Skin layer overview

Question 1

What are the 3 layers of the skin?

Answer 1

epidermis, dermis, subcutis

Question 2

What are the primary skin cells of the epidermis?

Answer 2

keratinocytes (primary), melanocytes, langerhans, Merkel cells

Question 3

What is an important feature the epidermis lacks?

Answer 3

no blood vessels or nerve endings

Question 4

What layer is primarily made of fibroblasts, collagen, and elastic cells?

Answer 4

dermis

Question 5

If you were to bleed from a pencil stick, what layer are you in at minimum?

Answer 5

dermis

Question 6

What layer of skin contains the fat?

Answer 6

subcutis

Question 7

What is also found in the subcutis layer?

Answer 7

blood vessels and fibrous septae

Question 8

What is the primary job of the epidermis?

Answer 8

primary barrier fxn, protection, and wound healing

Question 9

What are the jobs of teh dermis and subcutis?

Answer 9

structural support, vascular support, innervation

Question 10

How long does it take for a new epidermal layer to grow?

Answer 10

28+ days

Question 11

What part of the epidermis do stem cells grow?

Answer 11

basal layer (shed from surface)

Question 12

Describe the differentiation of the stem cells from the basal layer

Answer 12

cells terminally differentiate as they move upward

Question 13

What is the order of the layers in the epidermis? (outside-in)

Answer 13

corneum, granulosum, spinosum, basale

Question 14

What is important about hemidesmosomes?

Answer 14

basal cells adhere to the dermis (basement membrane zone) via hemidesmosomes

Question 15

As the cells that are migrating from the basale layer to the spinous layer, what is important about their growth?

Answer 15

they stop dividing and start terminal differentiation

Question 16

As the cells of the spinous layer develop, what improves the barrier function of the skin?

Answer 16

develops lipid from lamellar granules

Question 17

Where are desmosomes located?

Answer 17

spinous layer of the skin

Question 18

What is the function of the desmosomes?

Answer 18

spiny cells that adhere the KC to one another

Question 19

The granular cell layer synthesizes what to be used in the outer cell layers?

Answer 19

profilaggrin

Question 20

What type of granules are synthesized in the granular cell layer?

Answer 20

intracellular keratohyaline granules

Question 21

What would be histologically prevalent of the stratum corneum?

Answer 21

nuclei and organelles degenerate, cells flatten

Question 22

Another water barrier is in the stratum corneum. Describe it

Answer 22

profilaggrin processed into filaggrin that combines with keratins to form macrofibrils creating a protective layer

Question 23

T/F stratum corneum is different at different locations throughout the body

Answer 23

true

Question 24

What are the bricks of the stratum corneum?

Answer 24

flattened keratinocytes filled with keratin and filaggrin

Question 25

What is the mortar of the stratum corneum?

Answer 25

lipid mix surrounding keratinocytes providing a water barrier

Question 26

What forms the intermediate filaments?

Answer 26

keratins combining

Question 27

What is significant about keratin and its function?

Answer 27

pairs differently to stabilize the cell against stress (different in different locations)

Question 28

Melanocytes produce pigment. Where are they derived from? What is their function?

Answer 28

neural crest cells=> transfer melanin to surrounding keratinocytes

Question 29

Where are melancocytes found?

Answer 29

living with the basal cells and stretching into the spinosum layer

Question 30

Which skin cell is important in allergic reaction AND tumor/antigen surveillance? where does it live?

Answer 30

Langerhans cells and mid-epidermis

Question 31

What is an epidermal cell that that is associated with light touch sensation?

Answer 31

Merkel cells

Question 32

What is the primary function of the dermis?

Answer 32

support layer that varies in thickness

Question 33

What structures can be found in the dermis?

Answer 33

vasculature, nerves, sweat and oil glands, hair follicles

Question 34

What is the primary cell in the dermis? What is its origin?

Answer 34

fibroblasts and mesenchymal origin

Question 35

What is the responsibility of the fibroblasts in the dermis?

Answer 35

synthesis and degration of connective tissue proteins (collagen, elastin, GAGs)

Question 36

An injury to the skin triggers the mitotic activation of which cells?

Answer 36

fibroblasts (wound healing and scar formation)

Question 37

Which cells located in the skin are associated with wound healing and allergic reactions?

Answer 37

mast cells (wheal and flare rxn)

Question 38

Hair follicles extend through dermis into what? what does each follicle have associated with it?

Answer 38

hair follicles extend through dermis into subcutis and oil gland is associated

Question 39

What does the pilosebaceous unit consist of?

Answer 39

hair follicle, sebaceous gland, apocrine sweat glands, arrector pili muscle

Question 40

What are the "true" sweat glands and where are they?

Answer 40

Eccrine sweat glands are located throughout the body

Question 41

Where do the eccrine sweat glands open and what is their fxn?

Answer 41

open directly onto the skin and regulate temp by evaporative cooling of sweat

Question 42

What is the fat layer that separates the dermis from the underlying structures?

Answer 42

subcutis

Question 43

What is the role of the subcutis?

Answer 43

insulation, energy source, injury protection

Question 44

What is the normal response to sundamaged cells?

Answer 44

apoptosis of keratinocytes

Question 45

What occurs if the hemidesmosomes are damaged or altered?

Answer 45

Bullous pemphigoid

Question 46

If the desmosomes of the spinous layer are damaged, what is the result?

Answer 46

pemphigus vulgaris

Question 47

Genetic defects in filaggrin is assocated with what disease and what layer of the epidermis?

Answer 47

atopic dermatitis and stratum corneum

Question 48

What is a genetic mutation in keratin 5/14 associated?

Answer 48

epidermolysis bullosa simplex

Question 49

What will be the clinical Sx of epidermolysis bullosa simplex?

Answer 49

blisters due to K5/14 filament mutation not allowing the hemidesmosome and basal KC attachment

Question 50

What is a nevus?

Answer 50

Mole=> benign collection of melanocytes

Question 51

What is a melanoma?

Answer 51

growth of malignant melanocytes

Question 52

What are diseases that are associated with the subcutis?

Answer 52

panniculitis