INTEGUMENT-2 This resource is licensed under the Creative Commons Attribution Non-Commercial & No Derivative Works License

Objectives To be able to identify all the structural features of hair follicles. To be able to identify the features of a section of hoof wall.

SLIDE 79 Skin (foetal cat) hair follicles This is a section of developing skin from a foetal cat. 1 mm

SLIDE 79 Skin (foetal cat) hair follicles This is a section of developing skin from a foetal cat. 1 mm

SLIDE 79 Skin (foetal cat) hair follicles Identify - Epidermis. - Dermis. - Developing hair follicles. 250 µm

SLIDE 79 Skin (foetal cat) hair follicles Identify - Epidermis. - Dermis. - Developing hair follicles. epidermis developing hair follicles developing tactile hair follicles dermis 250 µm

SLIDE 79 Skin (foetal cat) hair follicles Why do some epidermal invaginations appear not to be connected to the epidermis? 50 µm

SLIDE 79 Skin (foetal cat) hair follicles Why do some epidermal invaginations appear not to be connected to the epidermis? Due to the plane of the section. If serial sections were prepared, all the developing hairs could be traced back to the surface. epidermis (refer to integument 1 for layers) epidermal invagination dermis 50 µm

Identify hair follicles in this section of lip of cat. SLIDE 1 Lip (cat) Identify hair follicles in this section of lip of cat. 1.0 mm

SLIDE 1 Lip (cat) Identify hair follicles in this section of lip of cat. Note muscle layer (orbicularis oris muscle) oral surface orbicularis oris muscle aboral surface hair follicles 1.0 mm

SLIDE 1 Lip (cat) Hair follicle (not sinus hair) Identify hair follicle cut in longitudinal section. 250 µm

SLIDE 1 Lip (cat) Hair follicle (not sinus hair) Identify hair follicle cut in longitudinal section. sebaceous gland H : hair follicles epidermis H 250 µm

SLIDE 1 Lip (cat) Hair follicle (not sinus hair) Hair follicle cut in longitudinal section. 100 µm

SLIDE 1 Lip (cat) Hair follicle (not sinus hair) Hair follicle cut in longitudinal section. root sheath HB : hair bulb hair shaft HB 100 µm

SLIDE 1 Lip (cat) Hair follicle (not sinus hair) Hair follicle cut in longitudinal section seen at higher magnification. 50 µm

SLIDE 1 Lip (cat) Hair follicle (not sinus hair) Hair follicle cut in longitudinal section seen at higher magnification. The thickness of the inner root sheath reduces distally and ends close to where glands open into the follicle. connective tissue sheath outer root sheath cortex of hair medulla of hair inner root sheath 50 µm

SLIDE 1 Lip (cat) Hair follicle (not sinus hair) Viewed under oil immersion, identify : connective tissue sheath. inner and outer root sheath. sheath cuticle and hair cuticle. hair cortex and medulla. 25 µm

SLIDE 1 Lip (cat) Hair follicle (not sinus hair) Viewed under oil immersion, identify : connective tissue sheath. inner and outer root sheath. sheath cuticle and hair cuticle. hair cortex and medulla. C C : connective tissue sheath OR OR : outer root sheath IR SC IR : inner root sheath cortex HC SC : sheath cuticle HC : hair cuticle medulla 25 µm

SLIDE 12 Head (mouse) Hair follicles Hair follicles cut in transverse section. Most hairs lie at an oblique angle to the surface of the skin. In histological sections they will most commonly be seen in transverse section. 1 mm

SLIDE 12 Head (mouse) Hair follicles Hair follicles cut in transverse section. Most hairs lie at an oblique angle to the surface of the skin. In histological sections they will most commonly be seen in transverse section. T oral cavity skin T tongue hair follicles in dermis T B T : teeth B : bone of mandible B 1 mm

SLIDE 12 Head (mouse) Hair follicles These profiles vary in appearance. This is because the sections are at different heights along the hair follicles (refer back to the longitudinal section to see how this can affect the layers seen). 100 µm

SLIDE 12 Head (mouse) Hair follicles These profiles vary in appearance. This is because the sections are at different heights along the hair follicles (refer back to the longitudinal section to see how this can affect the layers seen). A A : sections close to hair bulb B : section with most layers visible B 100 µm

SLIDE 12 Head (mouse) Hair follicles Hair follicle cut in transverse section. 25 µm

SLIDE 12 Head (mouse) Hair follicles Hair follicle cut in transverse section. connective tissue sheath outer root sheath inner root sheath medulla cortex 25 µm

SLIDE 85 Tail (puppy) Hair follicles Again, in the tail of the puppy hair follicles are seen in transverse section. As with slide 12, the layers visible in different profiles vary with the stage of development of the hair and the position along the hair shaft. T : area of tendons bone T T 1.0 mm 100 µm

SLIDE 85 Tail (puppy) Hair follicles Which layer might be missing in a TS of a hair follicle in the upper dermis compared to a TS in the lower dermis? 50 µm

SLIDE 85 Tail (puppy) Hair follicles Which layer might be missing in a TS of a hair follicle in the upper dermis compared to a TS in the lower dermis? The inner root sheath. outer root sheath medulla cortex inner root sheath 50 µm

SLIDE 1 Lip (cat) Sinus hairs Identify sinus hairs in this section of lip of cat. 1.0 mm

SLIDE 1 Lip (cat) Sinus hairs Identify sinus hairs in this section of lip of cat. oral surface orbicularis oris muscle aboral surface sinus hairs 1.0 mm

SLIDE 1 Lip (cat) Sinus hairs The sinus hairs in this section are cut in an oblique → transverse section. How does the size of these hairs compare with adjacent hairs? 1.0 mm

SLIDE 1 Lip (cat) Sinus hairs The sinus hairs in this section are cut in an oblique → transverse section. How does the size of these hairs compare with adjacent hairs? Sinus hairs many times larger. 1.0 mm

SLIDE 1 Lip (cat) Sinus hairs In which hair follicle layer is the blood sinus present? 250 µm

SLIDE 1 Lip (cat) Sinus hairs In which hair follicle layer is the blood sinus present? Located between the inner and outer layers of the connective tissue sheath. outer connective tissue sheath annular blood sinus inner connective tissue sheath outer root sheath T medulla cortex inner root sheath T : trabeculae in blood sinus sinus pad 250 µm

SLIDE 1 Lip (cat) Sinus hairs What structure is called the ‘glassy membrane’? 100 µm

SLIDE 1 Lip (cat) Sinus hairs What structure is called the ‘glassy membrane’? The thick basement membrane below the outer root sheath. inner connective tissue sheath glassy membrane outer root sheath inner root sheath cortex medulla annular blood sinus trabeculae 100 µm

SLIDE 1 Lip (cat) Sinus hairs How is the sinus hair thought to work? 50 µm

SLIDE 1 Lip (cat) Sinus hairs How is the sinus hair thought to work? Movement of the hair creates turbulence in the vascular sinus stimulating sensory endings in the inner dermal and outer root sheaths. inner connective tissue sheath glassy membrane outer root sheath blood sinus 50 µm

SLIDE W Section of sheep skin (secondary hairs) Whole slide seen under very low magnification. Hairs are vertical to surface rather than at an oblique angle as with most other hairs. Most of the actual hair shafts are lost during sectioning. 1.0 mm

SLIDE W Section of sheep skin (secondary hairs) Whole slide seen under very low magnification. Hairs are vertical to surface rather than at an oblique angle as with most other hairs. Most of the actual hair shafts are lost during sectioning. epidermis hair follicles dermis 1.0 mm

SLIDE W Section of sheep skin How do wool hairs differ from ordinary hairs? 250 µm

SLIDE W Section of sheep skin How do wool hairs differ from ordinary hairs? Small follicles high up in the dermis. No medulla in the hairs. hair follicle hair (no medulla) 250 µm

SLIDE W Section of sheep skin What are the large prominent glands in this section? 100 µm

SLIDE W Section of sheep skin What are the large prominent glands in this section? Large and extensive apocrine sweat glands. Lanolin is derived from sebum products of the sheep skin. apocrine sweat glands 100 µm

Dermal Component of the Equine Foot La - Lamellar Corium C - Coronary Corium Li - Limbic or Perioplic Corium D - Dermis of skin Epidermis overlying the coronary corium synthesises the hoof wall

Epidermal component of the Equine Foot H - Hoof wall L - Epidermal Lamellae Epidermal Lamellae interdigitate with dermal lamellae H S - So le L F - Fr og S F

Epidermal component of the Equine foot periople hoof wall with horn tubules epidermal lamellae

Midline Section of Equine Foot P - Proximal Phalanx P - Middle Phalanx P - Distal Phalanx N - Distal Sesamoid (Navicular) Bone H - Hoof Wall S - Sole D - Pulvinus Digitalis (Digital Cushion) Midline Section of Equine Foot C – Coronary Band L – Lamellar Corium S – Solar Corium J – Junction of Sole & Hoof Wall

Dermal & Epidermal components of the Equine Foot. growth rings Dermal & Epidermal components of the Equine Foot. Note growth rings of hoof wall and clinch marks of horseshoe nails in the hoof wall.

Epidermal component of the Equine foot lamellae hoof wall with horn tubules periople

Epidermal component of the Equine foot lamellae hoof wall with horn tubules periople

SLIDE Section of equine hoof wall Whole section at low magnification. lamellae horn 1.0 mm

SLIDE Section of equine hoof wall Identify - Tubular horn. - Intertubular horn. - Primary lamellae of the hoof. - Secondary lamellae of the hoof. 250 µm

SLIDE Section of equine hoof wall Identify - Tubular horn. - Intertubular horn. - Primary lamellae of the hoof. - Secondary lamellae of the hoof. primary lamellae (hoof) secondary lamellae (hoof) I : intertubular horn T T : tubular horn T I 250 µm

SLIDE Section of equine hoof wall Identify - Primary lamellae of the hoof. - Secondary lamellae of the hoof. - Primary lamellae of the corium. - Secondary lamellae of the corium. - Blood vessels in the corium. 250 µm

SLIDE Section of equine hoof wall Identify - Primary lamellae of the hoof. - Secondary lamellae of the hoof. - Primary lamellae of the corium. - Secondary lamellae of the corium. - Blood vessels in the corium. A : primary lamella (hoof) B B : primary lamella (corium) C : secondary lamellae (hoof) D D : Secondary lamellae (corium) blood vessels in corium A C 250 µm

SLIDE Section of equine hoof wall How does a section of bovine hoof wall differ from the equine hoof wall? 100 µm

SLIDE Section of equine hoof wall How does a section of bovine hoof wall differ from the equine hoof wall? There are no secondary lamellae in the bovine hoof. secondary lamellae hoof secondary lamellae corium blood vessels in corium 100 µm

Lectures. Prof N.Stickland. First Year Histology. 010. Integument-2. J.Bredl. 01-09-03. Gross Anatomy Correlates. Dr S.Frean. 08-09-03. Histology Slides and Stains. Tanya Hopcroft. Updated compressed version. 30-06-2006 2007.