Epidermis and Dermis

Question 1

What are the skin’s major regions?

Answer 1

1. Epidermis
2. Dermis
3. Hypodermis

Question 2

What is the epidermis?

Answer 2

A keratinized stratified squamous epithelium made up of 4 cell types and consists of 4 or 5 layers

Question 3

What is the dermis?

Answer 3

Tough, leathery layer composed of fiberous connective tissue

Question 4

What two tissues make up the epidermis?

Answer 4

Keratinized stratified squamous and nervous tissue

Question 5

What are the 4 cells in the epidermis?

Answer 5

1. Keratinocytes
2. Melanocytes
3. Langerhans’ cells
4. Merkel cells

Question 6

Keratinocytes

Answer 6

• Produce keratin
• Most epidermal cells are keratinocytes

Question 7

Melanocytes

Answer 7

• Cells that create melanin
• Provides color to skin, hair, and eyes
• helps protect skin from UV rays

Question 8

Langerhans’ Cells

Answer 8

• Epidermal macrophages that help activate the immune system

Question 9

Merkel (nervous) Cells

Answer 9

• Present at epidermal-dermal junction
• Shaped like a spiky sphere, functions as a sensory receptor for touch

Question 10

What are the 5 epidermal layers? (Deep-Superficial)

Answer 10

1. Stratum basal
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum
5. Stratum corneum

Question 11

Stratum Basal

Answer 11

• Deepest to epidermal layer firmly attached to the dermis.
• Consists of a single row of the youngest keratinocytes (cells undergo rapid division)
• Most vascularized layer

Question 12

Stratum Spinosum

Answer 12

• Several cell layers (3-5) thick that consists of a weblike system of intermediate filaments.
• Span cytosol to attach to desmosomes
• Consists of prekeratin filaments
• Among keratinocytes are melanin granules and Langerhans’ cells

Question 13

Stratum Granulosum

Answer 13

• 3-5 cell layers
• Keratinocyte appearance changes drastically
• Keratohyalin (keratin in upper layers) & lamellated granules (water proofing/glycolipid)
• Tight junctions for waterproof layer
• Cells flatten cause keratin replaces cytoplasm and organelles

Question 14

Stratum Lucidum

Answer 14

• Only visible in thick skin
• Few layers of clear, flat, dead keratinocytes with indistinct boundaries

Question 15

Stratum Corneum

Answer 15

Consists of 20-30 cell layers thick, it is protected by keratin and the thickened plasma membrane of cells

Question 16

“Epi”

Answer 16

above

Question 17

“derm”

Answer 17

skin

Question 18

“hypo”

Answer 18

Below

Question 19

Thick vs. Thin

Answer 19

Thick:
* has lucidum (sole of foot and palms of hands)

Thin:
*No lucidum (everywhere else)

Question 20

List the steps for cell keratinization

Answer 20

1. Rapid cell division (basal layer)
2. Older layers get pushed up (as they are pushed up, they die)
3. Cytoplasm is replaced by keratin

Question 21

Some Tissue in Dermis (list 3-4)

Answer 21

1. Adipose
2. Fibrous connective tissue
3. Blood
4. Nervous

Question 22

Cells within Dermis

Answer 22

• Fibroblasts
• Macrophages
• Mast cells
• White blood cells

Question 23

What are the layers in the dermis?

Answer 23

1. Papillary
2. Reticular

Question 24

Papillary

Answer 24

• Areolar connective tissue with collagen and elastic fibers.
• Epidermal ridge/ dermal papillae create fingerprint

Question 25

Reticular

Answer 25

* Dense irregular tissue * 80% of the thickness of dermis

Question 26

Name the 4 different skin colors

Answer 26

1. Melanin 2. Carotene 3. Hemoglobin 4.Cyanosis

Question 27

Melanin

Answer 27

Provides protection from UV rays

Question 28

Carotene

Answer 28

* Yellow-orange * Pigment found in plants such as carrots * Mostly seen in palms & soles where corneum is thickest

Question 29

Hemoglobin

Answer 29

* Pinkish hue of fair skin * High O2 circulation through dermal capillaries causing the epidermis to be nearly transparent

Question 30

Cyanosis

Answer 30

* Blue * Low O2 circulation

Question 31

What are the 5 emotional/disease impacts on skin color?

Answer 31

1. Redness/Erythema 2. Pallor/Blanching 3. Jaundice 4. Bronzing 5. Bruises

Question 32

Redness/Erythema

Answer 32

* Reddened skin * Embarrassment

Question 33

Pallor/Blanching

Answer 33

* Paleness * Low blood pressure, fear, anemia, etc.

Question 34

Jaundice

Answer 34

* Yellow cast * Liver disorder

Question 35

Bronzing

Answer 35

* Bronze or metallic * Addison's disease, hypofunction of adrenal cortex

Question 36

Bruises

Answer 36

* Reveals where blood escaped from circulation and clotted beneath the skin

Question 37

Which epidermal cell is a macrophage, arises from bone marrow and serves an immune function?

Answer 37

Langerhans' cells

Question 38

Cells of the stratum spinosum have many interlocking desmosomes that will remain between the cells as they migrate to the stratum corneum. These cell junctions serve the body by ...

Answer 38

Preventing mechanical stress or trauma from damaging the epidermis

Question 39

A needle would pass through the epidermal layers of the forearm in which order?

Answer 39

Corneum, granulosum, spinosum, and Basale

Question 40

What types of fibers make up the matrix?

Answer 40

Collagen, elastic, and reticular

Question 41

Dermicidin

Answer 41

* Acid mantle * Kills bacteria on the skin

Question 42

Why does the epidermis and the dermis undulate?

Answer 42

to significantly increase the surface area of contact between the two layers, allowing for better exchange of nutrients, fluids, and signals between them

Question 43

In terms of both function and benefit, why are surface keratinocytes dead?

Answer 43

The stratum corneum is so far removed from the underlying blood supply in the dermis that diffusion of nutrients is insufficient to keep the ells alive.

Question 44

Why does sunburned skin peel in sheets?

Answer 44

When skin peels as a result of sunburn damage, the deeper layers of the stratum corneum, which still maintain their desmosome connections, detach. The desmosomes hold the cells together within the layers.