Bone Tissue & Microscopic Structure

Question 1

What makes bone a living tissue?

Answer 1

Cells

Question 2

What do bone cells respond to?

Answer 2

External factors and trauma. If you use your body a certain way (sports) it will make slight adjustments to help with that. It responds to trauma to unite broken bits (that’s why good realignment is important)

Question 3

What are the two extracellular components that bone has that makes it hard?

Answer 3

Organic = Organic molecules
Inorganic = Mineral (makes bones hard)

Question 4

What percentage of the extra-cellular matrix (ECM) makes up the organic and inorganic sections on bones?

Answer 4

33% organic
67% inorganic

Question 5

What makes up the organic percentage of the ECM?

Answer 5

Collagen and Ground substance (what the collagen sits in)

Question 6

What makes up the inorganic percentage of the ECM?

Answer 6

Mineral component (not sure I need to know the names?)

Question 7

What is the function of the organic percentage of ECM?

Answer 7

To resist tension (so that the bone is not brittle)

Question 8

What is the function of the inorganic percentage of the ECM?

Answer 8

Makes the bone hard and resistant to compression

Question 9

What are the names of the cells that make up the cellular component of the bone?

Answer 9

Osteoblasts, Osteocytes, Osteoclasts, Osteogenic cells (not important, turns into osteoblasts),

Question 10

What do the three cells do?

Answer 10

Maintain the bones homeostasis by balancing the destruction and formation of bone so that the amount of bone stays the same

Question 11

What is the function of osteoblasts?

Answer 11

Produce new bone matrix

Question 12

What is the function of osteocytes?

Answer 12

Recycle protein and minerals from matrix

Question 13

What is the function of osteoclasts?

Answer 13

To destroy bone matrix

Question 14

The two types of bone tissue are made of the same thing but structured differently. What are the structures of both?

Answer 14

Osteon structure (compact)
Trabecular structure (cancellous)

Question 15

What is the anatomy word for holes?

Answer 15

Foramina

Question 16

What are osteons?

Answer 16

longitudinal unit within compact bone

Question 17

What is the function of osteons?

Answer 17

to provide a pathway for nutrients to get to the cells in the ECM

Question 18

What is the central canal?

Answer 18

A canal in the middle of an osteon that contains blood vessels and nerves

Question 19

What are lamellae?

Answer 19

a series of cylinders formed of ECM around the central canal

Question 20

What is the function of lamellae?

Answer 20

to form the shape of the osteon and the collagen fibres within the lamellae resist forces

Question 21

What are lacuna?

Answer 21

Lakes for osteocytes

Question 22

What are canaliculi?

Answer 22

channels for osteocytes through the extra-cellular matrix (ECM)

Question 23

What are trabeculae?

Answer 23

Struts of lamella bone. Makes up the cancellous bone structure.

Question 24

Where is bone marrow found in cancellous bones?

Answer 24

Within the cavities between trabeculae

Question 25

Why does cancellous bone not have a central canal?

Answer 25

Because there are lots of gaps between trabeculae so it is easy for nutrients to get into the blood stream

Question 26

Why trabecular bone?

Answer 26

It can take force from multiple directions, it directs the force from body weight in a single direction down the shaft and spreads it distally

Question 27

How is weight transferred in the hip joint?

Answer 27

trabeculae channel weight around the ilia into femora

Question 28

How do osteoblasts (formation) and osteoclasts (destruction) work together for bone formation?

Answer 28

Osteoblasts add bone matrix in lamellae to bone surface while osteoclasts remove bone matrix from medullary cavity.

Question 29

What is bone homeostasis?

Answer 29

The balance of osteoblasts and osteoclasts activity

Question 30

What does the fact that bone is constantly being destroyed/formed allow for? (called bone remodelling)

Answer 30

It allows the body to mobilise calcium, phosphate and other minerals from the bone matrix (the stuff that has been stored in the bone)

Question 31

What does the bone remodelling process allow for?

Answer 31

allows bone to respond plastically and allows shape change through life to resist strain etc.

Question 32

What happens if bone homeostasis isn’t maintained?

Answer 32

You can get an imbalance in osteoblastic and osteoclastic activity, which results in conditions like osteoporosis/osteopenia(less bad version of osteoporosis).

Question 33

What does osteoporosis look like inside the bone?

Answer 33

Loss of cortical(compact) bone, in cancellous bone it results in trabeculae becoming thinner, compression fractures or vertebrae.

Question 34

Causes of osteoporosis

Answer 34

Females = loss of oestrogen post-menopause, lifestyle factors (lack of excersise or certain nutrition).

Question 35

What are the nutritional factors that potentially cause osteoporosis?

Answer 35

Lack of sleep, smoking, drinking, lack of calcium (milk), too much salt, menopause.

Question 36

How does your starting point effect your risk of osteoporosis?

Answer 36

Peak bone mass in your 20’s and if this is already low then more likely to become osteoporotic, if you already exercise a lot your bones know they need to stay thicker/stronger.