Ch. 6 Cartilage & Bone Flashcards Preview

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Flashcards in Ch. 6 Cartilage & Bone Deck (31)
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Why are the bones of the skeleton considered organs?

They contain several tissues


What are the functions of the skeletal system?

Support, protection, movement, hemopoiesis (blood cell production), energy & mineral reserves


Know the difference between cartilage and bone tissue, including: cell types, relative strength/flexibility, density of matrix, vascularization.

--avascular (no blood supply),
--cell type: chondrocytes (in lacunae)
--strength/matrix: elastic cartilage is very flexible, fibrocartilage has thick dense collagen fibers and resists strong compression (shock absorber)

Bone tissue:
--well vascularized
--cell types: osteocytes, osteoblasts, osteoclasts
--strength: very strong, resists compression and tension
--matrix: organic fibers and inorganic fibers
-->inorganic: 65% mineral salts (calcium phosphate)
-->organic: fibers (lots collagen), ground substance


What is the difference between an osteoblast and an osteoclast? What's an osteocyte?

Osteoblast: builds new bone
Osteoclast: break down bone
Osteocyte: mature bone cells


What are the 3 types of cartilage and how do they differ? Be able to identify the cartilage type if given an example (e.g.: external ear, nose, pubic symphysis) and also be able to tell where each type is found.

3 types:
hyaline, elastic, fibrocartilage

--most common type
--has tiny, nearly invisible, collagen fibers called fibrils
--found: ends of long bones, respiratory structures, fetal skeleton

--similar to hyaline but lots of elastic fibers
--very resilient and flexible, tolerates repeated bending
--found: in pinna (outer ear) and epiglottis

--has little ground substance and the matrix has thick, dense collagen fibers
--resists strong compression (shock absorber)
--found: in intervertebral disks, knee joint, pubic symphysis


Which type of cartilage is the most common?

Hyaline cartilage


What are the two types of cartilage growth? Which is important for an increase in girth (size)? Which is important for length increase?

Types: appositional growth and interstitial growth

Girth size: appositional growth

Length increase: interstitial growth


What is Appositional Growth?

Chondroblasts in perichondrium make new cartilage tissue by secreting new matrix on the perichondrium.

On the outside. This widens the cartilage.


What is Interstitial Growth?

Chondrocytes within existing cartilage divide and secrete new matrix to lengthen the skeleton. Continues until skeletal maturity.


Which as more cartilage, an adult or a juvenile?



What is osteogenesis?

The process of bone formation


Explain the process of endochondral ossification. Include the following terms: diaphysis, epiphysis, primary center of ossification, secondary center of ossification, epiphyseal plate, periosteal bud.

Most of bones of skeleton form this way.

Skeleton begins as hyaline cartilage. From primary center of ossification in diaphysis, bone cells begin to replace cartilage cells. Secondary centers of ossification form in epiphysis. Skeleton continues to grow via division of cartilage (and bone) cells until maturity. When centers of ossification meet (at epiphyseal plate), growth stops.

Periosteal Bud: a vascular connective tissue bud from the perichondrium that enters the cartilage of a developing long bone and contributes to the formation of a center for ossification.


What happens when the epiphyseal plates have closed?

Growth stops


What are the cells involved in producing new bone tissue?



Be able to draw and label a long bone with the following structures: diaphysis, epiphyses, spongy bone, compact bone, epiphyseal line, periosteum, medullary cavity.

Um...go see the textbook and/or your notes!


What is the periosteum? Where is it located? How is this different from endosteum?

Periosteum: outer membrane on bone, well supplied w/ nerves and blood vessels, attached to underlying bone via collagen fibers, and provides a place for tendons and ligaments to attach to bone.

Periosteum location: most external surface of bones (ex: long bones). Helps things stick.

Endosteum: Layer of cells lining the inner surface of bone in the medullary cavity.


Differentiate between compact and spongy bone. What part of a bone has compact bone? What part has spongy bone?

Compact bone (cortical bone): smooth, dense, outsides of bones strong, rigid.

Spongy bone (trabecular bone): inside bones, better at shock absorption.


Be able to label a cross section of compact bone, including Haversian canal, osteon, lamellae, canaliculi.

So...go study the textbook and/or your notes.


What is an osteon? What are the concentric tubes that make up an osteon?

Osteon: structural unit of compact bone; also called a Haversian system.

Concentric tubes: concentric lamellae
-->rings of bone CT that surround the central canal and form the bulk of the osteon.


What is a Haversian canal? What is the function/job of the Haversian canal?

It's the central canal; cylindrical channel that lies in the center of the osteon. Traveling within the central canal are the blood vessels and nerves that supply the bone.


What are the perforating canals (Volkmann's canals)? What is their job/function?

Resemble central canals in that they also contain blood vessels and nerves. However, perforating canals run perpendicular to the central canals and help connect multiple central canals, thus creating a vascular and innovation connection among multiple osteons.


What are canaliculi? How are these different from perforating canals? What is their job/function?

Tiny, interconnecting channels within the bone CT that extend from each lacuna, travel through the lamellae, and connect to other lacunae and the central canal.

House osteocyte cytoplasmic projecting that permit intercellular contact and communication. Nutrients, minerals, gases, and wastes can travel through these passageways between the central canal and the osteocytes.


Consider the process of bone remodeling. How would bone respond to long-term, weight bearing exercise? How might bone respond to long term confinement/lack of use? To minimize risk of osteoporosis, should an individual sit quietly or exercise regularly?

Mechanical stress, in the form of exercise, is required for normal bone remodeling. In response, bone has the ability to increase strength over time. Weight-bearing activities, such as weight lifting or walking, help build and retain bone mass.

In contrast, lack of mechanical stress weakens bone through both demineralization of the bone matrix and reduction of collagen formation.

Exercising regularly will help minimize the risk of osteoporosis.


What property or properties of cartilage make osteoarthritis so painful and difficult to treat?

Can create bone spurs. Articular cartilage is thin and doesn't have good blood supply, heals poorly. Creates rubbing between 2 bones (ex: knee joint, bones rubbing back and forth).


What is a bony callus? What causes this?

Fibrocartilaginous callus is replaced by primary bone. The trabecular of the hard callus continue to grow and thicken for several months.

Cause: 3rd step of fracture repair


List the characteristics of irregular bones and provide examples.

Elaborate, complex shapes and do not fit into any of the categories.

ex: vertebra, ossa coxae (hip bones), ethmoid, sphenoid


List the characteristics of long bones and provide examples

Greater length than width. Elongated, cylindrical shaft (diaphysis). This is the most common bone shape.

ex: humerus, phalanges, femur, tibia, radius, ulna, fibula


List the characteristics of short bones and provide examples

They're as long as they are wide. External surface covered by compact bone, interior composed of spongy bone.

ex: talus and carpals


List the characteristics of flat bones and provide examples

Flat, thin surfaces. Roughly parallel surfaces of compact bone with layer of internally placed spongy bone. Provide extensive surfaces for muscle attachment and protect underlying tissues.

ex: sternum, roof of skull, scapulae, ribs, clavicles


What's intramembranous ossification?

Mesenchymal cells congregate in CT membrane.
Mesenchyme cells become osteoblasts and this region is an "ossification center" (osteoid).
Osteoblasts become osteocytes and new bone tissue is formed.
Embryonic blood vessels grow through the region, forming "woven" bone tissue (=trabeculae).
Forms flat bones