Full transcript
0:02structure of bone
0:04objective to learn the basic structure
0:08of bone
0:12as part of the skeleton of vertebrates
0:15bones offer support and protection to
0:18various organs of the body
0:21in addition they have the ability to
0:23produce blood cells
0:25and store minerals
0:28a bone has an elongated hollow central
0:31body
0:32referred to as diaphysis
0:36and two terminal parts known as
0:38epiphysis
0:42all bones are surrounded by a tough
0:44layer of connective tissue
0:47known as periosteum it is through this
0:50tissue that blood vessels pass
0:53carrying oxygen and nutrients to the
0:55bone
0:57inside this periosteum is a thick layer
1:00of cortical bone
1:02commonly referred to as compact bone
1:06this outer shell of the bone is dense
1:09strong and resistant to bending
1:13because of these characteristics it
1:16makes up about eighty percent of the
1:18skeleton
1:20this dense layer is filled with organic
1:23ground
1:23substance and inorganic salts
1:27in between these substances are very
1:29tiny spaces
1:31that contain the bone cells known as
1:33osteocytes
1:36as compact bone matures it develops a
1:39network of interconnecting
1:40vascular canals referred to
1:43as aversion canals which contain blood
1:47vessels
1:48that supply nutrients to osteocytes
1:52the compact bone will surround the
1:54haversian canals
1:55in layers known as osteons
1:59inside the compact bone is the
2:01cancellous bone
2:03commonly referred to as spongy bone or
2:07tribecular bone this layer is filled
2:10with numerous
2:11large spaces giving it a spongy or
2:14honeycomb-like appearance
2:17the porous nature of the spongy bone
2:19does not add mass to the overall
2:22structure but still provides greater
2:25strength
2:25and rigidity
2:31inside the bones can be found a soft
2:33spongy tissue
2:34known as bone marrow there are two types
2:38of bone marrow
2:39red and yellow red marrow
2:43which consists largely of hematopoietic
2:46tissue
2:48is responsible for the production of red
2:51and white blood cells
2:53as well as platelets yellow marrow
2:56consists largely of
2:58fat cells and produces some
3:01white blood cells
3:05summary bone is an organ
3:08composed of dense connective tissue
3:12bones are covered by periosteum while
3:15its two main layers are
3:17compact bone and spongy bone
3:21the hollow portion of the long bones is
3:23filled with marrow
3:25red marrow produces blood cells yellow
3:29marrow produces
3:30some white cells