRECKLES - MELANIN DISTRIBUTED IN PATCHES
MELANOCYTE – disease states
ALBINISM - FAILURE TO PRODUCE MELANIN
MALIGNANT MELANOMAS - CANCER
ADDISON’S DISEASE - PIGMENT DEPOSITION IN SKIN
DUE TO ADRENOCORTICAL INSUFFICIENCY
LANGERHANS CELLS
BONE MARROW
ORIGIN
LOCATED IN
STRATUM
SPINOSUM GOLD CHLORIDE
STAIN
CLEAR CELL - NO
DESMOSOMES
DENDRITIC CELL
LANGERHANS CELLS
DENDRITIC CELL
ROD OR RACKET
SHAPED GRANULES
FUNCTION IMMUNOLOGIC ROLE AS
AN ANTIGENPRESENTING CELL
CONTACT ALLERGIC
RESPONSES AND
OTHER CELL MEDIATED
REACTION OF THE SKIN
Epidermal – dermal interface
Epidermal – dermal interface
MELANIN is produced by MELANOCYTES
107
MELANIN-producing enzymes in MELANOCYTES
Space of
removed dermis
EPIDERMIS
107
Epidermal – dermal interface
face
trunk
nipple
finger
Epidermal – dermal interface
- finger pad
Epidermal – dermal interface finger pad
Skin, foot
408
Epidermal – dermal interface creates
unique finger ridges
Slide 30: Thick Skin (Pacinian corpuscle
and melanin)
Pacinian corpuscle
Melanin pigment
Melanin capping of nuclei
Pacinian corpuscles are
mechanoreceptors that detect
vibration and pressure.
105monkey finger
Pacinian corpuscles are
mechanoreceptors that detect
vibration and pressure.
105 monkey finger
Pacinian corpuscles
Skin, scalp
209
Slide 31: Thin Skin (scalp)
Copyright McGraw-Hill Companies
Hair follicle
location
Arrector pili
muscle
Sebaceous glands
Skin, scalp
209
Human Skin,
scalp 108
Skin,
scalp
sebaceous
glands
Human Skin,
scalp 108
Skin,
scalp
Mode of secretion of the
sebaceous glands is
holocrine where by the sebum is
released when cells burst.
sebaceous
glands
Human Skin,
scalp 108
Skin,
scalp
Mode of secretion of the
sebaceous glands is
holocrine where by the sebum is
released when cells burst.
sebaceous
glands
Eccrine sweat glands
Eccrine sweat glands
105
Slide 66: Recto-anal junction
Sebaceous gland
Hair follicle
Eccrine sweat glands
66
Stratified
squamous
epithelium
of anal wall
Simple
columnar
epithelium of
rectum with
goblet cells
Slide 66: Recto-anal junction
hair
Sebaceous gland
Apocrine sweat gland
MECHANISM FOR RELEASE OF
SECRETORY PRODUCTS
MEROCRINE SECRETION – EXOCYTOSIS W/O LOSS OF
SURFACE MEMBRANE
MECHANISM FOR RELEASE OF
SECRETORY PRODUCTS
MEROCRINE SECRETION – EXOCYTOSIS W/O LOSS OF
SURFACE MEMBRANE
APOCRINE SECRETION – LOSS OF PART OF APICAL
CYTOPLASM AND SOME PLASMA MEMBRANE
MECHANISM FOR RELEASE OF
SECRETORY PRODUCTS
MEROCRINE SECRETION – EXOCYTOSIS W/O LOSS OF
SURFACE MEMBRANE
APOCRINE SECRETION – LOSS OF PART OF APICAL
CYTOPLASM AND SOME PLASMA MEMBRANE
HOLOCRINE SECRETION – RELEASE OF WHOLE cell
OTHER GLANDS OF EPIDERMAL
ORIGIN
SWEAT GLANDS
• ECCRINE - COMMON
SWEAT GLAND LOCAL COOLING
• APOCRINE AXILLARY
REGION - FUNCTION
IN ANIMALS
SWEAT GLANDS secretions
SWEAT GLANDS secretions
Slide 29: Thick Skin (ventral surface of finger)
Myoepithelial
cells are
eosinophilic
because of the
presence of
muscle
contractile
proteins, which
contract to
expel sweat
when needed.
Ducts of eccrine sweat glands with
stratified cuboidal epithelium
Myoepithelial cells Eccrine sweat glands
SWEAT GLANDS
Functional diversity of skin
PROTECTS AGAINST INJURY (e.g.,UV
light or mechanical stresses)
AND DESICCATION
MAINTENANCE OF WATER BALANCE
EXCRETES
THERMOREGULATION
RECEIVES STIMULI
FAT METABOLISM
THREE TYPES OF GRANULES IN
KERATINOCYTES
MELANIN
• SKIN PIGMENT
• PRODUCED BY MELANOCYTES
AND PASSED BY CYTOCRINE
SECRETION TO KERATINOCYTES
MEMBRANE COATING GRANULES
(LAMELLATED GRANULES)
• WATER PROOFING FUNCTION
• PRODUCED BY KERATINOCYTES
KERATINOHYALIN GRANULES
• PRODUCED BY KERATINOCYTES
THREE TYPES OF GRANULES IN
KERATINOCYTES
MEMBRANE COATING GRANULES
(LAMELLATED GRANULES)
• Small, ovoid structures from the
Golgi containing various lipids
and they undergo exocytosis to
produce a lipid-rich
impermeable layer around the
cells of the s. granulosum –
water proofing.
THREE TYPES OF GRANULES IN
KERATINOCYTES
KERATINOHYALIN GRANULES
• CHEMICAL NATURE NOT
CLEARLY ESTABLISHED
• RICH IN HISTODINE
FORMS
• MATRIX OF CELLS IN
STRATUM CORNEUM,
STABILITY DUE TO
DISULFIDE BONDS
• ABSENT IN HAIR AND
NAILS
111
Melanocytes in Skin
Regeneration of epidermis
Clinical Correlation
Albinism can be caused by a
hereditary defect in tyrosinase
activity or the inability of cells to
take up tyrosine.
Tyrosine amino acid figure
chemistry.about.com.
Patient with albinism would be
more at risk for the development
of basal and squamous cell
carcinomas as albinism
produces skin hypopigmentation
so fewer melanin granules to
protect nuclear DNA from the
ionizing, mutagenic effects of UV
radiation.
Albino peacock
http://www.duskyswondersite.com/animals/albino-animals/
Many illustrations in these VIBS Histology YouTube videos were modified
from the following books and sources: Many thanks to original sources!
•
•
Bruce Alberts, et al. 1983. Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY.
Bruce Alberts, et al. 1994. Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY.
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William J. Banks, 1981. Applied Veterinary Histology. Williams and Wilkins, Los Angeles, CA.
•
Hans Elias, et al. 1978. Histology and Human Microanatomy. John Wiley and Sons, New York, NY.
•
Don W. Fawcett. 1986. Bloom and Fawcett. A textbook of histology. W. B. Saunders Company, Philadelphia, PA.
•
Don W. Fawcett. 1994. Bloom and Fawcett. A textbook of histology. Chapman and Hall, New York, NY.
•
Arthur W. Ham and David H. Cormack. 1979. Histology. J. S. Lippincott Company, Philadelphia, PA.
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Luis C. Junqueira, et al. 1983. Basic Histology. Lange Medical Publications, Los Altos, CA.
•
L. Carlos Junqueira, et al. 1995. Basic Histology. Appleton and Lange, Norwalk, CT.
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L.L. Langley, et al. 1974. Dynamic Anatomy and Physiology. McGraw-Hill Book Company, New York, NY.
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W.W. Tuttle and Byron A. Schottelius. 1969. Textbook of Physiology. The C. V. Mosby Company, St. Louis, MO.
•
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Leon Weiss. 1977. Histology Cell and Tissue Biology. Elsevier Biomedical, New York, NY.
Leon Weiss and Roy O. Greep. 1977. Histology. McGraw-Hill Book Company, New York, NY.
•
Nature (http://www.nature.com), Vol. 414:88,2001.
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A.L. Mescher 2013 Junqueira’s Basis Histology text and atlas, 13th ed. McGraw
The End!