1. INTEGUMENT-2
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2. 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.

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

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

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

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

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

8. 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

9. 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

10. 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

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

12. 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

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

14. 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

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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

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

24. 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

25. 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

26. 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

27. 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

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

29. 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

30. 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

31. 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

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

33. 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

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

35. 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

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

37. 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

38. 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

39. 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

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

41. 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

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

43. 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

44. 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

45. 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

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

47. 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

48. 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.

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

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

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

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

53. 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

54. 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

55. 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

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

57. 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

58. Lectures. Prof N.Stickland.
First Year Histology Integument J.Bredl
Gross Anatomy Correlates Dr S.Frean
Histology Slides and Stains Tanya Hopcroft.
Updated compressed version
2007.