💪3. Bone physiology

Question 1

What are the main components of the skeletal system?

Answer 1

• Bones
• Cartilage
• Joints
• Ligaments
• Other connective tissues

These components work together to provide structure and support to the body.

Question 2

List the functions of the skeletal system.

Answer 2

• Support against gravity
• Leverage for muscle action
• Protection of soft internal organs
• Storage (Calcium, Phosphorus, fat)
• Blood cell production

The skeletal system plays a crucial role in maintaining overall body function and health.

Question 3

What are the types of bone classification?

Answer 3

• Flat bones
• Long bones
• Short bones
• Irregular bones
• Sutural bones
• Sesamoid bones

Each type of bone has unique characteristics and functions.

Question 4

What is the function of flat bones?

Answer 4

• Protection
• Muscle attachment

An example of flat bones is the skull.

Question 5

What defines long bones?

Answer 5

• Longer than they are wide
• Leverage for movement

Examples include phalanges, humerus, and femur.

Question 6

What are short bones characterized by?

Answer 6

• Width approximately equal to length

An example of short bones is carpals.

Question 7

What are the characteristics of irregular bones?

Answer 7

• Complex shapes
• Transfer weight and support

An example of irregular bones is the vertebrae.

Question 8

What are sesamoid bones?

Answer 8

• Small bones that develop in tendons

An example of a sesamoid bone is the patella.

Question 9

What are the features of a typical long bone?

Answer 9

• Diaphysis (shaft)
• Epiphysis (ends)
• Articular cartilage

The diaphysis contains compact dense bone and a medullary cavity.

Question 10

What are the main constituents of bone tissues?

Answer 10

• Ground substance (2/3 of bone matrix)
• Protein (1/3 of matrix)
• Bone cells (osteoblasts, osteocytes, osteoclasts)

The ground substance primarily consists of hydroxyapatite, calcium salts, and ions.

Question 11

What is the role of osteoblasts?

Answer 11

Immature bone cells that secrete matrix proteins

Osteoblasts are crucial for bone formation.

Question 12

What do osteocytes do?

Answer 12

Mature bone cells that maintain the bone matrix

They are derived from osteoblasts.

Question 13

What is the function of osteoclasts?

Answer 13

Multinucleate cells that secrete acids and enzymes to dissolve bone matrix

Osteoclasts are essential for bone resorption.

Question 14

What is an osteon?

Answer 14

The basic functional unit of compact bone

Osteons are columnar and strong in the long axis.

Question 15

What are the components of spongy bone?

Answer 15

• Trabeculae (arches, rods, plates of bone)
• Red marrow (forms red blood cells)
• Yellow bone marrow (stores fat)

Spongy bone is strong in many directions.

Question 16

What is the periosteum?

Answer 16

The membrane outside of bone

It has an outer fibrous layer of collagen and an inner cellular layer.

Question 17

What is the endosteum?

Answer 17

The membrane lining the bone

It lines the medullary cavity, central canals, and trabeculae.

Question 18

What is ossification?

Answer 18

The formation of bone

It includes intramembranous and endochondral ossification.

Question 19

What is intramembranous ossification?

Answer 19

Flat bone formation from mesenchymal cells differentiating into osteoblasts

It forms spicules of bone.

Question 20

What is endochondral ossification?

Answer 20

Formation from a cartilage model

Chondrocytes enlarge and die, leading to the formation of ossification centers.

Question 21

What is appositional bone growth?

Answer 21

Growth in width of bone

Osteoblasts deposit bone on the outside while osteoclasts resorb bone on the inside.

Question 22

What are the requirements for normal bone growth?

Answer 22

• Minerals (Calcium, phosphate)
• Vitamins (Vitamin D3)
• Hormones (Growth hormones, sex hormones)
• Loading

These factors are essential for maintaining healthy bone development.

Question 23

What is bone remodeling?

Answer 23

Continuous breakdown and reforming of bone tissue

It is influenced by loading patterns and calcium homeostasis.

Question 24

True or false: Peak bone mass is usually reached in the 30s.

Answer 24

TRUE

Bone loss typically begins in the 40s, with rapid loss in women post-menopause.

Question 25

What are the steps in **fracture repair**?

Answer 25

* Bleeding and formation of clot * Formation of external callus and internal callus * External callus replaced by bone, internal callus unites broken ends ## Footnote These steps are crucial for healing broken bones.