Cartilage and Bone

Question 1

How do nutrients reach cartilage?

Answer 1

Cartilage is avascular. Nutrients/waste materials pass to and from the cells through the matrix.

Question 2

What is the function of cartilage?

Answer 2

Support soft tissues and guide the development and growth of long bones.

Question 3

What are the three types of cartilage?

Answer 3

hyaline, elastic, and fibrocartilage

Question 4

Where is hyaline cartilage located?

Answer 4

articular ends of long bones in adults, walls of respiratory system, the ventral ends of ribs, and temporarily skeleton for the fetus

Question 5

What is the hyaline cartilage matrix comprised of?

Answer 5

homogenous, amorphous ground substance with proteoglycan aggregates and chondronectin embedded type II collagen

Question 6

What is the name of the area adjacent to the chondrocytes? Describe this region’s contents.

Answer 6

Territorial (capsular) Matrix. Poor in collagen but rich in glycosaminoglycans.

Question 7

How will the territorial matrix stain?

Answer 7

Basophillic and metachromatic. More intensely with PAS stain compared to interrerritorial (intracapsular) matrix.

Question 8

What is the perichondrium?

Answer 8

A layer of dense irregular connective tissue surrounding hyaline cartilage (except at joints).

Question 9

Describe the two layers of the the perichondrium.

Answer 9

Outer Fibrous Layer – Type I Collagen, Fibroblasts, Blood Vessels
Inner Cellular Layer – Chondrogenic cells

Question 10

What provides blood flow for the avascular cartilage?

Answer 10

Perichondrium

Question 11

What are chondrocytes? Where are they found?

Answer 11

Mature cartilage cells. Embedded in lacunae.

Question 12

Describe the cellular stages required to form a chondrocyte.

Answer 12

Chondrogenic Cells –> Chondroblasts (Produce Matrix) –> Chondrocytes (Once totally surrounded by matrix)

Question 13

What cells are responsible for maintaining the cartilage matrix?

Answer 13

Chondrocytes

Question 14

What are isogenous groups?

Answer 14

When chondrocytes divide, they may stay in the same lacunae (forming pockets of 2-8 cells)

Question 15

Where in the body can elastic cartilage be found?

Answer 15

External ear, eustachian tube, epiglottis, larynx

Question 16

Is elastic or hyaline cartilage more prone to degrade?

Answer 16

Hyaline Cartilage

Question 17

What is unique about the make up of elastic cartilage?

Answer 17

A network of elastic fibers, which provide a yellowish color

Question 18

What types of cartilage has a perichondrium?

Answer 18

Hyaline and Elastic. Fibrocartilage does not have a perichondrium.

Question 19

Describe the cellular make-up of Fibrocartilage.

Answer 19

Alternating rows of chondrocytes and thick type I collagen fibers. The cells may align on lines of stress.

Question 20

Where in the body can fibrocartilage be found?

Answer 20

Intervertebral discs, articular disks, pubic symphysis, tendon and ligament insertions.

Question 21

What is fibrocartilage often confused for?

Answer 21

Dense regular connective tissue

Question 22

What types of locations is fibrocartilage most often needed?

Answer 22

Where support and tensile strength are needed in conjunction with hyaline cartilage.

Question 23

What is the function of bone?

Answer 23

Protects vital organs, supports fleshy structures, provides Ca reserve.

Question 24

What is bone?

Answer 24

A specialized connective tissue with a calcified extracellular matrix with osteocytes embedded in the matrix that makes up the adult skeleton.

Question 25

What is the bone matrix comprised of?

Answer 25

Primarily hydroxyapatite crystals.

Question 26

What can be found in the inorganic portion of bone?

Answer 26

Calcium, phosphate, bicarbonate, citrate, magnesium, potassium, and sodium.

Question 27

What can be found in the organic portion of bone?

Answer 27

Type I Collagen (95%), chondroitin sulfate, and keratan sulfate

Question 28

What is a primary bone?

Answer 28

First bone formed in fetal development and repair

Question 29

What two types of secondary bones are there?

Answer 29

Compact bone and spongy bone

Question 30

Where can compact bone be found?

Answer 30

With the outer circumferential lamellae, inner circumferential lamellae, and around osteons.

Question 31

What connects osteons?

Answer 31

Volkmann's canals

Question 32

What is bone periosteum?

Answer 32

A layer of noncalcified connective tissue covering the bone on external surfaces (except at joints)

Question 33

What is the periosteum comprised of?

Answer 33

An outer, fibrous dense collagenous layer and an inner, cellular layer.

Question 34

What connects the periosteum and the bone?

Answer 34

Sharpey's fibers (Type I Collagen)

Question 35

What is the endosteum?

Answer 35

Thin specialized connective tissue lining marrow cavities. It is the source of osteoprogenitor cells and osteoblasts for bone growth and repair.

Question 36

What are osteoprogenitor cells?

Answer 36

Inner layer of periosteum and endosteal cells that line marrow cavity. Flattened/Spindle Shaped. Become osteoblasts.

Question 37

What are osteoblasts?

Answer 37

Cells that secrete collagen, ground substance, and osteoid that regulate the mineralization of bone. They are cuboidal in shape and in a single layer at locations bone is forming.

Question 38

What is an osteocyte?

Answer 38

Cells that reside in the lacunae that maintain bone matrix through minimal acts of synthesis and resorption of matrix.

Question 39

How do osteocytes communicate?

Answer 39

Via processes that extend through canniculi and gap junctions with other cells

Question 40

Describe the staining of an osteoclast.

Answer 40

Multinucleated cell, acidophilic

Question 41

Describe the function of osteoclasts

Answer 41

They actively resorb bone by releasing lysosomes into extracellular space.

Question 42

What is Howship's lacuna

Answer 42

A depression in bon created by an osteoclast. The cell seals off the area, acidifies, and secretes acid hydrolases to resorb bone.

Question 43

What is osteoporosis?

Answer 43

A decrease in bone mass associated with a normal mineral to matrix ratio due to decreased bone formation, increased bone resorption, or both.

Question 44

List a few possible reasons for developing osteoporosis.

Answer 44

Diminished growth hormone secretion, lack of physical stress on bone, diminished estrogen secretion

Question 45

What is osteomalacia?

Answer 45

Deficient calcification of newly formed bone and decalcification of calcified bone due to calcium deficiency.

Question 46

What is often a cause for osteomalacia?

Answer 46

Pregnancy (from the little one leeching the life force from the mother)

Question 47

What is Rickets?

Answer 47

Osteomalacia in children due to Vitamin D deficiency or calcium deficiency. Often accompanied with deformation of bone spicules in epiphysial plates.

Question 48

What is acromegaly? How does it present?

Answer 48

Excess pituitary hormone in adults. Characterized by very thick bones in the extremities and facial skeleton.