Skin and Breast Flashcards
Describe epidermis
Rests on basement membrane
Made of type IV collagen
Describe stratum basale
Sits on basement membrane
Basal epithelial cells - stem cells
Melanocytes
Describe melanocytes
Synthesise melanin and transfer it to surrounding keratinocytes in melanosomes in response to MSH and ACTH stimulation
What is the role of melanin
Absorbs UV light protecting us from non-ionising radiation damage
What can contain melanin
Epithelial
Melanocytes
What is skin colour dependent upon
Melanocytes same in individuals
Depends on the amount and type of melanin
What is usually the largest layer of the epidermis
Stratum spinosum
Describe the stratum spinosum
Also called the prickle layer
Plump polygonal keratinocytes
Closely bound by desmosomes - Prominent intercellular adhesions (prickles between the cells)
Langerhans cells - antigen recognition
Merkel cells - sensory
What is the role of langerhans cells
Antigen recognition
What is the role of Merkel cells
Sensory
Describe the stratum granulosum
Flattened squames
Eosinophilic cytoplasm
Haematoxophilic kerato-hyaline granules
Keratin forms in this layer
Describe the stratum corneum
Acellular (cells are dead)
Plates of keratin
Prominent at certain sites - palms and soles
What are epidermal adnexae
Downgrowths of the epidermis into the dermis
- hair follicles
- sebaceous glands
- eccrine sweat glands
- apocrine sweat glands
Describe sebaceous glands
Accompany hair follicles
Produce sebaceous secretions which lubricate and waterproof hairs
Holocrine secretion - discharge entire cell
Where are apocrine glands found
Armpits
Groins
Genitals
Anus
Produce ear wax
Describe apocrine cells
Accompany hair follicles
Axillae and groins
Ceruminous glands in the ear
Simple coiled tubular glands
Eosinophilic cytoplasm
Apocrine secretions - cytoplasm of cells bud off from luminal surface
Function not entirely certain
Describe eccrine glands
Thin watery secretions
Everywhere
Coiled tubes, 2 cell layers thick - inner secretory, outer myoepithelial
Eccrine (merocrine) secretion - exocytosis
Describe the dermo-epidermal junction
Not flat
Epidermis protrudes downwards into the underlying dermis - rete pegs/ridges
Space between these is the papillary dermis
Describe the dermis
Fibrous connective tissue containing elastin, blood vessels, nerves
Deepest layers see presence of fatty connective tissue
Irregular loose connective tissue
What is the role of the meissners corpuscles
Fingers, palms and soles
Fine touch
What is the role of the pacinian corpuscle
Vibration and tickle
Deep dermis
Describe the subcutis
Adipose tissue and fibrovascular septa
Insulation
Shock-absorber
Food store
Where do ducts of the breast all empty
Nipple
Are there histological differences between male and female breasts
Yes
Males breast tissue only is the ductal system
What is the functional component of the breast
Terminal duct lobular
Lobules are arranged around a terminal duct
Set in loose fibrous connective tissue
How can you tell is a breast is in lactation
Cells become vacuolated
