Structure and function Flashcards
What cells compose the epidermis?
- Epithelial cells
- Stratified cellular epithelium
Where is the dermis found?
- Beneath the epidermis
- connective tissue
What is the subcutaneous fat involved in?
- thermoregulation
What do melanocytes produce?
- Melanin
- pigment producing
Describe Blaschko’s lines?
- Development growth pattern of skin, not following neves or vessels
- follows the dermatome map, genetic error?
Name some appendages?
- Hair
- Nails
- Glands
How many layers think is the basal layer?
- usually 1 cell thick
- cuboidal
Explain the prickle cell layer
- found in the epidermis
- keratin producing
- lots of desmosomes
Explain the granular layer
- 2 or 3 layers of flatter cells
- high lipid content
- cell nuclei lost
What is found in the keratin layer?
- Corneocytes (differentiated keratinocytes)
- regularly replaced
What are keratinocytes and where are they found
- form tight junctions with the nerves of the skin, hold everything together
- 90% of epidermal cells
What is the name given to the immune cell associated with the skin?
- Langerhans cells
What do merkel cells detect?
- Detect pressure changes
- mechanoreceptors
Where are merkel cells found?
- basal layer
- between keratinocytes and nerve fibres
Merkel cell cancer is associated with what type of infection?
- viral infection
Nelson’s syndrome?
- melanin stimulating hormone produced in excess by pituitary
What are the name of the muscle associated with the hair follicles?
- arrector pili muscle
- smooth muscle fibres
What type of gland secretes into the hair follicle?
- sebaceous gland
- produces sebum
What are the 3 phases of hair growth
- anagen (growing)
- catagen (involuting)
- telogen (resting)
Explain telogen effluvium
- most common cause of hair loss
- seen in pregnancy due to hormone changes
What is the dermo-epidermal junction and its role?
- interface between epidermis and dermis
- role: support, adhesion and to act as a semi-permeable membrane
What is found in abundance in the dermo-epidermal junction?
- collagen
What is seen when there is a spilt in the dermo-epidermal junction?
- blisters
Onion rings on histology?
- pacinian (pressure nerves)
When you brush your hair and some hair is see on brush, what stage of growth was that hair in?
- telogen
Where are apocrine glands found?
- axillary and anogenital region
Where are eccrine glands found
- hands and feet
- thermoregulation
- no hair follicle involved, straight to epidermis
What are some functions of the skin?
- barrier (physical and chemical)
- thermoregulation
- metabolism and detoxification
- immune defence
What are the 4 layers of the epidermis from superifical to deep?
- Keratin layer
- Granular layer
- Prickle cell layer
- Basal layer
What is the average nail growth daily?
- 0.1mm/day
Langerhans cells are _______ in origin?
- mesenchymal (bone marrow)
Where are Langerhans cells found?
- Prickle cell layer
What lies adjacent to hair follicles?
- Sebacous glands
Explain vitiligo?
- An autoimmune condition of melanocytes
What is the sheding phase of the hair follice called?
- Telogen phase
What are the 3 layers of the nail plate?
- Dorsal
- Intermediate
- Ventral
What protects the nuclear DNA in basal cells?
- Melanin caps
Pacinian nerves sense______
- pressure
Meisner nerves sense______
- vibration
What is the dermo-epidermal junction?
- Interface between the dermis and epidermis
- semi-permeable
What gland is responsible for odour?
- Apocrine gland
The eccrine gland is under _______ nerve supply?
- sympathetic cholinergic nerve supply
What is vitamin D3 stored as in the liver?
- Hydroxycholecalciferol
What is hydroxycholecalciferol converted to in the kidney?
- 1,25- dihydroxycholestrol
