Chapter 5 - Integumentary System Flashcards Preview

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Flashcards in Chapter 5 - Integumentary System Deck (67):
0

What are the three layers of skin

Epidermis
Dermis
Hypodermis

1

What are the characteristics specific to the epidermis

Primary cellular
Keratinized stratified epithelium
Vascular
Separated from dermis by basement membrane

2

What are skins specific characteristics

Largest organ
Covers external surface of body
Composed of all 4 tissue types

3

What are the characteristics specific to the dermis

Has projections: dermal papillae
Vascularized
Contains muscle and nervous tissue

4

What are the characteristics specific to the hypodermis

Composed mostly of adipose tissue
Vascularized

5

What is skin composed of

Stratified squamous epithelium

6

What is specific about stratified squamous epithelium

Contains keratinocytes
Dominant cell type in epidermis
Produces keratin
Along basement membrane
Basal layer divides by mitosis

7

How do cells become Keratinized

Lose nucleus, organelles, flatten and die

8

What are melanocytes

Produce keratin = dark pigment
Have octopus like projections
Melanin is released and absorbed by keratinocytes

9

What is a langerhans cells

Macrophage specific to epidermis
Wander through epidermis
Phagocytizes pathogens
Stimulates immune system
Formed in bone marrow and migrate to skin via blood

10

What is a merkel cell

Epithelial cells found at base of epidermis
Associated with sensory nerve endings

11

What type of cells cause skin cancer

Squamous cell carcinoma
Malignant melanoma
Basal cell sarcoma

12

What is specific about squamous cell carcinoma

Found in areas most exposed to u.v.
Aggressive locally - forms lesions
Spreads rapidly to lymph nodes:deadly

13

What is specific about malignant melanoma in horses

Very common in Greta
Start as nodules on ears,perianal area
Later ulcerate and spread to rest of body

14

What is specific about malignant melanoma in dogs

Oral cavity is the most common location and it is the most malignant

15

What is specific about basal cell tumours

Affect basal layer
Nodular masses beneath skin
Usually benign and don't spread
More common in cats than dogs
Found in head + neck region

16

What is the first layer of epidermis and what is specific about it

Stratum basale:
Single row of keratinocytes on top of basement membrane
Actively dividing
Newly forming cells are pushed upwards

17

What is the second layer of epidermis and what is specific about it

Stratum spinosum:
Several rows of keratinocytes
Cell layers held together by desmosomes
Projections of melanocytes reach into this layer

18

What is the third layer of epidermis and what is specific about it

Stratum granulosum:
2-4 rows of cells; flattened-diamond shaped keratinocytes

19

What is the fourth layer of epidermis and specific characteristics of it

Stratum lucidum:
Found only in thick skin
Few layers of Keratinized dead cells

20

What is the fifth layer of epidermis and what is specific about it

Stratum corneum:
Outermost layer
Majority of epidermis thickness
20-30 rows of dead, flattened keratinocytes

21

What is specific about the dermis?

Provides structural strength to skin
Hide of animal used to make leather
Contain large amount of fibers: collagen, elastic, reticular
Cells: fibroblasts

22

What are the two layers of the dermis:

Papillary layer
Reticular layer

23

Describe the papillary layer

Thin, superficial layer
Below basement membrane
Composed to Areolar connective tissue ** ground substance? Hyaluronic acid

24

WhAt is special about the papillary layer

Often has papillae rising up into epidermis and has sensory neurons

25

Describe the reticular layer

Thick, deep layer
Composed 80% of dermis
Composed of dense irregular connective tissue

26

Describe the hypodermis

Thick layer below dermis
Composed of Areolar and adipose tissue
Contains mostly elastic fibers
Has pacinan corpuscles

27

Why is the hypodermis special?

Location of subcutaneous injections

28

What is particular about pigmentation

Presence of melanin in keratinocytes
Formed and released in melanosomes
Controlled by hormones of pituitary gland
****ultimately controlled by genetics

29

What are melanosomes

Sac where melanin is stores

30

What are paw pads and what is distinct about them?

Toughest and thickest skin on body
Protect against abrasion etc
Shock absorbers
5 layers of epidermis +collagen and elastin
Stratum corneum has papillae which provide traction
Contains sweat glands

31

What is a planum nasale

Thin hairless region on nose
3 epidermis layers
No glands in cats and dogs

32

What are chestnuts

Found in equines
Soft horn like structures
Vestigial structures
Located on medial surface of carpus/tarsus

33

Where are ergots found

Located on palmar/plantar surface of fetlock

34

What is hair?

Mammalian characteristic
Keratinized structure made by hair follicles
Composed of dead cells: with or without pigment

35

What is the function of hair

Thermoregulation, camouflage, sensory

36

Where is hair usually thickest

Dorsal and lateral surfaces of body

37

What is a common problem associated with hairless animals

Difficulty with thermoregulation and skin cancer

38

Describe the structure of hair

Shaft: part of hair where keratinization is complete
Root: keratinization occurring in epidermal cells

39

Describe a hair follicle

Tube like structure through dermis
Hair bulb: invaginated by dermal cells called hair papilla - contains capillaries
Matrix: rapidly dividing epithelial cells covering hair papilla

40

What are the three layers of coat

* primary hairs
*secondary Hairs
* tactile hairs

41

Describe primary Hairs

Thicker longer "topcoat"

42

Describe secondary hairs

Softer, shorter, wooly "undercoat"

43

Describe tactile hairs

Ex: vibrissae
Sensory cells at base

44

What is the growth cycle of a hair

Anagen ➡️ early catagen ➡️ catagen ➡️ telogen ➡️ early anagen➡️ anagen

45

What are the three things shedding is determined by

Environment, hormones, genetics

46

How is shedding determined by environment:

Most outdoor lets usually shed undercoat in spring and fall

47

How is shedding determined by hormones

Bitches sometimes have a large hair loss after welping

48

How is shedding determined by genetics

Non shedding breeds have a very long anagen phase

49

What 3 things are hair composed of

Medulla, cortex, cuticle

50

What is a medulla?

Central core with loosely arranged cells in air or fluid; contain flexible, pigmented keratin

51

What is a cortex

Thickest layer of hair; contains pigmented keratin

52

What is a cuticle (hair)

Single layer of squamous cells; hard keratin

53

What is coat color due to?

1-2 types of melanin in varying amounts

54

What are the 5 gland types of the skin

Sebaceous
Sweat
Tail glands
Anal sacs
Musk glands

55

Describe sebaceous glands

Found all over body except pawpaws, planum nasale
Simple or branched Areolar shape
Produces and releases sebum into hair follicle

56

Describe sweat glands

Assist in evaporative cooling of body, defensive properties to protect skin
Coiled tubular shape
Located in dermis/hypodermis
Contains both eccrine and apocrine sweat glands

57

What do eccrine sweat glands do

Releases onto surface: found on paw pads

58

What do apocrine sweat glands do

Release into hair follicle

59

What are musk glands

Produce and release musk
Used in perfumes until modern times

60

What are tail glands

Located on dorsal surface of tail in dogs and cats
Area contains large sebaceous glands: contains pheromones
Used for identification
Affected by hormones

61

What are anal glands (sacs)

Located and 5 and 7 position inside anus
Contain sebaceous glands producing secretions with a strong odor.
Used in identification and marking of feces
Can become clogged

62

What are horns

Keratinized horny sheath covers bony processes of skull
Grows continuously and is not shed
Usually removed when the animal is young

63

What are claws

Keratinized covering of the distal phalynx
Cannot be removed thus requires amputation
RetrActable in felines

64

What are dewclaws

Remains of digits

65

What are hooves and what are hooved animals called

Ungulates

66

What is laminitis

Inflammation of lamina
Tissues cannot expand due to hoove wall
Compresses lamina, decreased blood flow, lamina does and pulls away from the hoof wall.
In severe cases p3 can penetrate the bottom of hoof