Biology 3.12

Question 1

Bone

Answer 1

Made of collagen fibres that have been mineralized by the deposition of calcium phosphate. Bone tissue remodelled by osteoblasts that synthesize bone, osteoclasts break down bone to release calcium and phosphate to bloodstream. Osteoblasts trapped in bone matrix mature into osteocytes

Question 2

Compact bone

Answer 2

Outer bone layer, dense without cavities, osteoblasts deposit bone tissues in columns called osteons (or Haversian systems)

Question 3

Haversian systems (osteon)

Answer 3

Where osteoblasts deposit bone tissues. It is a central Haversian canal containing bone’s vascular system and is surrounded by a number of circular layers of bony matrix called lamellae. Some osteoblasts become osteocytes and lie within spaces called lacunae and communicate with each other via canaliculi canals

Question 4

Spongy bone

Answer 4

Composed of interconnecting lattice of bony spicules called trabeculae. Less dense, found in centre, surrounded by compact bone, spaces filled with marrow. Consists of yellow bone marrow and red bone marrow

Question 5

Yellow bone marrow

Answer 5

Part of spongy bone. Filled with inactive adipocytes (fat cells)

Question 6

Red bone marrow

Answer 6

Part of spongy bone. Site of hematopoiesis (blood cell formation for RBC, WBC, platelets)

Question 7

Bone types

Answer 7

Flat bones, long bones, short (cuboidal) bones, sesamoid bones and irregular bones

Question 8

Flat bones

Answer 8

thin, wide, protects organs

Question 9

Long bones

Answer 9

Two ends called epiphysis, central region called diaphysis, in growing humans the metaphysic or epiphyseal plate has the growth plate and is in the centre of the bone

Question 10

Short (cuboidal) bones

Answer 10

square shaped

Question 11

Sesamoid bones

Answer 11

small, flat, sesame seed shaped bones found within tendons which increase angle movement

Question 12

Irregular bones

Answer 12

Bones of complex shapes and/or irregular layers

Question 13

Bone formation

Answer 13

Consists of two steps: Intramembranous ossification and endochondral ossification

Question 14

Intramembranous ossification

Answer 14

Part of bone formation. In fetus, undifferentiated mesenchymal connective tissue is transformed and replaced by bone tissue. Osteoblasts secrete bony matrix on connective tissue, followed by calcification (hardening) of bone. Occurs for flat bones of skull, clavicles and more

Question 15

Endochondral ossification

Answer 15

Part of bone formation. For long bones and most other bones in the body. Hyaline cartilage model of bone is replaced by bony matrix via deposition by osteoblasts during skeletal growth. Osteoclasts break down bone to help with reshaping and invasion of vasculature and nervous tissue in primary and secondary ossification centres. Endochondral ossification continues for skeletal growth in the metaphysis or epiphyseal plate of long bones:
- zone of reserve
- zone of proliferation
- zone of maturity and hypertrophy
- zone of calcification
- zone of ossification
End of skeletal growth is when entire cartilaginous region becomes bone

Question 16

Zone of reserve

Answer 16

Part of endochondral ossification for skeletal growth in the metaphysis or epiphyseal plate of long bones. Closest to the epiphysis, dormant cartilage depositing cells called chondrocytes are found here

Question 17

Zone of proliferation

Answer 17

Part of endochondral ossification for skeletal growth in the metaphysis or epiphyseal plate of long bones. Chondrocytes begin rapid mitosis and proliferation

Question 18

Zone of maturity and hypertrophy

Answer 18

Part of endochondral ossification for skeletal growth in the metaphysis or epiphyseal plate of long bones. Chondrocytes stop mitosis and begin hypertrophy

Question 19

Zone of calcification

Answer 19

Part of endochondral ossification for skeletal growth in the metaphysis or epiphyseal plate of long bones. Chondrocytes undergo apoptosis, matrix undergoes calcification

Question 20

Zone of ossification

Answer 20

Part of endochondral ossification for skeletal growth in the metaphysis or epiphyseal plate of long bones. Closest to diaphysis, osteoclasts dissolute the calcified cartilage and osteoblasts replace it with mineralized bone tissue

Question 21

Type of bone attachments

Answer 21

Sutures, ligaments, tendons, axial skeleton, appendicular skeleton

Question 22

Sutures

Answer 22

Type of bone attachment. Immovable joints connecting two bones

Question 23

Ligaments

Answer 23

Type of bone attachment. Connective tissue connecting 2 bones in regions where bones move relative to one another

Question 24

Tendons

Answer 24

Type of bone attachment. Connect muscle to bone to aid with movement, point of muscle attachment to stationary bone is origin. Point of muscle attachment to movable bone is insertion.

Question 25

Axial skeleton

Answer 25

Type of bone attachment. Skull, vertebral column, rib cage; the central body axis

Question 26

Appendicular skeleton

Answer 26

Type of bone attachment. Bones of appendages, pectoral/pelvic girdles; movement

Question 27

Cartilage

Answer 27

Connective tissue that is softer and more flexible than bone, not innervated, avascular, receives nutrients from surrounding extracellular fluids. Made by chondrocyte cells that secrete collagen and elastin proteins. Consists of hyaline cartilage, elastic cartilage and fibrous cartilage

Question 28

Hyaline cartilage

Answer 28

Most common type, in airways, between joints where bones articulate with one another. Reduces friction, absorbs shock. In growing people, can be found within bone for endochondral ossification.

Question 29

Elastic cartilage

Answer 29

In flexible regions, ears, epiglottis, provides shape and support

Question 30

Fibrous cartilage

Answer 30

In high stress areas between intervertebral disks, also in pubic symphysis. Absorbs shock, provides support