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Flashcards in Integumentary system 1 Deck (48):
0

Skin aka

cutaneous membrane

1

what % is skin in total body weight

7%, 10lb

2

function of integumentary system

1. Regulate body temperature
2. stores blood
3. protects body from external environment
4. Detects cutaneous sensations/provides sensory information about the surrounding environment
5. Excretes and absorbs substances
6. Synthesizes Vit. D

3

Epidermis

superficial thinner portion layer
contains epithelial tissue
Avascular
Stratified squamous epithelium

4

Dermis

Deep thicker portion/layer
Contains connective tissue
Vascular

5

Subcutaneous layer or hypodermis

Not a part of the skin
Attaches dermis to underlaying fascia
contains areolar and adipose tissue
Functions
Fat storage
an area of blood vessel passage
an area of pressure-sensing nerve endings

6

Deep to subcutaneous layer

Fascia
the connective tissue around muscle and bone

7

5 (or 4) layer of the Epidermis

Stratum basale (stratum germinativum)
Stratum spinosum
stratum granulosum
stratum lucidum (only in palms ad soles)
stratum corneum

8

Four principle cells of the Epidermis

Keratinocytes - produce the protein keratin. waterproof sealant
Melanocytes - produce the pigment melanin for skin color and absorbs uv light
Langerhans cells - derived from bone marrow, participating in immune response
merkel cells - sensory structure called tactile (Merkel) disc and function in the sensation of touch

9

slowly senses touch near surface

Merkel (tactile) disc

10

Rapidly senses touch near surface

Meissner corpuscle

11

Slowly senses stretching in deep layers of skin

Ruffini corpuscle

12

Senses movement of the hair

Hair root plexus

13

Senses pressure

Pacinian corpuscle

14

Free nerve endings that senses pain rapidly

Nociceptors

15

What does stratum basale aka stratum germinativum have

1. Deepest layer, a single row cuboidal or columnar keratinocytes
2. contains merkel cells, melanocytes, keratinocytes and stem cells that divide repeatedly to produce keratinocytes
3. Keratinocytes have a cytoskelton of tonofilaments
4. cells attached to each other and to basement membrane by desmosomes and hemi-desmosomes

16

When the germinal portion of the epidermis is destroyed...

new skin can not regenerate with a skin graft

17

Stratum spinosum is

- providing strength and flexibility to the skin
- 8-10 cell layers are held together by desmosomes
- During slide preparation, cells shrink and appear spiny (where attached to other cells by desmosomes)
- Melanin is taken in by keratinocytes (via phagocytosis) from nearby melanocytes

18

Stratum Granulosum is

transition between the deeper, metabolically active strata and the dead cells of the more superficial strata
- 3-5 layers of flat dying cells that show nuclear degeneration (example of apoptosis)
-contain lamellar granules that release lipid that repels water
-contain dark-staining keratohyalin granules that convert tonofilaments into keratin

19

Stratum Lucidum is

only in the finger tips, palms, soles
three to five layers of clear, flat, dead cells
contains precursor of keratin

20

Stratum corneum is

- 25-30 layers of flat dead cells filled with keratin and surrounded by lipids
- continuously shed
-barrier to light, heat, water, chemicals and bacteria
-lamellar granules in this layer make it water-repellent
-constant exposure to friction will cause this layer to increase in depth with the formation of a callus, an abnormal thickening of the epidermis

21

Keratinization is

replacement of cell contents with the protein keratin, occurs as cells move to the skin surface over 4-6 weeks

22

what hormon plays a role in epidermal growth

Epidermal growth factor (EGF)

23

What is dandruff

an excessive amount of keratinized cells shed from the skin of the scalp

24

a chronic skin disorder characterized by a more rapid division and movement of keratinocytes through the epidermal strata

Psoriasis
cells shed in 7-1- days as flaky silvery scales
commonly found at knees, elbows and scalp

25

skin grafts (3)

autograft - self
isograft - twin
autologous graft - patient's skin grown in culture

26

Dermis is

connective tissue layer composed of collagen and elastin fibers, fibroblasts, macrophages and fat cells
contains hair follicles, glands, nerves and blood vessels
THICKER than the epidermis, thickness varies, thickest in sole and palms

27

Two major regions of dermis

papillary region
reticular region

28

papillary region

top 20 %
thin Areolar collagen tissue and fine elastic fibres for strength and extensibility, adipose cells, hair follicles, sebaceous glands, sudoriferous gland
surface area is increased by finger like projections - dermal papillae

29

Dermal papillae does (3)

- anchors epidermis to dermis
- contain capillaries that feed epidermis
- contains Meissner's corpuscles (touch) and free nerve endings for sensations of heat, cold, pain, tickle and itch

30

The reticular region

bottom 80% of dermis
attached to the subcutaneous layer
Dense irregular connective tissue
contains interlacing collagen and elastic fibres
contains oil glands, sweat gland, ducts, fat and hair follicles, blood vessels, nerves
provides strength, extensibility and elasticity to skin

31

Epidermal ridges

from as downward projections of the epidermis in fetus (3 month)
Epidermis confirms to dermal papillae
Finger prints are left by sweat glands open on ridges
increase grip of hand

32

dermal tears from extreme stretching

stretch marks

33

3 pigments contributing to Skin color

Melanin - pale-yellow to reddish-brown to black
Carotene - yellow-orange pigment that gives egg yolks and carrots their color (located in Dermis, precursor of vitamin A used to synthesize pigments needed for vision)
Hemoglobin: red, oxygen-carrying pigment in blood cells

34

Where is Melanin produced and what converts to melanin?

produced in epidermis by melanocytes
melanocytes convert TYROSINE to melanin
UV in sunlight increases melanin production
Same number of melanocytes in everyone, but different amount of pigments produced

35

Where is Carotene found?

in dermis, in stratum corneum and dermis

36

paleness maybe due to shock or anemia

pallor

37

yellow color to skin and whites of eyes due to build up of yellow bilirubin in blood from lier disease

jaundice

38

bluish color to nail beds and skin due to hemoglobin depleted of oxygen

cyanosis

39

redness of skin due to enlargement of capillaries in dermis

Erythema - inflammation, infection, allergy or burns

40

Frecles

genetic prediposition
melanin accumulates in patches, reddish brown

41

age spots

(liver spots)
Flat blemishes, light brown to black (darker than freckles)
accumulations of melanin over time due to sunlight
don't fade in winter
>40 years of age

42

Nevus (mole)

Develops in childhood or adolescence
round flat or raised benign over-growth of melanocytes

43

inherited inability to produce melanin due to melanocytes inability to produce tyrosinase

Albinism
Affects vision and sunburn easily

44

Complete or partial loss of melanocytes from patches of skin creates white spots

Vitiligo
may be due to an auto-immune response in which antibodies attack melanocytes

45

Collagen fibers in reticular region orient in one direction

Tension lines (indicate direction of fibers)
Surgery along direction of fibers decreases scarring

46

Pigment injected into dermis

Tatooing

47

Body piercing may interfere with

resuscitation masks
airway management procedures
urinary catheters
radiographs
delivery of baby