skeletal system-Bone

Question 1

components of the skeletal system

Answer 1

Bone
Cartilage(Hyaline, Fibrocartilage, Elastic)
Tendons and ligaments

Question 2

functions of the skeletal system

Answer 2

support(bone=hard and rigid, cartilage=flexible and strong)
protection(e.g. skull around brain)
movement(tendons=bone to muscle)
storage(Ca+ and P stored in bones. adipose in marrow)
blood cell production(haemopoietic tissue/red bone marrow in marrow)

Question 3

what are the 4 categories of bone?

Answer 3

long(femur)
short(tarsals)
flat(scapula)
irregular(pelvis)

Question 4

what is the structure of a long bone?

Answer 4

Diaphysis(shaft)
Epiphysis(end)
Epiphyseal plate(growth plate)
epiphyseal line(bone stops growing in length)
Medullary cavity(inner cavity)

Question 5

What is the Diaphysis?

Answer 5

. the shaft of the bone

. exterior is compact bone

Question 6

What is the Epiphysis?

Answer 6

. the end of the bone

. contains spongy bone

Question 7

What is the Epiphyseal plate?

Answer 7

Hyaline cartilage; present until growth stops(only juveniles)

Question 8

What is the Epiphyseal line?

Answer 8

bone stops growing in length(narrowed Epiphyseal plate)

Question 9

What is the Medullary cavity?

Answer 9

In children medullary cavity is red marrow,

gradually changes to yellow in limb bones and skull

Question 10

what is the inner structure of a long bone?

Answer 10

Periosteum
Sharpey’s fibers
Endosteum

Question 11

what is the Periosteum?

Answer 11

Outer is fibrous
Double-layered connective tissue membrane covering the outer surface of bone except where articular cartilage is present.

Question 12

what is are Sharpey’s fibers?

Answer 12

some periosteal fibers penetrate
through the periosteum and
into the bone. Strengthen
attachment of tendon to bone

Question 13

what is the Endosteum

Answer 13

Similar to periosteum, but more cellular. Lines all internal spaces including spaces in spongy bone

Question 14

what is Articular cartilage?

Answer 14

thin layer of hyaline cartilage covering a bone where it forms a joint with another bone.

Question 15

structure of Flat bone?

Answer 15

No diaphysis, epiphysis

sandwich of spongy between compact bone

Question 16

structure of short and irregular bone?

Answer 16

. compact bone that surrounds spongy bone
similar structure of epiphysis of long bones
. no diaphysis and not elongated

Question 17

what do some flat and irregular bones have?

Answer 17

Some flat and irregular bones of skull have sinuses

lined by mucous membranes

Question 18

where does bone growth in length occur?

Answer 18

Growth in length occurs at the epiphyseal plate

Question 19

What does bone growth in length involve?

Answer 19

Involves the formation of new cartilage by
◦ Interstitial cartilage growth
◦ Appositional growth on the surface of the cartilage

Question 20

closure of epiphyseal plate

Answer 20

epiphyseal plate is ossified becoming the epiphyseal line. Between 12 and 25 years of age

Question 21

what is the process of bone growth in length?

Answer 21

1. new cartilage is produced on the epiphyseal side of the plate as the chondrocytes divide and form stacks of cells.
2. chondrocytes mature and enlarge
3. Matrix is calcified and chondrocytes die
4. the cartilage on the diaphyseal side of the plate is replaced by bone

Question 22

Growth at articular cartilage

Answer 22

Increases size of bones with no epiphyses(short bones)

Question 23

Growth in bone width stage 1

Answer 23

1. Osteoblasts beneath the periosteum lay down bone to form ridges separated by grooves. Blood vessels of the periosteum lie in the grooves.

Question 24

Growth in bone width stage 2

Answer 24

The groove is transformed into a tunnel when the
bone built on adjacent ridges meets. The periosteum of the
groove becomes the endosteum of the tunnel.

Question 25

Growth in bone width stage 3

Answer 25

Appositional growth by osteoblasts
from the endosteum results in the
formation of a new concentric
lamella.

Question 26

Growth in bone width stage 4

Answer 26

The production of additional concentric lamellae fills in the tunnel and completes the formation of the osteon.

Question 27

factors affecting bone growth?

Answer 27

Size and shape of a bone determined genetically but can be modified and influenced by nutrition and hormones

Question 28

factors affecting bone growth-Hormone

Answer 28

◦ Growth hormone from anterior pituitary. Stimulates
interstitial cartilage growth and appositional bone
growth
◦ Thyroid hormone required for growth of all tissues
◦ Sex hormones such as oestrogen and testosterone
- Cause growth at puberty, but also cause closure of the
epiphyseal plates and the cessation of growth

Question 29

Mechanical stress and bone strength

Answer 29

Stress causes bone remodelling to:
◦ Increase bone mass (density)
◦ Align trabeculae with stress

Question 30

What causes changes in bone strength?

Answer 30

Changes caused by:
◦ Osteoblast activity
- Increases with stress

Question 31

Bone repair stage 1

Answer 31

Hematoma formation:

Blood released from damaged blood vessels forms a hematoma

Question 32

Bone repair stage 2

Answer 32

Callus formation:

the internal callus forms between the ends of the bones, and the external callus forms a collar around the break

Question 33

Bone repair stage 3

Answer 33

Callus ossification:

woven, spongy bone replaces the internal and external calluses.

Question 34

Bone repair stage 4

Answer 34

Bone remodelling:

compact bone replaces woven bone, and part of the internal callus is removed, restoring the medullary cavity.

Question 35

Effects of aging on bone matrix-skeletal system?

Answer 35

Bone matrix decreases. More brittle due to lack

of collagen.

Question 36

Effects of aging on bone mass-skeletal system?

Answer 36

. Bone mass decreases
. Highest around 30
. Men denser due to 
testosterone and greater weight
. Rate of bone loss increases 10 fold after menopause.
. spongy bone lost first, then compact

Question 37

Effects of aging on bone-skeletal system?

Answer 37

. Increased bone fractures
. Bone loss causes deformity, loss of height, pain,
stiffness