A/P CH. 6 - Bone Tissue

Question 1

Bone

Answer 1

an organ of several different tissues working together: bones (osseous) tissue, cartilage, dense connective tissue, epithelium, adipose tissue, and nervous tissue.

Question 2

6 functions of the skeletal system

Answer 2

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

Question 3

Hemopoiesis

Answer 3

process of red bone marrow producing red blood cells, white blood cells, and platelets.

Question 4

Yellow bone marrow

Answer 4

mainly adipose cells which store triglycerides.

Question 5

6 parts of a long bone

Answer 5

diaphysis, epiphyses, metaphysis, articular cartilage, periosteum, medullary cavity

Question 6

Diaphysis

Answer 6

bones shaft or body, long cylindrical portion.

Question 7

Epiphysis

Answer 7

proximal and distal ends of the bone

Question 8

Metaphysis

Answer 8

regions between diaphysis and epiphyses. In a growing bone each metaphysis contains an epiphyseal (growth) plate, a layer of hyaline cartilage that allows the diaphysis of the bone to grow in length. When a bone ceases to grow the cartilage is replaced by bone known as the epiphyseal line.

Question 9

Articular cartilage

Answer 9

thin layer of hyaline cartilage covering the joint.

Question 10

Periosteum

Answer 10

tough connective tissue sheath and associated blood supply that surrounds the bone surface wherever it is not covered by articular cartilage. Attached to bone by perforating fibers.

Question 11

Medullary cavity

Answer 11

hollow space within diaphysis that contains fatty yellow bone marrow and numerous blood vessels in adults.

Question 12

Calcification

Answer 12

calcium phosphate combines with calcium hydroxide to form crystals of hydroxyapatite. As the crystals form they combine with other mineral salts, such as calcium carbonate, and ions such as magnesium, fluoride, potassium, and sulfate. These minerals are deposited in the framework formed by the collagen fibers of the extracellular matrix, they crystallize and the tissue hardens.

Question 13

Osteoblasts

Answer 13

bone building cells that initiate calcification

Question 14

4 types of cells in bone tissue

Answer 14

osteoprogenitor cells, osteoblasts, osteocytes, osteoclasts

Question 15

Osteoprogenitor cells

Answer 15

unspecialized bone stem cells derived from mesenchyme, the tissue from which almost all connective tissue is formed. Only bone cell to undergo division, resulting cell is osteoblasts.

Question 16

Osteocytes

Answer 16

mature bone cells

Question 17

Osteoclasts

Answer 17

digest the protein and mineral components of the underlying extracellular bone matrix. Regulate blood calcium level.

Question 18

Compact bone tissue

Answer 18

contains few spaces, strongest form of bone tissue. Found beneath periosteum and makes up the bulk of diaphyses of long bones.

Question 19

Osteons

Answer 19

repeating structural units that make up compact bone tissue

Question 20

Bone lacuane

Answer 20

small spaces between concentric bone lamellae, contains osteocytes.

Question 21

Metaphyseal arteries

Answer 21

enter metaphyses of a long bone and, together with branches of the nutrient artery, supple the red and yellow bone marrow and spongy bone tissue of the metaphyses.

Question 22

Epiphyseal arteries

Answer 22

enter the epiphyses of a long bone and supply the red and yellow bone marrow and spongy bone of the epiphyses.

Question 23

Veins that carry blood away from bones

Answer 23

1. Two nutrient veins accompany the nutrient artery and exit through the diaphysis 2. numerous epiphyseal veins and metaphyseal veins accompany their respective arteries and exit through the epiphses and metaphyses. 3. many small periosteal veins accompany their respective arteries and exit through the periosteum.

Question 25

Intramembranous ossification

Answer 25

Bone forms directly within the mesenchyme, which is arranged in sheet like layers that resemble membranes.

Question 26

Endochondral ossification

Answer 26

Bone forms within hyaline cartilage that develops from mesenchyme.

Question 27

4 steps of intramembranous ossification

Answer 27

1. Development of the ossification center 2. Calcification 3. Formation of trabeculae 4. Development of the periosteum

Question 28

6 steps of endochondral ossification (most bones)

Answer 28

1. Development of cartilage model 2. Growth of cartilage model 3. Development of primary ossification Center 4. Development of the medullary (narrow) cavity 5. Development of the secondary ossification Centers 6. Formation of the articular cartilage and the epiphyseal growth plate.

Question 29

Reactive phase of bone repair

Answer 29

Inflammatory phase. Clotted blood forms around site where vessels were broken. Nearby bone cells die, phagocytes and osteoclasts remove damaged tissue. May last several weeks.

Question 30

Reparative phase 2a: fibrocartilaginous callus formation

Answer 30

Formation of fibrocartilaginous callus, mass repair of tissue consisting of cartilage and collagen fibers, about 3 weeks.

Question 31

Reparative phase 2b: bony callus formation

Answer 31

Closer to well vascularized healthy bone tissue osteoprogenitor cells develop into osteoblasts, which begin to produce spongy bone tissue. Eventually reformed as bony (hard) callus. 3-4 months.

Question 32

Repair phase 3: bone remodelling phase

Answer 32

Dead portions resorbed by osteoclasts, compact bone replaces spongy bone.

Question 33

Hormones that regulate Ca

Answer 33

Parathyroid hormone increases the number of osteoclasts releasing Ca from bone into blood. PTH also acts on kidneys to retain Ca in urine. PTH also stimulates calcitrol, a hormone that promotes absorption of calcium from foods in GI. Calcitonin inhibits the activity of osteoclasts decreasing Ca in blood increasing uptake by bones.