skin
the first line of defense for the immune system. It waterproofs the body and is the major receptor for the sense of touch
cutane/o, dermat/o, derm/o
related combining forms of skin
sebaceous glands
secretes sebum (oil) to lubricate the skin and discourage the growth of bacteria on the skin
seb/o
related combining forms of SEBACEOUS GLANDS
sweat glands
secret sweat to regulate body temperature and water content, and these glands excrete some metabolic waste
hid/ro
related combining forms of SWEAT GLANDS
hair
aids in controlling the loss of body heat
pil/i. pil/o
related combining forms of hair
nails
protect the dorsal surface of the last bone of each finger and toe
onych/o, ungu/o
related combining forms of nails
skin
largest organ in the body in surface area and weight
2 square meters
coverage of the skin
4.5-5kg (16% of total body weight)
weight of the skin
0.5mm to 4mm
thickness of the skin
hirsut/o
word parts of hairy/rough
kerat/o
word parts of horny, hard
lip/o
word parts of fat, lipid
melan/o
word parts of black, dark
myc/o
word parts of fungus
onych/o
word parts of fingernail or toenail
py/o
pus
rhytid/o
wrinkle
seb/o
sebum
urtic/o
rash or hives
xer/o
dry
epidermis
the outermost layer of the skin made up of several specialized epithelial tissues
dependent on lower layers for nourishment
keratin
a fibrous, water-repellent protein
soft keratin
a primary component of the epidermis
hard keratin
found in the hair and nails
melanocytes
special cells that are also found in the basal cell layer, they produce and contain a dark brown pigment known as melanin
melanin
is the pigment that determines the color of the skin, which depends upon the type and amount of this pigment that is present
melanin
produces spots of color such as freckles and age spots; has the important function of protecting the skin from harmful ultraviolet rays
dermis
the thick layer of living tissue directly below the epidermis
corium
what is the dermis also known as?
connective tissue blood lymph vessels nerve fibers hair follicles sebaceous glands sweat glands sensory nerve endings
what does the dermis contain?
decubitus ulcer (bedsore)
injuries to skin and underlying tissue resulting from prolonged pressure on the skin
areas with little fat and muscle over bony prominences are common sites
subcutaneous layer
layer located below the dermis that contains loose connective tissues, adipose tissues, and major blood vessels that supply the skin
melanin
pigments responsible for pale yellow to tan and black colors
carotene
pigment with melanin that makes skin appear translucent
hemoglobin
pigment that's responsible for pink to red color
due to the amount of melanin produced by melanocytes; number of melanocytes remains the same in all people
distribution and size of pigment granules
why are there differences in skin color?
freckles
accumulation of melanin in patches
liver (age) spots
flat skin patches from light brown to black
albinism
inherited inability of a person to produce melanin in hair, eyes, and skin
environment (sunlight)
amount of oxygen -physiological factors
biochemical factors (newborn-jaundice)
factors that influence skin color
poor blood oxygenation
oxygen-depleted hemoglobin (deep, purplish blue)
what can bluish cyanotic skin and/or nail beds indicate?
build up of bilirubin in the blood
liver disease
what can yellow to the skin and whites of the eyes indicate?
capillary engorgement with blood in the dermis due to skin injury, heat exposure, infection, inflammation, or allergic reaction
what can skin redness indicate?
hair
nails
sweat glands
accessory structures of the skin
palms
palmar surfaces of the digits
soles
lips
nipples
parts of the external genitalia
hair is not present in these surfaces
arrector pili muscle
smooth muscle that connects each hair follicle to the papillary layer of the dermis
arrector pili muscle
contracts pulling the slanted hair to upright and dimpling the skin surface with "goosebumps"
arrector pili muscle
exerts pressure to sebaceous glands resulting to release of sebum
thermoregulation
protection
cutaneous sensation
excretion and absorption
vitamin D synthesis
functions of the skin
liberating sweat at skin surface
adjusting blood flow in the dermis
two methods of thermoregulation in the skin
keratinocytes
resist invasion from microbes
oily sebum
protects skin and hairs from drying and kills surface bacteria
melanin
protects skin from UVR damaging effects
touch
pressure
vibration
tickling
thermal
tactile sensations
400mL
how much water evaporates from humans daily?
calcitriol (most active form of vitamin D)
produced when UVR activates the vitamin D precursor molecule
calcitriol
helps absorption of calcium in foods from the GIT into the blood
bones
act as the framework for the body, protect the internal organs, and store the mineral calcium
oss/o, oss/i, oste/o, ost/o
related combining forms of bones
red bone marrow
located within the spongy bone, is a hemopoietic tissue that manufactures red blood cells, hemoglobin, white blood cells, and thrombocytes
yellow bone barrow
functions as a fat storage area composed chiefly of fat cells and is located in the medullary cavity of long bones
myel/o (also means spinal cord)
related combining forms of bone marrow
cartilage
creates a smooth surface for motion within the joints and protects the ends of the bones
chondr/o
related combining forms of cartilage
joints
work with muscles to make a variety of motions possible
arthr/o
related combining forms of joints
ligaments
connect one bone to another
ligament/o
related combining forms of ligament
synovial membrane
forms the lining of synovial joints and secretes synovial fluid
synovi/o, synov/o
related combining forms of synovial membrane/fluid
synovial fluid
lubricant that makes smooth joint movements possible
bursa
cushions areas subject to friction during movement
burs/o
related combining forms of bursa
bones
where is calcium stored?
spongy bone
where is red bone marrow located?
joints work in conjunction with muscles, ligaments, and tendons, making possible the wide variety of body movements
what do joints work in conjunction with?
ankyl/o
word part meaning crooked, bent, stiff
-desis
word part meaning bind, tie together
kyph/o
word part meaning bent, hump
spondyl/o
word part meaning vertebrae, vertebral column, backbone
-um
word part meaning singular noun ending
lord/o
word part meaning curve, swayback, bent
-lysis
word part meaning loosening or setting free
myel/o
word part meaning spinal cord or bone marrow
hemopoietic
pertaining to the formation of blood cells can also be spelled as hematopoietic
cartilage
smooth, rubbery, blue-white connective tissue that acts as a shock absorber between bones
cartilage
more elastic than bone which also makes up the flexible parts of the skeleton (e.g. outer ear, tip of nose)
articular cartilage
covers the surfaces of bones where they come together to form joints
meniscus
curved fibrous cartilage found in some joints such as the knee and temporomandibular joint of the jaw
axial skeleton
consists of the 80 bones of the head and body that are organized into the skull, middle ear, hyoid bone, thyroid, rib cage, and vertebral column
appendicular skeleton
consists of 126 bones that are organized into upper and lower extremities
types of bones
epiphyses
located at each end of the bone and are covered with articular cartilage and articulate with other bones
diaphysis
known as the shaft of the bone
tissues of the bone