Skeletal System Flashcards
What are five functions of the skeletal system?
support, protection, movement, storage (calcium, phosphate, adipose), blood cell production
________ connect bone to bone and _______ connect muscle to bone.
ligaments, tendons
Where are blood cells produced?
in the bone marrow
What are the four components of the skeletal system?
bone, cartilage, tendons, ligaments
What are the five types of bones?
long bones, flat bones, irregular bones, short bones, sesamoid bones
Ribs are considered to be what type of bone?
flat bones
What is an example of a sesamoid bone (a “suspended” bone)
patella
_____ bones are usually found in the limbs, while _____ bones are found in the extremities like the hands and feet
long, short
What are the three types of cartilage?
hyaline, fibrocartilage, elastic
Which type of cartilage is made mostly of large collagen fibers, and which is made mostly of fine collage arrayed fibers (is spongy)?
hyaline (large), fibrocartilage (fine)
What two fibers make up elastic cartilage?
collagen, elastin
Hyaline is associated with many ________ that help it trap water
glycoproteins
When do chondroblasts turn into chondrocytes?
once they make enough cartilage to surround themselves
What is found in the matrix of cartilage?
collagen fibers for strength, proteoglycans for resiliency
What is the perichondrium and where is it found?
double-layer connective tissue sheath that covers cartilage everywhere except at joints (articulations)
The _____ layer of the perichondrium contains chondroblasts and is more delicate, while the _____ layer of the perichondrium contains blood vessels and nerves.
inner and outer
What is articular cartilage and where is it found?
cartilage without perichondrium, covers bones at joints
What are the two kinds of growth cartilage undergoes and what is the characteristic growth pattern of each?
appositional growth, where new matrix/chondrocytes are added on the outer edge of the cartilage, and interstitial growth, where chondrocytes within the cartilage divide and add more matrix between cells
What are the organic components of bone and what are the inorganic components?
collagen, proteosomes (organic), hydroxyapatite, CaPO4 crystals (inorganic)
Osteoblasts (bone creating cells) have lots of _______ and an extensive _______ in order to create collagen.
ribosomes (ER), golgi apparatus
How do osteoblasts concentrate calcium and phosphate within cell vesicles until they are needed and can be released through exocytosis?
cells use active transport to move calcium and phosphate against their gradients into the cell
How do osteoblasts communicate with each other?
through gap junctions (connecting cell processes)
The formation of bone by osteoblasts is called…
ossification
What are bone lacunae?
spaces in the bone matrix occupied by the osteocyte cell body
What are bone canaliculi?
canals occupied by osteocyte cell processes
How do nutrients get from cell to cell in bone?
they diffuse through the small amount of liquid in lacunae and canaliculi and can travel through gap junctions
What is the role of osteoclasts?
bone resorption (breaking down)
What is the ruffled border of the osteoclast?
where the osteoclast cell membrane “suction cups” to the bone, where resorption taking place
What are osteoclast enzymes dependent on?
pH
Which bone cells are multinucleated?
osteoclasts
Which cells are osteoclasts derived from?
monocytes
What are perforating canals?
places where blood vessels from the periosteum penetrate the bone
What are the four “stages” of bone?
woven, lamellar, cancellous, compact
Which stage of bone is commonly found in infants and is characterized by many irregular collagen fibers going in all different directions?
woven bone
Which stage of bone often comes after woven, and is characterized by all collagen fibers going in the same direction?
lamellar
Which stage/type of bone contains many open spaces for vasculature and is also called spongy bone?
cancellous
Which stage/type of bone has bone arranged in concentric layers around a central blood source?
compact
Why can’t bone undergo interstitial growth like cartilage?
because the bone matrix is solid unlike cartilage matrix
What kind of growth does bone undergo?
appositional growth (cartilage added and then ossified)
Growth in bone length occurs at the ____________
epiphyseal plate
After the epiphyseal plate is ossified (between age 12-25), it becomes the ______________
epiphyseal line
Which type of cartilage does NOT ossify?
articular cartilage
What purpose does Vitamin D serve in bone growth? Vitamin C?
Vitamin D is needed for calcium to be absorbed from the intestines, and vitamin C is needed so osteoblasts can synthesize collagen
Where is growth hormone secreted from?
anterior pituitary gland
Bone remodeling converts ____ bone into _____ bone
woven, lamellar
Bone remodeling is caused by the migration of what?
basic multicellular units (groups of osteoclasts/osteoblasts)
Bone _____ grows faster than bone _____
length, width
