Unit4- 4.1~ Structure of bone

Question 1

What does a long bone consist of?

Answer 1

• Diaphysis
• Epiphysis
• Metaphysis
• Epiphyseal plates
• Hyaline cartilag

Question 2

Explain diaphysis

Answer 2

A long central shaft

Question 3

Explain epiphysis

Answer 3

Forms the larger rounded ends of long bones

Question 4

Explain metaphysis

Answer 4

Area between the diaphysis & epiphysis at both ends of the bone

Question 5

Explain epiphyseal plates

Answer 5

Plates of cartilage, known as growth plates. Once we stop growing the cartilage plates stop producing cartilage cells & gradually replaced by bone

Question 6

Explain hyaline cartilage

Answer 6

Covers the end of bones, where they form a joint with another bone. Is a firm but elastic cartilage which provides shock absorbtion to joint and has no neural or vascular supply

Question 7

What are the 2 types of bone tisse?

Answer 7

• Compact
• Spongy

Question 8

What are the 3 types of cells that contribute to bone homeostasis?

Answer 8

• Osteoblast: bone-forming cell
• Osteoclasts: resorb/break down bone
• Osteocytes: mature bone cell

Question 9

Explain compact bones

Answer 9

• Compact bone consists of tightly packed osteons (Haversian systems)
• Each osteon contains a central Haversian canal surrounded by concentric rings (lamellae) of matrix
• Osteocytes (bone cells) are located in spaces called lacunae between the rings of the matrix
• Canaliculi (small channels) connect the lacunae to the Haversian canal, facilitating nutrient and waste exchange
• The Haversian systems are tightly packed, forming a solid, dense structure
• Blood vessels in the Haversian canals run parallel to the bone’s axis
• Perforating canals connect the Haversian canals to surface vessels

Question 10

Explain spongy bone

Answer 10

• Spongy (cancellous) bone is lighter and less dense than compact bone
• It is composed of plates (trabeculae) and bars of bone surrounding small, irregular cavities containing red bone marrow
• Canaliculi in spongy bone connect directly to adjacent cavities for blood supply, instead of a central Haversian canal
• The trabeculae appear haphazardly arranged but are organized to provide maximum strength, similar to structural braces
• The trabeculae align with lines of stress and can realign if the direction of stress changes.