Skin

Question 1

Epidermis structure x3

Answer 1

• Epithelial
• Avascular
• Synthesises keratin

Question 2

Dermis structure x3

Answer 2

• Strong CT
• Collagen & elastic fibres
• Quite vascular

Question 3

Hypodermis structure x3

Answer 3

• Looser CT
• Superficial fascia
• Blood vessels, lymph

Question 4

Where are glands in the skin?

Answer 4

Buried in dermis/hypodermis

Question 5

Epidermis layers x5 (base –> surface)

Answer 5

• S. Basale
• S. Spinosum
• S. Granulosum
• S. Lucidum
• S. Corneum

Question 6

S. Corneum

• layer (from base)
• structure

Answer 6

• 5th

- Water-proof cell ghosts

Question 7

S. Lucidum

• layer (from base)
• processes

Answer 7

• 4th

- Specialised death programme

Question 8

S. Granulosum

• layer (from base)
• processes

Answer 8

• 3rd

- cells accumulate keratohyaline granules & start to die

Question 9

S. Spinosum

• layer (from base)
• structure

Answer 9

• 2nd

- Spiky= diff. immediate filaments join through desmosomes

Question 10

S. Basale

• layer (from base)
• processes

Answer 10

• 1st

- Stem cells divide

Question 11

Stratum Basale

• what cells
• function

Answer 11

• Stem cells

- Anchoring layer –> hemidesmosomes link w CT underneath

Question 12

How does S. Basal connect to the BM

Answer 12

Hemodesmosomes

Question 13

How does the dermis anchor to the basal lamina (= S. Basal BM)

Answer 13

Collagen VII

Question 14

What happens if collagen in the S. Basal is mutated

Answer 14

Blistering

Question 15

Stratum Spinosum

• structure
• expression of…
• at ‘end’ near S. Granulosum…

Answer 15

• Spikey –> due to desmosomes
• K1 & K10 (keratin)
• Filaggrin –> organises filaments as the cells die

Question 16

Filaggrin

• what
• where
• when
• function x2

Answer 16

• Main component of keratohyaline granules
• Stratum Spinosum
• As cells start their death programme
• Organises filaments as the cells die
• Natural moisturiser

Question 17

Melanocytes

• where
• what
• function

Answer 17

• Basal layer
• Release melanin
• Absorbs UV, preventing DNA damage

Question 18

Keratinocytes & melanin

Answer 18

Engulf melanin molecules –> form melanosomes

Question 19

Langherhans cells (monocytes)

• where
• structure x2
• function

Answer 19

• Epidermis
• Dendritic (big processes)
• Specialised lysosomes –> can degrade viruses
• Migrate to lymph nodes & present antigens

Question 20

Dermis

- sections x3

Answer 20

• Demo-epidermal junction
• Papillary dermis
• Reticular dermis

Question 21

What is the dermo-epidermal junction

Answer 21

• Where collagen VII connects in the dermis (to the epidermis)

Question 22

What is the papillary dermis?

Answer 22

• Contains lymphatics, sensory nerve endings

- Less dense than reticular dermis = below

Question 23

What is the reticular dermis?

Answer 23

• Below the papillary dermis

- Coarse collagen & elastic fibres

Question 24

Hypodermis

• structure
• components x4

Answer 24

• Loose connective & adipose tissue
• Sweat glands
• Hair follicles
• Vascular
• Ligaments –> determine skin motility

Question 25

Sweat glands in skin x2

Answer 25

- Merocrine/eccrine | - Apocrine

Question 26

Merocrine/eccrine glands - structure - Function

Answer 26

- Tubular gland = straightens into tubular duct | - Thermoregulation --> sweat

Question 27

Apocrine glands - structure - secretion

Answer 27

- In axillae, around hair follicles | - Alkaline --> odorous --> pheromones

Question 28

Hairs - structure - location - gland - movement

Answer 28

- Modified epithelium (as rod of keratin) - Hair follicle in hypodermis - Sebaceous --> = oil secretion gland - Arrector pilli miscela --> driven by autonomic nervous system

Question 29

Pilosebaceous unit | - components x4

Answer 29

- Hair follicle - Sebaceous glands - Hair shaft - Arrector pili muscle

Question 30

What are mammary glands?

Answer 30

Modified apocrine glands

Question 31

Functions of skin x3

Answer 31

- Barrier - Strength - Secretion

Question 32

Multifunctional skin | - what it does x3

Answer 32

- Protection (UV, organisms) - Homeostasis (metabolic, temp. reg) - Sensory info

Question 33

Mutations resulting in less filaggrin cause....

Answer 33

Larger risk of eczema (50% of eczema cases = this mutation)