Lecture 4 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Spongy bone is able to resist stress because of the…

A

trabeculae (think of the analogy of the rolled up magazine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Stress lines are thickest in what regions?

A

where stress is the highest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the periosteum?

A

the outside covering of bone; fibrous outside, cellular inside; functions in growth and repair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the endosteum?

A

the inside covering (the marrow cavity); functions in growth and repair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many layers of periosteum?

A

Two

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the layers of periosteum?

A

Fibrous outside (dense irregular connective tissue) and cellular inside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Compared to the periosteum, what does the endosteum lack?

A

the fibrous outside covering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The cellular layer of the periosteum and the endosteum contain what kind of cells?

A

osteoprogenitor cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Two modes of bone formation:

A

Endochondral ossification and intremembranous ossification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the cellular layer of periosteum connect so strongly to the bone?

A

Perforating fibers go deeply into the bone from the periosteum; when osteoprogenitor cells turn into osteoblasts, they secrete osteoid around the fibers and they become bone. The fibers are actually embedded in bone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Intramembranous ossification is also called what?

A

Dermal ossification(because bone develops directly inside the dermis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Endochondral ossification:

A

-bone that forms inside cartilage-cartilage is converted to bone (by bonding minerals to cartilage)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Endochondral ossification has a ___________ ______________.

A

cartilaginous precursor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Endochondral ossification is typical of the formation of what bones?

A

irregular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

2 ways bones grow with the method of endochondral ossification:

A

Interstitial growth and appositional growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Epiphyseal growth is another way to refer to…

A

interstitial growth

17
Q

The way bones grow with intermembranous ossification:

A

with bony spicules that spread out. -common in flat bones (many in the skull)

18
Q

In the cartilage during endochondral ossification, what starts growing larger and larger and creates big spaces, which eventually “kills” itself but cutting off nutrition to itself?

A

chondrocytes

19
Q

The spaces left from the “dead” chondrocytes is invaded by what?

A

blood vessels

20
Q

What differentiates into the first osteoblasts?

A

fibroblasts

21
Q

What migrates in with the blood vessels?

A

fibroblasts

22
Q

The primary center of ossification is located where?

A

inside of the diaphysis

23
Q

During ossification, perichondrium now turns into…

A

periosteum

24
Q

Secondary centers of ossification are located where?

A

epiphyses

25
Q

Where does interstitial (epiphyseal) growth occur?

A

metaphysis

26
Q

How does appositional growth occur?

A

The cells of the inner layer of the periosteum differentiate into osteoblasts and deposit bone matrix to outside. Osteoclasts from inside the bone are slowly removing bone matrix from the inner surface.Bone eventually increases in diameter.

27
Q

How can they tell how much more you’re gonna grow?

A

Look at the amount of cartilage still there among the bones

28
Q

Where does appositional growth occur?

A

at the periosteum

29
Q

How does intramembranous ossification occur?

A

Mesenchymal cells aggregate and form clusters that become osteoblasts and start forming osteoid

30
Q

Where does intramembranous ossification occur?

A

inside the dermis

31
Q

Endochondral bone comes from cartilage, so it’s from mesoderm. HOWEVER, intramembranous (dermal) bone comes from…

A

neural crest cells

32
Q

Since intramembranous bone forms in the dermis, there is no cartilaginous precursor. Is there a perichondrium? Periosteum?

A

Neither, UNTIL the very end when there is already some bone (a plate) formed

33
Q

Mesenchymal cells that form in intramembranous ossification condense to form what?

A

an ossification center

34
Q

Bone as a dynamic tissue increases bone formation by…

A

-Exercise-Estrogen/testosterone (more hormone, more bone. less hormone, less bone)-Growth hormone

35
Q

As you get older, your ________ activity slows down while your __________ activity doesn’t really slow down.

A

osteoblast, osteoclast

36
Q

Difference between osteopenia and osteoporosis:

A

Osteopenia: lack of bone; normal with ageOsteoporosis: porous ; not normal