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Flashcards in Skin and Appendages Deck (69)
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1
Q

what are the two principle layers of the skin?

A
  • epidermis

- dermis

2
Q

epidermis layer composition

A
  • outermost (surface) layer of skin

- composed of 30-50 layers of stratified keratinized squamous epithelium (mostly keratinocytes)

3
Q

dermis layer composition

A
  • deep to epidermis

- composed of CT (fibroblasts, collagen and elastic fibers)

4
Q

what are all the layers of the skin?

A
  • epidermis
  • dermis
  • hypodermis
5
Q

hypodermis layer composition

A
  • located beneath the skin
  • composed of loose CT (areolar) and adipose tissue
  • anchors skin loosely to underlying muscle
  • acts as a shock absorber and insulator of fat
6
Q

what are the functions of the skin?

A
  • protection
  • excretion
  • synthesis
  • communication
  • absorption
  • thermoregulation
  • sensation
7
Q

what is the hypodermis also called?

A

-subcutaneous tissue

8
Q

protection function types

A
  • physical barrier
  • chemical barrier
  • biological barrier
9
Q

physical barrier protection function

A
  • impermeable to water-soluble substances (due to keratin)

- prevents dehydration

10
Q

chemical barrier protection function

A
  • acidity skin secretions retards bacterial growth

- melanin protects against UV light

11
Q

biological barrier protection function

A

-langerhans cells and macrophages engulf foreign material and bacteria

12
Q

thermoregulation function

A
  • body temperature is regulated through activity of sweat glands and changes in the diameter of blood vessels
  • hair and adipose tissue also acts as insulators
13
Q

absorption function

A
  • lipid soluble substances
  • steroids
  • plant resins, organic solvents and heavy metals
14
Q

what are some types of lipid soluble substances?

A

-vitamin A, D, E, K

15
Q

excretion function

A
  • urea, ammonia and uric acid are excreted in sweat

- salts (NaCl) are also lost, especially with excessive sweating

16
Q

synthesis function

A

-exposure to sunlight aids in the production of Vitamin D

17
Q

sensation function

A

-contains receptors for touch, pain, and temperature, etc

18
Q

communication function

A

-various emotions are expressed through color changes and secretions

19
Q

what are the layers of the epidermis?

A
  • stratum germinativum
  • stratum spinosum
  • stratum granulosum
  • stratum lucidum
  • stratum corneum
20
Q

epidermis stratum germinativum layer special characteristics

A
  • deepest layer
  • single layer of cells
  • undergo mitosis and gradually move to the surface
21
Q

epidermis stratum spinosum layer special characteristics

A
  • several layer of squamous like cells
  • “prickle cells”
  • attacked and spine-like processes
  • keratin synthesis begins
22
Q

epidermis stratum granulosum layer special characteristics

A
  • cells contain dark glands
  • abundant keratin
  • cells begin to die (bc no active metabolism)
23
Q

epidermis stratum lucidum layer special characteristics

A
  • “clear layer”
  • cells appear empty
  • only found in thick skin
24
Q

epidermis stratum corneum special characteristics

A
  • artificial layer

- dead, scale-like keratinized cells

25
Q

dermis location

A

-deep to the epidermis

26
Q

dermis composition

A
  • CT (elastin and collagen fibers)
  • macrophages
  • mast cells
  • nerve fibers
  • blood vessels
  • sweat glands
  • hair follicles
  • sebaceous glands
27
Q

which components of the dermis help with the stability of the skin?

A
  • connective tissue

- blood vessels

28
Q

epidermis composition

A

-keratinized stratified squamous epithelium

29
Q

what are the layers of the dermis?

A
  • papillary layer

- reticular layer

30
Q

papillary layer components

A
  • dermal papilla

- friction ridges

31
Q

papillary layer location

A
  • most superficial

- just below epidermis

32
Q

dermis papillary layer dermal papilla layer special characteristics

A

-projections of dermis towards surface layer

33
Q

dermis papillary layer friction ridges layer special characteristics

A
  • elevations on epidermal surface (cause by CT of dermis)
  • distinct pattern (“finger prints”) genetically determined
  • help in grasping objects (identification)
34
Q

dermis reticular layer special characteristics

A
  • deep layer of dense, regular CT
  • contains many elastin and collagenous fibers
  • provides skin tone, strength, and resiliency
35
Q

dermis functions

A
  • serves as an attachment for the epidermis, provides supporting hase
  • contains a dense network of blood vessels for diffusion of nutrients to epidermis
  • plays a role in thermoregulation (due to hair glands)
36
Q

what are the other characteristics of skin?

A
  • skin color

- skin tone

37
Q

what causes skin color?

A

-the presence of three pigments

38
Q

skin color pigments

A
  • melatonin
  • carotene
  • hemoglobin
39
Q

melanin pigment special characteristics

A
  • produced by metactyes in epidermis

- yellow-brown-black pigment which protects again UV light damage

40
Q

carotene pigment special characteristics

A
  • yellow-orange pigment

- rich in vitamin A

41
Q

hemoglobin pigment special characteristics

A
  • iron-containing pigment in red blood cells

- -> transports oxygen

42
Q

skin tone special characteristics

A

-refers to strength and resiliency of skin caused by elastic and collagenous CT fibers located in the dermis

43
Q

appendages of the skin location

A

-derived embryologically from the epidermis

44
Q

types of appendages of the skin

A
  • nails
  • hair
  • sebaceous glands
  • sweat glands
  • mammary glands
45
Q

nails special characteristics

A
  • a modification of the stratum corneum of epidermis
  • composed of thick plates called keratin
  • cover distal ends of fingers and toes and function to protect them
  • root of nail is embedded in the skin and is covered by the cuticle (or eponychium)
  • the free edge of the nail is attached to the epidermis by the quick (or hypochium)
46
Q

hair location

A
  • aka pilli
  • originate in the epidermis and are embedded in the dermis
  • hair projects above the skin to cover the surface of the body
47
Q

hair function

A
  • protection: shields body from UV light and physical trauma and limits heat loss
  • sensory reception
48
Q

hair structure components

A
  • root
  • hair
  • shaft
49
Q

hair root

A

-location of active, multiplying epithelial cells from which hair growth occur

50
Q

hair follicle

A

-tube that surrounds the root and extends into the dermis

51
Q

shaft

A
  • portion of hair that projects above the skin’s surface

- composed of dead, keratinized cells

52
Q

other characteristics of hair components

A
  • color

- arrector pili muscles

53
Q

hair color characteristics

A

-primarily due to different proportions of melanin

54
Q

what does gray hair result from?

A

-results from a decreased production of melanin and air bubbles in the hair shaft

55
Q

arrector pili muscle characteristics

A
  • smooth muscles attached to the hair follicle
  • regulated by the autonomic nervous system
  • when they contract they put pressure on the sebaceous glands causing the release of sebum
  • their contraction causes the hair to stand “on end”(goosebumps)
56
Q

types of glands in the skin

A
  • sebaceous glands
  • sweat glands
  • mammary glands
57
Q

sebaceous gland structure

A

-holocrine glands: rupture to release their contents

58
Q

sebaceous gland location

A
  • all over body except palms of hands and soles of feet

- very numerous along the base of the hair

59
Q

sebaceous gland function

A
  • produces sebum

- secretion is stimulated by hormones

60
Q

what is sebum?

A

-an oily substance which lubricates the hair shaft

61
Q

what is the anatomical name for sweat glands?

A

-sudoriferous

62
Q

sweat gland structure

A

-coiled, tubular exocrine glands

63
Q

sweat gland location

A
  • body of gland located in the dermis

- coiled duct extends to surface of skin to release secretions through a pore

64
Q

sweat gland function

A
  • important for thermoregulation
  • excretion of waste products (urea)
  • protection by preventing growth of microorganisms
65
Q

types of classifications of sweat glands

A
  • merocrine glands

- apocrine glands

66
Q

merocrine glands special characteristics

A
  • most numerous
  • produces sweat consisting mostly of water, salt, and waste products such as urea
  • regulated by the ANS
67
Q

what does the root “-crine” mean?

A

sweat

68
Q

apocrine glands special characteristics

A
  • located only in axillary and anogenital regions of the body
  • secretes sweat and lipoproteins which produce odors when acted upon by bacteria
  • generally begin to function during puberty (bc linked to hormones)
69
Q

mammary glands special characteristics

A
  • exocrine glands (bc they secrete their product through a duct)
  • considered a accessory reproductive organ