integumentary system + epidermis Flashcards
how many organs are in the integumentary system? name the organ(s).
one. the skin
name four of the functions the skin has
- physical protection against the environment and microorganisms
- thermoregulation (temperature control)
- vitamin D production
- detection of stimuli (touch, temperature, etc)
how many layers of skin are there? what are they?
three: epidermis, dermis, hypodermis
what is the epidermis?
uppermost layer of the skin
what is the dermis?
the layer below the epidermis
what is the hypodermis?
a fat layer underneath both the epidermis and dermis
where is the dermal papilla located?
between the epidermis and dermis
name two things the cells in the dermal papilla does
regenerates hair follicles and is responsible for our finger prints
true or false: patterns for the dermal papilla on areas that DO NOT have hair give humans unique ridge patterns (ie. fingerprints)
true
how many layers of cells can the epidermis have?
4-5 layers of cells
how many layers do areas that contain THIN skin have? where is thin skin found?
4 layers; everywhere except the palms and soles
how many layers do areas that contain THICK skin have? where is thick skin found?
5 layers; only found on the palms and soles
what is the stratum corneum?
the most superficial layer of cells of the epidermis
the stratum corneum has 15-30 layers of _______. these layers are held super tightly by intercellular proteins called __________.
dead keratinocytes; desmosomes
what are two functions of the stratum corneum?
creates a water-resistant layer to prevent moisture loss and protects the living parts of the skin from physical, chemical, and UV damage
what is the stratum lucidum?
the layer under the stratum corneum
true or false: the stratum lucidum is only found in THIN skin
false; the stratum lucidum is only found in THICK skin
does the stratum lucidum have a denser or less dense layer of dead keratinocytes compared to the stratum corneum?
the stratum lucidum has a much more dense layer of dense keratinocytes
what is a primary function of the stratum lucidum?
it provides a much more protective layer for areas that are prone to more damage
where is the stratum granulosum located?
under the stratum lucidum
how many layers of keratinocytes does the stratum granulosum have? are they dead or alive?
about 3-5 layers of LIVING keratinocytes
the stratum granulosum’s keratinocytes are living, mature, and actively making _______?
keratin
what is keratin?
a protein fiber that helps to maintain skin’s elasticity, protects it, strengthens it, and regulates cell growth
true or false: the stratum granulosum’s cells are generally flat
if so, what do we call the flat shape?
true; squamous
what happens to the cells in the stratum granulosum when they die?
they get pushed into more superficial layers
where is the stratum spinosum?
under the stratum granulosum
how many layers of keratinocytes does the stratum spinosum consist of? are they dead, immature, mature, or stem cells?
8-10 layers; immature
what does it mean to be an immature keratinocyte?
immature keratinocytes are ones that recently differentiated from the deeper layers
where are langerhans cells located and what are they responsible for?
located in the stratum spinosum; responsible for the immune response in the skin, it destroys microorganisms and superficial cancer cells
what is the deepest layer of the skin in the epidermis? what is it located under?
stratum basale; under the stratum spinosum
what type of cells are found in the stratum basale? what do those cells do?
stem cells that differentiate into all the other layers of skin (merkel cells and melanocytes are also found here)
where are merkel cells located and what do they do?
located in the stratum basale; responsible for picking up touch stimuli
where are melanocytes located and what do they do?
located in the stratum basale; creates melanin to protect skin from UV rays
