Skin Flashcards
(27 cards)
What variations can you have in the Macroscopic structure of skin?
Colour Hair Thickness Wrinkling Oiliness
Define Vitiligo
A depigmentation of skin
Name some autoimmune responses that lead to hair loss
Alopecia areata
Alopecia totalis
What are the different layers of the Epidermis?
Horny layer
Granular layer
Prickle cell layer
Basal layer
Where does Keratinocyte mitosis mainly occur?
Basal layer
Where does terminal differentiation begin?
In the Prickle cell layer (Keratinocytes loose their ability to divide)
What do Keratinocytes synthesise?
Keratins. Heterodimeric fibrous proteins - contribute to the strength of the epidermis
What happens to Keratinocytes in the Granular layer?
Lose their plasma membrane
Begin differentiating to corneocytes
What does the Granular layer contain?
Keratohyalin granules (Made of Keratins, fibrous proteins, enzymes)
What is the Horny layer (Stratum Corneum) made of?
Layers of flattened corneocytes (Major barrier function)
Where are Melanocytes?
In the Basal layer of the Epidermis (Dendric cells of Neural crest origin)
What do Melanocytes make?
Melanin which creates pigmentation of the skin
Where are Langerhan’s cells?
In the Prickle cell layer of the Epidermis (Dendric cells of bone marrow origin)
What do Langerhan’s cells do?
Highly specialised capacity to present antigens to T lymphocytes
Mediate immune reactions
What type of tissue makes the Dermis?
Dense irregular connective tissue - Fibroblasts and extra cellular matrix (Contains Collagens and Elastins)
How are blood vessels distributed in the Dermis?
Few smaller ones in the more superficial layers of the Dermis, then thicker and more in the deeper layers of the Dermis
Where are Mast cells?
In the Dermis
What do Mast cells do?
Contain Histamine which they release to cause increased vascular permeability - causes local oedema (Can have negative effects if by respiratory tract)
What are the Skin Appendages?
Hair follicles & Sebaceous glands
Sweat glands
What type of secretion do Sebaceous glands exhibit?
Holocrine
What are the types of sweat glands?
Apocrine
Eccrine
Which sweat gland is usually involved in Thermoregulation?
Eccrine
What do Apocrine sweat glands do?
No function of value
Produce odourless, protein-rich, apocrine secretion. Digestion of this by Cutaneous microbes produces body odour
What lies deep to the Dermis?
Subcutaneous fat
