Adnexa Flashcards
What side of primary hairs do adnexa develop?
Cranial
What side of secondary hairs do adnexa develop?
Caudal
Which mammals do NOT have sebaceous glands?
Whales, porpoises
Where on the body are sebaceous glands absent?
Paw pad
Nasal planum
(no hairs to empty into)
Where on the body are sebaceous glands most prominant?
1) Mucocutaneous junctions
2) Interdigital spaces
Horse: Coronet, dorsal rump, mane
Carnivores: chin (submental gland), dorsal tail (supracaudal tail gland)
Hyperplasia of ___ results in stud tail in dogs, cats
Sebaceous glands
Secretion mechanism of sebaceous glands
Holocrine (cell surface ruptures, leaks material out)
Where do sebaceous glands release their material?
Infundibulum of hair
Where are the reserve cells for sebaceous glands?
Their basement membrane –> lipidize as they mature –>disintegrate to release sebum
Which receptors do sebocytes have to collect lipid from circulation?
LDL receptor
FATP4 receptor
What controls sebaceous secretion?
Hormones
Hypertrophy or Involution: androgens
Hypertrophy
Hypertrophy or Involution: estrogens
Involution
Hypertrophy or Involution: glucocorticoids
Involution
Hypertrophy or Involution: retinoids
Involution – reduce sebum production
What are the contents of sebum?
-Triglycerides
-Wax esters
-Squalene
-Cholesterol
-Cholesterol esters
*Lactones in horses ONLY
Which product is ONLY in the sebum of horses?
Lactones
Which resident skin bacteria produce lipase, to mix with sebum and produce antimicrobial free fatty acids?
Proprionibacterium
Staphylococcus sp
Why are Prioprionibacterium and Staphylococcus resident skin bacteria helpful with regards to sebum?
Produce lipase, which mixes with sebum to produce antimicrobial free fatty acids
Why are ferrets greasy with a musky odor?
Increased sebaceous gland activity
What type of immune cell is primarily implicated in sebaceous adenitis?
T cells
Breeds with known autosomal recessive inheritance of sebaceous adenitis (2)
Akita
Poodle
Other breeds predisposed to sebaceous adenitis (not akita, poodle)
Havanese
Lhasa apso
Chow chow
Springer Spaniels
Species with sebaceous adenitis
Dogs
Humans
Rabbits
Cats
Horses
Other diseases that can be associated with sebaceous adenitis
Leishmania
Hypothyroidism
Initial signs of sebaceous adenitis in long-coated dogs
Change in hair color
Change in hair texture from curly to straight
Where on the body does sebaceous adenitis begin
Head, cervical region, pinnae
Medication for sebaceous adenitis that can reverse histopath changes
Cyclosporine
Non-cyclosporine treatment options for sebaceous adenitis
-Fatty acids
-Systemic retinoids
-Vitamin A
-Doxy/niacinamide
-Topicals (keratolytic shampoo, emollient spot ons)
Type of secretion of epitrichial sweat glands
MEROCRINE
NOT apocrine
Where on the body are there LARGER epitrichial sweat glands?
Glaborous skin
Are epitrichial sweat glands located more deep or superficial to sebaceous glands?
Deeper
BUT orifice is more superficial
Areas on the body where epitrichial sweat glands largest/most numerous
Similar to sebaceous glands
1) Mucocutaneous junctions
2) Interdigital spaces
3) Dorsal neck
4) Rump
Horses: MC junctions, chin, mane, coronet
ONLY place with epitrichial sweat glands in rabbits
Lips
Animals that LACK epitrichial sweat glands
Rodents, ferrets
Season with largest volume of epitrichial sweat glands in thoroughbreds
Summer
Water channel in horses in epitrichial sweat glands, facilitates rapid movement of fluid while sweating
Aquaporin-5
What cells surround epitrichial cells
Myoepithelial cells
What makes myoepithelial cells in horses unique?
Myoepithelial cells surrounding epitrichial sweat gland is in a loose basket-weave form with a rich surrounding blood supply
T or F: epitrichial sweat glands are directly innervated
False
Control of epitrichial sweat glands
Neural (MAIN!): adrenergic agonists
Horses: Autonomic (Main!), but humoral control w/adrenergic agonists from adrenal medulla during exercise
What can cause equine epitrichial sweat glands to become refractory?
Continued stimulation
Triggers for epitrichial sweat glands in dogs, cats
Unknown
Triggers for epitrichial sweat glands in horses
-Fever
-Exercise
-Heat
-Pain
-Hypoglycemia
-Hyperadenocorticism
-Catecholamine release (excitement, stress, pheochromocytoma)
Contents of epitrichial sweat secretions
-Antimicrobial salts
-Pheromones
-IgA
Horses: protein –> Latherins
Anhidoris = ___
Inability to sweat
Cause of death from anhidrosis
Hyperthermia
Geographic location for anhidrosis
Gulf coast USA
Hot, humid climates
Breeds prediposed to anhidrosis
Thoroughbreds, warmbloods
Cause of anhidrosis
Continuously high levels of epinephrine –> desensitization, downregulation of aquaporin 5 –> degeneration of secretory cells
Antibiotics that can induce anhidrosis in foals
Macrolide (erythromycin)
Rhodococcus equi infections
Initial clinical signs of anhidrosis
Patchy/inadequate sweat response
Takes longer to cool down after exercise
Chronic clinical signs of anhidrosis
Dry coat, scale, partial alopecia of face/neck
Acute anhidrosis result
Collapse, death
Diagnosis of anhidrosis
Intradermal test with epinephrine, terbutaline, β-2 agonists
Should sweat within a few mins at all concentrations, but with anhidrosis, delayed sweating after 5+ hours at only most concentrated sites
Treatment of anhidrosis
Move to a dry, cooler climate
Time to recovery for anhidrosis
4-6 weeks
Location of eccrine/atrichial sweat glands
Paw pads (carnivores, rats, mice, hamsters)
Frog (ungulates)
Snout, medial carpus (pigs)
Nasal planum (cattle)
Location of eccrine sweat glands in horses
Do NOT have eccrine sweat glands
Where is the orifice for eccrine/atrichial sweat glands
Directly onto surface of skin
Trigger for atrichial sweating
Agitation, excitement
Breeds with highest concentrations of ceruminous glands
Cocker spaniel
English spaniel
Labrador retreiver
Breeds with lowest concentration of sweat glands
Greyhounds
Which breed develops ceruminous gland hyperplasia and ectasia with end stage otitis
Cocker spaniel
(other breeds get fibrosis instead)
T or F: normal cocker spaniels with no hx otitis can have ceruminous gland hyperplasia and ectrasia
T
(+87% of those w/hx otitis)
Which glands line the anal sacs?
Sebaceous glands
Epitrichial sweat glands
Modified sebaceous glands on the dorsal/ventral tail, around prepuce/mammary glands, caudal hindlimbs, dorsal midline
Perianal glands
What controls perianal glands
Androgens
How does the arrector pili muscle attach to the follicular epithelium
elastic fibers
How does the arrector pili muscle attach to the extracellular matrix in the dermis
Integrins
Where are arrector pili muscles the largest
Dorsal neck, rump
What controls contraction of arrector pili muscles
Epinephrine, norepinephrine
