what is an organ?
a group of tissues working together to perform functions
what is a tissue?
a group of cells working together to perform one or more functions
arrect
upright
cide
kill
corn
horn
ep
upon
lunul
crescent
melan
black
papill
a nipple
pil
a hair
seb
grease
strat
layer
tact
touch
therm
heat
skin
epidermis and dermis
epidermis
keratinized stratified squamous epithelium
most epidermal cells are called
keratinocytes
you get a totally new epidermis every
25 to 45 days
where are melanocytes found?
in the deepest epidermal layer
dermal papilla is made of …
areolar connective tissue
reticular layer is made of
dense irregular connective tissue
hypodermis also called superficial fascia is located deep to the dermis and is mostly made of
adipose connective tissue
dermis and hypodermis are avascular or vascular?
vascular
sweat glands are made of
simple cuboidal epithelium
eccrine sweat gland
secrete sweat
only areas of the integumentary system that do not have eccrine sweat glands are the …
nipples and external genitalia
apocrine sweat glands
larger than eccrine sweat glands, their ducts empty into hair follicles
- become active in puberty, secrete fatty substances and proteins
- found mainly in the axillary and anogenital regions
hair is composed of
dead keratinized cells
arrector pili muscle
band of smooth muscle tissue that extends from a hair follicle to the papillary layer of the dermis
-when contracted makes goose bumps
sebaceous glands are composed of what and are found where
epithelium and found near hair follicles
encapsulated sensory receptor
the dendritic endings are surrounded by a connective tissue capsule
-ex: lamellar and tactile corpuscle
tactile corpuscle (meissners corpuscle) found where
in the dermal papillae of hairless skin
lamellar corpuscles (or pacinian corpuscle) found where
deeper in the dermis and in the hypodermis
non-encapsulated sensory receptors
do not have connetive tissue capsules
free nerve ending
endings found both in epidermis and dermis (a nonencapsulated receptor)
hair follicle receptor
wrap around hair follicles
give two basic tissue types that compose tactile and lamellar corpuscles
nervous and connective
what is the function of soft keratin
toughens cells
true or false: soft keratin is a protein
true
true or false: when you look at someone the epidermal cells you see are dead
true
true or false: arrector pili muscles are composed of skeletalk muscle tissue
false: arrector pili muscles are composed of smooth muscle tissue
arrector pili muscle is composed of what
smooth muscle tissue
the epidermis and dermis compose the skin which is an eipithelial membrane called the ____
cutaneous membrane
is skin an organ
yes
eccrine sweat gland are endocrine or exocrine glands?
exocrine
which components of the skin are vascular?
dermis and hypodermis
the papillary layer is the superficial or deep dermal layer?
superficial (above the reticular layer)
epidermis
superficial layer of the skin
dermis
deep layer of the skin, has two layers
papillary layer of dermis
superficial layer of dermis
dermal papillae
nipple-like dermal projections that compose the papillary layer
reticular layer of the dermis
the deep layer of the dermis
hypodermis
deep to the dermis
hair follicle
surrounds the embedded part of a hair
hair bulb
expanded deep end of a hair follicle
hair
strand of keratinized cells
hair shaft
upper part of follicl and part that protrudes the skin
hair root
lower half of follicle
sebaceous gland
gound near hair follicles, secreats sebum
arrector pili muscle
extends from a hair follicle to the papillary layer of the dermis
blood vessels
found in the dermis and hypodermis
tactile corpuscle
sensory receptors found in the dermal papillae of hairless skin
lamellar corpuscle
sensory receptors found in the deeper dermis and the hypodermis
hair follicles are made of
epithelium
reticular layer of dermis is made of
dense irregular connective tissue
sebaceous gland is made of
epithelial tissue
eccrine sweat gland is made of
simple cuboidal epithelium
nail root
nonvisible part of the nail, embedded in the skin
nail body
the visible attached part of the nail
lunule
the white half moon part of the nail body
free edge of nail
the unattached part of the nail, it overhangs the tip of a finger or toe
hyonychium
the thickend epidermis beneath the free edge of the nail; commonly called the quick; dirt accumulates between the free edge of the nail and the hyponychium
nail bed
epidermis deep to the nail root and body
nail matrix
thickend proximal portion of the nail bed, nail growth occurs here
the fingernail is on the anterior or posterior surface of a finger?
posterior (think anatomical positioning)
the lunula is deep to, superficial to, or a part of the nail body?
a part of the nail body
melanin protects cells from what
UV radiation
the hypodermis protects what
underlying structures from physical trauma
nails protect what
the distal ends of the digits
scalp hair protects the head from what
physical trauma, heat loss, sunlight
what doe sthe thin fil of sebum covering the epidermis do
reduces water loss from the body and has a bacterial action
if body need to lose heat what does it do to blood vessels
dialates them causing more blood flow
if the body needs to conserve heat what does it do to the blood vessels?
constricts dermal blood vessels causing less blood flow through the dermis
tactile corpuscles detect
light touches to the skin
lamellar corpuscles detect
harder touches and pressure
free nerve endings respond to …
temperature and tissue damage (perceived as pain)
what does sebum do?
softens skin and hair
if the secretion of apocrine seat glands are odorless how does it end up smelling?
bacteria quickly metabolizes the secretion
four functions performed by the hypodermis
insulation, protection, binds skin to deeper structures, energy storage
