The Skeletal System: Bones And Bone Tissue

Question 1

What are the major functions of bones?

Answer 1

Support
Protection
Assistance in movement
Mineral storage and release
Blood cell production

Question 2

Where are axial bones?

Answer 2

Along the axis (middle)
(Houses the Vito organs of the body)

Question 3

Where are appendicular bones?

Answer 3

Along the appendage
(Responsible for locomotion)

Question 4

What are the 5 different types of bone?

Answer 4

Sesamoid (lie within tendons)
Short bone (transfer force from long bones)
Flat bone (protective)
Long bone (movement)
Irregular bone (protection combined with movement)

Question 5

What are the two different structures of bones?

Answer 5

Compact bone
Cancellous bone

Question 6

What are the characteristics of compact bone?

Answer 6

Dense and solid
Protection and strength
Repeating circular units

Question 7

What are the characteristics of cancellous bone?

Answer 7

Open space filled with needle like structure = trabeculau

Question 8

What is the composition of bone matrix?

Answer 8

Inorganic slats (hydroxyapatite =chemical crystals of calcium and phosphate)
Organic salts (composite of collagen fibres and proteoglycans)(flexible strength)

Question 9

What are the two types of bone marrow?

Answer 9

Red marrow
Yellow marrow

Question 10

What is the difference between red and yellow bone marrow?

Answer 10

Yellow marrow is no longer active in blood cell production (older)

Question 11

What are the major bone cells?

Answer 11

Progenitor cells (produce osteoblasts)
Osteoblasts (bone forming cells)
Osteocytes (mature osteoblasts)
Osteoclasts (reabsorb bone through dissolving mineral and breaking down collagen)

Question 12

What is the process of bone remodelling?

Answer 12

Removal of existing bone by osteoclasts and the deposition of new bone by osteoblasts

Question 13

What is the process of regulation of blood calcium level?

Answer 13

1) decreased blood calcium stimulates PTH secretion from parathyroid gland
2) PTH stimulates osteoclasts to breakdown bone and release calcium
3) in the kidney, PTH increases calcium reabsorption from the urine, PTH also stimulates active vitamin D formation
4) vitamin D promotes calcium absorption from the small intestine into the blood.
5) increased blood calcium stimulates calcitonin secretion from the thyroid gland
6) calcitonin inhibits osteoclasts, which allow for enhanced osteoblasts uptake of calcium from the blood to deposit into bone

Question 14

What are the characteristics of an ageing skeleton?

Answer 14

Decreased collagen=more brittle
Cancellous bone lost first
Followed by compact
Incomplete remodelling