Physiology Flashcards
(26 cards)
What are the 4 layers of the epidermis (from top to bottom)?
Keratin Layer
Granular Layer
Pickle Cell Layer
Basal Layer
What makes up most of the keratin layer?
Corneocytes
What are corneocytes?
Terminally differentiated keratinocytes
What are merkel cells?
Mechanoreceptors
Where are merkel cells found?
Basal layer
What are langerhans cells?
Immune cells of epidermis
Where are langerhans cells found?
Prickle cell layer (also dermis, lymph nodes and eyes)
What cells are langerhans cells like?
Dendritic cells (antigen presenting cells)
What are melanocytes?
Pigment producing cells
Where do melanocytes originate from?
Neural crest
Where are melanocytes found?
Basal layer and above
What is the reaction that occurs in melanocytes?
Tyrosine to melanin
What are the two types of melanin?
Eumelanin
Phaeomelanin
What colour is eumelanin?
Brown/ black
What colour is phaeomelanin?
Red/ yellow
What is the muscle found in hair follicles (pilosebaceous unit)
Arrector Pilli muscle
What are the 3 growth phases of hair?
Anagen
Catagen
Telogen
What is the anagen phase and how long does it last?
Growing phase (3-7 years)
What is the catagen phase and how long does it last?
Involuting phase (3-4 weeks)
What is the telogen phase and how long does it last?
Resting (shedding) - 1 day
What do pilo-sebaceous units secrete?
Sebum
What is the dermis made up of?
Connective tissue (Ground substance and cells)
What cells are found in the connective tissue?
Fibroblasts and immune cells
Pacinian corpsucles sense?
Pressure
