1. Chapter 10
Skin Deep

2. Functions of the Integumentary System
The integumentary system consists of skin and its accessories .
Accessory organs include glands, hair, fur, wool, feathers, scales, claws, beaks, horns, hooves, and nails.

3. Functions of the Integumentary System
Skin is largest organ system in the body
Skin plays a role in
protecting animals from infection,
waterproofs the body,
prevents fluid loss,
provides species-specific coloration/ camouflage,
Maintains and regulates body temps
and provides a site for vitamin D synthesis.

4. Skin
Skin covers the external surfaces of the body and is composed of epithelial tissue.
The combining forms for skin are cutane/o, derm/o, and dermat/o.
The suffix -derma also means skin.

5. Skin Layers Epidermis Dermis Subcutaneous layer most superficial layer
middle layer that contains blood and lymph vessels, nerve fibers, and accessory organs
Subcutaneous layer
deepest layer that contains connective tissue

6. Skin Skin is made up of three layers: Epidermis Epithelial tissue
3 – 5 distinct cell layers depending on species or location on body
Melanin is found in one of these layers (pigment / skin color)
“Thick skin” found on areas of hard usage such as
paw pads, dorsal neck, dorsal thorax, rump

7. Dermis Connective tissue containing blood vessels, nerves,
lymph vessels, tiny muscles attached to hair
follicles (arector pili)
Exocrine glands and touch receptors (called
Pacinian Corpuscles) for sensations such as hot,
cold, touch, pain

8. Hypodermis Made up of loose connective tissue and fatty tissue
Allows the skin to slide over structures without tearing
Subcutaneous

9. Glands Skin glands may be either sebaceous, sweat, or musk glands.
These glands are exocrine glands
Sebaceous glands secrete an oily sub-stance called sebum.
Hair covered areas / attached to hair follicles
Oily, waxy, waterproofing
Sweat glands secrete sweat.
Also called sudoriferous glands
Ceruminous glands = Earwax is sebum + dead cells

10. Hair
Hair is rodlike fibers made of dead protein cells filled with keratin.
Combining forms for hair are pil/i, pil/o, and trich/o.
Hair follicles are sacs that hold the hair fibers.

11. Telogen Effluvium Hair has Growth Cycles
Anagen Phase – active growth, hair is lengthening
Catgen Phase – transitory phase
Telogen Phase – hair stops growing / resting phase

12. Types of hair 1. Primary or guard hairs
Straight or arched; thicker and longer than secondary hairs
2. Secondary or wool-type hairs
Softer and shorter than primary hairs; wavy or bristled in the dog; predominant hair type in species with wool-type coats
Tactile hairs
Contain numerous sensory endings : probes and feelers for the animal
Commonly known as whiskers; also mixed intermittently throughout the hair coat

13. Nails, Claws, and Hooves
The distal phalanx of animals is covered by nails, claws, or hooves.
Nails and claws are keratin plates in dogs and cats.
Combining form is onych/o.
Hooves are the horny covering of the distal phalanx in ungulates such as horses, ruminants, and swine.

14. Pads Pads are thick areas of keratinized epithelium.
Dogs and cats have digital pads and metacarpal and metatarsal pads.
Livestock have walls, soles, and bulbs.

15. Paw Pads…if you ever wondered
Thick layers of fat and connective tissue with exocrine sweat glands and touch receptors
Outer surface is the toughest and thickest skin in the body
Often pigmented; composed of all five epidermal layers
Stratum corneum (top layer) is thicker than all other layers combined
Conical papillae can be seen covering entire pad

16. Planum Nasale Composed of three epidermal layers
Polygonal plaques separated by grooves in the epidermis
Top of the nose in cats, pigs, sheep, and dogs
Planum nasolabiale: the muzzle of cows and horses

17. Terms
Alopecia
Pruritis
Keratinization

18. Alopecia Hair loss Several causes Hypothyroidism Nutritional
Skin parasites

19. Pruritis
Itching
Allergies
Skin parasites
Behavioral
Bacterial

20. Keratinization Hyperkeratosis -idiopathic (unknown cause) condition
-characterized by the excessive formulation of nasal or footpad keratin. -common in older dogs.
-thickened, hard, dry keratin accumulates on the top of the nose, footpads, or both.

21. Mange Mites Mange Causes pruritus and alopecia Hyperkeratosis
Inflammation of the dermis and epidermis
Causes pruritus and alopecia
Hyperkeratosis
Bacterial infections

22. Caused by Mites
Chyletiella
Sarcoptic Mange Mite
Demodectic
Ear Mite

23. Skin Scraping

24. Medical Terms for the Integumentary System
Additional terms for integumentary system tests, pathology, and procedures can be found in the text.
Review StudyWARE to make sure you understand these terms.