Exercise 6 : Bone Tissue

In the mature bone, the region where the diaphysis joins the epiphysis is

metaphysis

Bone building cells that synthesize and secrete collagen fibers and other organic components needed to build the extracellular matrix of bone tissue, and initiate calcification are

osteoblasts

Mature bone cells that are the main cells in the bone tissue and maintain it's daily metabolism, such as the exchange of nutrients and wastes with the blood are

osteocytes

Microscopic structural units of compact bone made up of a central (haversian) canal plus it's surrounding lamellae, lacunae, canaliculi, an osteocytes are:

osteon

Mature bone cells located within a lacuna are

oxteocyte

Bones that are shaped like a sesame seed; small bones that develop in tendons and are variable in number are: Example: paired patellae (kneecaps).

sesamoid

Bones that are somewhat cube-shaped, nearly equal in length and width are: Examples: wrist bones and ankle bones.

short

The epiphyseal plate is thin layer of cartilage covering the epiphysis?

False

Thin layer of hyaline cartilage covering the epiphysis where the bone forms an articulation (joint) with another bone is

Articular cartilage

Circular canal in the center of an osteon (haversian system) that runs longitudinally through the bone; the canal contains blood vessels, lymphatic vessels, and nerves is a

Central (haversian) caneal

Compact bone tissue is arranged in microscopic units called ------ or haversian systems.

Compact bone tissue is arranged in microscopic units called osteons or haversian systems.

The external structures of a long bone are

Diphysis, epiphysis, metaphysis, articular cartilage, periosteum, medullary, and endosteum.

Bone's shaft or body of a bone; the long cylindrical main portion of the bone is

Disphysis

A thin membrane that lines the medullary cavity, contains a single layer of bone forming cells, and a small amount of connective tissue is

Endosteum

Endochondral ossification refers to the formation of bone directly within mesenchyme arranged in a sheetlike layers that resemble membranes. Such bones form directly from mesenchyme without first going through a cartilage stage. The flat bones of the skull and mandible (lower jawbone) form by this process. Also, the fontanels ("soft spots") of the fetal skull are replaced by bone via intranmembranous ossification.

False

Despite it's hardness, bone is also flexible, a characteristic that enables it to resist various forces. The flexibility of bone depends upon it's collagen fibers. Collagen fibers compose about 50% of the bone matrix is water.

False. Explanation: Collagen fibers compose about 25% of the weight of bone. The remaining 25% of the bone matrix is water.

Intramembranous ossification refers to the formation of bone within hyaline cartilage. In this process, mesenchyme is transformed into chondroblasts which produce a hyaline cartilage matrix that is gradually replaced by bone. Most bones of the body form by this process.

False. The correct answer is endochondral ossification.

The cells is bone tissue include:

Osteogenic cells, osteoblasts, osteocytes, and osteoclasts.

Unsecialized stem cells that are derived from mesenchyme, the tissue from which almost all connective tissues are formed. They are the only bone cells to undergo cell divisions; the resulting cells develop into osteoblasts are called

Osteogenic cells. Differentiation potential of mesenchymal stem cells that can differentiate in a large variety of human tissues. Including adipocytes, chondrocytes, osteoblasts, mescle cells, neurons.

Canals that extend from the periosteum and contain blood vessels, lymphatic vessels, and nerves; they extend into the central (haversian) canals, medullary cavity, and periosteum are:

Perforating (volkmann's) canals

A tough sheath of dense irregular connective tissue that surrounds the bone surface wherever it is not covered by articular cartilage. It functions in bone growth, assists in fracture repair, protects the bone, helps nourish bone tissue, and serves as an attachment site for tendons and ligaments and is called

Perioteum

Consists of developing blood cells, adipocytes, fibroblasts, and macrophages:

Red bone marrow

What are the function of bone?

Support, protection, assistance in movement, mineral homeostasis, blood cell production, triglyceride storage.

The entire framework of bones and their cartilages together constitute the skeletal system.

True

While histology is the study of tissues, osteology is the study of bone structure and the treatment of bone disorders.

True

Yellow bone marrow consists of mostly adipose cells.

True

Bone consists of these tissues

bone or osseous tissue, cartilage, dense connective tissue, epithelium, adipose tissue, and nervous tissue.

Minute channels that radiate in all directions from the lacunae and interconnect with each other and the central canals; contain slender processes of osteocytes; canaliculi provide routes for nutrients and oxygen to reach osteocytes and for wastes to diffuse away.

canaliculi

Bone tissue that contains few spaces and forms the external layer of all bones of the body and the bulk of the diaphysis of long bones is

compact bone tissue

Rings of hard, calcified matrix are

concentric lamellae

A layer of hyaline cartilage in the metaphysis of growing bone that consists of four zones is the

epiphyseal plate

The distal or proximal ends of the bone are

epiphysis

The fractured ends of a bone can be reduced (aligned to their normal positions) by manipulation without surgery. This procedure is called open reduction.*

false

The osteoblasts are responsible for cartilage formation. Chondroblasts form bone tissue by intramembranous or endochondral ossification.

false

compact bone tissue contains red bone marrow.

false. Compact bone tissue provides protection and support and resists the stresses produced by weight and movement.

Bones that are generally thin and composed of two nearly parallel plates of compact bone tissue enclosing a layer of spongy bone tissue are: Example: sternum (breastbone), ribs, and scapulae (shoulder blades).

flat

The space within the diaphysis that contains fatty yellow bone marrow in adults is the marrow cavity or the

medullary

The hardness of bone results from the presence of inorganic mineral salts, mainly

hydroxyapatite

Bones that are very complex in shape; cannot be grouped into the long, short, or flat category are: Example: vertebrae, some facial bones, and calcaneus.

irregular

Small spaces between lamellae which contain osteocytes are

lacunae

Bones that have greater length than width, consist of a shaft and a variable number of extremeties (ends) are called: Examples: thigh (femur), leg (tibia and fibula), arm (humerus), forearm (radius and ulna), and finger and toe (phalanges).

long

Bone tissue which contains many large spaces, composes most of the bone tissue of short, flat, and irregular shaped bones and most of the epiphysis of long bones is

spongy bone tissue

An irregular latticework of thin columns of bone that are microscopic units of spongy bone tissue

trabeculae

A fracture is any break in a bone.

true

A fracture that must be exposed by surgery before the break can be rejoined is a procedure called open reduction.

true

Bone tissue, like other connective tissues, contains an abundant matrix of intercellular materials that surrounds widely separated cells. Unlike other connective tissues, the matrix of bone is very hard.

true

Depending on the size and distribution of spaces between it's hard components, the regions of a bone may be categorized as compact or spongy.

true

During childhood, bones thoroughout the body grow in thickness by appositional growth (deposition of matrix on the surface), and long bones lengthen by interstitial growth:(the addition of bone material on the diaphyseal plate). Growth in length of bones normally ceases by age 21, although bones may continue to thicken.

true

Sutural bones are small bones in sutures between certain cranial bones.

true

The epiphyseal cartilage cells stop dividing and bone replaces the cartilage. The newly formed bony structure is called epiphyseal line.

true

The first stage in the development of bone is the migration of the embryonic mesenchymal cells into the area where bone formation is about to begin. These cells increase in number and size and become osteogenic cells. In some skeletal structures where capillaries are lacking, they become chondroblasts; in others where capillaries are present, they become osteoblasts.

true

The surfaces of bones contain various structural features that have specific functions. These features are called bone surface markings.

true

The zone that is only a few cells thick and consists mostly of dead chondrocytes because the matrix around them has calcified is the

zone of calcified cartilage

The zone that consists of even larger chondrocytes that are also arranged in columns is the

zone of hypertrophic cartilage

The zone that consists of slightly larger chondrocytes arranged like stacks of coins are

zone of proliferating cartilage

The zone nearest the epiphysis that consists of small, scattered chondrocytes is the

zone of resting cartilage