Ch 1 Structure and Function Flashcards Preview

Vet Derm Review > Ch 1 Structure and Function > Flashcards

Flashcards in Ch 1 Structure and Function Deck (54)
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1
Q

Fetal skin contains a larger percentage of what type of collagen compared to adult skin?

A

collagen III (adult skin has more type I collagen)

2
Q

What is different about where appendages such as the arrector pili muscle, sebaceous glands, epitrichial sweat glands form in primary vs. secondary hair follicles?

A

in primary - appendages develop on cranial side; in secondary - appendages develop on the caudal side

3
Q

T/F: At birth, the majority of hair follicles of dogs are primary follicles.

A

True - secondary follicles develop caudal to the primary hairs during the first 12-28 weeks of life.

4
Q

Is the skin surface of haired mammals generally acidic or basic?

A

acidic - but it is influenced by gender, coat color, breed, species

5
Q

T/F: In cats, secondary hairs are more numerous than primary hairs.

A

True - 10:1 dorsally, 24:1 ventrally

6
Q

Layers of the hair follicle near the dermal papilla (inner to outer)

A

hair medulla –> hair cortex –> hair cuticle –> Huxley’s layer –> Henle’s layer –> outer root sheath –> basement membrane –> fibrous sheath

7
Q

Hormones that stimulate the hair cycle (induce or prolong anagen)

A

thyroid hormones, corticotropin, melatonin, androgens, growth hormone

8
Q

Hormones that inhibit the hair cycle (inhibit anagen, induce catagen, and/or prolong telogen)

A

cortisol, estrogen, corticotrophin-releasing hormone, corticotropin, prolactin, parathyroid-related peptide

9
Q

Growth factors that stimulate the hair cycle (induce or prolong anagen)

A

Fibroblast growth factor (FGF) - 7; hepatocyte growth factor; insulin-like growth factor-1; Sonic hedgehog; Keratinocyte growth factor, WNTs, beta-catenin, TGF-alpha; nerve growth factor; GDNF

10
Q

Growth factors that inhibit the hair cycle (inhibit anagen, induce catagen, and/or prolong telogen)

A

epidermal growth factor; fibroblast growth factor (FGF)-2, FGF-5; brain-derived neurotrophic factor; neurotrophin 3,4; TNF-alpha; TGF-beta-1, TGF-beta-2

11
Q

Cytokines that stimulate the hair cycle (induce or prolong anagen)

A

TGF-alpha

12
Q

Cytokines that inhibit the hair cycle (inhibit anagen, induce catagen, and/or prolong telogen)

A

Interleukin-1, IL-6

13
Q

Does this substance inhibit or stimulate the hair cycle: activin?

A

stimulate

14
Q

Does this substance inhibit or stimulate the hair cycle: noggin?

A

stimulate

15
Q

Does this substance inhibit or stimulate the hair cycle: follistatin?

A

stimulate

16
Q

Does this substance inhibit or stimulate the hair cycle: cyclosporine?

A

stimulate

17
Q

Does this substance inhibit or stimulate the hair cycle: minoxidil?

A

stimulate

18
Q

Does this substance inhibit or stimulate the hair cycle: finasteride?

A

stimulate

19
Q

Does this substance inhibit or stimulate the hair cycle: retinoids?

A

inhibit

20
Q

Does this substance inhibit or stimulate the hair cycle: calcitriols?

A

inhibit

21
Q

What is the ratio of primary to secondary hairs in the “normal coat”? What breed is an example of this coat?

A

high proportion of hairs by number are secondary hairs; GSD, Welsh corgi, wolves, coyotes

22
Q

What is the ratio of primary to secondary hairs in the “coarse short coat”? What breed is an example of this coat?

A

strong growth of primary hairs and less secondary hairs; Rottweiler and terriers

23
Q

What is the ratio of primary to secondary hairs in the “fine short coat”? What breed is an example of this coat?

A

largest number of hairs per unit, secondary hairs are numerous and well-developed, primary hairs are reduced in size compared to those of the normal coat; Boxers, daschunds, miniature pinschers

24
Q

Characteristics of the fine long coat? Breeds with this type of coat?

A

greater weight of hair per unit area than the normal coat, except in toy breeds; Cocker Spaniel, Pomeranian, Chow Chow

25
Q

Characteristics of the woolly or coarse long coat? Breeds with this type of coat?

A

secondary hairs make up 70% of the total weight and 80% of the number of hairs; Poodle, Bedlington terrier, Kerry Blue terrier - less tendency to shed than many breeds

26
Q

Activation of melanocortin 1 receptors on melanocytes leads to production of what type of pigment?

A

eumelanin

27
Q

Inhibition of melanocortin 1 receptors on melanocytes leads to production of what type of pigment?

A

pheomelanin

28
Q

The shade of eumelanin is controlled by what gene?

A

tyrosinase related protein 1 gene

29
Q

What color gene results in a gradual replacement of eumelanin with phaeomelanin? What breed/species of animal is this recognized in?

A

amber gene (E); Norwegian Forest cats

30
Q

What breed of cats have a temperature-dependent enzyme that converts melanin precursors into melanin by a process of oxidation?

A

Siamese, Himalayan-Persian, Balinese, Birman

31
Q

The dilution gene (D, melanophilin, MLPH) dilutes black to blue (gray), orange to cream, and seal-point to blue-point. How is it inherited?

A

autosomal recessive

32
Q

Cornish or Devon rex: lacks primary hairs

A

Cornish rex

33
Q

Cornish or Devon rex: has primary hairs that resemble secondary hairs

A

Devon Rex

34
Q

Cornish or Devon rex: absent or stubbled whiskers

A

Devon rex

35
Q

Cornish or Devon rex: short and curly whiskers

A

Cornish Rex

36
Q

Cornish or Devon rex: absent coat on chest, belly, shoulders

A

Devon Rex

37
Q

What are Voight lines

A

boundaries of the areas of distribution of the main cutaneous nerve stems

38
Q

What are langer lines

A

course of blood vessels or lymphatics

39
Q

What are Blaschko lines

A

pattern assumed by many different nevoid and acquired skin diseases

40
Q

What are the four cell types within the epidermis?

A

keratinocytes, melanocytes, Langerhans cells, Merkel cells

41
Q

Layers of the epidermis (inner to outer)

A

stratum basale –> stratum spinosum –> stratum granulosum –> stratum lucidum –> stratum corneum

42
Q

What is the normal thickness of the epidermis in dogs and cats?

A

2-3 nucleated cell layers (not counting horny layer) in haired skin

43
Q

T/F: The surface of footpad epidermis is smooth in cats but papillated and irregular in dogs.

A

True - rete ridges (projections of epidermis into the underlying dermis) are normal to find in the footpad and nasal planum epidermis (and in lightly haired scrotum)

44
Q

What keratins are present in the stratum spinosum?

A

retain keratin-5/keratin-14, synthesize K1/K10

45
Q

T/F: The stratum granulosum is always present in haired skin.

A

False - variably present, ranges from 1-2 cells thick in areas where it occurs

46
Q

Where are keratohyalin granules synthesized?

A

stratum granulosum

47
Q

What do keratohyalin granules contain?

A

profilaggrin, keratin filaments, loricrin

48
Q

Filaggrin degradation produces what? What is the purpose of these products?

A

urocanic acid, pyrrolidone carboxylic acid – important for normal stratum corneum hydration and help filter UV radiation

49
Q

What is loricrin?

A

cystine-rich protein synthesized in the stratum granulosum; involved in binding keratin filaments together in the corneocyte and choring them to the cross-linked envelope

50
Q

Where is the stratum lucidum best developed?

A

footpads, less developed in nasal planum and absent from all other areas of normal skin

51
Q

What differentiates the stratum lucidum from the stratum corneum?

A

rich in protein-bound lipids; contains a semifluid substance called eleidin

52
Q

T/F: The corneocytes has no true cell membrane.

A

True - because it contains no phospholipids; instead has the cornified envelope

53
Q

What are transglutaminases? Deficiencies can result in what clinical disease?

A

enzymes that are important in apoptosis, keratinization, hair follicle formation; ichthyosis

54
Q

Where in the epidermis are transglutaminanses chiefly expressed?

A

stratum granulosum and upper stratum spinosum; they require catalytic amino acids and calcium