Lecture 41 4/24/24 Flashcards
How are glands classified?
-exocrine vs endocrine
-multicellular vs unicellular
-tubular vs acinar shape
-apocrine vs merocrine vs holocrine secretion
How do apocrine and eccrine glands differ?
apocrine:
-associated with primary hair follicles
-duct empties to hair follicle
-apocrine secretion
-throughout haired skin
-thermoregulation only in horses and cows
-secretions mix with sebum to form protective skin layer
eccrine:
-not associated with hair follicles
-duct empties to skin surface
-merocrine secretion
-specialized locations
-thermoregulation in all mammals
How are apocrine and eccrine glands similar?
-single layer of cuboidal/columnar epithelium surrounded by myothelium
-simple tubular - coiled shape
What are the specialized locations for eccrine glands?
-footpads of dogs and cats
-frog of ungulates
-nasal planum of cows
-snout and medial carpus of pigs
What are the characteristics of mammary glands?
-special apocrine gland
-produce secretions high in protein and lipid
What are the characteristics of ceruminous glands?
-special apocrine gland
-located in external ear canal
-produces cerumen/ear wax
-cerumen lubricates, waterproofs, entraps materials, and is antimicrobial
What are the characteristics of the apocrine glands of the anal sac?
-special apocrine gland
-located next to anal sacs
-open to anal skin or into sac
-allow for territorial markings
How do special/modified apocrine glands differ from normal apocrine glands?
they are not associated with hair follicles
What are the characteristics of sebaceous glands?
-holocrine secretion
-acinar shape
-multicellular
-exocrine
-associated with hair follicles (mainly primary)
-not found on footpads or nasal planum
What is a Meibomian gland?
sebaceous gland associated with the eyelids
What are the characteristics of the tail gland?
-special sebaceous gland
-found in dogs, cats, and other carnivores
-found in both sexes on the dorsal aspect of tail
What are the characteristics of perianal glands?
-special sebaceous gland
-associated with hair follicle
-resemble hepatocytes
-found on perianal skin, proximal tail, lumbosacral region, lateral to prepuce, and along ventral midline
-absent in cats
-allow for territorial markings
What are the layers of the panniculus and subcutis, from most superficial to least?
-panniculus adiposus: adipose tissue
-panniculus carnosus: skeletal muscle
-subcutis: adipose tissue
What are the characteristics of the panniculus and subcutis?
-form the deepest and thickest layer of skin
-absent in the lips, cheeks, eyelids, ear canal, and anus
-attached to underlying bone and muscle
What are the functions of the panniculus and subcutis?
-energy storage
-thermoregulation/insulation
-protective padding
-maintain surface contours
What are the components of the subcutis and panniculus?
-white adipose
-panniculus muscle
-blood vessels
-nerves
*NO LYMPHATICS
What are the characteristics of the nose in carnivores?
-aka planum nasale
-keratinizing stratified squamous epithelium
-thick keratin layer
-no hair follicles
-no glands
What are the characteristics of the nose in cows/small ruminants?
-aka planum nasolabiale/planum nasale
-keratinizing stratified squamous epithelium
-thick keratin layer
-no hair follicles
-eccrine glands present to moisten the surface
What are the characteristics of the foot pads?
-thickest epidermis on body
-often highly pigmented
-thick keratin layer
-keratin layer is smooth in cats, papillary in dogs
-prominent dermal papillae interdigitate with epidermal rete pegs
What are the characteristics of the foot pad dermis?
-no hair follicles
-numerous eccrine glands
What is the main characteristic of the foot pad hypodermis?
lots of adipose tissue; digital cushion
What are the characteristics of carnivore toenails?
-nail bed consists of stratified squamous epithelium and thick, dense keratin
-nails are supported by bone
What is the equine hoof?
insensitive keratinized layer
What is the equine hoof wall?
epidermis that makes the hoof
