Bone Tissue

Question 1

Bone does what?

Answer 1

support and attachments for muscles
Continuously remodeling. Building new bone and breaking down old bone

Question 2

Skeletal System is what?

Answer 2

framework of bones and cartilages

Question 3

Osteology is what?

Answer 3

Study of bone structure and
treatment of bone disorders

Question 4

Skeletons Basic Functions are?

Answer 4

1. Support: structural framework for body
2. Protection: organs from injury
3. Assistance in Movement: attach to bones and when they contract, result in movement
4. Mineral storage and release
   * Minerals: calcium and phosphorus
   * 99% of total body calcium
5. Blood cell production: RBM (a connective tissue) produces RBC, WBC, and platelets
6. Triglyceride storage: Yellow bone marrow consists of adipose cells storing triglycerides (energy source)

Question 5

What is hemopoiesis?

Answer 5

Process of blood making

Question 6

How many bones in adult skeleton?

Answer 6

206

Question 7

What are the five types of bones?

Answer 7

1. Long bones
2. Short bones
3. Flat bones
4. Irregular bones
5. Sesamoid bones

Question 8

Long bone consists of what?

Answer 8

1. Diaphysis: shaft, or body
2. Epiphysis: Proximal and Distal ends
3. Metaphysis: Region b/w diaphysis and
   epiphysis
   * In growing bone, it contains
   epiphyseal (growth) plate
4. Articular Cartilage: hyaline cartilage
   covering part of epiphysis (bone articulates with
   another bone). Reduces friction / absorbs shock
5. Periosteum: Tough connective tissue
   blood supply, fracture repair, nourish bone ands attachment for ligaments / tendons
6. Medullary Cavity : Marrow cavity, Contains yellow bone marrow and blood vessels
7. Endosteum: thin membrane that lines medullary cavity

Question 9

Four Types of Bone Cells are?

Answer 9

Osteoprogenitor, Osteoblasts, Osteocytes and Osteoclasts

Question 10

What is an Osteoprogenitor?

Answer 10

Genic = producing
Develop into osteoblasts

Question 11

Osteoblasts

Answer 11

Bone-building Immature cells, Secrete collagen fibers
and other organic compounds to form extracellular matrix and initiate calcification

Question 12

Osteocytes

Answer 12

Osteoblasts become embedded in extracellular matrix = become osteocytes Mature bone cells, Maintain daily metabolism of bones

Question 13

Osteoclasts

Answer 13

Break down bone (bone resorption)
Hugh cells made from fusion of 50 monocytes (WBC)

Question 14

Two types of bone tissue are?

Answer 14

1. Compact bone tissue: dense bone
   * On bone surfaces
   * Compose bulk of long bone diaphysis
   * Protection/support and resists stresses produced by weight and movement.

Question 15

What are Osteons?

Answer 15

concentric lamellae arranged around osteonic (central) canal of blood vessels and nerves

Question 16

Between lamellae rings are spaces called?

Answer 16

lacunae (dark brown lining)

Question 17

Radiating from lacunae are small channels called?

Answer 17

canaliculi which are filled with extracellular fluid

Question 18

what do Osteocytes fingerlike projections do?

Answer 18

Allows osteocytes to communicate with one another

Question 19

What is Spongy bone tissue?

Answer 19

Spongy bone tissue aka trabecular bone tissue
Located in bone interior and protected by a covering of compact bone

Question 20

Spongy bone tissue consists of?

Answer 20

trabeculae (thin columns)
* Trabeculae composed of lamellae
* Red and Yellow bone marrow spaces b/w trabeculae

Question 21

Osteogenesis is?

Answer 21

Osteogenesis: involves ossification

Question 22

Ossification is what?

Answer 22

process of bone formation

Question 23

Bone formation follows one of two patterns. Both lead to same structure but just use different methods. What are they?

Answer 23

A. Intramembranous ossification
* Bone forms directly with mesenchyme (simple method)
* Flat bones, fascial bones (primarily bones of head)
B. Endochondral ossification (EO)
* Mesenchyme forms hyaline cartilage
* Bone forms within hyaline cartilage
* All other bones of body

Question 24

What is Endochondral ossification?

Answer 24

Mesenchymal cells bone and cartilage creation
Differentiate into Chondroblasts (create) cartilage
Osteoblasts create bone

Question 25

Bone Growth in infancy, childhood, adolescence (A) Growth in Length (Interstitial) what are the 4 zones?

Answer 25

Epiphyseal plate = layer of hyaline cartilage consists of four zones 1. Zone of resting cartilage 2. Zone of proliferating cartilage 3. Zone of hypertrophic cartilage 4. Zone of calcified cartilage

Question 25

What are the six steps of Endochondral ossification (EO)

Answer 25

Step 1: Development of Cartilage model *pregnancy Mesenchymal (stem cells) form into a bone like shape * Mesenchymal cells differentiate into Chondroblasts (secrete ECM hyaline cartilage (blue bone-like shape) Step 2: Growth of Cartilage model * Chondroblasts embedded in hyaline cartilage differentiate into Chondrocytes and undergo rapid cell division = interstitial growth (increase in length) Step 3: Primary Ossification (PO) Center * Surrounding matrix calcifies Chondrocytes die = cartilage begins to disintegrate * Nutrient artery enters bone = Osteoprogenitor cells begin to create Osteoblasts (bone forming cells) * Osteoblasts replace disintegrating cartilage with Spongy bone(trabeculae) Step 4: Medullary Cavity (MC) (marrow) * Osteoclasts break down spongy bone which creates the Step 5: Secondary ossification centers * time of birth, an artery enters the two epiphyses * Osteoblasts replace epiphyseal Hyaline cartilage with spongy bone. * Difference: in epiphysis, spongy bone (trabeculae) remains (no cavity created Step 6: Formation of Articular Cartilage and Epiphyseal (growth) plate * Hyaline cartilage that covers epiphyses is now referred to as Articular cartilage * Hyaline cartilage between diaphysis and epiphysis (Epiphyseal plate) remains until puberty

Question 26

Chondrocytes are responsible for?

Answer 26

cartilage formation

Question 27

What is the Zone of resting cartilage?

Answer 27

Small scattered chondrocytes near epiphysis * Resting because they don’t function in bone growth * Rather they anchor epiphyseal plate to epiphysis of bone

Question 28

Zone of proliferating cartilage?

Answer 28

* Larger chondrocytes arrange like stacks of coins * Undergo interstitial growth as they divide

Question 29

Zone of calcified cartilage?

Answer 29

Chondrocytes are dead and matrix is calcified * Osteoclasts and osteoblasts move in * Osteoclasts dissolve calcified cartilage * Osteoblasts replace cartilage with extracellular matrix * Result: area firmly cemented to bone diaphysis = diaphysis longer = bone has increased in length