Physiology of bone and calcium homeostasis

Question 1

How is soft tissue growth measured?

Answer 1

By weight

Question 2

How is bone growth measured?

Answer 2

By height

Question 3

What does tissue and bone growth require?

Answer 3

Multiple hormones and paracrines

Question 4

What are the 2 effects hormones and paracrines have on tissue and bone growth?

Answer 4

Direct or permissive effects on growth

Question 5

Which hormones are required for bone protein and cell division?

Answer 5

GH and IGF

Question 6

What role do thyroid hormones play in tissue and bone growth?

Answer 6

Permissive role

Question 7

What does thyroid hormone directly contribute to?

Answer 7

Nervous system development

Question 8

What role does insulin play in bone and soft tissue growth?

Answer 8

Supports growth

Provides glucose energy

Question 9

Which steroids play a role in bone and soft tissue growth?

Answer 9

Sex steroids

Question 10

What does bone growth require?

Answer 10

Adequate dietary calcium and protein

Question 11

What is bone growth impacted by?

Answer 11

Hormonal control of calcium homeostasis

Question 12

What do calcium phosphate crystals precipitate and attach to?

Answer 12

Collagen fibre lattice

Question 13

What is the most common calcium phosphate?

Answer 13

Hydroxyapatite (Ca10(PO4)6(OH)2)

Question 14

What do bone cells occupy?

Answer 14

Spaces within the matrix, and are well supplied with blood

Question 15

Which layer is compact/cortical bone?

Answer 15

On the outer surface of the bone

Question 16

What does the compact/cortical bone provide?

Answer 16

Strength

Question 17

Which layer is trabecular bone?

Answer 17

Inner spongy layer

Question 18

What is trabecular bone?

Answer 18

Open, cell‐filled spaces between struts of calcified lattice

Question 19

Is bone marrow found in all bones?

Answer 19

No, just some

Question 20

What does bone growth require regarding the matrix?

Answer 20

That matrix is deposited faster than it is broken down (resorbed)

Question 21

What are osteoblasts?

Answer 21

Modified fibroblasts that are specialised bone-forming cells

Question 22

What do osteoblasts produce?

Answer 22

Enzymes & osteoid (collagen & protein mix)

Question 23

What binds to the enzymes and osteoid produced by osteoblasts?

Answer 23

Hydroxyapatite

Question 24

Which proteins are produced by osteoblasts?

Answer 24

Osteocalcin and osteonectin

Question 25

What do osteocalcin & osteonectin do?

Answer 25

Aid in deposition

Question 26

What will matrix deposit on outer surface of bone result in?

Answer 26

Bone diameter increase

Question 27

What is the epiphyseal plate the site of?

Answer 27

Linear growth of long bone growth

Question 28

What is the diaphysis?

Answer 28

End of bone shaft

Question 29

Where are chondrocytes found?

Answer 29

Near epiphysis

Question 30

What are chondrocytes?

Answer 30

Collagen-producing cells of cartilage

Question 31

How do chondrocytes produce collagen?

Answer 31

Continuously dividing columns, increasing length

Collagen layer thickens & old chondrocytes disintegrate leaving spaces

Question 32

What do osteoblasts do?

Answer 32

Lay down bone on top of cartilage base where chondrocytes degenerated

Shaft lengthens, epiphyseal plate is active

Question 33

What happens to osteoblasts when they complete work?

Answer 33

Revert to less active form

Question 34

What does bone serve as a depot for?

Answer 34

Stored calcium