Lecture 41 4/24/24

Question 1

How are glands classified?

Answer 1

-exocrine vs endocrine
-multicellular vs unicellular
-tubular vs acinar shape
-apocrine vs merocrine vs holocrine secretion

Question 2

How do apocrine and eccrine glands differ?

Answer 2

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

Question 3

How are apocrine and eccrine glands similar?

Answer 3

-single layer of cuboidal/columnar epithelium surrounded by myothelium
-simple tubular - coiled shape

Question 4

What are the specialized locations for eccrine glands?

Answer 4

-footpads of dogs and cats
-frog of ungulates
-nasal planum of cows
-snout and medial carpus of pigs

Question 5

What are the characteristics of mammary glands?

Answer 5

-special apocrine gland
-produce secretions high in protein and lipid

Question 6

What are the characteristics of ceruminous glands?

Answer 6

-special apocrine gland
-located in external ear canal
-produces cerumen/ear wax
-cerumen lubricates, waterproofs, entraps materials, and is antimicrobial

Question 7

What are the characteristics of the apocrine glands of the anal sac?

Answer 7

-special apocrine gland
-located next to anal sacs
-open to anal skin or into sac
-allow for territorial markings

Question 8

How do special/modified apocrine glands differ from normal apocrine glands?

Answer 8

they are not associated with hair follicles

Question 9

What are the characteristics of sebaceous glands?

Answer 9

-holocrine secretion
-acinar shape
-multicellular
-exocrine
-associated with hair follicles (mainly primary)
-not found on footpads or nasal planum

Question 10

What is a Meibomian gland?

Answer 10

sebaceous gland associated with the eyelids

Question 11

What are the characteristics of the tail gland?

Answer 11

-special sebaceous gland
-found in dogs, cats, and other carnivores
-found in both sexes on the dorsal aspect of tail

Question 12

What are the characteristics of perianal glands?

Answer 12

-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

Question 13

What are the layers of the panniculus and subcutis, from most superficial to least?

Answer 13

-panniculus adiposus: adipose tissue
-panniculus carnosus: skeletal muscle
-subcutis: adipose tissue

Question 14

What are the characteristics of the panniculus and subcutis?

Answer 14

-form the deepest and thickest layer of skin
-absent in the lips, cheeks, eyelids, ear canal, and anus
-attached to underlying bone and muscle

Question 15

What are the functions of the panniculus and subcutis?

Answer 15

-energy storage
-thermoregulation/insulation
-protective padding
-maintain surface contours

Question 16

What are the components of the subcutis and panniculus?

Answer 16

-white adipose
-panniculus muscle
-blood vessels
-nerves

*NO LYMPHATICS

Question 17

What are the characteristics of the nose in carnivores?

Answer 17

-aka planum nasale
-keratinizing stratified squamous epithelium
-thick keratin layer
-no hair follicles
-no glands

Question 18

What are the characteristics of the nose in cows/small ruminants?

Answer 18

-aka planum nasolabiale/planum nasale
-keratinizing stratified squamous epithelium
-thick keratin layer
-no hair follicles
-eccrine glands present to moisten the surface

Question 19

What are the characteristics of the foot pads?

Answer 19

-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

Question 20

What are the characteristics of the foot pad dermis?

Answer 20

-no hair follicles
-numerous eccrine glands

Question 21

What is the main characteristic of the foot pad hypodermis?

Answer 21

lots of adipose tissue; digital cushion

Question 22

What are the characteristics of carnivore toenails?

Answer 22

-nail bed consists of stratified squamous epithelium and thick, dense keratin
-nails are supported by bone

Question 23

What is the equine hoof?

Answer 23

insensitive keratinized layer

Question 24

What is the equine hoof wall?

Answer 24

epidermis that makes the hoof

Question 25

What is the perioplic epidermis?

Answer 25

epidermis at the junction of the skin and the hoof

Question 26

Which tissues are present and interdigitate at the epidermal-dermal junction of the hoof?

Answer 26

-stratum lamellatum/epidermal laminae
-lamellar corium/dermal laminae

Question 27

How do the primary and secondary laminae differ?

Answer 27

-primary laminae are the main large laminae
-secondary laminae are smaller and branch off the primary laminae

Question 28

Which laminae keratinize to form the hoof?

Answer 28

primary laminae

Question 29

What are the components of each primary or secondary laminae?

Answer 29

-insensitive epidermal component
-sensitive dermal component

Question 30

How do the hooves of ruminants and pigs differ compared to horses?

Answer 30

-technically have claws instead of hooves
-no secondary laminae
-more primary laminae