skin & mucous membranes Flashcards
what are the functions of skin?
protection thermoregulation water retention sensation absorption storage & synthesis
what are the skin layers?
epidermis
dermis
subcutaneous layer
what are the associated structures of skin?
nails
sweat glands
sebaceous glands
hair follicles
describe the epidermis
stratified squamous epithelium layers slate, scale-like cells no bv 4-5 layers
what are the layers of the epidermis?
stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale
what are the cells of the epidermis?
keratinocytes (95%) Langerhans cells -antigen presenting merkel cells -sensory receptors melanocytes -produce melanin
what is the difference between thick and thin skin?
presence of stratum lucidum (thick)
describe thick skin
stratum lucidum present
thicker stratum corneum
palms of hands
soles of feet
describe thin skin
no stratum lucidum
all strata thinner
rest of body
what is the dermis?
strong, flexible CT layer rich in collagen and elastic fibres
what does the dermis contain?
fibroblasts macrophages few adipocytes nerve endings bv SM lymphatics hair follicles
what are the 2 layers of the dermis?
papillary layer -epidermal ridges -capillarie & nerve rich reticular layer -dense CT fiber components
give some clinical correlations of skin
pemphigus
acne
psoriasis
vitiligo-loss of skin pigment
give 2 types of skin cancer
squamous cell carcinoma
basal cell cancinoma
how does skin cancer occur
keratinocytes in epidermis grow out of control to form a tumour
what are risk factors of malignant melanomas?
UV radiation, moles, fair skin with freckles, sunburn, family history
what are mucous membranes?
specialized epithelial lining which produces a lubricating fluid containing the sticky protein mucin which traps microbes and dirt particles and protects any body structure continuous with external environment
what are the basic layers of mucous membranes?
epithelium
lamina propria
what are the components of lamina propria?
cells: fibroblasts immune virtually lacking adipocytes ECM: collagen elastin fibres
epithelium + lamina propria=
mucosa
what is the composition of the trachea?
ciliated, pseudostratified epithelium and elastic, fiber-rich lamina propria
describe the histology of oral mucosa?
stratified squamous epithelium lamina propria types: lining-buccal mucosa, soft palate masticatory-hard palate gustatory-tongue
what are the functions of oral mucosa?
protection
sensation
secretion
permeability & absorption
what is cystic fibrosis?
inherited disorder of ion transport
abnormal viscous secretions
affects epithelial lining of respiratory, GIT, reproductive
salivary glands can be affected
