Integument 2 Flashcards
where is hair produced
by hair follicles embedded in the dermis
what is the function of hair
- mechanical protection
- thermoregulation
- snesory perception
what does a simple hair follicle contain
cuticle, cortex and medulla
what are these structures
where does the hair shaft project
above the surface of the skin epidermis
what is the hair follicle embedded in
the dermis and hypodermis
where is the hair anchored
within the follicle
what does the root consist of
consists of the hair and surrounding root sheaths
what does the bulb consist of
the dermal papilla and hair matrix cells (stem cells)
where do cells become keratinized
in the keratogenous zone
what occurs in the hair bulb and the keratogenous zone
matrix cells are mitotically active (cylcic activity)
actively dependant on dermal papilla
migrating matrix cells pass through keratogenous zone (hard keratin) –> differentiate to form hair and internal root sheath
what are the phases of the hair cycle
- terminal follicle (anagen)
- regressive (catagen)
- quiescent (telogen)
- renewed growth –> shedding –> new (early anagen)
what is the hair cycle controlled by
- photoperiod
- ambient temperature
- health
- genetics
- nutrition
- hormones
- local factors that directly influence the growth of hair follicles
how are compound hair follicles formed
- at birth –> simple hair follicle (gaurd hair)
- development of secondary follicles (undercoat)
- compound hair follicle –> adult
what are the features of sinus or tactile hair
- limited facial distribution
- extremely large
- specialized for tactile sense (blood filled sinus, skeletal muscle, innervated)
what is the function of sebaceous glands
- waterproofing
- suppleness
- spread sweat
what do sebaceous glands secrete
sebum
what are the features of the secretory portion
pale staining
flask shape
holocrine secretion
what are the features of excretory duct
empties into hair follicle
what is sweat
ultra-filtrate of blood plasma
what are the functions of sweat
- thermoregulation
- excretion
- scent signalling
what are the features of the secretory portion of sweat glands
- simple cuboidal epithelium
- myoepithelial or “basket” cells surround aid secretion
what is the difference between apocrine and eccrine sweat glands
apocrine = empty into hair follicle
eccrine = empty directly onto skin surface via sweat pore
how many layers of epithelium does the excretory duct on a sweat gland contain
2 layers of cuboidal epithelium
what type of glands are mammary glands
modified sweat glands
which glands are which
sweat gland left
sebaceous right
what are specialized skin glands
localized accumulations of sweat or sebaceous glands
ex. supracaudal (or tail) gland in dog –> concentration of sebaceous glands on dorsum of tail
what are claws, hoofs and horns
highly specialized forms of derivatives of the skin
what are the features of claws, hoof and horn
retain structural organization of epidermal, dermal and subcutis equivalent layers –> modified form
identify the numbers
thin hairy skin
- epidermis
- sebaceous gland
- dense irregular connective tissue
- hair
what structures can be seen
hair matrix cells
dark pigmentation is melanocytes
