INTEGUMENT-1 This resource is licensed under the Creative Commons Attribution Non-Commercial & No Derivative Works License

Objectives To identify the main features of non-hairy heavily keratinised skin and to compare with thinner hairy skin. 2. To identify sebaceous and sweat glands.

SLIDE 77 Digital skin (monkey) Examine this section under very low magnification, (Masson’s trichrome stain). Skin is a difficult structure to cut for histology; the outer keratinised layers often pull apart or tear during sectioning. Part of the epidermis in the section below has been lost (arrowed). 1.0 mm

SLIDE 77 Digital skin (monkey) Identify - thick stratum corneum. What colour does it stain? - rest of the epidermis. What colour does it stain? - dermis - hypodermis 250 µm

SLIDE 77 Digital skin (monkey) Identify - thick stratum corneum. What colour does it stain? Red. - rest of the epidermis. What colour does it stain? Purple. - dermis - hypodermis hypodermis dermis stratum corneum other epidermal layers 250 µm

SLIDE 77 Digital skin (monkey) What glands and their ducts can be seen in this section? 250 µm

SLIDE 77 Digital skin (monkey) What glands and their ducts can be seen in this section? Sweat glands. What is the predominant tissue in the hypodermis? S S : sweat glands S ducts from sweat glands S 250 µm

SLIDE 77 Digital skin (monkey) What glands and their ducts can be seen in this section? Sweat glands. What is the predominant tissue in the hypodermis? Adipose tissue. S S : sweat glands A : adipose tissue in hypodermis A S ducts from sweat glands S 250 µm

SLIDE 77 Digital skin (monkey) The stain used is Masson’s Trichrome. Dermal papillae interdigitating with the epidermal layers, strengthen the layers. What is stained blue-green in the dermis? 100 µm

SLIDE 77 Digital skin (monkey) The stain used is Masson’s Trichrome. Dermal papillae interdigitating with the epidermal layers, strengthen the layers. What is stained blue-green in the dermis? The collagen fibres in the dermis stain blue-green. D D : dermal papillae D D D epidermis D D dermis 100 µm sweat gland

SLIDE 77 Digital skin (monkey) Label the five strata in the epidermis. 50 µm

SLIDE 77 Digital skin (monkey) Label the five strata in the epidermis. stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale 50 µm

SLIDE 77 Digital skin (monkey) Label the five strata in the epidermis. Label the five strata in the epidermis. In which of these layers might one observe (a) mitosis? (b) melanocyte (cell bodies)? stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale 50 µm

SLIDE 77 Digital skin (monkey) Label the five strata in the epidermis. Label the five strata in the epidermis. In which of these layers might one observe (a) mitosis? Stratum basale. (b) melanocyte (cell bodies)? stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale (The stratum lucidum is often difficult to distinguish). 50 µm

SLIDE 77 Digital skin (monkey) Label the five strata in the epidermis. Label the five strata in the epidermis. In which of these layers might one observe (a) mitosis? Stratum basale. (b) melanocyte (cell bodies)? Stratum basale. stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale (The stratum lucidum is often difficult to distinguish). 50 µm

Sensory Receptors in Skin (revision from nerve cell histology class)

SLIDE 77 Skin to observe Sensory Receptors digital skin of monkey Most of the sensory nerve fibres in the skin have free, uncapsulated endings and are concerned with detecting temperature, pain etc . 1.0 mm

SLIDE 77 Skin to observe Sensory Receptors digital skin of monkey Pacinian corpuscles are found in the hypodermis. 1.0 mm

SLIDE 77 Skin to observe Sensory Receptors Pacinian corpuscle. 250 µm

SLIDE 77 Skin to observe Sensory Receptors Pacinian corpuscle. Pacinian corpuscle hypodermis dermis epidermis 250 µm

SLIDE 77 Skin to observe Sensory Receptors Pacinian corpuscle. 50 µm

SLIDE 77 Skin to observe Sensory Receptors digital skin of monkey Meissner’s corpuscles are found in the dermal papillae. 1.0 mm

SLIDE 77 Skin to observe Sensory Receptors Meissner’s corpuscle. 25 µm

SLIDE 76 Footpad (dog) Another example of thick skin. This section has been stained with H&E. The keratinised stratum corneum forms a thick outer layer. 1.0 mm

SLIDE 76 Footpad (dog) Another example of thick skin. This section has been stained with H&E. The keratinised stratum corneum forms a thick outer layer. dermal papillae epidermis dermis sweat glands hypodermis 1.0 mm

SLIDE 76 Footpad (dog) Higher magnification showing the very thick stratum corneum. Note the spiralling ducts from sweat glands passing through this layer. 250 µm

SLIDE 76 Footpad (dog) Higher magnification showing the very thick stratum corneum. Note the spiralling ducts from sweat glands passing through this layer. stratum corneum ducts from sweat glands 250 µm

Again identify the five strata in the epidermis. SLIDE 76 Footpad (dog) Again identify the five strata in the epidermis. 50 µm

Again identify the five strata in the epidermis. SLIDE 76 Footpad (dog) Again identify the five strata in the epidermis. Stratum : 1 : basale 1 50 µm

Again identify the five strata in the epidermis. SLIDE 76 Footpad (dog) Again identify the five strata in the epidermis. Stratum : 1 : basale 2 : spinosum 1 2 50 µm

Again identify the five strata in the epidermis. SLIDE 76 Footpad (dog) Again identify the five strata in the epidermis. Stratum : 1 : basale 2 : spinosum 3 : granulosum 1 3 2 50 µm

Again identify the five strata in the epidermis. SLIDE 76 Footpad (dog) Again identify the five strata in the epidermis. Stratum : 1 : basale 2 : spinosum 3 : granulosum 4 : lucidum 1 3 4 2 50 µm

Again identify the five strata in the epidermis. SLIDE 76 Footpad (dog) Again identify the five strata in the epidermis. Stratum : 1 : basale 5 2 : spinosum 3 : granulosum 4 : lucidum 1 3 4 5 : corneum 2 50 µm

Keratinised layer of thick skin – electron micrograph Keratinised squamous cells of the stratum corneum : note the lack of nuclei and other cell organelles. The stratum granulosum contains keratohyalin granules and keratin filaments. Stratum corneum Stratum granulosum 1 2

SLIDE 83 Ventral abdominal skin (dog) The epidermis of the dog is at its thinnest on the ventral side of the abdomen. Hair follicles are visible, cut at varying angles from TS to LS. 1.0 mm

SLIDE 83 Ventral abdominal skin (dog) The epidermis of the dog is at its thinnest on the ventral side of the abdomen. Hair follicles are visible, cut at varying angles from TS to LS. epidermis H H H : hair follicles dermis hypodermis 1.0 mm

SLIDE 83 Ventral abdominal skin (dog) oblique section through hair follicle epidermal layers transverse section through hair follicle dermis 250 µm

SLIDE 83 Ventral abdominal skin (dog) Glands associated with the hair follicle 100 µm

SLIDE 83 Ventral abdominal skin (dog) Glands associated with the hair follicle sebaceous glands hair follicle duct from apocrine sweat gland 100 µm

SLIDE 83 Ventral abdominal skin (dog) Surface of thin skin. Note although the surface is not flat, there are no dermal papillae. The stratum corneum and stratum spinosum are clear, but only a few cells deep. Stratum granulosum not prominent. 50 µm

SLIDE 83 Ventral abdominal skin (dog) Surface of thin skin. Note although the surface is not flat, there are no dermal papillae. The stratum corneum and stratum spinosum are clear, but only a few cells deep. Stratum granulosum not prominent. stratum granulosum stratum spinosum stratum corneum stratum basale 50 µm

SLIDE 83 Ventral abdominal skin (dog) Apocrine sweat glands close to hair follicle. open lumen of sweat gland lined by a low epithelium 25 µm

SLIDE 74 Dorsal skin (dog) Hairs are more numerous on the dorsal skin of the dog. Compound hair follicles (as in the ventral skin). 1.0 mm

SLIDE 74 Dorsal skin (dog) Hairs are more numerous on the dorsal skin of the dog. Compound hair follicles (as in the ventral skin). epidermis dermis hair follicles hypodermis muscle (in deep layers) 1.0 mm

SLIDE 74 Dorsal skin (dog) What is the arrector pili muscle? 250 µm

SLIDE 74 Dorsal skin (dog) What is the arrector pili muscle? A smooth muscle running from below the epidermis and attaching to the root sheath of the hair. R : root sheath epidermis arrector pili muscle R 250 µm

SLIDE 74 Dorsal skin (dog) Compound hair follicles in the dorsal skin of the dog. 250 µm

SLIDE 74 Dorsal skin (dog) Compound hair follicles in the dorsal skin of the dog. thin epidermis compound hair follicles 250 µm

SLIDE 74 Dorsal skin (dog) The epidermis from the dorsal region skin. Again no evidence of dermal papillae and very few layers of cells present. 50 µm

SLIDE 74 Dorsal skin (dog) The epidermis from the dorsal region skin. Again no evidence of dermal papillae and very few layers of cells present. stratum corneum other epidermal layers dermis 50 µm

SLIDE 74 Dorsal skin (dog) Detail from a sebaceous gland. Sebaceous glands usually open into the hair follicle. What method of secretion does this gland use? 50 µm

SLIDE 74 Dorsal skin (dog) Detail from a sebaceous gland. Sebaceous glands usually open into the hair follicle. What method of secretion does this gland use? Holocrine. sebaceous glands cells have a ‘foamy’ appearance 50 µm

SLIDE 74 Dorsal skin (dog) Deeper to the hair follicle are apocrine sweat glands. Why are they called apocrine? 50 µm

SLIDE 74 Dorsal skin (dog) Deeper to the hair follicle are apocrine sweat glands. Why are they called apocrine? Apical blebs of cytoplasm form part of the mucoserous secretion. A : apocrine glands unilocular adipocytes A 50 µm

SLIDE 74 Dorsal skin (dog) Deeper to the hair follicle are apocrine sweat glands. Where does the duct from this gland open? A : apocrine glands unilocular adipocytes A 50 µm

SLIDE 74 Dorsal skin (dog) Deeper to the hair follicle are apocrine sweat glands. Where does the duct from this gland open? In the hair follicle. A : apocrine glands unilocular adipocytes A 50 µm

SLIDE 81 Eyelid (horse) van Geisen stain Low magnification view of whole section. 1 mm

SLIDE 81 Eyelid (horse) van Geisen stain Low magnification view of whole section. outer surface of eyelid with hair follicles muscle margin of eyelid tarsal gland inner surface of eyelid 1 mm

SLIDE 81 Eyelid (horse) van Geisen stain The opening onto the margin of the eyelid is not visible in the cut of this section; it can be seen better on slide 82. Of what type of skin gland is this a modification? 250 µm

SLIDE 81 Eyelid (horse) van Geisen stain The opening onto the margin of the eyelid is not visible in the cut of this section; it can be seen better on slide 82. Of what type of skin gland is this a modification? Sebaceous gland. 250 µm

SLIDE 81 Eyelid (horse) van Geisen stain What is the function of this gland? 50 µm

SLIDE 81 Eyelid (horse) van Geisen stain What is the function of this gland? It allows a film of oily sebum to remain on the free margin of the eyelid and prevent tear overflow. Detail of tarsal gland multilobular sebaceous gland 50 µm

SLIDE 82 Eyelid (horse) H&E stain Low magnification view of whole section. 1.0 mm

SLIDE 82 Eyelid (horse) H&E stain Low magnification view of whole section. tarsal gland opening outer surface tarsal gland inner surface 1.0 mm

SLIDE 82 Eyelid (horse) H&E stain Outer surface showing hair follicles, sweat glands and sebaceous glands. 250 µm

SLIDE 82 Eyelid (horse) H&E stain Outer surface showing hair follicles, sweat glands and sebaceous glands. sebaceous gland hair follicle prominent apocrine sweat glands 250 µm

SLIDE 84 Planum nasale (dog) At low magnification, note the prominent grooves in the thick epidermal layer. 1.0 mm

SLIDE 84 Planum nasale (dog) The planum nasale is characteristically devoid of hair follicles and glands. 250 µm

SLIDE 84 Planum nasale (dog) The planum nasale is characteristically devoid of hair follicles and glands. Areas of dermal papillae may appear isolated in thin sections. Three dimensionally they are continuous with the dermis. grooves dermis 250 µm

Lecturer. Prof N.Stickland. First Year Histology. 009. Integument-1. J.Bredl. 29-08-03. Gross Anatomy Correlates. Dr S.Frean. 08-09-03. Histology Slides and Stains. Tanya Hopcroft. This compressed version 12-07-2006, 2007