skeletal system

Question 1

Consists of 80 bones, comprising the skull, vertebral column, and thoracic cage

Answer 1

Axial Skeleton

Question 2

Consists of 126 bones, including all bones of the upper and lower limbs, plus the bones of the pectoral and pelvic girdles that attach each limb to the axial skeletal

Answer 2

Appendicular skeletal

Question 3

How are bones of the skeletal system classified based on their shape?

Answer 3

Flat
Long
Sesamoid
Irregular
Short
Sutural

Question 4

What are the four types of cells in bones and what are their functions?

Answer 4

Osteogenic cell - stem cell
Osteoblast - bone builders
Osteoclast - bone cleaver (resorption)
Osteocyte - maintains bone

Question 5

What are some of the major differences and similarities between endochondral ossification and inter membranous ossification?

Answer 5

Endochondral ossification consists of chondrocytes forming matrix in hyaline cartilage where calcfication leads to cell death and produces osteogenic cells for the bone to develop.

Intermembranous Ossification consists of osteoblasts gathering in ossification center to secrete osteoid and calcium. Calcified matrix traps osteoblasts to form osteocytes and eventually leads to surface bone tissue to form compact bone

Question 6

What are the 5 zones in long bone formation?

Answer 6

Reserve Zone
Proliferative Zone
Zone of maturation and hypertrophy
Zone of calcified matrix
Zone of ossification

Question 7

what are the steps in bone appositional growth? (diameter growth)

Answer 7

Osteoclasts resorbs old bond that lines medullary cavity while osteoblasts produce new bone tissue beneath the periosteum. Both diameters of the diaphysis and medullary cavity increase.

Question 8

What are the steps in bone remodeling after an injury?

Answer 8

Origination
Activation
Resorption
Formation
Mineralization

Question 9

How do osteocytes regulate bone resorption and bone formation via RANKL-RANK interaction?

Answer 9

RANKL (osteocyte) - RANK (preosteoclast) interaction promotes osteoclastogenesis

Question 10

How do osteocytes regulate bone resorption and bone formation via RANKL-OPG interactions ?

Answer 10

RANKL (osteocyte) - OPG (osteocyte) interaction promotes bone formation

Question 11

How do osteocytes regulate bone resorption and bone formation via the SOST pathway?

Answer 11

SOST inhibit bone formation and activate bone resorption

Question 12

progressive systemic skeletal disease characterized by low bone mass and micro-architectural deterioration of bone tissue, with consequent increase in bone fragility and susceptibility of fracture

Answer 12

Osteoporosis

Question 13

What are the associated risk factors for osteoporosis?

Answer 13

early menopause (low estrogen)
eating disorders
small body frame
family history of osteoporosis
early malnutrition
low vitamin D
certain medications
intestinal pathology
space flight

Question 14

What are the preventative measures for osteoporosis?

Answer 14

Weight bearing exercise

Question 15

What are the functions of the skeletal system?

Answer 15

Support
Movement
Protection
Mineral Storage
Energy Storage
Hematopoiesis

Question 16

What step in long bone formation consists of small chondrocytes within the matrix that do not participate in bone growth but secure the epiphyseal plate to the osseous tissue of the epiphysis?

Answer 16

Reserve Zone

Question 17

What step in long bone formation consists of stacks of slightly larger chondrocytes and makes new chondrocytes (mitosis) to replace those that die at the diaphyseal end of the plate?

Answer 17

Proliferative Zone

Question 18

What step in long bone formation consists of chondrocytes being older/larger and mature cells are situated closer to the diaphyseal end of the plate?

Answer 18

Zone of maturation and hypertrophy

Question 19

What step in long bone formation contains chondrocytes that are dead because the matrix around them has calcified. Capillaries and osteoblasts from the diaphysis penetrate this zone. The osteoblasts secrete bone tissue on the remaining calcified cartilage. (zone closest to diaphysis)

Answer 19

Zone of calcified matrix

Question 20

What step in long bone formation consists of the zone of calcified matrix connecting to the epiphyseal plate to the diaphysis and osseous tissue added to the diaphysis results in length growth?

Answer 20

Zone of ossification