Unit 6: Chapter 47

Question 1

Axial Skelton

Answer 1

composed of the bones of the skull, thorax, and vertebral column, forms the axis of the body.

Question 2

Appendicular skeleton

Answer 2

consists of the bones of the upper and lower extremities, including the shoulder and hip.

Question 3

Cortical Mature Bones

Answer 3

compact) bone comprises 80% of the skeleton and forms the outer shell of a bone; it has a densely packed, calcified intercellular matrix that makes it more rigid than cancellous bone.
Major comment of tubular bones
Found along the lines of stress on long bones and forms an outer protective shell on bones
Receives blood from nutrient and perforation arteries.

Question 4

Cancellous Mature Bones

Answer 4

spongy) bone is found in the interior of bones and is composed of trabeculae and spicules, of bone that form a lattice-like pattern.
These lattice-like structures are lined with osteogenic cells and filled with red or yellow bone marrow. Relatively light, but its structure is such that it has considerable tensile strength and weight-bearing properties
Not penetrated by blood vessels

Question 5

Long BOnes

Answer 5

Found in the upper and lower extremities

Question 6

Short Bones

Answer 6

Are irregularly shaped bones located in the ankle and the wrist.
Surface is compact bone but spongy bone through.

Question 7

Flat Bones

Answer 7

Composed of a layer of cancellous bone between 2 layers of compact bone.
Found in areas such as the skull, rib cage where extensive protection of underlying structure is need.
Also found in the scapula where a broad surface for muslce attachment much be provided

Question 8

Irregular Bones

Answer 8

Due to their shape cannot be classified in any of hte previous groups
Includes vertebra and ethmoid bones

Question 9

Bone Marrow

Answer 9

Bone marrow occupies the medullary cavities of the long bones throughout the skeleton and the cavities of cancellous bone in the vertebrae, ribs, sternum, and flat bones of the pelvis.
The cellular composition of the bone marrow varies with age and skeletal location

Question 10

Red Bone Marrow

Answer 10

Contains developing RBC and is the site for blood cell formation.
Gradually replaced with yellow bone marrow.
In adult: persists in the vertebra, ribs, sternum, ilia

Question 11

Yellow Bone Marrow

Answer 11

Composed largely of adipose cells

Question 12

Bloody Supply

Answer 12

Distrubtion of blown in the cortex occurs from the Haversian and Volkmann canals

Question 13

Haversian Canals of Blood Supply

Answer 13

are spaces in the bone of the cortex that move parallel through the long axis of the bone for a short distance and then branch and communicate with other, similar canals.
Each canal carries one or two blood vessels, lymphatics, and some nerve fibers.

Question 14

Volknmann Canals of Blood Supply

Answer 14

which also contain blood vessels, are spaces in the cortex that run perpendicular to the long axis of the cortex to connect adjacent Haversian canals.

Question 15

Bone Tissue

Answer 15

connective tissue in which the intercellular matrix has been impregnated with inorganic calcium salts so that it has great tensile and compressive strength but is light enough to be moved by coordinated muscle contractions.

Question 16

Intercellular Matrix of BOne Tissue

Answer 16

is composed of two types of substances—organic matter, which includes bone cells, blood vessels, and nerves, and inorganic salts.
The organic matter consists of 88% type I collagen, 10% other proteins, and 1% to 2% lipids and glycosaminoglycans.
The inorganic matter consists of hydroxyapatite, an insoluble macrocrystalline structure of calcium phosphate salts, and small amounts of calcium carbonate and calcium fluoride.

Question 17

Protective Mechanism of Bone Tissue

Answer 17

May take up lead and other heavy material thereby removing these toxic substances from circulation.
(Ie) tetracycline abx being bound to calcium deposits in newly fomed nones and theta causing discoloration and deformity

Question 18

Lamellae Bones Vs Woven Bone

Answer 18

Both forms of bone can be mineralized or unmineralized, the latter being referred to as osteoid.

Question 19

Lamellar Bone

Answer 19

is a strong, mature form of bone that is formed slowly and is highly organized.
found in the adult skeleton.
is composed largely of cylindrical units called osteons or Haversian systems.
osteons consist of concentric lamellae of bone matrix, surrounding a central canal, called the Haversian canal, that contains the blood vessels and nerve supply for the osteon.

Question 20

Woven Bone

Answer 20

often referred to as bundle bone, is deposited more rapidly than is lamellar bone.
It is of low tensile strength, serving as temporary scaffolding for support. It is found in the developing fetus, in areas surrounding tumors and infections, and as part of a healing fracture

Question 21

Bone Cells

Answer 21

Four types of bone cells participate in the formation and maintenance of bone tissue:
osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts

Question 22

Osteoprogenitor Bone Cells

Answer 22

ndifferentiated cells that differentiate into osteoblasts. They are found in the periosteum, endosteum, and epiphyseal growth plate of growing bones.
Also participate in the continual replacement of worn out bones

Question 23

Osteoblasts

Answer 23

Bone-building cells that synthesize and secrete the organic matrix of bone.
participate in the calcification of the organic matrix.
2 stages: ossification and calcification
Secrete growth factors and tumor necrosis factor neede for bone growth regulation
Secrete: alkaline phosphatase. Levels increase with injury

Question 24

Osteocytes

Answer 24

Mature bone cells that function in the maintenance of bone matrix.
Death of these cells means reabsorption of the matrix.
play an active role in releasing calcium into the blood.
Surround by extracellular fluid called lacuna.
Canaliculi passageways (fluid filled) is how these cells connect to one another. Serve as communicating channels for exhange of nutrients and metabolites between the cells and blood vessels.

Question 25

Osteoclasts

Answer 25

sponsible for the resorption of bone matrix and the release of calcium by secreting an actin and phosphate from bone Largely phagocytic cells

Question 26

Hormone Influence of Osteoclasts

Answer 26

PTH increased the number and respective function of these cells. Calcitonin and Estrogen both reduce the number and fucntion of these cells. With menopause we see increased reapportion of bone due to lack of estrogen.

Question 27

Cartilage

Answer 27

Constitutes the articular cartilage of joints Found in the tendinitis and ligamentous insertions, menisci, symphysis pubis, and the insertion of joint capsules

Question 28

Cartilage: Fibrocartilage

Answer 28

has characteristics that are between dense connective tissue and hyaline cartilage. It is found in the intervertebral disks, areas where tendons are connected to bone, and the symphysis pubis. In pregnancy, the flexibility of the fibrocartilage allows the symphysis pubis to widen.

Question 29

Hormonal Control of Bone Formation and Metabolism

Answer 29

Complex It involves the interplay among the actions of PTH, calcitonin, and vitamin D. Other hormones, such as cortisol, growth hormone, thyroid hormone, and the sex hormones, also influence bone formation directly or indirectly

Question 30

PTH

Answer 30

Regulator of calcium (by releasing from bone) and phosphate levels in blood advantageous in fracture healing and prevention of further deterioration of osteoporosis if given as a supplement Increased intestinal absorption of calcium due to its activation of vit D by the kidney Stimulates tubular reabsorption of calcium while reducing reabsorption of phosphate

Question 31

Calcitonin

Answer 31

O thyrocalcitonin Lowers calcium levels. Secreted by parafollicular or C cells of the thyroid gland Inhibits the release of calcium from bone into extracellular fluid Reduces renal tubular reabsorption of calcium and phosphate Reduced osteoclastic active thus effective treatment of Piagets disease

Question 32

Vitamin D

Answer 32

Steriod hormone, fat soluble Stimulated by PTH and prolactin D2: ergocalciferol D3: cholecalciferol Differ by presence of double bond but identical biology activity No activity until it is converted to be activiedf and metabolized. Intestinal absorption (jejunum) and skin production Foods: fish, liver, and irradiated milk

Question 33

Ligaments

Answer 33

dense CT structures that connect muscles and bones. Has a limited blood supply and is composed largely of intercellular bundles of collagen fibers arranged in the same direction and plane fibrous thickenings of the articular capsule that join one bone to its articulating mate. They vary in size and shape depending on their specific role. considered inelastic, they are pliable enough to permit movement at the joints. tear rather than stretch when exposed to excess stress. Torn ligaments are extremely painful and accompanied by local swelling.

Question 34

Solid Joints

Answer 34

Or synarthroses Either fibrous or cartilaginous Fibrous: sutures (head), gomphoses (connect teeth to jaw), syndesmoes (IgM,ent connect 2 adjacent bones) Cartilaginous: Synchondroses-layer of cartilage separates two ossification centers in a developing bone such as the growth plate found in developing long bone. These are designed for bone growth and eventually ossify. Symphyses are joints in which 2 separate bones are connected by cartilage

Question 35

Synovial Joint

Answer 35

Or Diarthrodial Freely moveable The bony surfaces are covered with thin layers of articular cartilage, and the cartilaginous surfaces of these joints slide past each other during movement. Are the joints most frequently affected by rheumatic disorders.

Question 36

Synovial Fluid

Answer 36

Slippery fluid secreted by synovium Lubricants and facilitates movement Clear or pale yellow, does not clot and contains fewer than 100 cells/mm. Altered when inflammation is present