Bone structure 19

Question 1

Describe and name types of long bones.

Answer 1

Longer rather than wide bones such as thigh, leg, arm, forearm, fingers & toes.

Question 2

Describe and name types of short bones.

Answer 2

Almost cubed shaped bones such as most wrist and ankle bones.

Question 3

Describe and name types of Flat bones.

Answer 3

Bones with a thin and extensive surface such as cranial bones, sternum, ribs and scapulae.

Question 4

Describe and name types of irregular bones.

Answer 4

Bones that don’t fit in any other category such as vertebrae and some facial bones.

Question 5

What are the four bone shapes?

Answer 5

Long, flat, short, irregular.

Question 6

Extracellular matrix consists of what (including %)

Answer 6

25% water, 25% collagen fibres, 50% crystallised mineral salts called hydroxyapatite (hydrated calcium phosphate).

Question 7

What do osteogenic cells develop into?

Answer 7

Osteoblasts.

Question 8

Where are osteogenic cells found?

Answer 8

Periosteum.

Question 9

Explain the functions of osteoblasts.

Answer 9

Secrete collagen fibres. Build matrix & become trapped in lacunae to become osteocytes.

Question 10

Explain how osteoblasts become osteocytes.

Answer 10

osteoblasts become trapped in lacunae.

Question 11

What is the function of osteocytes.

Answer 11

To maintain bone.

Question 12

What are osteoclasts formed from?

Answer 12

Monocytes (white blood cell)

Question 13

What is the function of osteoclasts?

Answer 13

Digest, breakdown bone matrix for normal bone turnover.

Question 14

Describe The microscopic structure of bone.

Answer 14

Osteogenic cells (found in periosteum) develop into osteoblasts (secrete collagen fibres, forms matrix) and become osteocytes (by becoming trapped in lacunae). Osteocytes maintain bone tissue. White blood cells (monocytes) form osteoclasts (digest, breakdown bone matrix for normal bone turnover.

Question 15

Compact bone structure takes up what % of bone in the body?

Answer 15

80%

Question 16

Spongy/cancellous bone takes up what percentage of bone in the body?

Answer 16

20%

Question 17

what do ‘volkmanns (perforating) canals’ do?

Answer 17

Complete the communication pathway from the outside of the bone to its interior. These run into the compact bone at right angles to the shaft.

Question 18

what part of the bone uses osteons as units?

Answer 18

Compact bone structure.

Question 19

What part of the bone include both lacunae and canaliculae?

Answer 19

Both parts; compact bone structure & spongy/cancellous bone.

Question 20

What are the 6 functions of the bone.

Answer 20

support,
protection,
leverage - for motion,
mineral homeostasis e.g. calcium,
blood cell production - haemopoiesis in red bone marrow,
triglyceride (fat) storage- yellow bone marrow.

Question 21

Negative feedback loops control blood levels of what mineral during homeostasis?

Answer 21

Calcium (Ca2+)

Question 22

What 3 hormones are used during homeostasis to regulate calcium transport in the blood?

Answer 22

Parathyroid Hormone, Calcitriol, calcitonin.

Question 23

What does parathyroid hormone do?

Answer 23

Detect lowered calcium levels. Increases osteoclast activity & decreases loss in urine.

Question 24

What does hormone Calcitriol do?

Answer 24

Secreted from kidneys, increases absorption of calcium from the blood.

Question 25

What does hormone Calcitonin do?

Answer 25

Secreted from thyroid glands, opposes parathyroid hormone. Decreases osteoclast activity.

Question 26

In the macroscopic structure of a bone, what is the shaft known as?

Answer 26

Diaphysis.

Question 27

In the macroscopic structure of a bone, what is the terminal portion known as?

Answer 27

Epiphysis

Question 28

In the macroscopic structure of a bone, describe the metaphysis.

Answer 28

vascular region adjoining epiphyseal cartilage.

Question 29

In the macroscopic structure of a bone, what is the part situated at a joint known as?

Answer 29

Articular Cartilage.

Question 30

In the macroscopic structure of a bone, what is the fibrous membrane called?

Answer 30

Periosteum.

Question 31

In the macroscopic structure of a bone, what is the central hollow space called?

Answer 31

Medullary cavity.

Question 32

In the macroscopic structure of a bone, what is the membrane lining the inner cavity called?

Answer 32

Endosteum.

Question 33

draw an osteogenic cell.

Answer 33

Now draw an osteoblast, an osteocyte & an Osteoclast

Question 34

what does lacunae contain?

Answer 34

osteocytes.