Cartilage and Bones

Question 1

What are the three types of cartilage?

Answer 1

Hyaline, elastic, and fibrocartilage

Question 2

What are some locations of hyaline cartilage?

Answer 2

respiratory pathways (laryx, trachea, bronchii), articular surfaces of moveable joints, end of ribs

Question 3

What are the various, general functions of cartilage?

Answer 3

• Provide structural support for soft tissues
• Reduces symphysis friction
• prototype in endochondrial ossification
• Shock absorption

Question 4

What type of collagen is predominant in each type of cartilage?

Answer 4

Hyaline - type II; elastic - type II; fibrocartilage - type I.

Question 5

What are the locations for fibrocartilage?

Answer 5

pubic symphysis, anulus fibrosis in intervertebral disks; knee joint meniscus

Question 6

What are the locations for elastic cartilage?

Answer 6

Auricle of ear (visible portion); Eustachian tube (connects middle to inner ear); epiglottus

Question 7

What are the locations for hyaline cartilage?

Answer 7

around articular surfaces (e.g. glenohumeral joint, vertebral disks); ends of ribs; respiratory passage ways (bronchii, larynx)

Question 8

What are some ways to distinguish between hyaline, elastic, and fibrocartilage?

Answer 8

All may have isogenous nests, may have multiple cells per lacunae. But elastic cartilage has visible fibers, even if not stained; Fibrocartilage has even more visible fibers such that chondrocytes (in mature cartilage) are grouped in almost oblong lacunae, pushed into such shape due to longitudinal type I collagen fibers. Fibrocartilage often darker staining.

Question 9

how can you differentiate between a fibroblast and chondroblasts?

Answer 9

Fibroblasts are often squished, with small nuclei. Chondroblasts have very circular nucleii, and visible cytoplasm.

Question 10

Which type of tissue growth increases tissue thickness?

Answer 10

Appositional, not interstitial

Question 11

What kind of growth leads to long bone lengthening? At long bone epiphysis, what feature prevents bone thickening?

Answer 11

Interstitial growth, not appositional. At epiphysis, there is no perichondrium, which is necessary for appositional bone thickening.

Question 12

When a chondroblast contributes to tissue growth, what kind of growth is it? When a chondrocyte contributes to tissue growth, what kind of growth is it?

Answer 12

Appositional; interstitial.

Question 13

What is the primary function of bone? What are the others?

Answer 13

Primary: Structural support for soft tissue. others: protection of vital organs; Reservoir of calcium and phosphate; Site of hematopoiesis; Site of muscle attachment.

Question 14

Between epiphysis, metaphysis, and diaphysis, which likely has the most spongy bone? which likely has the highest %age compact bone?

Answer 14

Epiphysis likely has most spongy bone; diaphysis likely has most compact bone.

Question 15

Name the layers in bone from outer periosteum to bone marrow in mature, secondary, regular long bone.

Answer 15

Outer fibrous dense layer of periosteum; inner osteogenic layer of osteoblasts and osteoprogenitor cells; circumferential lamella layer of bone - osteocytes; concentric lamella in osteons; endosteum layer of osteoblasts; bone marrow

Question 16

What anchors periosteum to bone?

Answer 16

Sharpeys fibers

Question 17

Is mature, non-fractured compact long bone more likely to have squished or circular osteoblasts?

Answer 17

squished - inactive bone will have less chondroblast activity, and so will be squished instead of circular.

Question 18

If you see multiple cells within one lacunae in a tissue, what conclusion can you make?

Answer 18

It is not bone, because osteocytes only have one nucleus.

Question 19

How do osteocytes maintain access to nutrients and blood?

Answer 19

They have cytoplasmic processes called caniculi that connect lacunae to each other via gap junctions, and these access blood vessels traveling through Haversian cannals and VolkmAn canals.

Question 20

How do you distinguish osteoblasts from osteoclasts?

Answer 20

Osteoclasts are multinucleate; osteoblasts and osteocytes are mononucleate. Also osteoclasts are on surface of bone…. with resorption bay and ruffled border.

Question 21

What has more cancellous bone, invertebral body or humerus?

Answer 21

Humerus. Intervertebral body needs to resist compression, so spongy bone; humerus needs to resist bending, so compact bone.

Question 22

What are the microscopic differences between cancellous and compact bone?

Answer 22

Cancellous/spongy: linear, circumferential lamella, irregular appearance; compact: circular osteons (haversian systems), regular organized.

Question 23

What are differences between immature primary woven and mature secondary lammelar bone?

Answer 23

Woven immature: swirly appearance; mature lammelar bone: organized, has lamella.

Question 24

How do you distinguish between cartilage and bone?

Answer 24

Cartilage is more indicated with circular nuclei. Also, cartilage has more discoloration in the tissue, from territorial (darker usually) and interterritorial matrix (usually a little lighter). Also, if you see any isogenous nests, or multiple nuclei within one lacunae.

Also, often cartilage has higher density of cells per comparable area, but this is not a dependable difference.

Also, in perichondrium, you see fibroblasts, periosteum just has pregenitor cells. Also, in bone, you see vessels nearby or within the tissue (Haversian canals), whereas cartilage is avascular.