intro to skeletal

Question 1

Endosteum

Answer 1

• a layer of bone cells that cause the bone to grow, repair, and remodel throughout life.
  *Lining the inside of the bone adjacent to the medullary cavity

Question 2

Periosteum

Answer 2

Part of the outer double layered structure on the outside of bones that grow, repair and remodel bone as well.

Question 3

Osteoblasts

Answer 3

*responsible for building new bone tissue
* FORM OSTEOCYTES
* cells that synthesize bone matrix and coordinate the mineralization of the skeleton.

Question 4

Osteocytes

Answer 4

FORM NEW BONES
The longest living bone cell, making up 90–95% of cells in bone tissue

Question 5

Osteoclasts

Answer 5

BREAKDOWN BONE
The cells that degrade bone to initiate normal bone remodeling and mediate bone loss in pathologic conditions by increasing their resorptive activity.

Question 6

Diaphysis

Answer 6

is the hollow, tubular shaft that runs between the proximal and distal ends of the bone.

Question 7

Epiphysis

Answer 7

The area of the long bone where bone growth takes place.

Question 8

Long bones have

Answer 8

a long longitudinal axis

Question 9

Short bones have

Answer 9

a short longitudinal axis and are more cube-like

Question 10

Flat bones are

Answer 10

thin and curved such as some of the bones of the skull

Question 11

Irregular bones are

Answer 11

often found in groups and have a variety of shapes and sizes

Question 12

Sesamoid bones are found in

Answer 12

ligaments

Question 13

There are also 2 types of bone tissue in different amounts in bones.

Answer 13

Compact bone (sometimes called cortical bone) is very dense. Cancellous bone (sometimes called spongy bone) looks more like a trabeculated matrix.

Question 14

The bone forming cells (called osteoblasts) get their nutrients by

Answer 14

diffusion

Question 15

Compact bone is organized according to structural units called

Answer 15

Haversian systems or osteons. These are located along the lines of force and line up along the long axis of the bone. The Haversian systems are connected together and form an interconnected structure that provides support and strength to bones.

Question 16

Osteons contain a central canal (Haversian canal) that serves as

Answer 16

a pathway for blood vessels and nerves.

Question 17

Bone is deposited along concentric rings called

Answer 17

lamellae

Question 18

Along the lamellae are small openings called

Answer 18

lacunae

Question 19

The lacunae contain fluid and bone cells called

Answer 19

osteocytes

Question 20

Radiating out in all directions from lacunae are small canals called

Answer 20

canaliculi

Question 21

Osteons are interconnected by a series of larger canals called

Answer 21

Volksmann’s canals (perforating canals).

Question 22

Osteoblasts undergo

Answer 22

mitosis and secrete a substance that acts as the framework for bone. Once this substance (called osteoid) is secreted, minerals can deposit and form hardened bone. Osteoblasts respond to certain bone forming hormones as well as from physical stress.

Question 23

Osteocytes

Answer 23

are mature osteoblasts that cannot divide by mitosis.

Question 24

Osteocytes reside in

Answer 24

lacunae

Question 25

Osteoclasts are capable of

Answer 25

demineralizing bone. They free up calcium from bone and release it into the blood depending on the body’s needs.

Question 26

There are 2 bone forming processes.

Answer 26

Flat bones called intramembraneous bones develop in sheet like layers. Tubular bones called endochondral bones develop from cartilage templates.

Question 27

During intramembranous ossification, bones form from

Answer 27

sheet-like layers of connective tissue.

Question 28

These layers have a vascular supply and contain bone forming cells called

Answer 28

osteoblasts

Question 29

The osteoblasts secrete

Answer 29

bony matrix in all directions around the cell. The matrix unites with that secreted by other osteoblasts as the bone forms.

Question 30

Eventually the osteoblasts may be walled off by the bony matrix. At this point the osteoblast is called

Answer 30

an osteocyte

Question 31

Tubular bones develop from a process known as

Answer 31

endochondral ossification. During this process, bones develop from hyaline cartilage templates.

Question 32

Some important steps of Endochondral ossification include:

Answer 32

Formation of the outer covering called the periosteum. Development of the primary and secondary ossification centers. Development of the medullary cavity Formation of the epiphyseal plates and spongy bone.

Question 33

The middle tubular portion is called ___ and then ends are called___

Answer 33

diaphysis epiphyses

Question 34

Between the diaphysis and epiphysis is the

Answer 34

metaphysis

Question 35

The outer covering of long bone is called

Answer 35

the periosteum

Question 36

the hollow inner cavity of long bone is called

Answer 36

the medullary cavity the contains the bone marrow

Question 37

The epiphysis contains

Answer 37

the epiphyseal plate or growth plate

Question 38

what type of bone is in the epiphysis

Answer 38

spongy trabeculated bone

Question 39

what type of bone is in the diaphysis

Answer 39

compact bone