BIOL 207 Lecture Notes - Lecture 22: Haversian Canal, Bone, Hyaline Cartilage
Compact Bone (pgs 180 - 183)
• there are very few spaces in compact bone. mostly all solid material
• all compact bone is deposited over cancellous bone (cancellous bone will never be exposed to
the outside)
• provides the support, protection and strength of bone
• Osteon/haversian system (figure 6.7 pg 181)
• usually run along the axis, the length, of bone
• central canal OR haversian canal; an open structure that will allow for blood vessels to course
through.
• lamella/lammallae; the layers outside the central canal. lamella refers to a thin plate or
membrane or scale.
• lacunae; there are little depressions at the junction in the lamella called lacunae.
• osteocytes; residing within the lucane is osteocytes.
• canaliculi; the microscopic channels/canals that connect one lucane to another are known as
canaliculi, which refers to the very small canals.
• aals that rah off at right agles sere as the feeder of lood essels to the etral aal
of the osteo, are ko as olka’s anal. feed blood vessels into the central canal of the osteon.
there are blood vessels in this canal that give rise to smaller vessels that go into each canal of the
osteon. this ultimately feeds the osteons.
• Volka’s aal: these are the sall haels in compact bone that allow passage of blood
essels fro the periosteu ito the oe ad that suh aals olka’s a lie perpediular to ad
(b) communicate with the haversian/central canals of each osteon.
The formation and growth of bone (pg. 183, 185)
• osteogenesis is another name for formation and growth of bone. also another term is
ossification.
• ossification begins about 1 and a half months into the gestation period, some cartilaginous and
membrane structures are beginning to show the beginning stages of ossification. this continues well into
late teens.
• there are 2 strategies of ossification based on the structure that is being ossified; (A)
intramembranous and (B) endochondral
• (A) also referred to as membrane bone. cranial bones, facial bones, clavicle. these are the 3
structures that are not hyaline cartilage. they eventually become ossified and it is unable to tell the
difference. A small portion of ossification occurs in these structures. the cells within these CT
membranes themselves have ability to produce osteoblasts, which then start producing bone material
and replace the membranes with solid bones.
• (B) the rest of the skeleton is going to become ossified endochrondral. the cells have capacity to
give rise to osteoblasts. then the osteoblasts invade, and theres a disintegration of cartilage replaced by
bone.
figure 6.6 - volkmanns canal (textbook)
figure 6.4 - flat bone (outside compact bone w/ inside cancellous bone)
figure 6.5/6.14 - spongy bone - trabeculae
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Document Summary
Osteon/haversian system (figure 6. 7 pg 181) usually run along the axis, the length, of bone. Deposition - when calcium and phosphate are deposited onto the bone. depositing something, Bone maintenance and remodeling (pgs 187, 188) somewhere. promoted by osteoblasts promoted by osteoclasts back into regular circulation. Deposition from circulation, onto the bone, reabsorption back into the. Reabsorption - whenever this comes up, materials are going back into the circulation. situations where bone is being demineralized so ions making up bone structure are reabsorbed blood. osteoblasts promote deposition, osteoclasts promote reabsorption. Physiology of calcium transmission of impulses across nerve fibers proper release of neurotransmitters at the synaptic ending contraction of muscles the coagulation of blood. ***** parathormone and calcitonin regulate calcium levels in the blood. Gh is produ(cid:272)ed (cid:271)y the pituitary gla(cid:374)d. (cid:449)he(cid:374) gh rea(cid:272)hes liver, it stimulates the liver to produce a 2nd growth factor, and that is known as somatomedin. Thyroid hormone - produces 4 categories of thyroxin.
