The Skeletal System 2

Question 1

True or False
Teeth are part of the human skeleton

Answer 1

False

Question 2

True or False: There are equal numbers of bones in infants and adults

Answer 2

False: Infants have more

Question 3

True or False: There are an equal number of bones in females and males

Answer 3

True
- tho size and shape can differ

Question 4

True or False: The stapes, a bone in the middle ear, is the smallest bone in the human skeleton

Answer 4

True

Question 5

Cartilage

Answer 5

Are flexible structural support found throughout the body
- forms the template for bone development

Question 6

True or False
Cartilage lacks both blood supply (avascular) and nerve fibres (not

Answer 6

True:

• The cartilage does not contain any blood vessels and receives nutrients through diffusion.
• They heal very slowly.
• The cartilage also does not contain nerve fibres.

Question 7

Types of Cartilage

Question 8

Hyaline Cartilage

Answer 8

Found at the end of long bones, nose, trachea, larynx and cartilage of the ribs
- cushions the ends of bones from compressive stress

Question 9

Fibrocartilage

Answer 9

Found as the discs between vertebra(intervertebral discs) and knee joints
Think this is the reason we’re not smushed by gravity

Question 10

Elastic cartilage

Answer 10

Found at the ear, tip of nose and the corniculate cartilage(voicebox)
- maintains shape and flexibility

Question 11

Which of the following types of cartilage is the most compressible and resists tension well?
A. Hyaline cartilage
B. Elastic cartilage
C. Fibrocartilage
D. Articular cartilage

Answer 11

C because it contains thick collagen fibres

Question 12

The human skeleton initially consists of only cartilage

Answer 12

Which is replaced by bone through intramembraneous or endochondral ossification(development of bone) as the fetus grows

Question 13

Endochondral ossification

Answer 13

• this is the process where bones form by replacing hyalin cartilage
• responsible for the creation of most bones

Question 14

Where each part is formed

Answer 14

Early osteoblasts appear in a cluster called an ossification centre.
Primary ossification centre develops into the diaphysis.
Secondary ossification centre develops into the epiphysis.

Question 15

Where do we still find hyaline cartilage in an adult bone that underwent endochondral ossification?

Answer 15

At the external surfaces of the epiphysis and articular cartilage

Question 16

Intramembraneous Ossification

Answer 16

• Is the process where bone develops from fibrous membrane(collagen and connective tissue)
  Creates the frontal, parietal, occipital, temporal and clavicle bones

Question 17

The steps of intramembraneous

Answer 17

Stem cells clusters form an ossification centre
- osteoid lay down around blood vessels resulting in a trabeculae
- trabeculae bones are replaced by compact bones though bone remodeling

Question 18

Skull bones

Answer 18

Are incompletely formed at birth and are connected by membrane coveriing called frontelles that have small openings to allow the brain to grow

Question 19

Throughout life, bones grow in 2 ways

Answer 19

Interstitial growth and appositional growth

Question 20

Interstitial growth

Answer 20

• new matrices are made working a bone
• matrices are deposited and cells are pushed away from each other
• increasing the size of the bone from all directiobs

Question 21

Appositional growth

Answer 21

New bone matrices are laid down on the surface of already established bones
- increases bone thickness

Question 22

Bones grow in

Answer 22

Length at the epiphyseal plate
Width at the endosteum/periosteum

Question 23

Bone growth in length

Answer 23

At the epiphyseal plate:
- hyaline cartilage continues to grow(in the proliferation zone)
- ossification continues to form the bone(ossification zone)

Question 24

What type of bone growth occurs at the epiphyseal plate?

Answer 24

Interstitial growth of hyaline cartilage and endochondral ossification

Question 25

What happens to the epiphyseal plate near the end of adolescence when chondorblasts divide less often?

Answer 25

- the bone making finally catches up to the cartilage - the cartilage cell division slows down - it’ll shrink and get replaced by bone

Question 26

Bone growth in width

Answer 26

Osteoblasts lay down osteoid on the outer surface and osteoclasts dissolve the bone matrix in the interior

Question 27

Why do osteoclasts need to dissolve bone matrix on the interior during bone growth?

Answer 27

ensures bones are not too heavy to lift • during bone growth, there is more build-up than breakdown, which leads to thicker, stronger bones

Question 28

Bone remodelling

Answer 28

- bone restoration- bones are broken down by osteoblasts - bone deposition- rebuilt by osteoblasts

Question 29

Why do bones need to remodel?

Answer 29

- get used to different weights applied to the bones - replace old or damaged bones - get access to minerals stored in bones

Question 30

True or False Astronauts lose both bone and muscle mass during long space missions

Answer 30

True- a possible cause is low gravitational forces in earth

Question 31

Bone remodeling is maintained by 2 major mechanisms

Answer 31

Mechanical stress decides where it occurs(ex. adapting to new loads) and hormone stimulation whether and when it occurs

Question 32

What is not considered a weight bearing excersise

Answer 32

Cycling, swimming, streching

Question 33

Bone remodeling is maintained through

Answer 33

Parathyroid hormone(PTH) - creates osteoclasts to release Ca Calcitonin - creates Ca Opposites of each othet