Chapter 6

Question 1

Name the two types of cartilage cells and their funtion

Answer 1

Chondroblasts: produce matrix
Chondrocytes: surrounded by matrix and occupy small spaces called lacunae

Question 2

What are the three types of cartilage?

Answer 2

Hyaline, Elastic, Fibrocartilage

Question 3

What are some functions of cartilage?

Answer 3

Support soft tissue
Articulations
Precursor model for bone growth

Question 4

Describe interstitial cartilage growth

Answer 4

Growth from within the inside of cartilage:
-A chondrocyte inside lacunae undergoes mitosis and produces 2 chondroblasts who begin to produce matrix and cause their separation from each other

Question 5

Describe apositional cartilage growth

Answer 5

Growth from the outside
-Mitosis of stem cells in the perichondrium, adds chondroblasts to the periphery who begin to secrete new matrix, push apart and become chondrocytes

Question 6

How are bones strengthened?

Answer 6

By calcification (minerals deposited in the matrix), Ca++, PO4–

Question 7

Give 5 functions of bones

Answer 7

Support, Protection, Movement, Hemopoiesis (blood cells), Storage ( yellow bone marrow for energy, and minerals)

Question 8

Give the 4 bone classifications and an example

Answer 8

Long bone (femur) 
Short bone (tarsal) 
Flat bone (frontal)
Irregular bone (os coxa)

Question 9

Name the 3 regions of long bones

Answer 9

Epiphyses (ends of long bone which contain articular cartilage)
Diaphysis (middle/shaft which contains medullary cavity with yellow bone marrow)
Metaphysis (region in the middle of above two, contains the epiphyseal plate in growing bone)

Question 10

Periosteum

Answer 10

Covers the external surfaces of bones, anchored by perforating fibers

Question 11

Endosteum

Answer 11

Covers the internal surfaces of bones

Question 12

Name and describe the 4 types of bone cells

Answer 12

Osteoprogenitors: mesenchymal stem cells found in both bone coverings that produce more stem cells or osteoblasts
Osteoblasts: form the bone matrix
Osteocytes: reside in lacunae, maintain the bone matrix
Osteoclasts: dissolve bone and cause calcium release

Question 13

Bone matrix composition

Answer 13

1/3 organic: made from living cells

2/3 inorganic: bone salt crystals(hydroxyapatite)

Question 14

Compact bone description, location?

Answer 14

Solid and dense; will be on external surfaces of flat and long bones

Question 15

Spongy bone description, location?

Answer 15

Porous ; forms an open lattice of narrow plates (trabeculae) and will be on internal surfaces **Replaced every 3 years

Question 16

Osteon/Haversian system organization:

Answer 16

Canals:

• central which carries blood vessels and nerves
• perforating which connects perpendicularly with the central
• caniliculi which are tiny channels extending from lacunae and allow for metabolic interactions

Lamellae:
-layers of bone around the central canals, made up of collagen fibers with alternating orientation

Question 17

What does intramembranous ossification develop from?

Answer 17

Develops from mesenchyme

Question 18

Where does endochondral ossification begin with?

Answer 18

Begins with a hyaline cartilage model

Question 19

What is the epiphyseal plate? Location?

Answer 19

layer of hyaline cartilage at the boundary of the epiphysis and diaphysis **Site of bone lengthening

Question 20

What are the two types of bone growth?

Answer 20

Appositional (outside), growth in width

Interstitial (inside) , growth in length

Question 21

Osteoporosis

Answer 21

Loss of bone density

Question 22

Name the 5 microscopic zones of the epiphyseal plate, starting from nearest the epiphysis (ends) to diaphysis (shaft)

Answer 22

• Zone of resting cartilage (small chondrocytes)
• Zone of proliferating cartilage (mitosis, growth)
• Zone of hypertrophic cartilage (chondrocytes becoming enlarged)
• Zone of calcified cartilage ( Ca++ kills chondrocytes)
• Zone of ossification (capillaries and bone stem cells)