Ch 5, 1 Skin Flashcards Preview

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Flashcards in Ch 5, 1 Skin Deck (21):
1

Epidermis

superficial region, epithelial cells
keratinized stratifies squamous
Cells:
keratinocytes-produce keratin
melanocytes-produce melanin, 10-20% of lower epidermis
epidermal dendritic -(Langerhans)-macrophages, help to activate body defenses
tactile (mekel) - touch receptors
Thickness: 4-5

2

Dermis

middle region
fibrous connective tissue
vascularized

3

hypodermis

deepest region
--not part of the skin
1. subcutaneous layer deep to skin
2. mostly adipose tissue -padding and insulation
-anchors skin loosely to muscles

4

thin skin

4 layers

5

thick skin

palms, soles of feet, fingertips
5 layers
extra layer called stratum lucidum

6

stratum basale
epidermis

deepest epidermal
single row of stem cells at base
cells undergo rapid mitosis
journey from basal layer to surface take 25-45 days
contains melanocytes and merkel, and dendritic cells

7

stratum spinosum
epidermis

several layers (usually 5)
cells become flattened as they move up
cells contain network of prekeratin filaments attached to desmosomes
abundant in melanin granules and dendritic cells

8

stratum granulosum
epidermis

3-5 layers in which cells flatten from a cube shape
keratin and lamellated granules accumulate
membrane becomes tough and water resistant
cells lose nuclei and other organelles as they die


9

stratum lucidum
epidermis

only in thick skin
thin, transparent band superficial to the stratum granulosum
few rows of flat, dead keratinocytes

10

stratum corneum
epidermis

20-30 layers of dead, fat, keratinized membranous sacs
three quarters of the epidermal thickness
Functions; protection against abrasion, water proofing

11

Dermis

strong, flexible connective tissue
cells include fibroblasts, macrophages, occasionally mast cells amd WBC
2 layers

12

Papillary Layer
dermis

1. areolar connective tissue with collagen and elastin fibers and blood vessels
2. dermal papillae contain..
capillary loops--aid in diffusion
meissners corpuscles--touch and light receptors
free nerve endings--pain sensors
3. Fingerprints-dermal papillary ridges form the epidermal ridges that produces fingerprints

13

reticular layer
dermis

1. 80% of the dermis thickness
2. collagen fibers provide strength and resiliency
3. elastic fibers provide stretch-recoil properties
4. pacinian corpuscle--deep pressure sensors

14

Skin Colour

three pigments contribute

15

melanin

-produced by melanocytes
-yellow to reddish brown to black colour
-migrates to keratinocytes where forms pigment shields for nuclei
-local accumulations of melanin-freckles and moles
-against UF light

16

Carotene

yellow to orange, most obvious in the palms and soles

17

Hemoglobin

pinkish hue of skin

18

cyanosis

abnormal skin colour
lack of oxygen
blue colour

19

jaundice

abnormal skin colour
high bilirubin in blood-liver malfunction
yellow

20

Pallor

abnormal skin colour
anemia-blood loss

21

Blushing

abnormal skin colour
nervous system response to embarrassment
dilation of surface blood vessels