Bone

Question 1

to accomodate changes related to mechanical stresses and demands on calcium homeostasis bones are in a dynamic state of ____ and _____ throughout life

Answer 1

growth and resorption

Question 2

What provides the framework and necessary tensile strength of bones and who produces it?

Answer 2

collagen fibers produced by osteoblasts

Question 3

what serves as a carrier for minerals?

Answer 3

osteoid = the extracellular matrix

Question 4

What layer acts as a site of insertion of muscles, tendons and ligaments?

Answer 4

periosteum

Question 5

What tissue layer lines the trabeculae of spongy bone?

Answer 5

endosteum

Question 6

osteocytes originate from _____

Answer 6

osteoblasts

Question 7

osteoblasts secrete what type of collagen?

Answer 7

type 1

Question 8

What cells are found in a single layer external to the osteoid matrix? Where do they originate?

Answer 8

osteoblasts (immature bone cells)

from osteoprogenitor cells

Question 9

What bone cell is responsible for the synthesis and secretion of collagen and osteoids?

Answer 9

osteoblast

Question 10

When the osteoid mineralizes, osteoblasts are entrapped as _______

Answer 10

osteocytes

Question 11

How do osteoclasts decalcify bone?

Answer 11

When they are activated and in contact with bony surface, they release acid and lysosomal enzymes

Question 12

What kind of cells are occupied within lacunae? Are they mature or immature?

Answer 12

osteocytes = mature

Question 13

How do osteocytes maintain contact with adjacent osteocytes?

Answer 13

filopodia connecting each other via canaliculi

Question 14

how do osteocytes transfer nutritional needs to the next cell?

Answer 14

gap junctions

Question 15

are osteocytes capable of undergoing mitosis?

Answer 15

no

Question 16

Do osteoclasts have basophilic or acidophilic cytoplasm? What are they closely related to?

Answer 16

acidophilic

macrophages

Question 17

Osteoclasts induce osteolysis in order to ____ in response to ______

Answer 17

maintain calcium homeostasis and remodel in response to growth or mechanical stresses

Question 18

filopodia are extensions of ____

Answer 18

osteocyte cytoplasm

Question 19

Where does intramembranous ossification occur? In what bones?

Answer 19

within membranes of condenses primitive mesenchymal tissue, in flat bones of the skull

Question 20

Where does endochondral ossification occur?

Answer 20

At ossification centers in the diaphysis of bones. occurs in majority of bones in the skeleton (limbs, vertebral column, pelvis, base of the skull)

Question 21

bone develops from what kind of cartilage?

Answer 21

hyaline cartilage

Question 22

Can bone grow longitudinally in a mature animal?

Answer 22

no not when the growth plate is closed

Question 23

What is woven bone and how are the collagen fibers arranged?

Answer 23

Immature bone present during fetal development and the early stages of bone repair.
Collagen fibers are crisscrossed or woven

Question 24

What kind of bone is composed of successive concentric layers around a central canal?

Answer 24

lamellar bone = mature bone

Question 25

What is the functional unit of mature bone?

Answer 25

osteons

Question 26

What is in the center of each osteon?

Answer 26

Haversian canal

Question 27

What hormone increases the recruitment/activity osteoclasts?

Answer 27

PTH

Question 28

Where is articular cartilage found?

Answer 28

On the bone surfaces in a synovium

Question 29

What happens with decreased production of synovial fluid?

Answer 29

Bones can rub against each other, arthritis

Question 30

where are epitheliod cells found and what do they do?

Answer 30

lining the joint cavity. they secrete hyaluronic acid and phagocytize debris

Question 31

Why are synovial cells epitheliod and not epithelial?

Answer 31

because they do not sit on a basement membrane or have intercellular junctions

Question 32

What is the function of synovial fluid and what should it look like?

Answer 32

Clear and viscous. Functions include nutrition, lubrication and protection of articular surfaces

Question 33

The structure of bones is designed for providing _____

Answer 33

maximum resistance to mechanical stress while gaining the least body mass

Question 34

The organic matrix of bone is made up of mostly ____

Answer 34

collagen (95%)

Question 35

The inorganic matrix of bone is composed of mainly ______ for the purpose of ______

Answer 35

hydroxyapitate crystals within collagen fibrils | enhance tensile strength

Question 36

What is rickets?

Answer 36

vitamin d deficiency, bones curve

Question 37

What type of cell digests bone to maintain Calcium homeostasis? And where do they originate?

Answer 37

osteoclasts | from pluripotent stem cells of the bone marrow

Question 38

What kind of cytoplasm do osteoblasts have?

Answer 38

basophilic

Question 39

Can osteocytes undergo mitosis?

Answer 39

no. they are mature

Question 40

The circumferential zone is associated with what kind of bone cells?

Answer 40

osteoclasts

Question 41

What kind of ossification is characterized by subsequently replacing osseous tissue at ossification centers? Where does it occur

Answer 41

endochondral | at growth plates (epiphysis)