02 - Structure (Continued)

Question 1

(Dermis)

(Fibers of the Dermis)

(collagen)

1. the major fiber of the dermis (90%) - provides tensile strength… resistant to most what?
2. is collagen static?
3. diseases can be causd by abnormal synthesis or excessive degradation… what is the name of a disease which is a group of genetic disorders characterized by enzymatic defects in collagen synthesis?

Answer 1

1. proteases
2. no… it is continuously synthesized and degraded
3. Ehler-Danlos Syndrome

Question 2

(Fibers of the Dermis)

(Elastic Fibers)

1. comprise what percentage of fibers in the dermis?
2. what are two diseases affecting the elastic tissue?

Answer 2

1. 10%
2. cutis laxa and solar elastosis

Question 3

(Fibers of the Dermis)

(Reticulin Fibers)

1. how do they differ from collagen? take up what stain?
2. surround the epidermal appendages, vessels and nerves
3. comprise what % of the dermis?

Answer 3

1. fine, branching structures; silver stain
2. 1%

Question 4

(Fibers of the Dermis)

(Muscle Fibers)

1. What muscles originate near the basement mebrane zone and attach to the hair follicle near its base? fucntion to do what? smooth or striated muscles? Most prominent where on the carnivore?

Answer 4

1. the arrector pili muscles; cause erection of the hairs; smooth; dorsal midline

Question 5

(Ground Substance of the Dermis)

1. consists of several anionic polysaccharides known as what?
2. in vivo usually linked to proteins, and known as what?
3. produced and degraded by what and what?

Answer 5

1. glycosaminoglycans
2. proteoglycans
3. fibroblasts and mast cells

Question 6

(Ground Substance of the Dermis)

(Ground substance exists as a viscoelastic sol/gel whose functions are)

1. interactions with what and what?
2. influence water binding and flow of solutes
3. examples… what are three?
4. Present in large quantities in dermis of what breed? causing what disease?
5. can also be in large quantities in hypothyroidism - causing a condition called what?

Answer 6

1. collagen and cell surfaces
2. hyaluronic acid, dermatan sulfate, chondroitin sulfate
3. Shar Pei dogs; cutaneous mucinosis
4. myxedema

Question 7

(Species Differences in the Dermis)

1. what has less compicated dermal surface - hair or non-hair?
2. Glabrous skin has prominent dermal papillae (called what?) - rete ridges are also found in the what and what of dogs and cats?

Answer 7

1. hairy skin
2. rete ridges (with well formed capillary loops which project upward between epidermal rete pegs)
3. footpads and nasal planum

Question 8

(Species Differences in the Dermis)

1. what are two divisions of the dermis?
2. which is more cellular and contains finer fibers? which is less cellular and has coarse fibers?
3. (In hairy animals, dermal papillae with well-formed capillary loops are not present in haired skin (it is present in non-haired skin such as the footpads and nasal planum), so the terms superficial and deep dermis are preferred.)

Answer 8

1. papillary dermis (superficial) and reticular dermis (deep)
2. papillary, reticular

Question 9

(Hypodermis (Subcutis))

1. aka panniculum adiposum… composed primarily of what?
2. The lipocytes are grouped together in lobules surrounded by what three things?
3. What is the function of the subcutis (three things)?
4. Fat in footpads and hooves act as important what?
5. Sterile inflammation of the panniculum adiposum is called what? presents clinically as what?

Answer 9

1. fat
2. connective tissue, blood vessels, and nerves
3. fat storage, heat insulation, and body contour
4. shock absorbers
5. sterile nodular panniculitis…. nodulues (that may or may not drain)

Question 10

(Epidermal Appendages)

1. include what 8 things?

Answer 10

1. sebaceous glands, sweat glands (sweat and eccrine), hair follicles and hair, claws, nails, hooves, horns

Question 11

(Epidermal Appendages)

(Sebaceous glands)

1. present in what kind of skin?
2. empty into what?
3. sebum forms what?
4. other functions of sebum include bacteriostasis and fungistasis

Answer 11

1. haired skin
2. hair follicle
3. emulsion that lubricates, gives pliability, aids in water retention, provides shine to hair (skin animals get dry skin)

Question 12

(Epidermal Appendages)

(Sebaceous glands)

(Factors influencing sebum production)

1. What three increase?
2. which two decrease?
3. Dietary fat deficiencies increase or decrease sebum production?
4. Examples of diseases associated with sebaceous glands… sebaceous adenitis, sebaceous hyperplasia, or adenomas

Answer 12

1. androgens, progesterone, thyroid hormones
2. corticosteroids, estrogen (large doses)
3. can do either (can also change qualitative qualities)

Question 13

(Epidermal Appendages)

(Sweat Glands)

(Apocrine glands)

1. most extensive in what kind of animals?
2. like sebaceous glands present thorughout what type of skin? why?
3. what is distribution like in animals?
4. apocrine secretion in association with sebum secretion forms what?

Answer 13

1. domestic
2. haired skin; duct opens in the hair follicle canal
3. generalized (unlike humans)
4. an emulsion which coats the skin and hair

Question 14

(Epidermal Appendages)

(Sweat Glands)

(Apocrine glands - cont)

1. in horses, apocrine glands important in what?
2. What disease is characterized by an inability to sweat?

Answer 14

1. temp regulation (produce seat during exercise and high temp);
2. anhydrosis (resulting in hyperthermia)

Question 15

(Sweat Glands)

(Eccrine (Merocrine) Glands)

1. associated with hair follicles?
2. restricted to what on dogs and cats? on ungulates? on pig? of ruminants?

Answer 15

1. no!
2. foot pad; frog; carpus and snout; planum nasale

Question 16

(Hair Follicles and Hair)

1. The hair follicle, sebaceous and apocrine glands make up what? which develops as a growth of what?
2. the hair follicle is dilated at the base to form a bulb, which encloses what?

Answer 16

1. the pilo-sebaceous/apocrine apparatus; the epidermis
2. the dermal papilla

Question 17

(Hair follicles and hair)

1. how is keratinization of hair differ from that in the epidermis?

Answer 17

1. is hard keratin (higher in sulfur and cysteine) (processs related to hair growth cycle)

Question 18

(Hair follicles and hair)

(Phases)

1. growth phase
2. intermediate phase
3. resting phase (club hair)

Answer 18

1. anagen
2. catogen
3. telogen

(the size and shape of follicle is altered during each of these phases. hair follicles in anagen are long and the bulb may reach the subcutaneous fat tissue. telogen hair follicles are much shorter and their distal end is in the mid dermis)

Question 19

(Hair follicles and hair)

(Hair color)

1. similar to epidermal cells, except that melanocytes of hair bulb are only active during what phase?

Answer 19

1. anagen

Question 20

(Hair follicles and hair)

(Factors affecting the hair growth)

(hormones)

1. what stimulates anagen? what inhibits?

(nutrition)

2. deficienty in what leads to weird color and hair structure?

(disease)

3. what occurs 2-3 months after a stressful event as a result of excessive glucocorticoid secretion?

Answer 20

1. thyroid; excessive glucocorticoids or estrogen
2. proteins
3. telogen defluxion (glucocorticoids will inhibit anagen, the growing stage of hair follicle, resulting in many hair follicles staying in telogen at one point in time)

Question 21

(Types of Hair Follices)

(Simple follicles)

1. one hair emerging from a single pore
2. hair follicle is large and rooted deep in what?
3. what three things associated with each follicle?
4. seen in what animals?

Answer 21

2. dermis
3. apocrine, sebaceous, and arrector pili
4. omnivores and herbivores (horses, cattle, pigs, rats, mice)

Question 22

(Types of Hair Follicles)

(Compound follicles)

1. combo of primary and secondary follicles
2. secondary follicles arise as buds from what?
3. smaller or larger diameter than primary? closer or further to superficial dermis? lack what?
4. compound follicles characterized by what? Seen in what animals?

Answer 22

2. original primary follicles
3. smaller; closer; apocrine sweat glands and arrector pili muscle
4. having multiple hairs emerging from a single hair follicle pore; dogs, cats, goats, ferrets and sheep

Question 23

(The parts of the hair)

1. the free portion above the skin surface
2. the proximal portion inside the follicle? the root is attached by what to the underlying papilla?

Answer 23

1. the shaft
2. the root; its terminal end (the hair bulb)

Question 24

(The layers of the hair)

1. the outermost layer of the hair; formed by what?
2. densely packed keratininzed cells; contain what?
3. loose cuboidal or flattened cells wedged between the cortex; do all hairs have this?

Answer 24

1. the hair cuticle; flar, cornified, anuclear cells
2. the cortex; melanin that give color to hair
3. the medulla (melanin may be present - no influence on color though); no

Question 25

(types of hair) 1. large medullated coarse hairs (aka guard hairs) 2. fine medullated hairs, the undercoat of many breeds of dogs 3. fine non-medullated hairs; not present in dogs and cats post birth 4. various propotions affect hair coat type 5. are fine: are usually non-medullated, thightly crimped hair fibers 6. located on muzzle and above the eye in the dog and cat, behind the carpus in the cat

Answer 25

1. primary 2. secondary 3. lanugo 5. wool fibers 6. sinus or tactile hairs (whiskers or vibrissae)