Chapter 5a: Bone and Cartilage

Question 1

Name all three types of mineralized tissues and where they come from

Answer 1

• Enamel comes from ameloblasts
• Dentin comes from odontoblasts
• Osteocytes are living cells in bones

Question 2

What kinds of cells a) make cartilage/bone, b) remove cartilage/bone?

Answer 2

o A)chondroblasts make cartilage and osteoblasts make bone
o B) chondroclasts remove cartilage and osteoclasts remove bone

Question 3

What are the functions of bone/cartilage?

Answer 3

o Movement and support
o Protection of vital organs(skull, ribcage)
o Production of blood cells(marrow: produces red and white blood cells/stem cells)
o Calcium and phosphorus metabolism

Question 4

Cartilage

Answer 4

Connective tissue primarily associated with the skeleton; Can make substantial parts of the skeleton in some groups

Question 5

Collagen matrix

Answer 5

glycosaminoglycans and proteoglycans

Question 6

Name the 3 types of cartilage

Answer 6

Hyaline, Elastic, and Fibrous

Question 7

Hylaine cartilage

Answer 7

On the ends of ribs and on the trachea; Joint surfaces; Skeleton of cartilaginous fishes, parts of bony fish skeletons

Question 8

Elastic cartilage

Answer 8

matrix + elastic fibers
External ear, auditory tubes, epiglottis, larynx

Question 9

Fibrous cartilage

Answer 9

matrix + collagen fibers

Intervertebral disks of the spine; At the insertions of ligaments and tendons; Dense collagen fiber

Question 10

Bone

Answer 10

a composite tissue

Has inorganic hydroxyapatite; Comrpession

Has organic collagen; Tension(pulls on part of skeleton, thinks it is elastic fiber)

Question 11

Understand the difference between a) non-lamellar bone and b) lamellar bone

Answer 11

Lamellar bone: Orderly, regular arrangement of collagen fibers within the matrix
Can be spongy or compact bone in appearance

Nonlamellar (woven) bone: Immature bone with a disorderly, irregular arrangement of collagen within the matrix; Is not stress oriented
Can be spongy bone in appearance

Question 12

Understand the difference between spongy bone and compact bone

Answer 12

Spongy bone: Lighter and less dense than compact bone; Consists of plates (trabeculae) and bars of bone adjacent to small, irregular cavities that contain red bone marrow

Typically at the end of bone

Compact bone: dense, made of haversian systems

Question 13

What are the 3 kinds of forces that create mechanical stress?

Answer 13

compression, shear, and tension

Question 14

What is bone hypertrophy and atrophy?

Answer 14

Atrophy: loss of bone due to lack of activity

Hypertrophy: gain of bone due to activity

Question 15

What kind of stress does the organic component of bone tissue resist?

Answer 15

Organic Component (Collagen): The organic part of bone, primarily made up of collagen fibers, resists tensile stress. This means it helps bones withstand stretching and twisting forces.

Question 16

What kind of stress does the inorganic component of bone tissue resist?

Answer 16

(Hydroxyapatite Crystals): The inorganic part, mainly hydroxyapatite, resists compressive stress. This means it helps bones handle heavy loads and pressure.

Question 17

What is the trajectorial theory and how does it influence bone structure?

Answer 17

A beam projecting from a wall tends to bend under its own weight, placing internal stresses on the material from which it is made – lines called stress trajectories ; Compressive forces concentrated along the bottom of the beam, tensile forces along the top

Both forces are greatest at the surface of the beam

How it is seen in bones:
Latticework of bone, with material concentrated at the surface ; A cross section through the proximal end of a femur reveals the lattice of bone spicules within the head that become concentrated and compacted along the wall within the shaft of the femur

Question 18

What does Wolff’s Law describe?

Answer 18

Remodeling of bone occurs in proportion to the mechanical demands placed upon it

Physiological response that both thickens and straightens it; New bone forms along the concave surface ; Bone remodels - shape is restored; The walls are now thicker to withstand the new, increased load

Question 19

in compact bone, describe structure of osteon

Answer 19

o Cylinders surrounding blood vessels
o Haversian system
o Cylinder structure incases osteocytes

Question 20

Describe how Intramembraneous Ossification works

Answer 20

Bone forms directly from mesenchyme without a cartilage precursor

Mesencymal cells(connective tissue cells) lay down collaen, turn into osteoblast; Osteoid tissue: Unmineralized, oranic part of bone

Sheet of tissue with large supply of blood vessels; Osteoblast formed from tissue and blood vessels will begin ossification; Osteocyte forms and bone matrix(mineralized stuff) forms

Spongy bone forms first and eventually spongy bone and compact bone will form

Question 21

Describe how endochondral Ossification works

Answer 21

Bone develops from a cartilage precursor (an anlage)

Chondrocytes growing cartilage die and matrix calcifies

Osteoblsats will cover the shaft of the cartilage in a thin layer of bone

Blood vessels penetrate cartilage and form primary ossification center

Bone of the saft thickens and epiphysis cartilage areas are replaced by shafts of bone

Blood vessels enter epiphyses and osteoblasts to form secondary ossification centers

Question 22

Describe Diarthrosis

Answer 22

o Diarthrosis - moveable
o An articular capsule made up of the fibrous cpasule and synovial membrane has fluid inside of it to allow movement

Question 23

What are synarthroses?

Answer 23

o Little to no movement
o Sutures example: start as series of bones, develop sutures(fused together later on, will allow brain to grow first)
o Example: Symphysis pubis