Histology

Question 1

What are characteristics of hyaline cartilage?

Answer 1

Characterized by matrix containing:

Type II Collagen
Glycosaminoglycans (GAGs)
Proteoglycans
Multiadhesive glycoproteins

Question 2

Where is hyaline cartilage found?

Answer 2

Articular surface of joints

respiratory passages

precursor to bones during development

Question 3

What are chondrocytes?

Answer 3

Cells that forme the cartilage matrix, they are surrounded by lacunae

Question 4

What are osteoblasts?

Answer 4

Cells that secrete the extracellular matrix of bone;

once the cell is surrounded with its secreted matrix, it is reffered to as an osteocyte

Question 5

What are osteoclasts?

Answer 5

boen-resorbign cells present on bone surfaces where bone is being removed or remodeled

or where bone has been damaged

Is of granulocyte/monocyte lineage (not the same lineage as osteoblasts)

Question 6

What are lamellae?

Answer 6

They appear on mature bone and make op osteons.

They are bone matrix surrounding a central (Haversian) canal

Question 7

What are interstitial lamellae?

Answer 7

Remnants of previous concentric lamellae

Question 8

What are circumferential lamellae?

Answer 8

Follow the entire inner and outer circumferences of the shaft of long bone

Question 9

What are canaliculi?

Answer 9

Small tunnels that course through mineralized matrix, connecting adjacent lacunae and allowing contact between the cell processes of neighboring osteocytes

Question 10

What is an osteon?

Answer 10

Cylindrical units that compose the majority of mature bone

They contain lamellae, lacunae, and the encompassed osteocyte

Question 11

What is an osteoid?

Answer 11

unmineralized, organic portion of the bone matrix that forms prior to the maturation of bone tissue

Question 12

What is the periosteum?

Answer 12

Covering of an actively growing bone that consists of:

outer fibrous layer that resembles other dense connective tissues

inner, more cellular layer that contains osteoprogenitor cells

Question 13

What is the endosteum?

Answer 13

The lining tissue of both the compact bone facing the marrow cavity and the trabeculae of spongy bone within the cavity

Question 14

What is the trabeculae?

Answer 14

Thin, anastomosing spicules of bone tissue that make up the spongelike meshwork of spongy bone

Question 15

What is articular cartilage?

Answer 15

Hyaline cartilage covering the articular surfaces of movable joints

(does not have a perichondrium)

Question 16

What is appositional growth?

Answer 16

The process that forms new cartilage at the surface of an existing cartilage

Question 17

What is interstitial growth?

Answer 17

The process that forms new cartilage within an existing cartilage mass

Question 18

What are isogenous groups?

Answer 18

Clusters of chondrocytes produced by proliferation of chondrocytes

Question 19

What is endochondral ossification?

Answer 19

Production of bone with a cartilage precursor

Question 20

What is intramembranous ossification?

Answer 20

Formation of bone by differentiation of mesenchymal cells into osteoblasts

Question 21

What is the process of intramembranous ossification?

Answer 21

• Mesenchymal cells migrate and aggregate at the site of bone formation
• Mesenchymal cells differentiate into osteoprogenitor cells
• further differentiating to osteoblasts that secret collagens (mainly Type I) and other bone matrix proteins developing the bone through appositional growth
• In time, the matrix becomes calcified the bone-forming cells, now osteocytes, are contained within canaliculi

Question 22

What is the process of endhochondral ossification?

Answer 22

• Also begins with migration and proliferation of mesenchymal cells at site of future bone, but initially, hyaline cartilage is formed
• The cartilage grows through interstitial and appositional growth
• Perichondrial cells at midregion begin to produce osteoblasts, producing an osteogenic layer and a distinctive cuff of periosteal bone (bony collar)
• midregion chondrocytes become hypertrophic and undergo calcification (not to be confused with mineralization that occurs in bone tissue)
• Calcified cartilage matrix inhibits diffusion of nutrients, killing chondrocytes
• Mesenchymal and hemopoietic stem cells from periosteum migrate along penetrating blood vessels and differentiate into osteoprogenitor cells and bone marrow in bone marrow cavity.
• Osteoprogenitor cells come in apposition with remaining calcified cartilage spicules, become osteoblasts and begin ossification of the bone framework

Question 23

Where does growth of endochondral bone occur after primary ossification?

Answer 23

in the presence of epiphyseal cartilage at epiphyseal growth plates

Question 24

What are the zones of endochondral bone formation?

Answer 24

The zones of epiphyseal cartilage are:

Resting

Proliferative

Hypertophy

Calcification

Ossification

Question 25

What is a Haversian canal?

Answer 25

Central canals in the bone matrix that contain vascular and nerve supply of the osteon

Question 26

What is a Volkmann’s canal?

Answer 26

Perforating canals that are channels in lamellar bone through which blood vessels and nerves travel from the periosteal and endosteal surfaces to reach the osteonal canal

Question 27

What is Howship’s lacunae?

Answer 27

Shallow resorption bays observed in the bone directly under osteoclasts

Question 28

What are Sharpey’s fibers?

Answer 28

In areas where ligaments and tendons attach to the bone, Sharpey’s fibers are collagen fibers from these structures that extend directly, but at an angle, into the bone tissue

Question 29

What is an epiphyseal closure?

Answer 29

Elimination of the epiphyseal plate after individual achieves maximal growth

Question 30

What is synarthrosis?

Answer 30

A joint that allows little to no movement under normal conditions

Question 31

What is osteomalacia?

Answer 31

A softening of bones, generally caused by a lack of Vitamin D

Question 32

What is rickets?

Answer 32

Calcium deficiency during growth, leads to bone matrix not able to calcify normally

May be caused by insufficient vitamin D, which can also lead to osteomalacia in adults

Question 33

What is scurvy?

Answer 33

Vitamin C deficiency in which matrix produced in scurvy is not calcifiable

Cartilage is unable to undergo hydroxylation