Skin Structure

Question 1

What type of epithelium is skin?

Answer 1

Stratified sqaumous

Question 2

Name the 4 layers of the epidermis from superficial to deep?

Answer 2

Strateum corneum
Granular
Prickle cell
Basal cell

Question 3

How thick is the epidermis + what cell accounts for 95% + what do they differentiate into?

Answer 3

1.5 mm
Keratinocyte
Corneocytes

Question 4

How many days does it take for a keratinocyte to migrate from the basal layer to the strateum corneum?

Answer 4

28

Question 5

What is special about corneocytes + explain?

Answer 5

No nuclei

Lost at granular cell layer

Question 6

What organelle is found in the strateum corneum and granular layer + function + role in each layer?

Answer 6

Lamellar/ Odland bodies
Secrete lipids
SC = form waterproof seal
GCL = trap water to provide moisture

Question 7

Where is the keratin layer at its thickest?

Answer 7

Palms and soles of feet

Question 8

What shape of keratinocytes are found in the granular layer + type of granule and contents?

Answer 8

Flat cells
Keratohyalin granules
Fillagrin and involucrin

Question 9

What shape of keratinocytes are found in the prickle cell layer + key layer feature + resident APC?

Answer 9

Polyhedral
Desmosomes
Langerhans

Question 10

Most metabolically active layer responsible for epidermal proliferation?

Answer 10

Basal cell

Question 11

Shape of basal cell layer keratinocytes + arrangement?

Answer 11

Cuboidal

Single layer

Question 12

Name 4 other features of the basal cell layer?

Answer 12

Hemidesmosomes
Laminin
Collagen IV
Free nerve endings

Question 13

How is the epidermis vascularised?

Answer 13

By the vessels within the papillary dermis

Question 14

What type of tissue is the DEJ + 2 layers?

Answer 14

Connective tissue
Lamina lucida
Lamina densa

Question 15

What anchors the basal cell layer to the DEJ?

Answer 15

Hemidesmosomes

Question 16

What is the function of ground substance + what does it contain/not contain?

Answer 16

Fill the space between fibres and cells

All the components of the extracellular matrix EXCEPT from fibres

Question 17

Name the 3 main components + 3 main cells of the DEJ?

Answer 17

Ground substance
Collagen
Elastin

Fibroblasts
Mast cells
Macrophages

Question 18

Explain how wrinkles form.

Answer 18

Damage to collagen/elastin forms long fibres. Further damage forms short fibres (wrinkles)

Question 19

What 2 types of collagens are found in the dermis + what are they made by?

Answer 19

Type I
Type III
Fibroblasts

Question 20

What are anchoring fibrils made of + attachments?

Answer 20

Type VII collagen

DEJ to type III collagen in dermis

Question 21

Name the 2 layers of the dermis from superficial to deep?

Answer 21

Papillary

Reticular

Question 22

Function of the papillary vs reticular dermis?

Answer 22

Projects into the epidermis

Contains more fibre for support

Question 23

Which layer of skin contains the free nerve ending + most nerves and vessels?

Answer 23

Basal cell layer

Dermis

Question 24

What specialised nerve is found in the papillary dermis + what does it feel?

Answer 24

Meissener’s corpuscle

Light touch and vibration

Question 25

What specialised nerve is found in the reticular dermis + what does is feel + shape?

Answer 25

Pacinian corpuscle Deep pressure Onion

Question 26

Blood supply is less than metabolic needs of the dermis. True or False?

Answer 26

False - blood supply greater than metabolic needs

Question 27

Where are melanocytes mainly found + explain the production, transfer and function of melanin.

Answer 27

Basal cell layer Melanosomes convert tyrosine to melanin Dendrites transfer melanin onto nucleus of adjacent Acts as protection against UV radiation

Question 28

Name the 2 types of melanin + colour.

Answer 28

``` Eumelanin = brown/black/blue Phaeomelanin = red/pink/yellow ```

Question 29

Where do Langerhans cell originate + 3 places found + type of cell + key organelle?

Answer 29

Bone marrow Prickle cell layer, dermis, lymph nodes APC Birbeck/ racket granule

Question 30

What layer and position are Merkel cells found + type of cell + what causes cancer of these cells?

Answer 30

Basal cell layer between a keratinocyte + nerve Mechanoreceptors Viral infection

Question 31

Explain the stem of the pilosebaceous unit in the dermis.

Answer 31

Papilla stemming from matrix with blood vessels

Question 32

Name the layers of a hair from internal to external.

Answer 32

Medulla Cortex Internal root sheath External root sheath

Question 33

Name 2 associated structures of the pilosebaceous unit + function.

Answer 33

Arrector pili muscle = movement | Sebaceous gland = lubrication

Question 34

Name the 3 types and meanings of hair growth phase (ACT) + meaning + which phase is 90% of hairs in?

Answer 34

``` Anagen = growing = 90% of hairs Catagen = involuting Telogen = resting ```

Question 35

Name the 3 types of hair (LVT) + where they are found.

Answer 35

Lanugo = foetus Vellus (fine hair over body) Terminal (coarse hair on scalp, axilla etc.)

Question 36

Name the main component of hair and nails.

Answer 36

Keratin

Question 37

How fast to fingernails grow each day + are toenails slower or faster?

Answer 37

0.1 mm | Slower

Question 38

Name the 3 regions of nail.

Answer 38

Matrix Nail root Nail Plate

Question 39

Name for the white semi-circle part of the nail, cuticle and area where free edge meets skin.

Answer 39

Lanula Eponychium Hyponychium

Question 40

Where does the epidermis, dermis and melanocytes originate from in embryology?

Answer 40

``` Epidermis = ectoderm cells forming single layer periderm Dermis = mesoderm Melanocytes = neural crest ```

Question 41

Name the layers of the skin at 4 weeks.

Answer 41

Periderm Basal layer Dermis

Question 42

By what week have all the skin layers formed and melanocytes migrated + week when appendages form?

Answer 42

Week 16 | Week 26

Question 43

What are Blaschko's lines?

Answer 43

Direction of skin growth that does not follow vessels or nerves

Question 44

Name the 3 types of skin gland and secretion + which is the most common?

Answer 44

``` Eccrine = sweat = most common Sebaceous = lubricant Apocrine = odorous fluid ```

Question 45

Difference in eccrine and sebaceous gland control?

Answer 45

``` Eccrine = sympathetic Sebaceous = hormonal ```

Question 46

Where are sebaceous glands found + 3 functions?

Answer 46

Next to pilosebaceous unit Lubricates hair follicle Moisture loss Prevents fungal infection

Question 47

When do apocrine glands develop + what do they produce + only 3 places found?

Answer 47

Puberty Scent Axilla, genitals, nipples