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Flashcards in Chapter 5 Deck (61)
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1

Skin (2 regions)

Epidermis- superficial region
Dermis- underlies epidermis

2

Hypodermis

Not part of skin
Mostly adipose tissue
Anchors skin to underlying structures
Muscles

3

Epidermis

Keratinized stratified squamous epithelium
4 or 5 layers
4 cell types

4

5 Layers of Epidermis

Deep to Superficial
Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Stratum Corneum

5

4 Cell Types of Epidermis

Keratinocytes
Melanocytes
Dendritic (Langerhans) Cells
Tactile (Merkel) cells

6

Keratinocytes

Produce fibrous protein keratin
No long living, stratified squamous cells
Location; mostly in epidermis
Connected by desmosomes

7

Melanocytes

10-25% of cells in deepest epidermis
Produce pigment melanin

8

Dendritic (Langerhans) Cells

Macrophages- involved in the immune system

9

Tactile (Merkel) Cells

Sensory touch receptors

10

Layers of Epidermis: Stratum Basale (Basal Layer)

Deepest epidermal layer
Firmly attached to dermis
Single row of stem cells
-Actively mitotic
-Produces two daughter cells
--One cell journeys from basal layer to surface

11

Layers of Epidermis: Stratum Spinosum (Prickly Layer)

Several layers thick
Cells contain web-like system of filaments attached to desmosomes
Abundant dendritic cells

12

Layers of Epidermis: Stratum Granulosum (Granular Layer)

Thin- 4 to 6 cell layers
Cell appearance changes
-Cell flatten
-Nuclei and organelles disintegrate
-Keratinization begins

13

Layers of Epidermis: Stratum Lucidum (Clear Layer)

Only in thick skin
Thin, Translucent band superficial to the stratum granulosum
A few rows of flat, dead keratinocytes

14

Layers of Epidermis: Stratum Corneum (Horny Layer)

20-30 rows of dead, flat, anucleate keratinized membranous sacs
3/4 of epidermal thickness
Cells Functions:
-Protection of deep layers
-Protection from physical factors
-Barrier

15

Cell Differentiation in Epidermis

Cells change from stratum basale to stratum corneum
Accomplished by specialized form of apoptosis (flake off)

16

Dermis

Strong, flexible connective tissue
Many cells
Fibers in matrix bind together
Contents:
-Nerve fibers
-Blood and lymphatic vessels
-Epidermal hair follicles
-Oil and sweat glands
Two layers
-Papillary
-Reticular

17

Papillary Layer

Areolar connective tissue with collagen and elastic fibers and blood vessels
Dermal Papillae

18

Dermal Papillae

Superficial peglike projections into the epidermis
Contents:
-Capillary loops
-Meissner's corpuscles (Touch receptors)
-Free nerve endings (Pain receptors)
Function:
-Enhance Gripping
-Contributes to sense of touch
-Contributes to sense of pain
-Fingerprints

19

Other Skin Markings

Striae
Blister

20

Striae

Slivery-White Scars
stretch marks
Extreme stretching causes dermal tears

21

Blister

From acute, short term trauma
Fluid-filled pocket that separates epidermal and dermal layers

22

Skin Color

Three pigments contribute to skin color
-Melanin- only pigment made in skin
-Carotene
-Hemoglobin

23

Melanin

Two forms
-Reddish-yellow to Brownish-black
Color is due to amount
Produced in melanocytes
-Same relative number in all people
Freckles and pigmented moles
-Local accumulations of melanin
Sun exposure stimulates melanin production

24

Carotene

Yellow to orange pigment
-most obvious in palms and soles
Can be converted to vitamin A for vision and epidermal health
Yellowish-tinge of some Asians- carotene and melanin variations

25

Hemoglobin

Pinkish hue of fair skin

26

Skin Color in Diagnosis Cyanosis

Blueish
Low oxygen

27

Skin Color in Diagnosis Erythema

Redness
Fever, Hypertension, Inflammation

28

Skin Color in Diagnosis Pallor

Blanching
Anemia, Low blood pressure, fear, anger

29

Skin Color in Diagnosis Jaundice

Yellowish
Liver disorder

30

Skin Color in Diagnosis Bruises

Clotted blood beneath skin