Chapter 7 review pt 2 Flashcards
calcification is also known as
mineralization
mineralization is the
deposition of hydroxyapatite crystals
what precipitates from crystals in mineralization
calcium and phosphate
mineralization/calcification requires
vitamin D, vitamin C (for collagen formation), and calcium and phosphate
compact bone is composed of small cylindircal structures known as
osteons
osteon components (7)
central/haversian canal, concentric lamellae, osteocytes, canaliculi, perforating canals, interstitial lamellae, circumfererntial lamellae
central canal
Cylindrical channel at center of osteon and parallel to it
Blood vessels and nerves extend through channel
central canal
concentric lemallae are rings of connective tissue that surround
central canal
osteocytes found in small pockets called
lacunae
osteocytes maintain cell
matric
Canaliculi are
tiny interconnecting channels within bone CT
caniculi also allow for an exchange of
nutrients and minerals
what * House osteocyte projections that allow intercellular contact
caniculi
caniculi extend from
Extend from each lacuna, travel through lamellae and connect to
lacunae and central canal
Perforating (Volkmann) canals
these are Perpendicular to central canals
what do perforating canals do
Connect central canals within different osteons
Circumferential lamellae
runs the entire circumference of the bone
what 2 types of circumferential lamellae are there
internal and external
external Circumferential
runs along periosteum
internal Circumferential
runs along endosteum
Interstitial lamellae
Components of compact bone between osteons or partially
resorbed osteons
lamellae
extracellular matric that is highly calcified
structure of hyaline cartilage
chondroblasts, chondrocytes, perichodrium
chondrocytes occupy
lacunae
chondroblasts
produce cartilage matrix
chondrocytes are chondroblasts encased within the
matrix
chondrocytes maintain
matrix
perichondrium is made of
dense irregular connective tissue
what coveres hyaline cartilage and helps maintain shape
perichondrium
ossification/osteogenesis
formation and development of bone connective tissue
where does osteongenesis/ossification start____ and where does it end___
embryo, childhood/adolescense
in the 8-12 weeks of embryotic development what foprms
skeleton
where does skeleton form from
intramembraneous ossification/endochondrial ossification
intramembraneous ossifiation produces what bones
facial bones ,flat bones. mandible, clavicle
intramembraneous ossification has bone growth from
membrane
endochondral ossification starts with
hyaline cartilage model
what ossification produces the most bones of skeleton
endochondral ossification
endohondral ossification bones made examples
upper, and lower limbes, pelvis, vertebrate
epiphyseal plate made of
hyaline cartilage
blood calcium levels regulated by 2 hormones
calcitriol, calcitonin and parathyroud
regulating blood calcium levels is required for
muscle contraction, bood clotting, exocytosis
vitamin D conversion summary
we get inactive form of vitamin d from sun, calcitriol turns vitamin d into active form,
Vitamin D conversion in debt
UV Light Activation: UV light converts 7-dehydrocholesterol to vitamin D3 (cholecalciferol),
released into the bloodstream.
Dietary Absorption: Vitamin D3 is also absorbed from the diet in the small intestine.
Liver Conversion: Vitamin D3 is converted to calcidiol by liver enzymes, occurring continuously.
Kidney Conversion: Calcidiol is converted to calcitriol by kidney enzymes, with PTH increasing this rate.
Calcium Absorption: Calcitriol stimulates calcium absorption from the small intestine into the blood.
parathyroid hormone (PTH) is secreted by
parathyroid glands
parathyroid glands release PTh as a result of
reduced blood calcium levels
parathyroid hormone and calcitrol interact with major organs such as
bone, kidneys, and small inteestines
calcitonin inhibits
osteoclast activity
calcitonin also aids in
regulating blood calcium
calcitonic is released from
thyroid gland
parathyroid hormone helps ______bone and calcitonic ________ of bone
breakdown, stop breakdown
osteopenia is the
precursor of osteoporosis
osteoporosis
deminirilzation of body. osteoclast is hight. osteoblasts is low
osteopenia occurs in ages of
35-40
