Lecture 7: Cartilage

Question 1

5 specialized types of connective tissue

Answer 1

• Cartilage
• Bone
• Ligaments
• joints
• tendons

Question 2

Bone

Answer 2

Rigid protective and supporting framework for soft tissues

Question 3

Cartilage

Answer 3

Avascular semi-rigid form of connective tissue characterized by absence of blood vessels, lymphatic vessels, and nerves

Question 4

Purpose of cartilage

Answer 4

Supports soft tissues, very important in bone growth

Question 5

Cartilage is composed of

Answer 5

cells which are embedded in an amorphous gel-like substance (ground substance) and CT fibers, making this tissue resilient and pliable

Question 6

Mesenchymal cells

Answer 6

stem cells of bone and cartilage

Question 7

Differentiation and maturation is most advanced where

Answer 7

At the center of a mass of growing cartilage

Question 8

On completion of growth, the cartilage consists of

Answer 8

chondrocytes embedded in a large amount of extracellular matrix

Question 9

Perichondrium

Answer 9

• Located at the periphery of mature cartilage
• Zone of condensed connective tissue
• Contains elongated fusiform cells that resemble fibroblasts and has cartilage forming potential (give rise to chondroblasts)

Question 10

Perichondrium outer layer

Answer 10

Composed of dense fibrous connective tissue

Question 11

Perichondrium inner layer

Answer 11

• Cellular and is present in all hyaline cartilages except on articular surfaces
• Chondrogenic, contains cells with the capacity to become chondroblasts

Question 12

Ground substance is composed of

Answer 12

Sulfated polysaccharide units called glycosaminoglycans (GAGS)

Question 13

GAGs bound to a protein core form macromolecules called

Answer 13

proteoglycans

Question 14

Proteoglycans are responsible for

Answer 14

strong and flexible property of cartilage

Question 15

Within the ground substance are embedded varying proportions of _____ and ____ ___ giving rise to:

Answer 15

collagen
elastic fibers
different types of cartilage (hyaline, elastic, fibro-cartilage)

Question 16

Chondrocytes

Answer 16

• Mature cell
• Occupy lacunae
• Have an active role in synthesis of both the ground substance and fibrous elements of cartilage matrix

Question 17

Within normal articular cartilage the only type of highly specialized cell is

Answer 17

the chondrocytes

Question 18

Chondrocytes are arranged in clusters of __-__ fully differentiated cells called

Answer 18

2-4

isogenous groups

Question 19

Chrondrocyte clusters are surrounded by

Answer 19

the extracellular matrix

Question 20

Chondrocytes do not form

Answer 20

cell to cell contacts

Question 21

Mature chondrocytes are characterized by

Answer 21

• Small nuclei with dispersed chromatin and basophilic, granular cytoplasm reflecting a well developed rough ER
• Lipid droplets are prominent
• Glycogen-rich cytoplasm

Question 22

Cartilage matrix components

Answer 22

collagen
elastic fibers
proteoglycans

Question 23

What is the main structural glycoprotein

Answer 23

Chondronectin

Question 24

Basophilia of cartilage matrix is due to

Answer 24

high concentration of GAGs

Question 25

Surrounding each chondrocyte is the

Answer 25

Territorial matrix - the portion of the extracellular matrix surrounding each cell

Question 26

The matrix near the clusters of chondrocytes (territorial) is more ____ than the matrix further away (inter-territorial)

Answer 26

Basophilic

Question 27

Glycosaminoglycans near the clusters of chondrocytes are _____ abundant and _____ in composition than matrix further away

Answer 27

More | different

Question 28

Two manners of cartilage growth

Answer 28

- Interstitial | - Appositional

Question 29

Interstitial growth

Answer 29

from within cartilage

Question 30

Appositional growth

Answer 30

at the periphery

Question 31

Classification of cartilage is based mainly on

Answer 31

the amount of collagen or elastic fibers present within the extracellular matrix

Question 32

Three types of cartilage

Answer 32

- Hyaline - Elastic - Fibro

Question 33

What is the most common type of cartilage

Answer 33

Hyaline

Question 34

Mature hyaline cartilage is characterized by

Answer 34

Small aggregation of chondrocytes embedded in an amorphous matrix of ground substance reinforced by collagen type 2 fibers

Question 35

Locations of hyaline cartilage

Answer 35

- Fetal axial and appendicular skeleton - Growth plates (physis) - Articular cartilage - Costo-chondral junctions - Nasal septum, larynx, tracheal rings, bronchii

Question 36

Hyaline cartilage chondroblasts and chondrocytes arise from

Answer 36

perichondrium

Question 37

Hyaline chondroblast matrix

Answer 37

- GAGs of chondroitin sulfate + protein (proteoglycans) - Hyaluronic acid - Glycoprotein is chondronectin - Type 2 collagenous fibrils

Question 38

Hyaline cartilage stains slightly

Answer 38

basophilic

Question 39

Articular hyaline cartilage

Answer 39

Covers joint surfaces and forms the physis (growth plate) of bones in young growing individuals

Question 40

Does articular cartilage have perichondrium?

Answer 40

Nope

Question 41

Elastic cartilage has

Answer 41

a perichondrium, chondroblasts, and chondrocytes in large lacunae

Question 42

Elastic cartilage stain

Answer 42

The elastic fibers stain dark

Question 43

Why is elastic cartilage flexible?

Answer 43

Due to presence of numerous bundles of branching elastic fibers in the cartilage matrix

Question 44

Where is elastic cartilage found?

Answer 44

Larynx (epiglottis and the corniculate and cuneiform processes of the arytenoid cartilage), in the external auditory canal and ear pinna

Question 45

Fibrocartilage lacks a _____ and thus lacks

Answer 45

perichondrium | the capacity to regenerate

Question 46

Fibrocartilage contains

Answer 46

chondrocytes and lacunae

Question 47

Features of fibrocartilage are between

Answer 47

cartilage and dense fibrous connective tissue

Question 48

Fibrous cartilage contains type __ collagenous fibers

Answer 48

1

Question 49

Inactive fibroblasts are called

Answer 49

fibrocytes

Question 50

Fibrocartilage is located where what is required?

Answer 50

Support and tensile strength

Question 51

Where is fibrocartilage found?

Answer 51

- Intervertebral discs - Menisci - Insertions of tendons - Mandibular symphysis - Pubic symphysis