Skin Flashcards

Question

The skin is a SENSORY organ

Answer 1

Merkle cells - basal epidermis - light touch Encapsulated mechanoreceptors in dermis - Pacinian corpuscles (pressure/vibration) = Meissner corpuscles (touch) - Myelinated and unmyelinated sensory nerve endings in dermis (pain, itch, temperature)

Answer 2

- Cutaneous blood flow - Deep vascular plexus (lower reticular dermis) - Superficial vascular plexus (upper reticular dermis) - Loops of blood vessels from superficial plexus extend to reticular dermis

Answer 3

- Arrector pili muscles innervated by sympathetic α1-adrenergic fibres - Contraction raises cutaenous hairs - Likely little significant impact on heat conservation

Answer 4

stratum corneum granular layer spinous layer basal layer

Answer 5

Glands | tough connective tissue

Answer 6

fats | connective tissue

Answer 7

Lipid lamellae – water barrier, allows cells to swell Natural moisturising factor (NMF) – maintains pH Corneocytes – cells of the skin filled with NMF Cornified envelope – surrounds corneocytes Corneodesmosomes – link corneocytes

Answer 8

trap moisture in the skin and allow it to rebuild

Answer 9

trap moisture and maintain low pH

Answer 10

Natural moisturising factor

Answer 11

acids, which make the pH of normal skin low (around 5)

Answer 12

the breakdown of filaggrin

Answer 13

by breaking down the corneodesmosomes that link the skin cells together IMPORTANT: They are only broken down near the surface and not further down, otherwise the skin would fall apart and allergens would fall through

Answer 14

it switches off proteases and prevents the breakdown of corneodesmosomes It is also optimum for lipid processing enzymes, so they form a robust 'mortar' for lipid lamellae

Answer 15

1) Mutations in the filaggrin gene means theres less filaggrin in AD and so less NMF. Therefore there's less acid so the pH of the skin goes up to 7 and beyond. 2) High skin pH switches on the proteases, so they break down the desmosomes all across the skin barrier. 3) High pH switches off the lipid processing enzymes so the 'mortar' breaks up like crumbling mortal in an old brick wall.

Answer 16

1. Environmental factors interact w gene susceptibility and cause the skin barrier to break down and cause sub-clinical inflammation 2. This then causes mild atopic dermatitis without allergic antibodies 3. Allergens then penetrate through this defective barrier and cause 'sensitisation' → **type 1 allergic response** and produce high levels of IgE to the allergens 4. Inflammation then feeds back and down-regulated filaggrin and so makes the skin barrier defect worse → vicious cycle

Answer 17

producing the anti-microbial peptides necessary to defend the skin from bacteria and viruses

Answer 18

If profilaggrin and thus filaggrin are not present for any reason, there will be a lack of NMF meaning there will be less water retention in the corneocytes. This means that pH will increase, resulting in damage to the skin barrier since the corneodesmosomes become damaged by the increased pH resulting in breakdown of the skin barrier and thus increasing the risk of infection.

Answer 19

Hypercornification of skin, this blocks the hair follicle entrance Sebum released from sebaceous glands Trapped in narrow hair follicle No oxygen provides anaerobic conditions This allows propionic bacteria to multiply These bacteria breakdown triglycerides into fatty acids Result Increased irritation Increased inflammation Attraction of neutrophils This leads to pus and further inflammation

Skin Flashcards

(43 cards)