Bones

Question 1

What are the functions of the skeleton?

Answer 1

• support
• protection
• movement
• blood and immune formation
• electrolyte balance

Question 2

What are the 4 types of bones?

Answer 2

1. Long bones, ex- femur
2. Short bones, ex- tarsals
3. Flat bones, ex- ribs
4. Irregular bones, ex- scapula

Question 3

What tissues are found in a bone?

Answer 3

1. Osseous tissue: osteocytes
2. Blood
3. Bone marrow: both red and yellow
4. Articular cartilage
5. Adipose tissue: in yellow bone marrow
6. Nervous tissue
7. Other connective tissue: reticular

Question 4

What does mineralization mean?

Answer 4

The process involved in gardening of bone by deposition of calcium phosphate and other minerals.

Question 5

How many bones are in the human body?

Answer 5

206 in adult human

Question 6

What are the general features of long bones?

Answer 6

Diaphysis(compact bone) 
Epiphysis
Metaphysis 
Medullary cavity - space inside contains marrow
Spongy bone 
Articular cartilage 
Nutrient foramina 
Coverings: periosteum(surrounds outside of bone) 
Endosteum(lines the medullary cavity)

Question 7

Describe the general features of bone coverings

Answer 7

Periosteum: has some collagen fibers continuous with tendons

Perforating fibers: collagen fibers of periosteum continuous with matrix

Endosteum: lines medullary cavity

Question 8

Describe the general features of the epiphyseal plate

Answer 8

• epiphyseal(hyaline cartilage)
• separates epiphysis and diaphysis in children and adolescents
• growth zone in long bones
• cartilage expands to create bone length (=your height)
• disappears when epiphysis and diaphysis join ~age 18-20
• epiphyseal line visible in some adults

Question 9

What are the major cell types found in bone tissue and their functions?

Answer 9

• osteogenic\osteoprogenitor
• osteoblasts
• osteocytes
• osteoclasts

Question 10

Give a general description of osteogenic( AKA osteoprgenitor) cells

Answer 10

Osteogenic cells develop from mesenchyme. They occur in endosteum, inner surface of periosteum, and in central canals. These cells are capable of mitosis, and are the source of new osteoblasts and osteocytes.

Question 11

Describe the function and development of osteoblasts

Answer 11

Bone-forming cells (B for build). They develop from osteogenic cells. Osteoblasts make collagen and glycosaminoglycans(GAGs) of bone matrix. They play role in mineralization osteoblasts do not divide. If needed, osteogenic cells can rapidly make more osteoblasts. Lacunae formed as matrix develops around the osteoblasts(they cement themselves in).

Question 12

Describe the function and development of osteocytes

Answer 12

These cells arise from osteoblasts trapped in lacunae.

• they maintain the matrix
• osteocytes manage blood calcium and bone calcium.
• they also are greatly responsible for phosphate and magnesium balance in the blood.

Question 13

Describe the function and development of osteoclasts

Answer 13

-larger cells arising from monocytes(a type of white blood cell)
-cells have multiple nuclei(from many fused monocytes)
Dissolve matrix by acids and enzymes, puts minerals into blood
-responsible for increasing blood levels of calcium by releasing calcium from bone into the bloodstream