SM_219a: Bone Histology

Question 1

Types of bones are _____ and _____

Answer 1

Types of bones are flat bones and long bones

Question 2

Flat bones include bones of the _____, _____, and _____

Answer 2

Flat bones include bones of the skull, face, and clavicle

(long bones are everything else)

Question 3

_____ is the shaft of a long bone

Answer 3

Diaphysis is the shaft of a long bone

Question 4

_____ is the end of a long bone

Answer 4

Epiphysis is the end of a long bone

Question 5

_____ connects the diaphysis and epiphysis and includes the ______

Answer 5

Metaphysis connects the diaphysis and epiphysis and includes the epiphyseal plate

Question 6

_____ sit on the surface and synthesize bone

Answer 6

Osteoblasts sit on the surface and synthesize bone

Question 7

_____ are old osteoblasts that sit within lacunae and are connected bu canaliculi to diffuse nutrients and waste

Answer 7

Osteocytes are old osteoblasts that sit within lacunae and are connected bu canaliculi to diffuse nutrients and waste

Question 8

_____ are multinucleated giant cells the resorb bone

Answer 8

Osteoclasts are multinucleated giant cells the resorb bone

Question 9

Bone remodeling involves _____ and _____ of bone on the _____ by _____ and _____, respectively

Answer 9

Bone remodeling involves apposition and resorption of bone on the surface by osteoblasts and osteoclasts, respectively

Question 10

Bone is composed of ______ and ______

Answer 10

Bone is composed of 70% inorganic material (hydroxyapatite) and 30% organic material (90% type I collagen)

(hydroxyapatite is a complex of calcium and phosphate)

Question 11

Collagen is mineralize through ______

Answer 11

Collagen is mineralize through exocytosis of small vesicles containing alkaline phosphatase and pyrophosphatase from the osteoblasts into newly formed bone (osteoid) to initiate mineralization and bind Ca and P

Question 12

Describe the role of Ca and PTH in bone metabolism

Answer 12

1. Low serum Ca sensed by parathyroid gland
2. Parathyroid gland secretes PTH
3. PTH stimulates bone resorption

(PTH regulated through Vitamin D and kidney activation of Vitamin D)

Question 13

_____ is found on the outside of long bones, while _____ is found inside long bones

Answer 13

Compact/lamellar bone is found on the outside of long bones, while trabecular/spongy bone is found inside long bones

Question 14

____ is the structural unit of compact bone

Answer 14

Haversian systems (osteons) are the structural unit of compact bone

(osteocytes surround a central canal that carries blood vessels and nerve fibers, concentric rings around the canal are from layers of bone laid down by osteoblasts)

Question 15

_____ extend out of _____ to connect osteocytes together, allowing them to _____ and _____

Answer 15

Canaliculi extend out of lacunae to connect osteocytes together, allowing them to acquire nutrients and excrete wastes

Question 16

_______ is when new bone develops from and replaces hyaline cartilage and occurs in long bones, bones at the base of the skull, and short bones in the hands and feet

Answer 16

Endochondrial ossification is when new bone develops from and replaces hyaline cartilage and occurs in long bones, bones at the base of the skull, and short bones in the hands and feet

Question 17

______ is when new bone develops directly from a capsule of undifferentiated connective tissue and occurs in the flat bones of a face, cranial bones, and clavicles

Answer 17

Intramembranous ossification is when new bone develops directly from a capsule of undifferentiated connective tissue and occurs in the flat bones of a face, cranial bones, and clavicles

Question 18

Describe endochondrial ossification

Answer 18

Endochondrial ossification

1. Primary ossification center in the shaft extends out both ways
2. Secondary ossification center starts at epiphysis
3. Ossification centers grow together until they meet
4. Epiphyseal plate forms

Question 19

Endochondrial ossificiation includes zones, namely _____, _____, _____, and _____

Answer 19

Endochondrial ossificiation includes zones, namely zone of ossification, zone of hypertrophy, zone of proliferation, and reserve cartilage

Question 20

Intramembranous ossification involves bone forming out of ______ as ______ buld bone layer by layer outwards

Answer 20

Intramembranous ossification involves bone forming out of primitive connective tissue as osteoblasts build bone layer by layer outwards

Question 21

_____ forms the edge of woven/immature bone

Answer 21

Osteoid forms the edge of woven/immature bone

(lacks lamellar structure)

Question 22

Lamellar/mature bone has _____

Answer 22

Lamellar/mature bone has organized lamellae of bone