A&P Study Guide

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Chapter 6 Osseous Tissue and Bone Structure
1. classifications of bones by shape
(1) long bone
- long and thin
- arm and forearm, thigh (femur) and legs, palms, soles, fingers, toes

(2) flat bone
- thin with parallel surfaces
- skull, sternum, rib, scapulae

(3) sutural bone (Wormian bones)
- small, irregular bones
- between flat bones of the skull

(4) irregular bone
- complex shapes with short, flat, notched, or ridged surfaces - spinal vertebrae, the bones of the pelvis, and several skull bones

(5) short bone
- small , thick and boxy
- tarsal (ankle), carpal (wrist)

(6) sesamoid bone
- small, flat, and shaped somewhat like a sesame seed
- develop inside the tendons; most commonly located near joints at the knees, the hands, and the feet - everyone has sesamoid patellare/ kneecaps

2. bone markings
p172

3.
(1) osteogenesis (“make new bone”)
- bone formation

(2) ossification
- the process of replacing other tissues with bone
- 2 main forms: intramembranous and endochondral

(3) calcification
- the process of depositing calcium salts
- occurs during bone ossification and in other tissues

4. long bone
p173
(1) structure
Diaphysis
- the shaft
- heavy wall: compact bone/ dense bone
- central space: medullary(marrow) cavity

Epiphysis
- wide part at each end
- articulation with other bones
- mostly spongy bone/ cancellous/ trabecular bone
- covered with compact bone (cortex)

Metaphysis
- where the diaphysis and epiphysis meet (where the bone increase their length)

(2) compact bone p176
- osteon (Haversian system) is the basic unit
* osteocytes are arranged in concentric lamellae
* around a central canal (Haversian canal)
generally run parallel to the surface of the bone
contain blood vessels (normally a capillary and a venule)

- circumferential lamellae
* lamellae wrapped around the long bone (outer and inner), where they are covered by periosteum and endosteum ??? * bind osteons together
* produced during the growth of the bone

- interstitial lamellae
* fill in spaces between osteons in compact bone
* remnants of osteons whose matrix components have been almost recycled by osteoclasts

- canaliculi
* form pathways for blood vessels
* exchange nutrients and wastes
* radiate through the lamellae interconnect the lacunae of osteons with one another and with the central canal

- perforating canals (volkmann’s canal)
* perpendicular to the central canal

* carry blood vessels into bone and marrow
blood vessels in canals supply blood to osteons deeper in the bone and to tissues of the medullary cavity * allow for blood exchange between individual osteons and the cardiovascular system

- centric lamellae
wrapped by collagen fibers which wind in “opposite” directions between adjacent lamellae

(3) spongy bone
- does not have osteons
- the matrix forms an open network of trabeculae
- trabeculae has no blood vessels
nutrients reach osteocytes by diffusion along canaliculi that open onto the surface of canaliculi

- the space between trabecullae is filled with red bone marrow * has blood vessels
* form red blood cells (spongy bones within epiphysis of long bone, e.g. femur, and the interior of the other large bones, e.g. sternum, ilium) * supply nutrients to osteocytes and remove wastes

- yellow bone marrow
* in some bones
* yellow because it stores fat (energy reserve)

- * framework of trabeculae supports and protects cells of the bone marrow * located where bones not heavily stressed or where stress arrive from many directions * much lighter than compact bones; reduce weight of skeleton and make it easier for muscles to move bones

(4) ossification
- endochondral ossification
* ossify bones that originate as hyaline cartilage
* interstitial growth: expansion of cartilage matrix
appositional growth: production of new cartilage at outer surface appositional growth
* 6 main steps
I. i. chondrocytes near the...
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