Week 3 (skin) Flashcards
What are the 3 basic layers of the skin
Epidermis , dermis, hypodermis
What are the three main cell types of the epidermis
Keratinocytes, Melanocytes, and Langerhans
What are the 5 layers of the epidermis
(Stratum = Layer)
- Stratum Corneum (“horny” outermost layer)
- Stratum Lucidum (clear layer) (lucid = clear)
- Stratum Granulosum (granular layer)
- Stratum spinosum (“spiny” layer)
- Stratum Basale (germinativum) (innermost – base)
Downloaded by
where is the Stratum lucidum Found
hands and feet
Melanocytes do what?
Secrete melamin which accumalates in membrane-bound granules called melanosomes that are trafficked to kertinocytes via actin filaments
What are the two types of Melanin
Eulamelanin (dark) and Phaeomelanin (red/yellow)
Is the dermis vascularised
yes
The Dermis consists of _____
layers (elaborate)
Papillary 20%
- Areolar
connective
tissue – loose
- Dermal
papillae
Reticular 80%
- Dense
irregular
connective
tissue
Two types of sweat glands
o Eccrine
o Apocrine
Where are Eccrine Sweat Glands found
Everywhere but especially the Palms of hands, soles of feet and forehead
What type of glands are sweat
Exocrine
Where are Apocrine Sweat Glands
armpits and genitals
What differentiates Apocrine Sweat Gland from Eccrine sweat glands
Larger than eccrine glands and deeper in the dermis
Secrete into ducts that empty into hair follicles
Similar components as true sweat but also the addition of fatty substances and proteins
Role in pheromone secretion and sexual arousal
What differentiates Eccrine Sweat Gland from Apocrine sweat glands
Major role is to regulate body temperature
Similar components as true sweat but also the addition of fatty substances and proteins
Secrete “true” sweat
o 99% water, slats vitamin C, antibodies
Modified Apocirne sweat glands
Ceruminous glands
o Secrete cerumen – bitter, waxy secretion (ear-wax)
o Found in the outer one third of the external ear canal
Mammary glands
o Secrete milk (in human female)
A specialized “sweat” secretion
What do Sebaceous (oil) glands secrete, what type of galnd is it, and its purpose and controlled by what
Secrete sebum (oily substance), Holocrine gland, Functions to lubricates hair and slow water loss from the skin, and Secretion is controlled mainly by sex hormones
o E.g. testosterone
how does a sebaceous cyst form
Sebaceous glands fills with sebum
how do blisters form
extracellular fluid seberates the epimeris and the sermis
What are the coats of hair and where are they located
During our lifetime, humans have 3 different types of hair
o Lanugo (down – lose it 1 to 2 months before birth)
o Vellus (fleece – fine, pale, body hair)
o Terminal hair (scalp, eyebrow, lashes, axilla, pubis)
what is hair made up of
keratinised cells
outline the diagram
Characteristics of the hypodermis
Anchors the skin to the underlining structures (mostly muscle)
Consists of
adipose tissue
(adipo = fat)
Hair colour is determined by pigments produced (which melanin and colour associated 3)
Hair-raising experiences
Around hair follicles and associated oil glands are:
o Nervous (sensory) tissues
o Microscopic muscle tissue
Arrector pili muscle -controls each hair
o Causes “goose-bumps” – hair stands on end
o Contraction forces sebum out of hair follicles lubricating the skin
