Cartilage/Bone Histology

Question 1

Three components of the connective tissue cartilage

Answer 1

Cells, fibers, and matrix

Question 2

Cells which produce and maintain cartilage

Answer 2

chondrocytes

Question 3

Precursor to chondrocytes

Answer 3

chondroblasts

Question 4

Two types of fibers typically found in cartilage

Answer 4

collagen or elastic fibers

Question 5

Two components of extracellular matrix found around cartilage

Answer 5

hyaluronic acid and glycosaminoglycans (GAGs)

Question 6

What can be said about the nutrient supply to cartilage?

Answer 6

the tissue is avascular

Question 7

Three functions of cartilage

Answer 7

1) provides support for soft tissues
2) resists compression, acting as a shock absorber
3) template for bone development

Question 8

Three types of cartilage

Answer 8

1) hyaline
2) elastic
3) fibrocartilage

Question 9

Found in the developing skeleton of an embryo. Makes up the epiphysial plate (growth plate) of growing bones. Found in the respiratory tract and also called articular cartilage.

Answer 9

Hyaline cartilage

Question 10

Type of cartilage found in the ear, epiglottis, and eustachian tube.

Answer 10

Elastic cartilage

Question 11

Type of cartilage found in intervertebral disks, meniscus of the knee, mandible, sternoclavicular joints, and the pubic symphysis

Answer 11

fibrocartilage

Question 12

Structure containing capillaries to supply chondrocytes of avascular matrix with nutrients

Answer 12

fibrous perichondrium

Question 13

What type of connective tissue is the fibrous layer of the perichondrium?

Answer 13

dense irregular connective tissue

Question 14

Most common type of cartilage

Answer 14

hyaline

Question 15

Cartilage type with glassy appearance. Features type II collagen, proteoglycans, and water. Resists compression and provides a smooth surface for joints. Has a perichondrium layer.

Answer 15

Hyaline Carilage

Question 16

What is different about the articular cartilage subtype of hyaline cartilage?

Answer 16

It has no perichondrium (in general, no perichondrium if next to bone/joint)

Question 17

Types of cartilage growth (2)

Answer 17

1) appositional growth

2) interstitial growth

Question 18

cartilage growth type where cells from the inner layer of perichondrium differentiate into chondroblasts. Matrix is deposited next to existing matrix.

Answer 18

Appositional growth

Question 19

cartilage growth type where growth of chondroblasts by mitosis occurs within the cartilage matrix. New territorial matrix is deposited. Forms isogenous (all formed through division of a single progenitor cell) groups

Answer 19

interstitial growth

Question 20

Cartilage type with fibers which make it much more flexible so it can bend without breaking. The matrix has collagen II and it is surrounded by perichondrium

Answer 20

Elastic cartilage

Question 21

Cartilage type which has Type I and II collagen in a dense regular pattern. Cells (chondrocytes and fibroblasts) grow in rows. Provides tensile strength to resist compression and stretching. No perichondrium

Answer 21

fibrocartilage

Question 22

Appearance of cartilage on x-ray

Answer 22

Radiolucent (black)

Question 23

Functions of bone (5)

Answer 23

1) weight bearing
2) attachments for muscle
3) protection for internal organs
4) site of hematopoiesis
5) reservoir for minerals

Question 24

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

Answer 24

Osteoid

Question 25

Components of osteoids (3)

Answer 25

1) Type 1 Collagen Fibers 2) proteoglycans 3) Non-collagenous proteins

Question 26

Non-collagenous proteins in osteoids (4)

Answer 26

1) osteopontin 2) osteocalcin 3) osteonectin 4) bone sialoprotein

Question 27

Inorganic component of bones

Answer 27

Hydroxyapatite (calcium phosphate)

Question 28

Proximal and distal ends of the long bones adjacent to physis (growth plate) or physis remnant (epiphyseal line)

Answer 28

epiphysis

Question 29

Region adjacent to growth plate where bone deposition occurs

Answer 29

metaphysis

Question 30

Shaft of the bone. Has medullary cavity with marrow.

Answer 30

diaphysis

Question 31

Dense bone on the outside of long bones. Arrange in lamellae (osteons)

Answer 31

Compact bone

Question 32

Less dense bone which lines marrow cavities and at the ends of long bones. Arranged in trabeculae (spicules) to create more surface area.

Answer 32

Cancellous (spongy or trabecular) bone

Question 33

Contains concentric layers of cells (lamellae) and matrix around a central canal. Bone type

Answer 33

compact bone

Question 34

Contains irregular arrangement of cells and matrix forming trabeculae. Bone type.

Answer 34

Cancellous bone

Question 35

series of microscopic tubes in the outermost region of bone called cortical bone that allow blood vessels and nerves to travel through them

Answer 35

haversian canal

Question 36

Composed of the lamellae (rings) surrounding a haversial canal and the canal itself. Maintained by a single capillary in haversian canal.

Answer 36

Osteon (Haversian System)

Question 37

Osteons run lengthwise of widthwise in a bone?

Answer 37

lengthwise

Question 38

Found on the outer and inner surface of compact bone

Answer 38

Circumferential lamellae

Question 39

Partial osteons in the middle of the compact bone. Remnants of former osteons from remodeling process

Answer 39

Interstitial lamellae

Question 40

Canal that runs transversely across the long axis of the bone (across width). Carry capillaries that interconnect longitudinal haversian capillaries or carry capillaries into the bone from periosteum

Answer 40

Volkmann's Canal

Question 41

Stem cells that give rise to osteoblasts.

Answer 41

Osteoprogenitor Cells

Question 42

Where are osteoprogenitor cells found?

Answer 42

Line the bone in the periosteum and endosteum

Question 43

Cuboidal epithelial like cells. Form new bone. Secrete osteoid and contribute to mineralization.

Answer 43

Osteoblasts

Question 44

Osteoblasts that become trapped in osteoid. Reside lacunae. Highly branched cells with processes connected to others (of the same cell type) through canaliculi. Contribute to Ca2+ homeostasis

Answer 44

Osteocytes

Question 45

Multinucleated osteoclasts are derived from what cell lineage?

Answer 45

monocytes

Question 46

What reside in Howship's lacunae (small cavities in degrading bone)

Answer 46

osteoclasts

Question 47

How do osteoclasts breakdown bones during remodeling?

Answer 47

Create acidic environment that causes demineralization (H+-ATPase). The organic components are degraded enzymatically.

Question 48

True/False: Osteoclasts are hormone sensitive?

Answer 48

true

Question 49

Single layer of cells lining inner bony surfaces

Answer 49

endosteum

Question 50

Two mechanisms of bone formation

Answer 50

1) intramembranous | 2) endochondral

Question 51

Bone formation mechanism where it forms directly in the mesenchyme and drives appositional growth of long bones (widens them). Process used to form skull, parts of mandible and clavicles

Answer 51

intramembranous

Question 52

Bone formation mechanism in which it forms in a cartilage template. This is the process used to form long bones.

Answer 52

Endochondral

Question 53

What do both bone formation mechanisms begin with?

Answer 53

Forming trabeculae of spongy bone. Later it's remodeled into compact bone.

Question 54

Pluripotent stem cells which can form fibroblasts, chondroblasts, and osteoblasts

Answer 54

Mesenchymal cells

Question 55

What do aggregates of mesenchymal cells differentiate into in intramembranous ossification

Answer 55

osteoblasts

Question 56

Intramembranous ossification. Osteoblasts secrete osteoid to form what?

Answer 56

ossification center

Question 57

In intramembranous ossification, ossification centers enlarge and fuse to form...

Answer 57

trabeculae. They then continue to enlarge by appositional growth and calcium phosphate is deposited in the osteoid.

Question 58

Why does the medullary cavity expand in appositional growth?

Answer 58

osteoclasts break down the inside

Question 59

Bones of the extremities, vertebral column and pelvis grow with which mechanism?

Answer 59

endochondral ossification

Question 60

What forms first in endochondral ossification?

Answer 60

hyaline cartilage template

Question 61

[Endochondral Ossification] Chondrocytes at the site of a _____ _____ _____ secrete factors that induce the growth of blood vessels from the perichondrium.

Answer 61

primary ossification center

Question 62

What happens to chondrocytes as the matrix calcifies in endochondral ossification

Answer 62

apoptosis

Question 63

Interstitial growth of the cartilage increases.... (Endochondral ossification)

Answer 63

the length of the template

Question 64

Where does cartilage remain after maturation of bones (2)

Answer 64

1) articular surface | 2) epiphyseal plate

Question 65

First bone formed is immature or _____ bone. Collagen fibers in random orientation, more ground substance, less mineralization.

Answer 65

woven bone

Question 66

When does dense immature woven bone get remodeled into mature lamellar bone? Here you see formation of lamellae with collage fibers in regular spiral bundles.

Answer 66

Begins after birth and completed by 4 years age.

Question 67

This type of bone is seen in rapid bone growth (ex: healing fracture), resists forces in all directions and is always pathologic in adults.

Answer 67

woven bone

Question 68

This type of bone has ordered collagen deposition and is stronger than other types.

Answer 68

lamellar bone

Question 69

After the ossification of the cartilage template is complete ,all increase in length takes place at the _____ _____

Answer 69

epiphyseal plate

Question 70

When is the epiphyseal plate sealed and no further increase in length occurs

Answer 70

puberty

Question 71

Reduced osteoclast activity results in too much bone

Answer 71

osteopetrosis

Question 72

Too much degradation of bone and not enough deposition causes weakness

Answer 72

osteoporosis

Question 73

Immediate response to a bone fracture

Answer 73

blood clot

Question 74

Infiltration of which cells (2) from the periosteum create a bone callus after the blood clots

Answer 74

fibroblasts and osteoprogenitor cells

Question 75

In bone repair, what do progenitor cells far and near blood vessels differentiate into, respectively.

Answer 75

Far: differentiate into chondroblasts and form cartilage scaffold Near: osteoblasts and convert cartilage to woven bone. The woven bone later becomes lamellar bone