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Vet Microanatomy 1 > Integument > Flashcards

Flashcards in Integument Deck (75):
1

List 5 epidermal derivatives

foot pads, claws, hooves, horns (but not antlers), anal sacs/glands, mammary glands, uropygial glands, wattles, spurs, feathers

2

Skin Functions

protection, prevent water loss, temperature regulation, sensation, immune functino, excretion, water-ion balance (sweating), calcium homeostasis, energy storage

3

functions of hair

insulation, camouflage, social display, sensory, protection

4

what are the 3 layers of the skin?

epidermis, dermis, and hypodermis

5

epidermis is made of

stratified squamous keratinized epithelium

6

what are the two layers of dermis

papillary and reticular layers

7

hypoddrmis/subcutis is sometimes rich in what? What does the hypodermis attach to?

-rich in adipocytes
-attaches loosely to organs

8

what layer of skin is thick skin? what are some other characteristics of thick skin?

Epidermis
-hairless, merocrine sweat glands present, ie. digital pads, muzzles

9

what layer is thin skin? name some characteristics

thin skin is part of the epidermis
-hair follicles with arrector pili muscles, sebaceous and sweat glands

10

[thick vs thin skin picture]

-

11

[epidermal pegs picture] what are the names of these structure, and where is it found?

1. epidermal pegs: downward projections of epidermis into the underlying dermis
2. dermal papillae: upward projections from dermis
-footpad, nasal planum, scrotum; found at areas subject to traction stress

12

dermal papillae function

increase area of contact between dermis and epidermis
-bring blood vessels near epithelium

13

what is the main component of dermis?

connective tissue

14

Papillary layer: what type of connective tissue is it made of? What type of ollagen? What other chatacteristics does it possess?

-loose CT
-type 1 and 3 collagen
-mast cells, macrophages, vessels, and nerves
[insert picture of papillary and reticular layers]

15

Reticular layer: type of connective tissue, type of collagen, and other characteristics

-dense irregular ct
-type 1 collagen
-network of elastic fibers, blood vessels, and nerves

16

skin elasticity refers to what in the dermis?

the network of elastic fibers present in the reticular layer [insert skin elasticity picture]

17

cells of the epidermis can fall into one of two categories:

keratinocytes or non-keratinocytes

18

keratinocytes are...

most common cell type of the epidermis: they make up 95% of the epidermis

19

non-keratinocytes include...

-langerhans cells - part of immune system
-merkel's cells - sensory cells
-melanocytes - protective
-intraepithelial lymphocytes

20

adhere cells of the epidermis include

desmosomes between cells and hemidesmosomes attaching to the basal lamina

21

epidermal layers are constantly replacing...

cytoplasm with keratin, to continually add to the outer layer

22

layers of the epidermis include [picture of layers of epidermis]

stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum

23

[picture of stratum basale]

stratum basale
-epidermal-dermal junction
-single layer of cuboidal-columnar cells
-rests on basal lamina, possesses hemidesmosomes and desmosomes
-melanocytes may be present

24

[picture of adhere cells]

1. adherens junctions
2. keratin filaments
3. desmosomes
4. hemidesmosomes

25

stratum basale function

-mitotic division allows new cells to move up to keratinize on upper layers

26

[pictures of stratum spinosum]
-what is this layer called and what are its characteristics?

-cuboidal or slightly flattened
-in thin skin there are 1-2 layers, in thick there are many
-desmosomes give spiny appearance (aka prickle cells layer)
-cohesive cells that resist abrasion
-layer retains some mitotic capability if needed

27

[pictures of desmosomes]
what are these structures?

desmosomes

28

[stratum granulosum]

-stratum granulosum
-3-5 thin layers, may be hard to see
-possesses keratohyalin granuales
-stains basophilic
-no mitotic activity; it is the last living layer, last to have nucleus and organelles
-has lamellar gramules

29

lamellar granules

-secreted by cells to form waterproof lipid sheets aka intercellular cement

30

stratum lucidum

-stratum lucidum
-translucent lyaer present only in thick skin
-many keratin filaments and desmosomes present
-cells fully keratinized
-cytoplasm contains eleidin, protein related to keratin
-have pyknotic nuclei

31

what is the last living layer of epidermis?

stratum granulosum

32

stratum cornerum

-15-20 layers thick ie. footpad
-cells made of keratin
-known as horny cells surrounding thicker plasma membrane and lipid matrix aka bricks and mortar
-cells continually shed at surface

33

keratin is a...

water resistant protein forming a barrier against external environment

34

non-nucleated cells of the epidermis are...

dead, keratinized cells

35

keratinization vs cornification

-keratinization is process of keratinocytes differentiating, takes about 21 days for dog
-cornification is the production of stratum corneum

36

langerhans cells are found in what layers of epidermis? From what cells are they derived? What is their function?

-stratum basale and stratum spinosum
-derived from bone marrow monocytes
-function as antigen presenting cells to process surface bound antigens and present them to T lymphocytes

37

[picture of langerhans cells]

langerhans cells

38

[merkel's cells picture]

-merkel's cells
-found in thick skin near stratum basale
-sensory mechanoreceptors for cutaneous sensation and neuroendocrine system
-free nerve endings found at their base

39

[melanocytes]
-where are theses structures found?
-t/f: they are short lived?
-what is their function

-melanocytes
-False: they are long lived, stable cells
-produce melanin, are present in stratum basale and spinosum
-melanin protects cells from UV radiation

40

what must be present for melanin to functinon properly?
-how does melanin work?

-tyrosinase
-melanin transforms energy into harmless heat, stopping uv radiation from generating free radicals in cells

41

what is the most common type of melanin?

eumelanin: brown black pigment

42

what is pheomelanin

-red brown polymer responsible for red hair and freckles

43

what causes albino animals?

-no tyrosinase means no melanin can be produces

44

what type of nerve endings sense pain, itch, and temperature, and where are they found?

-nociceptors, found in the stratum granulosum

45

[meissner's corpuscles]

-meissner's corpuscles, a type of nerve ending

46

name the layers of the hair follicle

external glassy membrane, external root sheat, internal rooth sheat, cuticle, and dermal papilla

47

what are the three layers of hair, from inner to outer?

medulla, cortex, cuticle

48

This hair layer has loose cuboidal cells, with air filled in areas

medulla, the inner layer of hair

49

this hair layer is made up of a single layer of flat keratinized cells

hair cuticle, the outer layer of the hair

50

this hair layer is made of dense keratinized cells parallel to hair shaft

the cortex

51

dermal papilla functions

carries blood supply to the cells of the hair
-hair's matrix cells comparable to stratum basale

52

external glassy membrane is equivalent to what part of the epidermis? Which layer is this layer external to?

basal lamina
-external to the external root sheath

53

external root sheath is continuous with the...

epidermis

54

internal root sheath consists of layers of what cell shape

squamous

55

why are hairs so difficult to pull out?

the cuticle has keratinized cells with free edges oriented towards the hair bulb, while the hair cuticle has cell edges oriented in the opposite direction

56

primary vs secondary hair follicle

Primary: large diameter, rooted deep in dermis, possess sebaceous glands, arrector pili mucsle, and sweat glands
Secondary: smaller diameter, rooted nearer the surface, +/-sebaceous gland, no sweat glands, and no arrector pili muscle

57

guard hair is another name for

primary hair follicle

58

under hair is another name for

secondary hair follicle

59

compound hair follicle

clusters of hair follicles, as opposed to just one
-follicles merge at the sebaceous gland and emerge from one external orifice
-usually made up of a single primary follicle and many secondary hair follicles

60

whiskers of a cat or dog are properly called...
-what makes them different from other hair types?

sinus hair or tactile hair
-differ due to the nearby sensory nerves that are stimulated when the hair moves, and the surrounding blood-filled venous sinuses

61

sebaceous gland function

-produce sebum - a mix of lipid and disintegrated cells
-act as an antibacterial and waterproofing agent
-ducts empty into hair follicle or skin surface

62

name some special types of sebaceous glands

-supracaudal glands in dogs, mental glands in cats, horn glands in goats, circumanal glands in ruminants, preputial glands in horses, uropygial/preen glands in birds

63

sweat glands are found where in domestic animals; what is their function?

throughout most of the skin
-function mainly for communication, be it attraction or marking

64

horses produce sweat for...
-a major component of horse sweat is...

thermoregulation - a major component of which is latherin

65

most sweat glands associated with hair follicles perform what type of secretion

apocrine

66

t/f dogs produce sweat for thermoregulation

false: though merocine glands in foot pads secrete watery solution similar to human prespiration
-apocrine glands at hair follicles in dogs function to seal the outer layer of epidermis and to secrete pheromones

67

name other specialized sweat glands

-mammary glands
-glands of moll (eyelid tear glands)
-apocrine glands of anal sac
-ceruminous glands (ear wax)

68

What tissue are hooves and claws a modification of? what do they lack?

-mod of skin; variation of stratum corneum
-lack stratum granulosum and lucidum

69

what are the two layers of the hoof

outer epidermis and underlying dermis aka corium

70

insensitive laminae is made of epidermis or dermis

epidermis (hint: epidermis is avascular)

71

coronary and laminar corium (sensitive laminae) are made of epidermis or dermis

dermis: corium contains nerves and vascularture

72

what are the three epidermal layers of the hoof?

stratum tectorium/externum
stratum medium
stratum lamellatum/internum

73

stratum tectorium/externum

-thin layer known as the glaze
-continuation of the perioplic epidermis

74

stratum medium

-main supportive layer
-tubular and intertubular horn produced by stratum basale/spinosum of coronary groove

75

stratume lamellatum/internum

-lamellar horn; insensitive lamellae