Ch 6 Powerpoint 1b Flashcards
What are cutaneous pouches in sheep?
Infoldings of skin containing fine hair, sebaceous and oil glands
Located in three areas: infraorbital, interdigital, inguinal.
What substance do cutaneous pouches secrete?
A fatty yellow substance that covers and sticks to the skin when dry.
What are the main functions of hair?
- Maintenance of body temperature
- Protection via camouflage
What are the parts of the hair?
- Hair shaft: visible above the skin
- Hair root: buried within the skin
- Hair follicle: anchors the hair
- Hair bulb: expands at the base of the follicle
- Papilla: mound of dermal cells at the base of the hair bulb
What are the three concentric layers of hair?
- Medulla
- Cortex
- Cuticle
What are the layers in the wall of a hair follicle?
- Internal epithelial root sheath
- Outer epithelial root sheath
- Dermal or connective tissue root sheath
What are compound follicles?
Follicles that average one hair strand but can have multiple hair strands in a single pore.
What are the phases of hair growth?
- Anagen phase: cells added at the base, hair lengthens
- Catagen phase: transition between anagen and telogen
- Telogen phase: maximum length achieved, hair stops growing
What determines hair color?
- Quantity of melanin
- Type of melanin
- Location of melanin
What are the types of melanin produced in dogs?
- Pheomelanin: reddish & yellowish hairs
- Tyrosine melanin: brown-black hairs
What is the role of arrector pili muscle?
Pulls the hair to an erect position when contracted.
What are sebaceous glands?
Glands located in the dermis that produce sebum and can empty into hair follicles or directly onto skin.
What is sebum?
Oily lipids manufactured and stored by sebaceous glands, which coat hair and skin.
What are the two types of sweat glands?
- Eccrine sweat glands
- Apocrine sweat glands
Where do eccrine sweat glands empty?
Onto the surface of the skin.
Where do apocrine sweat glands empty?
Into hair follicles.
What is the function of tail glands?
Assist animals in identification of one another.
What are anal sacs?
Reservoir for malodorous secretions lined with sebaceous and apocrine glands.
What can cause anal sacs to become infected?
Contents being expressed during defecation or when the animal is frightened.
What are tactile hairs also known as?
Sinus hairs or whiskers.
What is the function of tactile hairs?
Used as probes and feelers for the slightest touch.
What is the classification of sebaceous glands?
Holocrine structure.
What is lanolin?
A product produced by the sebaceous glands of sheep.
