Intro to Dermatology Flashcards
What are the functions of the skin?
Protection, regulation and sensations.
Protects against: mechanical and pressure impacts, microorganisms, radiation and chemicals.
Regulation of: body temperature, fluid balance and synthesis of vitamin D.
Sensation: detects heat, cold, touch and pain
Label the different skin layers
What are the layers of the epidermis
- Granulosa layer is filled with lots of granules
- Spinosum has lots of tiny spines between cells
Explain the embryological development of the skin
- Epidermis is derived from the ectoderm.
- By the 5th week, the embryo is covered by simple cuboidal epithelium.
- By the 7th week a single squamous layer (periderm) and a basal layer form.
- By the 4th month an intermediate layer forms between periderm and basal layer.
- Melanocytes (derived from neural crest cells) invade epidermis.
- Hair develops in the 3rd month and sebaceous gland buds form
What are the cells of the immune system in the skin?
Langerhans cells which are members of the dendritic cell family. They reside in the basal layers. They preform antigen presentation to naïve T cells causing them to activate. Activated T cells initiate cytokine release cascade.
What are the effects of ultraviolet of the skin?
- Causes direct cellular damage and alterations in immunological function. This can result in photoaging, DNA damage and carcinogenesis.
- Chronic exposure to UV can lead to loss of skin elasticity, fragility, abnormal pigmentation and haemorrhage of blood vessels
What tumour suppressor gene is damaged by UV light?
p53 TSG. Mutations in this gene are implicated in skin cancers
What cells protect skin against UV damage?
Keratinocytes and melanocytes
Briefly explain the formation of vitamin D and why can occur dur to deficiency
UV light gets absorbed by 7-dehydrocholesterol in the skin and concerted to pre-vitamin D. Pre vitamin D then undergoes transformation within the plasma membrane into active vitamin D.
Vitamin D deficiency can increase the risk of common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases.
Name some cutaneous nerve endings
- Merkles cells
- Meissner corpuscles
- Ruffini’s corpuscles,
- Pacinian corpuscles
What is the function of Merkel cells and where are they located?
Located at the base of the epidermis. Merkel cells respond to sustained gentle and localised pressure.
Where are Meissner corpuscles located and their function
Located immediately below the epidermis. Many found within palmer surfaces/lips. Sensitive to light touch.
Where are Ruffini’s corpuscles located and what do they respond to?
Located in the dermis. Receptors are sensitive to deep pressure and stretching
Where are Pacinian corpuscles located and what do they respond to?
They are mechanoreceptors present in deep dermis. They are sensitive to deep touch, rapid deformation of skin surface as well as JPS.
What is the Fitzpatrick skin colour types?
Gives numerical value to skin colour and whether a person burns/tans easily
