Cartilage

Question 1

What is the developmental origin of cartilage?

Answer 1

mesenchyme

Question 2

What are 4 ways cartilage differs from bone?

Answer 2

1. bone matrix can become mineralized. If cartilage becomes mineralized, it will degrade
2. Cratilage is avascular while bone is highly vascular
3. Cartilage lacks innervation
4. Cartilage growth is appositional and interstitial while bone growth is only appositional

Question 3

What are the two cell types in cartilage?

Answer 3

chondroblasts

chrondocytes

Question 4

Where are the cells located?

Answer 4

within lacunae

Question 5

Why do the cells in cartilage have few mitochondria?

Answer 5

they’re primarily anaerobic

Question 6

What are the components of the ground substance in cartilage?

Answer 6

60-80% is water

proteoglycan: aggrecan (chondroitin sulfates and keratan sulfates covalently bound to protein backbone - all linked with hyaluronate into aggregates)

Question 7

What protein linkes aggrecan together to form proteoglycan aggregates? What does this doe for the cartilage?

Answer 7

hyaluronate

it’s extremely hydrophilic so that the cartilage will bind water and become a stiff gel

Question 8

What glycoprotein adheres the chondrocytes to type II collagen?

Answer 8

chondronectin

Question 9

What are the two main types of fibers in cartilage?

Answer 9

collagen

elastin for elastic cartilage only

Question 10

How are the collagen fibers arranged in general in cartilage?

Answer 10

they’re NOT bundles into large fibers - microfibrillar

so its sometimes hard to see them because they have a similar refractive index as the ground substanc.

Question 11

WHat are the three types of cartilage?

Answer 11

hyaline (most common)

Elastic

fibrocartilage

Question 12

Where is hyaline cartilage located int he body?

Answer 12

fetal skeletal

epiphyseal plate in children

nose, larynx, trachea, ribs articular cartilage

Question 13

What type of collagen is in hyaline cartilage?

Answer 13

type 2

Question 14

What is the outer layer of hyaline cartilage? What cells are located there?

Answer 14

It’s called the perichondrium

In the fibrous layer there is fibroblasts and in the chondrogenic zone there are chondroblasts

Question 15

Where are the chondrocytes located in hyaline cartilage?

Answer 15

in lacunae, surrounded by intercellular substance

Question 16

Where is the perichondrium lacking?

Answer 16

on articular surface of articular cartilage

Question 17

How does hyaline cartilage gets its nutrients and remove its waste?

Answer 17

through diffusion (this is why mineralization is bad for cartilage - it prevents diffusion)

Question 18

What do you call it when a chondroblasts multiplies within a lacuna?

Answer 18

it becomes an isogenous nest

Question 19

What is the difference between appositional growth and interstitial growth?

Answer 19

appositional growth is the addition of chondroblasts onto the surface of the cartilage

interstitial growth is mitototic activity of chondrolasts and ormation of isogenous nests to synthesize the matrix from the inside of the cartilage

Question 20

Why is regeneration of damaged cartilage difficult?

Answer 20

it’s avascular

Question 21

Where is elastic cartilage located?

Answer 21

the pinna of the ear, eustachian tube, and external auditory canal

epiglottis and some laryngeal cartilage

Question 22

What type of fibers are in elasti cartilage?

Answer 22

elastic fibers and some type 2 collagen

Question 23

True or false: elastic cartilage has a higher density of cells/isogenous nests than hyaline cartilage.

Answer 23

true

Question 24

What is the outer layer of elastic cartilage called (again)?

Answer 24

perichondrium

Question 25

Where is fibrocartilage located?

Answer 25

intervertebral disks and pubic symphysis

tendon and ligament attachments

Question 26

What type of collagen is present in fibrocartilage?

Answer 26

type 1

Question 27

In comparison to the other 2 types, does fibrocartilage have more or less ground substance? How about cells perunit area?

Answer 27

it has less ground substances and fewer cells

Question 28

True or false: fibrocartilage has a perichondrium.

Answer 28

false

Question 29

What happens in achondroplasia?

Answer 29

it’s a hereditary disease that reults in the failure of chondroblasts proliferation in epihphyseal plates, so you get premature fusion of epiphysis with the diaphysis resulting in dwarfism - small limbs

Question 30

How is a herniated disc a pathology of cartilage?

Answer 30

the annulus fibrosis is fibrocartilage that can become weak with age, allowing the nucleus pulposus to leak through.