Integumentary System (Ch 5) Flashcards Preview

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Flashcards in Integumentary System (Ch 5) Deck (30):
1

Skin

-largest organ in body (different tissues working together)
-7% of body weight

2

Functions of skin

-protection against mechanical damage
-barrier to fluid loss/pathogens
-Vit D production
-sensory reception
-body temp regulation
-excretion of salts/wastes

3

Epidermis

-->keratinized stratified squamous epithelium
-four cell types
-avascular
-regenerates often
-4/5 cell layers (thin vs. thick)

4

What are the four cell types of the epidermis?

1. keratinocytes: product keratin, most abundant
2. melanocytes: produce melanin --> helps shield nuclei of keratinocytes from UV radiation)
3. merkel cells: sensation
4. dendritic cells: immune cells

5

What is the structure of the epidermis?

1. Stratum Corneum (sup)
2. Stratum Lucidum
3. Stratum Granulosum
4. Stratum Spinosum
5. Stratum Basale (inf)
--> "Come Let's Get Sun Burnt"

6

Stratum Corneum

*layer of epidermis (most superior)
dead cells full of keratin, shed regularly

7

Stratum Lucidum

*layer of epidermis (2nd layer)
"clear" layer, only in THICK skin, consists of a few rows of flat/dead keratinocytes

8

Stratum Granulosum

*layer of epidermis (3rd layer)
1-5 layers of cells, granules in this layer help waterproof skin

9

Stratum Spinosum

*layer of epidermis (4th layer)
multiple cells layers of keratinocytes, only layer with DENDRITIC cells

10

Stratum Basale

*layer of epidermis (most inferior)
attached to dermis, mostly keratinocytes with rapid division, melanocytes/merkel cells

11

Dermis

-underlies epidermis
-strong/flexible CT
-highly vascularized
-innervated (= sensation)
-2 cell layers: papillary and reticular

12

Papillary Layer

*layer of dermis
-20% of dermis
-areolar CT
-provides nutrients to epidermis
-dermal papillae increase SA for transport of materials into epidermis

13

Reticular Layer

*layer of dermis
-mostly dense irregular
-network of collagen + elastic fibers provide stretch/strength

14

Hypodermis

-supports skin (dermis/epidermis)
-areolar + adipose loose CT (mostly adipose)

15

What are the functions of the hypodermis?

-stores fat
-provides insulation
-anchors skin to muscles
-allows movement of skin over muscle and bones

16

Fingerprints

-increase friction for grasping
-have dermal papillae which push up/elevate the overlying epidermis
-patterns are unique

17

Hair

-flexible strands made of KERATIN
-pigment comes from MELANOCYTES

18

What are the functions of hair?

-sensation (light touch)
-protection (ex. eyelashes)
-insulation

19

Structure of Hair

1. Basic
-shaft (exposed)
-root (embedded into dermis/epidermis)
2. Hair Follicle
-bulb (innervated)
-papilla (blood supply)
3. Arrestor Pili muscle
--> contraction raises hair/causes goosebumps

20

Eccrine Sweat Glands

--> secreted onto skin surface
-allows for evaporative cooling
-development: invaginate from skin surface
-product: 99% water, 1% salts/wastes
-acidic/antibacterial properties

21

Apocrine Sweat Glands

--> discharge into hair follicles
-development: outgrowths from hair follicles
-product: complex molecules, odorous
-found in armpits/genitals

22

Ceremonious Glands

line external ear canal, produce earwax

23

Mammary Glands

secrete milk

24

Sebaceous Glands

multicellular exocrine glands (secrete onto hair follicles)
-secrete sebum (oil) --> holocrine secretion (cells accumulate sebum then burst to release)
-moisturizes hair/skin
-blocked hair follicle = acne

25

Melanin

-acts as natural sunblock against UV radiation
-determines skin tone
-# of melanocytes among individuals does not vary, but activity level does (ex. pale = less active)

26

Why is some exposure to sunlight necessary?

production of Vit D --> calcium absorption

27

What are the dangers of too much exposure to sunlight?

reduction in folate levels needed for embryonic development
-promotes skin cancer

28

Basal Cell Carcinoma

-most common form of skin cancer
-originates from stratum basale (a.k.a. stratum germinativum)
-metastasis is rare

29

Melanoma

-potentially life threatening
-cancerous melanocytes grow rapidly and spread throughout lymphatic system

30

How to detect skin cancer

A: asymmetry- irregular shape
B: border- indistinct
C: color- mottled
D: diameter- >5mm is dangerous
E: elevation- not flat