Histology - 514-3 Flashcards
Does the periosteum extend to the articular surfaces in a long bone?
No. Articular surfaces are free of periosteum
What is the inner lining membrane in a bone called?
Endosteum
Define:
Periosteum
Endosteum
Sharpey’s fibers
periosteum - dense irregular connective tissue contiguous with internal endosteum containing potentiating fibroblasts.
Sharpey’s are type I collagen that connect periosteum to the compact bone matrix
Is bone innervated
highly
bone cancer patients feel extreme pain
Where is dipole and what is its function?
Middle layer of spongy bone Collapsing layer (absorbs blows)
What are small, thin, isolated pieces of bone called?
Spicules
What kind of junctions exist at the end of pseudopods?
Gap
What four components flow through the central canal of an osteon?
Artery, Vein, Nerve, Lymphatic
What is the organic/inorganic make-up of bone matrix?
35% organic / 65% inorganic
What are the two structural components of the organic matter in bones?
Proteoglycans and Type I collagen
Name 3 non-structural, non collagenous proteins making up the organic material in bone?
Osteocalcin (mineralizes / regulated by Vita D3)
Osteopontin (remodeling)
Sialoprotein (binds osteoblasts to ECM via integrins)
Inorganic matter of bone is mostly…
Hydroxyapatite (85%)
Name 5 zones in the metaphysis
Zone of: Reserve Cartilage Cell Proliferation Cell Hypertrophy Calcification Bone Deposition
What is indicative of a hypertrophic chondrocyte?
Swelling
What’s another name for the metaphysis
Growth plate (epiphyseal plate)
What type of growth increases bone length?
Interstitial
What type of growth increases bone width?
Appositional
Why do girls grow faster?
Estrogen
Growth hormone causes…
bone elongation
thyroid hormone increases metabolic rate of…
osteoblasts
Calcitonin
deposits calcium
inhibits osteoclasts
PTH
stimulates osteoclast growth and increases blood Ca+ levels
Glucocorticoids are increased by…
stress
cause bone loss / impair growth
What gland secretes GH (growth hormone)
Anterior Pituitary
Why are multiple samples necessary to determine GH levels?
Pulsatile secretion
Hypersecretion of GH can lead to
giantism
Thickening of hand, foot, jaw, and brow bones throughout life is called…
Acromegaly (hormone disorder)
How many types of dwarfism are there?
Over 200
What type of dwarfism is characterized by normal sized head and short longbones?
Achondroplastic dwarfism
What is pituitary dwarfism characterized by?
Normal proportions
What is primordial dwarfism?
growth proportional but severely delayed
What are the four types of bone cells?
osteoprogenitor, osteoblasts, osteocytes, and osteoclasts
What type of collagen do osteoblasts secrete?
Type I
What cell secretes osteocalcin and what does it do?
Osteoblasts
Directs hydroxyapatite and forms mineralized matrix
What binds osteoblast to the matrix through itegrins?
Sialoprotein
What creates a low pH at the osteoclast ruffled border?
Hydrogen ions (HCl)
What are the two main components of bone and how do osteoclasts break them down?
Matrix - HCl
Collagan fibrils - acid phosphatase (released by lysosomes)
________ are stimulated by increased pressure and ________ are stimulated by decreased pressure.
OsteoClasts
OsteoBlasts
