Cartilage and bone

Question 1

cartilage

Answer 1

specialized form of dense connective tissue, often at joints.
high tensile strength, flexible, resilient.
- made of: chondrocytes and matrix (collagen and ground substance)
3 types (hyaline, elastic and fibro-cartilage)

Question 2

perichondrium

Answer 2

layer of CT surrounding cartilage,
where most of cartilage grows from.
2 layers: fibrous (vascular) and cellular (w/ chondroblasts)
*NOT in articular or fibrous cartilages

Question 3

lacuna

Answer 3

space in cartilage matrix for each chondrocyte

Question 4

isogenous group/cell nest

Answer 4

cluster of closely packed chondrocyte daughter cells

6-8, all related

Question 5

ground substance

Answer 5

an amorphous gel made of proteoglycans + hyaluronic acid,

part of cartilage matrix

Question 6

chondrocyte

Answer 6

a single (mature) cartilage cell

Question 7

pericellular capsule

Answer 7

narrow layer of collagens and chondronectin surrounding each chondrocyte,
bind to matrix and protect from mechanical stress

Question 8

territorial matrix

Answer 8

the area of cartilaginous matrix immediately surrounding the lacunae and cell nests.

Question 9

interterritorial matrix

Answer 9

the area of cartilage matrix just beyond the territorial matrix.
add’l support

Question 10

hyaline cartilage

Answer 10

most common form of cartilage,
in freely moving joints and surface coatings of articulating bones.
type II collagen.
*temporarily in epiphyseal growth plates

Question 11

elastic cartilage

Answer 11

cartilage type, w/ collagen II and elastic fibers.
in auditory tube/ears, epiglottis, laryx.
*Elastin: branches > coll. II; see w/ verhoeff stain!

• starts as hyaline cartilage, then begins synthesizing elastin too

Question 12

fibrocartilage

Answer 12

cartilage type, w/ mostly type I collagen.
in symphyses and synovial joints (ie: menisci, intervertebral disks)
- replacement of fibroblasts w/ chondrocytes

Question 13

“regressive changes”

Answer 13

calcification of cartilage,

kills cartilage cells, but builds bone.

Question 14

osteocytes

Answer 14

bone cells in matrix,

help maintain bone

Question 15

3 types of bone cells

Answer 15

1. osteoblasts
2. osteoclasts
3. endosteal cells

Question 16

tissue(s) surrounding bone

Answer 16

External: periosteum.
a dense CT that envelopes bones

Internal: endosteum.
loose CT, lines internal bone surface (ie: marrow cavity)

Question 17

Organization of bone tissue

Answer 17

in lamellae (layers of old and new osteoclasts). 
*receive blood supply and innervation

Question 18

4 types of bone

Answer 18

1. long
2. short
3. flat
4. irregular

Question 19

2 categories of bone (based on macroscopic appearance)

Answer 19

1. Cancellous (aka: spongy/trabecular) - VERY porous

2. Compact (aka: dense/cortical) - more direct blood supply, denser

Question 20

canaliculi

Answer 20

tiny channels radiating out from lacunae,
carry nutrients and communicate w/ neighbor cells
(via gap junctions)

Question 21

haversian system (osteon)

Answer 21

newest/youngest lamellae of compact bone,
concentric around vascular channels (haversian canal),
6-8 lamellae,
type I collagen matrix in radial pattern
*connected by Volkman’s canals

Question 22

Haversian canal

Answer 22

in compact bone,
down center of haversian system (osteon)
contains blood vessels,
lined by endosteal cells

Question 23

Volkmann’s Canals

Answer 23

in compact bone,
connect Haversian canals from 1 osteon to another,
*communicate w/ periosteum and marrow cavity
carry blood vessels and sensory nerves to bone matrix

Question 24

interstitial lamellae

Answer 24

type of lamellae in compact bone,
= remnants of old osteons,
btwn adjacent Haversian systems (new osteons)

Question 25

circumferential lamellae

Answer 25

layer of lamellae in compact bone,
Outer: adjacent to periosteum
Inner: along bone marrow

Question 26

trabecular packet

Answer 26

the (only) type of lamellae in spongy bone
similar to circumferential lamellae (in compact bone)
no blood vessels!

Question 27

periosteum

Answer 27

dense (fibrous) CT sheath surrounding bone,
2 layers:
1. dense fibrous layer (outer): fibroblasts, collagen, blood vessels
2. inner layer: looser, cellular w/ undifferentiated cells (osteoprogenitor cells)

Question 28

endosteum

Answer 28

thin, loose layer of CT.
covers all bone cavities
(haversian canals, marrow cavities, etc.)

Question 29

osteoblast

Answer 29

from osseous tissue, basophilic.

synthesize and secrete bone matrix components

Question 30

osteoclast

Answer 30

large, multi-nucleated cells.
mediate breakdown of bone matrix
*in Howship’s lacunae (aka: resorptive cavitites)

Question 31

osteocytes

Answer 31

cells for bone maintenance.
inside lacunae, connected by canaliculi
helps mobilize calcium and phosphatse

Question 32

mesenchymal cells

Answer 32

precursor cells to osteoprogenitor and ostoblasts,
cluster around capillaries.
*differentiate into trabeculae
(membranous sheets —> form flat bone by “intramembranous bone formation”)

Question 33

osteoid

Answer 33

organic bone matrix.
produced by osteoblasts,
–> make up “Primary Ossification Center”

Question 34

long and short bone come from…

Answer 34

hyaline cartilage!
*and periosteum
(cartilage dies off, calcifies, ==> bone)

Question 35

epiphyseal growth plate

Answer 35

developing cartilage
(= new bone complex)
continuously lengthen the bone
(esp. long and short bones)