what is the integumentary system made up of
skin and accessory structures
what are the accessory structures that make up part of the system
hair, nails, muscles, glands and nerves
what are the two tissues that make up the organ
epidermis + dermis = skin
what happens when you add the accessory structures to the already formed organ
it becomes a system- the integumentary system
what kind of tissue is the epidermis made up of
epithelium, epithelial tissue
what kind of tissue is the dermis made up of
connective tissue- loose and dense irregular
what are the accessory structures specific to skin
Accessory structures of skin
Hairs (E)
Arrector pili muscles (M)
Sebaceous glands (E)
Sweat glands (E)
Sensory receptors (N)
Blood vessels (E-CT-M-N)
what type of epithelial tissue is the epidermis classified/ made up of
*Stratified squamous keratinised epithelium
what two layers is the dermis made up of
- the papillary layer
- the reticular layer
what type of tissue is the papillary layer made up of and what does this mean
Loose connective tissue MEANING fibres not bundles of collagen and elastin
what type of tissue is the reticular layer made up of and what does this mean
Dense irregular connective tissue MEANING bundles of fibres- collagen and elastin
what type of tissue is the dermis as a whole made up of
connective tissue
what is the third layer of the epidermis that is not actual considered a layer
Hypodermis (Subcutaneous tissue/
Subcutis)
what is the hypodermis or subcutaneous made up of
white adipose tissue and connective tissue
what accessory structure can sometimes be seen in the hypodermis and does this have an advantage if burnt?
hair follicles may protrude into the hypodermis- beneficial as may contain epithelial stem cells, therefore if seriously burnt may have a chance to rebuild skin.
structure of the dermis
divided into two layers
papillary (loose connective tissue)
- directly below the epidermis
- peg like structures form upward toward the epidermis called dermal papillae
reticular (dense irregular connective tissue
- between the papillary layer and the subcutaneous
- the largest layer of the dermis, thus considered the true dermis
function of the dermis
To provide support to the epidermis
- strength
- flexibility to skin (due to collagen and elastic fibres and bundles)
- supply nutrients and remove waste (dermal papillae)
structure of the epidermis
Stratified (layers) squamous (flat, wider than tall) keratinised epithelial tissue
- makes the top layer of skin
- consists of 4 or 5 layers depending on the thickness of the skin
- forms pegs protruding toward the dermis
what are the four layers of the epidermis from base to surface and what type of skin are they found in?
- stratum basale
- stratum spinosum
- stratum granulosum
- stratum corneum
FOUND IN THIN SKIN
what are the five layers of the epidermis from base to surface and what type of skin are they found in and what is the purpose of the other layer?
- stratum basale
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
FOUND IN THICK SKIN
- the stratum lucidum makes the layer of dead cells much thicker which is important in areas of high friction
where is thick skin commonly found and why
palms and soles of feet because these are areas of high friction, need to be thick to prevent abrasion
what are keratinocytes?
the cells of the skin- epithelial cells!!
where are keratinocytes formed and what happens to them after this formation?
- they divide via mitosis in the stratum basale (deepest layer of the epidermis) and travel upward through the layers toward the corneum
- they go through a process of keratinisation
- they accumulate intermediate filaments and keratohyalin granules as they travel upward which at cell death come together to form keratin
- they also accumulate lamella granules which form a waterproofing layer
what is the process of keratinisation and where does it occur?
it occurs in the skin
it is the whole process
- production of keratin
- cell death
- filling of keratin
- organelle death
