Skin Structure and Function 1

Question 1

What are the 5 components of skin in mammals?

Answer 1

Epidermis
Dermo-epidermal junction
Dermis
Sub-cutis
Appendages

Question 2

What layer of the skin makes up the epithelium?

Answer 2

Epidermis

Question 3

What type of epithelium is the epidermis?

Answer 3

Stratified squamous epithelium

Question 4

Is the epidermis or dermis more cellular?

Answer 4

Epidermis

Question 5

What of the 4 basic tissue types is the dermis?

Answer 5

Connective tissue

Question 6

What is the sub-cutis mainly composed of?

Answer 6

Fat

Question 7

What are the 4 skin appendages?

Answer 7

Nails
Hair
Glands
Mucosae

Question 8

What type of epithelium lines the blood vessels?

Answer 8

Simple squamous epithelium

Question 9

Where is glandular epithelium found in the skin?

Answer 9

In sweat and sebaceous glands

Question 10

What is the periderm?

When does this generally disappear?

Answer 10

Outer layer of the bilaminar foetal epidermis

Before birth

Question 11

What does the epidermis form from in the embryo?

Answer 11

Ectoderm cells form a single layer of periderm

There is a gradual increase in layers of cells before the periderm is cast off

Question 12

What is the ectoderm?

Answer 12

One of 3 primary germ layers in the very early embryo

Question 13

What is the embryonic origin of the dermis?

Answer 13

Mesoderm

Question 14

What is the neural crest?

Answer 14

A temporary group of cells unique to vertebrates that arise from the embryonic ectoderm cell layer and in turn give rise to a diverse cell lineage

Question 15

What is the embryonic origin of melanocytes?

Answer 15

Neural crest

Question 16

At 4 weeks, what layers is the skin made up of? (3)

Answer 16

Periderm
Basal layer
Dermis (corium)

Question 17

At 16 weeks, what layers is the skin made up of? (5)

Answer 17

Keratin Layer
Granular layer
Prickle ell Layer
Basal Layer
Dermis

Question 18

At how many weeks is the skin fully formed with appendages?

Answer 18

26 weeks

Question 19

What is the basal layer formed from?

Answer 19

Basal keratinocyte cells (“Stem cells of the skin”) and melanocytes

Question 20

What “lines” show the developmental growth pattern of skin?

Answer 20

Blaschko’s lines - don’t follow vessels, nerves or lymphatics

Question 21

What forms the basement membrane of the epithelium (epidermis)?

Answer 21

the demo-epidermal junction

Question 22

How thick is the epidermis?

Answer 22

Very thin - 1.5mm thick

Question 23

What cells make up 95% of the epidermis?

Answer 23

Keratinocytes

Question 24

what structural protein does keratinocytes contain?

Answer 24

Keratin

Question 25

Apart from keratinocytes, what other cells does the epidermis contain? (3)

Answer 25

Melanocytes Langerhans cells Merkel cells

Question 26

What are melanocytes?

Answer 26

Melanin producing cells

Question 27

What are lagerhans cells?

Answer 27

Dendritic cells

Question 28

What are merkel cells?

Answer 28

Mechanoreceptors

Question 29

What are the 4 layers of the epidermis with their Latin name?

Answer 29

``` Keratin layer (stratum corneum) Granular layer (stratum granulosum) Prickle cell layer (stratum spinosum) Basal layer (stratum basale/ germinativum) ```

Question 30

How many cells thick is the basal layer generally?

Answer 30

1 cell thick

Question 31

What is the ratio of melanocytes to basal cells in the basal layer?

Answer 31

1:10

Question 32

what do basal cells contain lots of?

Answer 32

intermediate filaments - parts of the cytoskeleton

Question 33

What shape are prickle cells?

Answer 33

Polyhedral

Question 34

What does the pricked cell layer have lots of between cells?

Answer 34

Desmosomes (connections)

Question 35

How many layers of cells does the granular layer have?

Answer 35

2-3 layers of flatter cells

Question 36

What type of cells make up the granular layer of the skin?

Answer 36

Keratinocytes known as granular cells

Question 37

What do granular cells contain? (2)

Answer 37

Large keratohyalin granules | Odland bodies

Question 38

What 2 things are contained within the large keratohyalin granules of granular cells?

Answer 38

Filagrrin | Involucrin proteins

Question 39

What are odland bodies? | Other name for these?

Answer 39

A type of epithelial organelle with a high lipid content | Lamellar bodies

Question 40

What cells make up the keratin layer? | What are these?

Answer 40

Corneocytes | Type of terminally differentiated keratinocyte that is non-nucleated

Question 41

What is the name for the outer part of a corneocyte that makes up the outer layer of the epidermis?

Answer 41

Cornified envelope - made from keratin

Question 42

What creates the tight waterproof barrier of the keratin layer?

Answer 42

Lamellar granules release lipid

Question 43

Where are keratinocytes produced?

Answer 43

in the basal layer

Question 44

What controls the balance between cells in/ out e.g. keratinocyte production at the basal layer? (3) What 2 conditions are caused by a loss in this control?

Answer 44

``` Growth factors Hormones Cell death Skin cancer Psoriasis ```

Question 45

What causes white plaques in the oral mucosa?

Answer 45

Thickening of the oral epidermis