Hell aka bones Flashcards
Cells of perichondrium secrete matrix against external face of existing cartilage
Appositional growth
Cells of perichondrium secrete?
matrix against external face exsiting cartilage
Chondrocytes divide and secrete new matrix, expanding cartilage from within.
Interstitial growth
What is the skeletal cartilage surround by?
Perichondrium, Dense Irregular CT, Blood vessels
What are the three types of cartilage?
Hyaline, elastic, fibrocartilage
Which type of cartilage: Collagen fibers only, looks smooth and glossy?
Hyaline
Axial skeleton contains…?
skull, vertebral column and rib cage
Axial skeleton purpose?
protection, support
Appendicular skeleton contains..?
limbs and girdle
Appendicular skeleton purpose?
movement
4 types of bone?
long, short, flat, irregular
longer than wide
limb, wrist and ankle
long bones
cube shape- wrist and ankle
sesamoid bones
short bones
thin, flat and slightly curved- sternum, ribs, skull
flat bones
complicated shapes- vertebrae
irregular
Secreted by parafollicular cells of thyroid; inhibits osteoclasts (at pharmacological/high doses in humans)
calcitonin
secreted by parathyroid; stimulates osteoclasts (when Ca2+ is low)
Parathyroid hormone
: Secreted by osteoblasts (and high conc. is therefore a surrogate marker to indicate bone deposition/growth
Osteocalin
stimulates pancreatic beta cells to secrete insulin, and stimulates adipocytes to secrete adiponectin, which augments insulin sensitivity of cells.
Osteocalin
are bones organs?
yessssss
Bone textures; dense outer layer, smooth and solid
compact
Bone textures: aka cancellous or trabecular, sparse inner layer
spongy
outer or inner
periosteum
outer
outer or inner
endosteum
inner
What covers articular surfaces?
hyaline cartilage
Osteogenic layer contains?
osteogenic cells
Yellow marrow is
triglyceride (fat) storage
Red marrow is
Hematopoiesis
Where is red marrow found?
within the trabecular cavities of spongy bone and diploe of flat bones and irregular bones
Can yellow marrow change to red?
if necessary yas
Three types of bone growth?
Appositional, interstial and Calcification
5 types of bone cells
osteogenic, osteoblasts, osteocytes, bone lining cells and osteo clasts
Osteogenic cells can become?
osteoblast and bone lining cell and self renew
which cell is a bone stem cell?
osteogenic
Which cell secretes ECM
osteoblast
Does proteoglycans attract or detract water
attract
Osteoblast can become
bone lining cell and osteocyte
which cell helps maintain ECM
bone lining cell
which cell is trapped in lacuna
osteocyte
which cell breaks down ecm
ostoclast
unit of compact bone
osteon
What is hydroxyapatites
mineral salts
What are the two types of ossification?
endochondral and intramembranous
Which ossification forms within hyaline cartilage?
Endochocdral
Which ossification forms within fibrous membrane?
Intramembranous
Endochodral is done in which type of bones?
Long bones and most of skeleton
Intramembranous is done in which type of bones?
flat bones
postnatal bone growth how does appositional bone grow?
it increases in bone thickness
postnatal bone growth how does interstitial bone grow?
it increases in length of long bones
What are the 5 cartilage growth zones
resting, proliferation, hpertophic, calcification and ossification
What is the epiphyseal plate replaced by?
bone
which cell will beneath periosteum secrete bone matrix on external bone
osteoblasts
which cell will remove bone on endosteal surface
osteoclasts
which hormone is Most important in stimulating epiphyseal plate activity in infancy and childhood.
Growth hormone
Which hormone modulates activity of growth hormone and ensures proper proportions?
Thyroid Hormone
Which hormone promotes adolescent growth spurts and end growth by epiphyseal plate closure
Testosterone and estrogen
How often is spongy bone replaced?
3-4 years
How often is compact bone replaced?
ten years
Bone remolding has two processes
deposit and resorption
bone remolding happens in what two location
periosteum and endosteum
What secretes lysomal enzymes and protons?
osteoclasts
Acidity converts what to soluble forms?
calcium
Transcytosis does what
Releases into the interstitial fluid which then goes to the blood
Once bone resorption is complete what has happened
osteoclasts become apoptosis
What degrades bone matrix and releases Ca2+ into the blood?
osteoclasts
Hypocalcemia is
low Ca2+
what does hypocalcemia lead to?
hyperexcitability which leads to seizures
Hypercalcemia is
High Ca2+
Hypercalcemia does what
deposits calcium salts in blood vessels and organs
What is wolfs law
bone features reflect stresses (weight, muscle pull)
What are the three fracture classifications
position of bone ends, completeness and skin penetration
Fracture classification; nondisplaced
ends retain normal position
Fracture classification; displaced
ends out of normal alignment
Fracture classification; open or compound
penetrated
Fracture classification; closed or simple
not penetrated
What is rickets?
bowed legs, bent bones in children epiphyseal plate doesn’t ossify
Rickets in adults?
osteomalacia
Cause of rickets and osteomalacia?
hypocalcemia or insufficient Ca intake or absorption
What is Pagats disease
Excessive and haphazard bone deposit and resorption
