Bone Cell Types

Question 1

Name cell types that make up the bone:

Answer 1

Osteoprogenitors, osteoblasts, osteocytes and osteoclasts

Question 2

What are osteoprogenitors?

Answer 2

Immature version of osteoblasts, they differentiate into osteoblasts (form osteoblasts), have growth factors

Question 3

What are osteoblasts?

Answer 3

They synthesise the inorganic and organic portion of the bone matrix to form new bone!

Question 4

What are osteocytes?

Answer 4

The occupy the lacunae (empty space Within the bone)
Have little branches to communicate with each other
Entrapped osteoblasts

Question 5

What are osteoclasts?

Answer 5

They break down bone. Derived from monocytes, they reabsorb bone using acid and enzymes
They break the bone down using an enzyme

Question 6

Name the functions of the skeleton:

Answer 6

Mineral storage (calcium and phosphate)
Support (framework that supports the body and cradles soft organs) 
Protection (for delicate organs/brain)
Movement (bones act as attachment points)

Question 7

Name the parts of the bone

Answer 7

• cartilage
• epiphysis/metaphysis
• epiphyseal line
• trabecular bone
• cortical bone
• bone marrow

Question 8

Name the types of bone:

Answer 8

Long bones (metacarpals, metatarsals, phalanges, humerus, ulna)
Short bones (carpals, tarsals)
Flat bones (rib, scapula, skull, sternum)
Irregular bones (vertebrae and some facial bones) 
Sesamoid bones (patella)

Question 9

Explain the Haversian systems: inner portion of the bone is made of?

Answer 9

Cancellous/trabecular bone: looks like a sponge (lots of gaps: v large surface area)

Question 10

The layer that surrounds the spongy bone is the?

Answer 10

Compact (cortical bone) surrounds the spongy bone. Made of hydroxyapatite and of cylindrical osteons with layers (lamellae) of calcified bone

Question 11

What is in the centre of the lamellae (in the compact bone)?

Answer 11

The central canal (in this travels blood vessels/lymph vessels)

Question 12

What’s in between the sheets if lamellae?

Answer 12

Tiny channels called canaliculi (these contain osteocytes which radiate through the osteons)

Question 13

What’s the very outer layer of bone called?

Answer 13

Periosteum membrane

Question 14

Bone surfaces in synovial joints are covered with?

Answer 14

With smooth articular cartilage lubricated by synovial fluid

Question 15

What happens in osteoporis?

Answer 15

Trabecular bone is reabsorbed faster by osteoclasts then it’s reformed by osteoblasts causing bone thinning and greater fracture risk

Question 16

What does the cartilage do?

Answer 16

Protects the ends of long bones

Question 17

What’s an epiphysis/metaphysis and an epiphyseal line?

Answer 17

Epiphysis/metaphysis Is found at each end

The epiphyseal line is a layer of growing cartilage

Question 18

Where is the trabecular bone and what’s the shaft?

Answer 18

Trabecular bone is on each side of the epiphyseal line

The shaft is cortical bone, it contains bone marrow where red and white blood cells come from

Question 19

What kind of tissue Is bone?

Answer 19

Connective tissue and is highly metabolically active

Question 20

Explain human skeleton compartments?

Answer 20

It contains 10-12g of bone (1-2kg of calcium, 0.75kg phosphorus) require 1g per day
70% Of bone is hydroxyapatite (calcium phosphate)
30% is proteins/collagen