Chapter 6 - Cartilage

Question 1

General properties of cartilage

Answer 1

• abundant in ECM, relatively few cells
• type of connective tissue
• flexible support (very little distortion when subjected to mechanical stress)
• covers/cushions articular surfaces (meniscus)
• supports soft tissues
• template for development of skeleton

Question 2

How does cartilage receive O2 and get rid of metabolic waste products if it is avascular and does not have lymphatic vessels?

Answer 2

• receives O2 through diffusion through the ground substance
• metabolic waste products are removed through diffusion

Question 3

Chondrocytes

Answer 3

• chondroblasts mature into these
• round/oval shape, but usually shrink or break down during fixation of tissue
• synthesize ECM
• can undergo mitosis, but at a slower rate than chondroblasts
• anaerobic respiration

Question 4

What hormonal control do chondrocytes have?

Answer 4

• GH, TH, and testosterone stimulation - promote cartilage growth and repair
• cortisone, hydrocortisone inhibition- inhibit cartilage growth and repair

Question 5

Chondroblasts

Answer 5

• located on periphery of cartilage
• flattened shape
• do undergo mitosis
• derived from mesenchymal cells (stem cells that can differentiate into diff CT cells) in perichondrium
• secrete ECM and become trapped in it

Question 6

Isogenous groups of cells in lacunae

Answer 6

Groups/clusters of cells derived from the same chondroblast, arranged in a nest (lacuna)

Question 7

Territorial matrix

Answer 7

matrix is not mature

Question 8

interterritorial matrix

Answer 8

fibers are mature, and it is further away from the cells that made it

Question 9

What are the two fiber types of cartilage?

Answer 9

Collagen (type 3), elastic

Question 10

What is the ground substance composed of?

Answer 10

• main glycoprotein is condronectin
• GAGs are chondroitin sulfate and hyaluronic acid

Question 11

What are the 3 kinds of cartilage in the body?

Answer 11

Hyalin, elastic, fibrocartilage

Question 12

Hyaline cartilage

Answer 12

• glassy appearance in LM
• most common
• cells are in clusters
• articular surfaces, tracheal rings, bronchial rings
• template for bone formation during development
• perichondrium not present

Question 13

Elastic cartilage

Answer 13

• pinnae in ears, epiglottis
• contains many elastic fibers
• requires a special stain

Question 14

Fibrocartilage

Answer 14

• rows of chondrocytes oriented parallel to stress
• pubis symphysis, intervertebral disks (annulus fibrosis), menisci of the knee joints

Question 15

What are the two parts of intervertebral disks, which contains fribrocartilage, and how do herniated disks occur?

Answer 15

• annulus fibrosus
• occurs when the fibrocartilage in the annulus fibrosus tears, allowing the nucleus pulposus to push out and press on the nerve

Question 16

Perichondrum

Answer 16

• surrounds elastic and fibrocartilage
• dense CT layer

Question 17

What are the two types of cartilage growth?

Answer 17

• interstitial - synthesis of matrix by existing chondrocytes
• appositional - matrix added (from the outside) as chondroblasts become mature chondrocytes

Question 18

What are the age-related changes in cartilage?

Answer 18

• calcification of ECM
• slower rate of collagen deposition
• slower rate of mitosis
• thinning of intervertebral disks, articular cartilage, menisci,
• osteoarhritis