Flashcards in Physiology Deck (40)
What is the largest organ in the body?
What is the outermost layer of skin called?
Which type of epithelium makes up epidermis?
Stratified squamous epithelium
Which layer of skin is deep to epidermis?
Which tissue type makes up dermis?
Which germ layer forms epidermis?
Ectoderm (forms periderm)
Which germ layer forms dermis?
In foetal skin development, which layers are formed after 16 weeks?
Keratin layer + granular layer
Prickle cell layer
Which cell makes up 95% of epidermis?
The basal layer of skin is highly metabolically active. True/False?
Lots of intermediate filaments
Name 3 other epidermal cells (other than keratinocytes)
Where do melanocytes derive from?
Neuronal cell crest
What are melanocytes? Which layer of skin are they found?
Pigment-producing dendtritic cells
What do melanocytes do?
Convert tyrosine to melanin pigment and load colour onto adjacent keratinocytes
Eumelanin is brown/red
Phaeomelanin is brown/red
Which disease results due to loss of melanocytes?
Where do Langerhans cells derive from?
What are Langerhans cells? Which layer of skin are they found?
Prickle cell layer
What are Merkel cells? Where are they found?
Mechanoreceptors that aid sensation
Between keratinocytes + nerve fibres
What are the 3 phases of growth of a hair follicle?
Catagen (curve inwards)
What is the dermo-epidermal junction (DEJ)?
The interface between the dermis and epidermis
List 2 key roles of the DEJ
Support, anchoring, adhesion and growth of epidermal cells
Semi-permeable membrane acts as a filter/barrier
Give an example of inherited skin fragility as a result of mutation to one of the proteins in the DEJ
Epidermolysis bullosa complex in young infants
Give an example of acquired skin fragility
What do fibroblasts in the dermis produce?
Procollagen (becomes collagen)
The blood vessel supply to skin is greater than its metabolic need. True/False?
Which nerve receptors sense pressure in skin?
Which nerve receptors sense vibration in skin?
What do free nerve endings provide sense for in skin?
Which inherited condition arises due to overgrowth of nerve endings?
List the 3 main secretory glands in skin
Eccrine glands secrete ?
Apocrine glands secrete ?
Sebaceous glands secrete ?
Eccrine glands secrete sweat
Apocrine glands secrete odourous fluid
Sebaceous glands secrete moisturiser
Which areas of the body have a high concn of sebaceous glands?
Head, neck and chest
What is the significance of the melanin cap on basal cells?
Absorbs UV rays to protect DNA in the cells' nuclei
Which vitamin does skin metabolise?
20% of thyroxine conversion to triiodothyronine (T4 to T3) is done in peripheral tissues such as skin. True/False?
Which cells help protect skin from UV rays?
Ratio of melanocytes : basal cells = ?