Exam 1 9/15 Davenport Bone

Question 1

Definition of bone

Answer 1

connective tissue characterized by a mineralized extracellular matrix

Question 2

Osteocytes in _____ with _____

Answer 2

lacunae; canaliculi

Question 3

Bone cell types

Answer 3

osteocytes, osteoprogenitor cells, osteoblasts, osteoclasts

Question 4

Two types of bone

Answer 4

spongy bone, compact bone

Question 5

Describe spongy bone

Answer 5

1. Similar to adult compact bone except that tissue is arranged as trabecular or spicules
2. numerous interconnecting marrow spaces
3. matrix is lamellated

Question 6

Mature bone

Answer 6

Adult; has lamellar pattern

Question 7

Immature bone

Answer 7

Initially deposited bone, non-lamellar, more cells per unit area and more randomly arranged, matrix has more ground substance

Question 8

True false: bone is highly vascularized

Answer 8

True - no osteocyte is more than 300 microns from a blood vessel

Question 9

Bone blood supply is ______

Answer 9

Centrifugal

Question 10

Another name for spongy bone

Answer 10

Cancellous, trabecular

Question 11

Bone is covered by:

Answer 11

Periosteum - sheath of dense connective tissue

Question 12

Periosteum is made of:

Answer 12

osteoprogenitor cells, periosteal cells (potential osteoblasts), Sharpey’s fibers

Question 13

Bone marrow cavity is lined by:

Answer 13

endosteum (more delicate layer of CT)

Question 14

Endosteum is made of:

Answer 14

osteoprogenitor cells, endosteal cells (potential osteoblasts)

Question 15

Mature bone is composed of structural units called:

Answer 15

Osteons

Question 16

Another name for osteons

Answer 16

Haversian systems

Question 17

Osteon structure

Answer 17

Osteon canal in the center, canaliculi around it, osteocyte in lacuna around periphery

Question 18

Volkmann canals

Answer 18

Connect Haversian canals together

Question 19

What happens when minerals are removed?

Answer 19

Fibers still form the same structure, but strength is decreased

Question 20

Initial appearance of bone occurs around:

Answer 20

Blood vessel

Question 21

Osteoclast derived from:

Answer 21

macrophage (resorbs mineralized bone)

Question 22

True or false: if you see osteoclasts, there would be no presence of osteoblasts nearby

Answer 22

False - osteoblasts found near osteoclasts to help balance out how much bone is there

Question 23

Osteoprogenitor cell is derived from:

Answer 23

Mesenchymal cell lineage

Question 24

Mesenchyme is precursor for:

Answer 24

mesoderm

Question 25

Osteoprogenitor cell

Answer 25

Resting cell that can transform into an osteoblast and secrete bone matrix

Question 26

How do osteoblasts/osteocytes communicate?

Answer 26

Gap junctions

Question 27

Osteoblast

Answer 27

A differentiated bone forming cell that secretes bone matrix

Question 28

Osteocytes

Answer 28

Mature bone cells enclosed by bone matrix that was secreted when it was an osteoblast

Question 29

Osteocytes reside in:

Answer 29

Lacunae (processes extend into canaliculi

Question 30

3 functional states of osteocytes

Answer 30

1. quiescent
2. formative
3. resorptive

Question 31

Osteoclast releases _____ into extracellular space

Answer 31

lysosomes

Question 32

True or false: osteoclasts are phagocytic

Answer 32

True

Question 33

Bone serves as a reservoir for:

Answer 33

calcium

Question 34

What hormones do bone respond to to help maintain blood calcium levels?

Answer 34

Parathyroid hormone; calcitonin

Question 35

Somatotropin

Answer 35

Pituitary growth hormone - stimulates growth in general as well as growth of the epiphyseal cartilage and bone

Question 36

Oversecretion of somatotropin results in:

Answer 36

giantism; leads to acromegaly as an adult

Question 37

Hyposecretion of somatotropin results in:

Answer 37

Dwarfism

Question 38

Thyroid hormone

Answer 38

Hyposecretion in infancy and childhood results in cretinism

Question 39

Cretinism

Answer 39

failure of bone growth and dwarfism