Structure and Function 1 & 2 Flashcards
What kind of epithelium is the epithelium made out of?
Stratified cellular epithelium
Which embryological layer gives rise to the epithelium?
Ectoderm
What are the 4 layers of the epithelium?
Keratin
Granular
Prickle cell
Basal
What is the dermis made of?
connective tissue
Which embryological layer gives rise to the dermis?
endoderm
What is below the dermis and what is this made of?
Subcuteanous tissue - predominantely fat
What are melanocytes and where are they from?
Pigment producing cells
Neural crest
What are Blaschko’s lines?
Developmental growth pattern of skin
Apart from the 4 layers of cells, which other cells can be found in the epidermis?
Langerhans, Merkel cells and melanocytes
Describe the basal layer of the epidermis?
Small cuboidal cells usually only one cell thick
Describe the cells in the prickle cell layer,
large polyhedral cells with lots of desmosomes
What are the important granules found in the granular layer?
Large keratohyalin granules
What do the keratohyalin granules do/contain?
Contain structural filaggrin and involucrin proteins
Main function of waterproof barrier trough the production of keratin and lipids
What are corneocytes in the keratin layer?
Overlapping non-nucleated cell remnants
these create an insoluble cornified envelope
Does the keratin layer allow transpiration?
Yes
Name the organelles in melanocytes that produce the pigment?
melanosomes
What pigment(s) are produced by melaoncytes?
Eumelanin and phaeomelanin
Why is the melanin pigment produced by the melanocytes?
Full melanosomes (melanin granules) are transferred to adjacent keratinocyes via dendrites and form a protective cap over the nucleus to protect the nuclear DNA
What are freckles?
Bundles of melanocytes
Why are Langerhans cells found in the skin?
Involved in skin immune system - antigen presenting cells
Where do Langerhans cells originate?
Bone marrow (mesenchymal origin)
What are the cells that are always asked in exams called?
Racket organelles/ Birbeck granules
Where are Merkel cells found in skin?
basal - between keratinocytes and nerve fibres
What is the use of Merkel cells?
Mechanreceptors, linked to free nerve endings, therefore very sensitive and allow “touch”
What causes Merkel cell cancer?
Merkel cell virus
What is the correct name for hair follicles?
Pilosebaceous unit
What are the phases of growth of hair?
Anagen = growing Catagen = involuting Telogen = resting
Within the nail, the nail matrix is said to be what?
“stem cells reservoir” - cells move up the nail to become keratinized and replace lost cells
Where is the nail matrix?
beneath the cuticle
What do the lacrimal glands, eye lashes and sebaceous glands have in common?
Ocular mucosa
