[PT11] Organ Systems

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