BB1701 integumentary system Flashcards
what is an organ?
multiple tissues with similar structures that work together to perform a specialised function
what is the largest organ in the integumentary system?
the skin (cutaneous membrane)
what are the two important layers of the skin?
epidermis
dermis
which tissues in the skin are most important?
epithelial
connective
what is the epidermis?
- outer layer of the skin
what is the epidermis composed of?
stratified squamous epithelium
what are the four layers of the epidermis?
stratum basale
stratum spinosum
stratum granulosum
stratum corneum
what are the characteristics of the stratum basale?
- the deepest layer
- contains a thin layer of dividing cells
- nourished by blood vessels of the dermis
what are the characteristics of the stratum corneum?
- the outermost/superficial layer
- consists of layers of dead, flattened, dehydrated, densely packed, keratinised cells
what causes epidermal cells to die?
blocked blood supply
where is the stratum lucidum located?
on the hairless and thickened skin
palms, soles
role of desmosomes in the epidermal layers/strata?
hold together keratinocytes
function of epidermis?
- protective
- shields moist underlying tissues against excess water loss, mechanical injury and harmful chemicals
- keep out pathogens
- epidermal cell production in the stratum basale balance loss and shedding of dead cells
- allow thickness to remain constant
what happens as new epidermal cells are produced?
keratinocytes are pushed from the dermis towards the skin surface
they die as nutrient supply is poorer
keratinisation
what is keratinization?
- process where epidermal cells harden
- cytoplasm fills with strands of tough, fibrous, waterproof keratin
layers of the keratinised cells gather and shed in the stratum corneum
what is the dermis?
inner layer of the skin
thicker than epidermis
function of dermis?
binds the epidermis to underlying tissues
dermal blood vessels supply nutrients to all skin cells
vessels regulate body temperature
what is the dermis composed of?
areolar connective tissue
connective tissue
what does the connective tissue include?
collagen fibres
elastic fibres with gel like ground substances
smooth muscle tissue
nervous tissue
blood
function of connective tissue?
bind epidermis to subcanteous layer
function of collagen?
strength
function of elastic fibres?
ability to stretch
function of blood?
bring oxygen and nutrients to cells
function of nerve tissue?
detection of changes