Connective tissue (Bone)

Question 1

what are the 3 key cell types?

Answer 1

1. osteoclasts
2. osteoblasts
3. osteoclasts

Question 2

bone has a typical _______ organization

Answer 2

lamellar

Question 3

__________ secrete the matrix that then hardens by calcification, trapping the differentiating cells now called osteocytes in individual lacunae

Answer 3

Osteoblasts

Question 4

__________ maintain the calcified matrix and receive nutrients from microvasculature in the central canals of the osteons via very small channels called canaliculi that interconnect the lacunae

Answer 4

Osteocytes

Question 5

The ____________ consists of dense connective tissue, with a primarily fibrous layer covering a more cellular layer

Answer 5

periosteum

Question 6

Bone is vascularized by small vessels that penetrate the matrix from the periosteum. __________ covers all trabeculae around the marrow cavities

Answer 6

Endosteum

Question 7

________ osteoblasts are more flattened and cover the bony surface

Answer 7

inactive

Question 8

________ are located within lacunae surrounded by matrix

Answer 8

osteocytes

Question 9

Osteoblasts secrete _________containing collagen type I, proteoglycans and other molecules, and matrix vesicles

Answer 9

osteoid

Question 10

As osteoid undergoes calcification, hardens, and traps the osteoblasts, these cells differentiate further as _________

Answer 10

osteocytes

Question 11

how are osteoclasts made?

Answer 11

produced by the fusion of blood monocytes, where they reside on bondy surfaces and erode the matrix during bone remodeling

Question 12

________ secrete type I collagen, several glycoproteins, and proteoglycans

Answer 12

osteoblasts

Question 13

Osteoblasts also release very small membrane-enclosed _______ ________ with which alkaline phosphatase and other enzymes are associated

Answer 13

matrix vesicles

Question 14

what is an osteoclast?

Answer 14

large cell with several nuclei derived by the fusion in bone of several blood-derived monocytes

Question 15

In living tissue the compact bone is covered externally with ______________ and all trabecular surfaces of cancellous bone are covered with ____________

Answer 15

periosteum, endosteum

Question 16

describe the development of an osteon

Answer 16

During remodeling of compact bone, osteoclasts act as a cutting cone tunneling into existing bone matrix. Behind the osteoclasts, a population of osteoblasts enters the newly formed tunnel and lines its walls. The osteoblasts secrete osteoid in a cyclic manner, producing layers of new matrix (lamellae) with cells (osteocytes) trapped in lacunae. The tunnel becomes constricted with multiple concentric layers of new matrix, and its lumen finally exists as only a narrow central canal with small blood vessels

Question 17

where does osteogenesis: endochondral ossification take place?

Answer 17

within a piece of hyaline cartilage whose shape resembles a small version of bone be formed.

Question 18

Calcified cartilage matrix are __________ and devoid of chondrocytes and become enclosed by more lightly stained osteoid and woven bone produced by active osteoblasts.

Answer 18

basophilic

Question 19

The large and growing primary ossification center in long bone diaphyses and the secondary ossification centers in epiphyses are separated in each developing bone by a plate of cartilage called the _____________ __________

Answer 19

epiphyseal plate

Question 20

what are the five general zones of bone elongation?

Answer 20

1. reserve of normal hyaline cartilage
2. cartilage with proliferating chondroblasts aligned as axial aggregates in lacunae
3. degenerating cartilage in which the aligned cells are hypertrophic and the matrix condensed
4. an area in which the chondrocytes have disappeared and the matrix is undergoing calcification
5. a zone in which blood vessels and osteoblasts invade the lacunae of the old cartilage, producing marrow cavities and osteoid for new bone

Question 21

bone matrix consists of?

Answer 21

1. calcium hydrocyapatite
2. type 1 collagen
3. proteoglycan and osteonectin

Question 22

what is periosteum and endosteum?

Answer 22

surround the bone on outside and inside, respectively. Nourishment and growth.

Question 23

what are the types of bone?

Answer 23

Compact or Cancellous. Lamellar or Woven

Question 24

osteogenesis consists of?

Answer 24

Intramembranous (flat bone) and endochondral ossification (long bone).

Question 25

bone remodeling consists of ?

Answer 25

Osteoclasts (breakdown), osteoblasts (rebuild).

→ Osteoporosis

Question 26

describe joints

Answer 26

regions where adjacent bonds are capped and held together firmly by connective tissue. Example diarthrose joints (knee) capped with hyaline cartilage.