Biology of Skin Flashcards
Name the 3 main layers of skin
1) Epidermis
2) Dermis
3) Subcutis/hypodermis
What structure of cells make up the epidermis
keratinised stratified squamous epithelium, cornified
Name the layers of the epidermis in order of outer most surface first
1) Cornified layer
2) Granular layer (stratum granulosum)
3) Spinous layer (stratum spinosum)
4) Basal layer (stratum basale)
What is the function of the basal layer?
Contains stem cells of the epidermis.
What is the function of the spinous layer
thicker layer of the epidermis. desmosomes (tight junctions) between cells gives epithelia their properties of things like high electrical resistance
What two molecules does the granular layer contain and what is their function?
Keratohyalin granules (contain keratin) and lamellar bodies (contain lipids) which provide a hydrophobic barrier to water.
what is unique about cells in the cornified layer
cells undergo apoptosis to form the tough surface layer of the skin. shed in a process called desquamation
What is the name of the cell responsible for skin pigmentation and protection against UV damage?
Melanocytes
What are Langerhans cells
antigen presenting cells of the epidermis
What do merkel cells do?
in association with nerve fibres responsible for fine touch sensation
What are the two layers of the dermis called?
papillary dermis and reticular dermis
what type of fibres make up the papillary dermis?
collagen and elastin fibres - gives skin its flexibility
Which part of the dermis do you find fibroblasts and what do they secrete?
in the reticular dermis.
they secrete collagen
What part of the skin do you find various skin appendages such as hair follicles and glands?
Reticular dermis
What is the hypodermis predominantly made up of and what is its function
adipose tissue. functions as insulator, protector and E source
What is sweat comprised of?
water, sodium ions, chloride ions, urea and some low mol. wt. metabolites
by what type of secretion is sweat secreted?
Merocrine secretion
Where are apocrine glands found on the body?
axillae, mammary and groin regions
What do aprocrine glands secrete?
viscous, cloudy secretion which may contain pheromones and cause body odour upon reaction with skin bacteria
What do sebaceous glands secrete and what is the purpose of this substance?
Sebum, a lipid containing substance which coats hair keeping it soft, supple and waterproof
What method of secretion do sebaceous glands use?
Holocrine secretion - acinar cells become distended with increasing lipid contents and die, releasing their contents
Name the 5 physiological functions of skin
1) Thermoregulation
2) Sensation
3) Vitamin D synthesis
4) Immunological Role
5) Protection against UV radiation
Name the 5 phases of healing involved in deep wounds that extend into dermis
1) Haemostasis
2) Inflammation
3) Fibroplasia
4) Epithelialisation
5) Remodelling
What layers would you find fluid filled lesions such as blisters?
Within epidermis or at epidermis-dermis junction
Define scaling
shedding of cornified layer
Define callus
hyperplasia of epidermis following pressure or friction
define erosion
loss of superficial epidermis
define ulcer
loss of epidermis and papillary layer of dermis
define bruising
leakage of blood into dermis
