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Flashcards in Ch. 5 Deck (26):
1

skin

1st line of defense, largest organ 7% body weight, last a life time

Accessories: hair, nail, skin gland

2

Function of Integumentary System Protection
body temperature regulation, Vitamin D synthesis, Sensation, Secretion

Protection- First line defense against bacteria/virus

protect from UV ray and dehydration

Too hot- Dermal vessel dilate
vessel carry blood to surface

Too cold- Dermal blood vessel constrict
Prevent heat escape

Calcium Absorption

Sensory receptor

Waste lost through sweat

3

Protective function

Mechanical damage- keratin toughen skin

pressure receptor- alert possible damage

Chemical damage- Keratinized cell relatively impermeable

pain receptor- alert possible damage

Bacterial damage- acid seretion inhibit bacteria

phagocyte- ingest foreign substance and pathogens

UV radiation- melanocyte produce melanin

dessication- drying out

keratin- waterproof

4

Skin Region

Epidermis- superficial

Dermis- underlies epidermis
-made of fibrous connective, nerve, muscle

Hypodermis (SubCutaneous) not skin but share function
- mostly adipose absorb shock and insulate
-Anchor skin to underlying structure-muscle

5

Epidermis

keratinized stratified squamous epithelium

5 layer-
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum corneum

4 cell type-
Keratinocytes
Melanocytes
Dendritic (Langerhans) cells
Tactile (Merkel) cells

6

stratum basale (Germinativum)

Deepest epidermal layer

single row of stem cell, actively mitotic, produce 2 daughter cells. 25-45 days to surface dies on journey.

7

Stratum Spinosum (prickly layer)

several layers thick by desmosomes

web-like system of intermediate pre-keratin

abundant melanosomes and dendritic cells

8

Stratum granulosm (granular level)

Thin 4-6 layer

cell appearance change- cell flatten
-cell accumulate keratohyaline granules which help form keratin in upper layer

water resistant glycolipid slow water loss

cell above this layer die

9

stratum Lucidum (clear layer)

only in thick skin, thin, translucent

10

stratum corneum (horny layer)

20-30 rows of dead anucleated keratin membranous sacs 3/4 epidermal thick

dead but functions: protect from: abrasion, environment and water loss, barrier against bio physical and chem assault.

11

keratinocytes

produce fibrous protein keratin, most cells of epidermis, connected by desmosomes

pushed upward, become dead scale-like, millions rub off.

12

melanocytes

10-25% of deepest epidermis produce melanin and protect apical surface from UV

transfer melanin to keratinocyte

synthesize melanin

13

dendritic (langerhans cells)

macrophage- key activators of immune system

formed in bone

14

tactile (merkel cells)

sensory touch receptors

spike appearance

connect to nerve cell from dermis

15

dermis

strong, flexible

2 layers: Papillary and Reticular

contains: nerve fiber, blood and lymphatic vessel, epidermal follicle, oil and sweat gland.

16

Papillary layer

upper dermal layer (uneven).

fingerlike projection/ indent epidermis/

(Tactile)Meissner corpuscles-light touch receptor

free nerve endings- pain receptor

Epidermal ridges collectively make- friction ridges
- grip, touch, fingerprint

17

Reticular layer

deepest layer, blood vessel, sweat gland, oil gland

Lamellar Pacinian corpuscle- vibration/pressue receptor

Ruffini ending- skin stretch/ finger position

dense fibrous connective tissue

elastic fiber

phagocyte

cleavage line- most collagen fiber parallel to skin surface.

18

Skin color pigment

melanin- pigment made in skin, natural sunscreen

carotene- yellwo to orange pigment found in stratum corneum

hemoglobin- oxygen-carrying pigment in bloodcell

19

Hair

dead keratinized cell of hard keratin

Function: warn of insect, physical trauma, heat loss, sunlight

gray hair- decrease melanin production, increased air bubble in shaft.

20

hair follicle

dermis and epidermis

hair bulb- hair follicle receptor, sensory nerve endings, hair matrix,

arrector pili- smooth muscle attached to follicle

hair papilla- dermal tissue- blood supply

21

hair thinning and baldness

alopecia- immune system attacks hair follicle

true baldness- genetically determined

22

nails

pick small objects, made of keratinized epidermal cells

23

sweat gland (sudiferous)

all skin except nipple and some genitalia

2 types: eccrine- secret sweat
thermoregulation- sympathetic nervous system

Apocrine- armpit and anogenitalia- sweat fat protein

24

Sebaceous (oil) gland

widely distributed come from hair.
active at puberty

secrete sebum- oily holocrine, softens hair and skin

25

burns classification

first- epidermal

second- epidermal and upper dermal

third- entire skin removed, nerve ending destroyed

26

deep wound healing

injury extend to dermis and subcutaneous layer