EXAM 1 Skeletal System Flashcards
membrane covering bone except at articular surfaces
periosteum
lines the inner spaces of spongy bone, medullary cavities, and aversion canals of compact bone
endosteum
____ bone is formed in layers
mature
diaphysis contains ____.
marrow
end of long bone is called
epiphysis
why are epiphysis broader?
to support weight and avoid bending
after puberty the growth plate is lost, what merges?
metaphysis and epiphysis.
osteocytes are derived from
osteoblasts
where are osteocytes located?
in the lacunae.
how are lucanae connected to each other?
canaliculi
growth in length of long bones occurs at the ___.
epiphyseal growth plate.
what Is calcitonin secreted by?
parafollicular (c cells) of the thyroid.
what makes up the skeletal system?
bones, cartilage, tendons, ligaments
connect muscle to bone
tendon
connect bone to bone
ligament
allows stretch with rapid return to normal
elastin
firm, flexible type of connective tissue
cartilage
does cartilage have blood vessels?
no
3 types of cartilage
elastin. hyaline, fibrocartilage
type of cartilage that forms articulating surfaces
hyaline
most abundant type of cartilage
hyaline
cartilage that forms intervertebral disks, tendon connection to bone, and symphysis pubis
fibrocartilage
cartilage is formed by ____.
chondrocyte
chondrocytes are found in the
lacunae
immature bone is called _____.
woven bone
lamellar bone is mature bone that is formed in ____.
layers
membrane covering bone except at articular surface
periosteum
lines the inner spaces of spongy bone, medullary cavities, and haversion canals of compact bone
endosteum
this is between diaphysis and epiphysis in growing bones
metaphysis
type of bone that is in interior of flat bones, epiphysis, and metaphysis
Cancellous (spongy) bone
type of bone that forms outer shell, has densely packed calcium matrix
COMPACT (CORTICAL) BONE
the cells become osteoblasts when stimulated
osteoprogenitor cells
undifferentiated stromal cells located in the periosteum, endosteum, and epiphyseal plate
osteoprogenitor cells
Where are osteoblasts found?
periosteum, endosteum,
epiphyseal plate
osteoblasts form _____ on which calcium apatite and other minerals are deposited
protein matrix
cells that enhance calcification of osteoid
osteoblasts
when do osteoblast number increase?
bone growth
where are osteocytes derived from
osteoblasts
when do osteoblasts turn into osteocytes
as they mature within bone
where are osteocytes located?
lacunae
what Contributes to bone remodeling by sensing bone stress-strain and communicating to osteoblasts and osteoclasts the need to build or remove bone
osteocytes
cells in charge of bone “remodeling”
osteocytes
bone removing cells
osteoclasts
what do osteoclasts dissolve when removing bone?
calcium hydroxyapatite
Lysosomal hydrolytic enzymes and matrix metalloproteases are secreted to degrade _____.
bone protein matrix
what enhances activity of osteoclasts?
Parathyroid hormone (PTH), Interleukin-6 (IL-6), and 1,25-dihydroxy vitamin D
what decreases activity of osteoclasts?
Calcitonin, estrogen, testosterone
where do osteoclasts come from?
red bone marrow
regulates cancer production in bone
Parathyroid hormone
when does bone growth predominate?
first 20-30 years
Starts as predominantly protein matrix (hyaline cartilage) which begins _____ from center out
calcifying
Growth in length of long bones occurs at the
______.
epiphyseal growth plate
what lengthens the diaphysis?
when Chondrocytes multiply and secrete cartilage into the metaphysis
Osteoblasts enhance _____ deposition
hydroxyapatite
when does growth in length stop?
when epiphyseal plate chondrocytes stop protein matrix production
Factors Affecting Bone Growth
Separation or injury to epiphyseal plate, Mechanical stress, Nutritional status, Hormones
what increases serum calcium when serum calcium is low
Parathyroid hormone (PTH)
how does calcitonin reduce blood calcium?
Inhibiting calcium absorption from the GI tract,
Inhibiting osteoclast activity,
Inhibiting kidney calcium and phosphate reabsorption
when is calcitonin released?
Released in response to elevated serum calcium or elevated gastrin
cells that secrete calcitonin
parafollicular (C cells) of the thyroid
how does vitamin d become active hormone?
Hydroxylation in liver to 25-OH,
Hydroxylated in kidney to 1,25-OH (active form), which increases GI absorption of Ca++ and promotes PTH actions
name of vitamin D3, most active
Cholecalciferol
name of vitamin d2, in vitamin pills
Ergocalciferal
Effects of Vitamin D include
Increasing calcium and phosphate absorption from GI tract,
Increase calcium and phosphate reabsorption from kidney,
Stimulate osteoclast activity,
Net effect to increase serum calcium and phosphate
people with liver and kidney disfunction will probably develop ____.
osteoporosis
Inner layer of joint capsule secretes this
synovial fluid
function of synovial fluid
lubricant
what are bursae?
Closed sacs containing synovial fluid
function of bursae?
Prevent friction between tendon / skin and tendon / bone
is bursae part of the joint?
no
