Lecture 21 9/26/23

Question 1

What are chondrocytes?

Answer 1

cells of cartilage

Question 2

What are the characteristics of chondrocytes?

Answer 2

-live in lacunae
-secrete matrix

Question 3

Why is cartilage not a source of pain?

Answer 3

it has no blood vessels or nerves

Question 4

What is appositional cartilage growth?

Answer 4

-expansion of cartilage from the periphery
-continues throughout life
-from the perichondrium/outer sack

Question 5

What cells are contributed by the perichondrium?

Answer 5

cartilage stem cells

Question 6

Which type of cartilage lacks a perichondrium?

Answer 6

articular cartilage

Question 7

Which type of cartilage has a perichondrium?

Answer 7

cartilage embedded within tissue

Question 8

What is interstitial cartilage growth?

Answer 8

-expansion from within
-matrix and cell numbers increase
-cells undergoing mitosis form clusters/isogenous groups
-most important in young animals

Question 9

Why are we unable to regrow articular cartilage?

Answer 9

interstitial cartilage growth rarely occurs in adulthood

Question 10

What are the characteristics of hyaline cartilage?

Answer 10

-smooth matrix
-forms fetal skeleton framework
-found on articular surfaces of bone

Question 11

What locations have hyaline cartilage?

Answer 11

-nose
-larynx
-trachea

Question 12

What are the characteristics of elastic cartilage?

Answer 12

-has elastic fibers between chondrocytes
-elastic fibers only visible with special stains

Question 13

What locations have elastic cartilage?

Answer 13

-pinnae
-external ear canal

Question 14

What are the characteristics of fibrocartilage?

Answer 14

-cartilage mixed with dense collagen
-chondrocytes in rows

Question 15

What locations have fibrocartilage?

Answer 15

-menisci
-intervertebral discs
-tendons and ligaments

Question 16

What are the three cell types in bone?

Answer 16

-osteoblasts
-osteocytes
-osteoclasts

Question 17

What are the characteristics of osteoblasts?

Answer 17

-produce/build bone
-polygonal cells in rows along bone surface
-secrete and mineralize osteoid

Question 18

What is osteoid?

Answer 18

the first type of bone produced that is unmineralized

Question 19

What are the characteristics of osteocytes?

Answer 19

-osteoblasts that become embedded
-live in lucunae
-maintain bone structure

Question 20

What are the characteristics of osteoclasts?

Answer 20

-remove/cut bone
-multi-nucleated, giant cells
-remove bone along brush/ruffled border

Question 21

What is a Howship’s lacunae?

Answer 21

depression in bone formed by osteoclast

Question 22

What are the characteristics of the mineral portion of the matrix?

Answer 22

-makes up majority of bone
-formed from hydroxyapatite (calcium + phosphorus)
-gives bone rigidity

Question 23

What are the characteristics of the collagen portion of the matrix?

Answer 23

-can only be seen using polarized light
-gives bone tensile strength

Question 24

What are the two organizations of bone collagen?

Answer 24

-woven
-lamellar

Question 25

What are the characteristics of woven bone?

Answer 25

-immature bone -one step after osteoid -formed during growth and repair -haphazardly arranged collagen fibers

Question 26

How does lamellar bone form?

Answer 26

from the organization of woven bone

Question 27

What are the characteristics of lamellar bone?

Answer 27

-mature bone -parallel collagen fibers -osteons/cylinders of collagen -haversian canals at center of osteon contain blood vessels and nerves -stronger than woven bone

Question 28

What are the two configurations/shapes of bone?

Answer 28

-compact -cancellous

Question 29

What are the characteristics of compact bone?

Answer 29

-solid bone with minimal marrow -woven or lamellar -forms cortex of adult bone

Question 30

What are the characteristics of cancellous bone?

Answer 30

-trabeculae arranged in 3D lattice -more bone marrow spaces -woven or lamellar -inside bone medullary cavity

Question 31

What is the epiphysis?

Answer 31

-end of bone -covered by articular cartilage

Question 32

What is the physis?

Answer 32

growth plate made of cartilage in young animals

Question 33

What is the metaphysis?

Answer 33

cone-shaped transition/neck between diaphysis and epiphysis

Question 34

What is the diaphysis?

Answer 34

cylindrical shaft of bone containing the nutrient foramen

Question 35

What are the characteristics of bone marrow?

Answer 35

-contains hematopoetic cells -becomes increasingly fatty with age

Question 36

What are the characteristics of the periosteum?

Answer 36

-fibrous outer bony envelope -contains osteoprogenitor cells -involved in repair and remodeling

Question 37

What are the characteristics of the endosteum?

Answer 37

-inner bony envelope -can differentiate into osteoblasts