Bone Formation and Joints

Question 1

Cellular structure of Cartilage

Answer 1

Chondrocytes embedded in an extracellular matrix

Question 2

Is Cartilage vascularized?

Answer 2

Cartilage is Avascular.

Question 3

Howw do chondrocytes receive Oxygen and nutrients?

Answer 3

via diffusion from the Perichondrium.

Question 4

What is the Perichondrium?

Answer 4

A fibrous connective tissue layer that nourishes the cartilage, lays down new cartilage, and provides attachment for the tendons and ligaments

Question 5

What are the 3 types of Cartilage?

Answer 5

Elastic Cartilage, Hyaline cartilage, and Fribrocartilage

Question 6

What type of cartilage is made of mostly Elastin fibers and is stiff and elastic? )e.g. can be found in the ear)

Answer 6

Elastic Cartilage

Question 7

This type of cartilage is blue/translucent, composed of few elastin fibers?

Answer 7

Hyaline Cartilage: occurs in external nose, larynx, costal cartilage, and articular surfaces of synovial joints.

Question 8

Which type of cartilage has the highest proportion of Collagen fibers and occurs in areas requireing tensile Strength?

Answer 8

Fibrocartilage (found btwn intervertebral discs, pubic symphysis, and others)

Question 9

What are Ligaments and tendons made of?

Answer 9

Dense connective tissue of parallel bundles of collagen fibers with fibroblasts

Question 10

Tendons attach…

Answer 10

muscle to bone (or coartilage) via periosteum or perichondrium

Question 11

Ligaments attach…

Answer 11

bone to bone (or coartilage) via periosteum or perichondrium

Question 12

What are intrinsic ligaments?

Answer 12

Thickenings of joint capsules

Question 13

Ligaments Function to…

Answer 13

Provide stability to joints and prevent excessive movement.

Question 14

Bones are composed of…

Answer 14

Osteocytes (mature bone cells), with an extracellular matix composed of collagen, glycoproteins, and mineral salts of calcium and phosphorus

Question 15

What is the outer connective tissue covering all non-articulating surfaces of the bone?

Answer 15

Periosteum — it also contains sensory fibers and arteries that nourish the bone (periosteal and nutrient arteries)

Question 16

Remodeling

Answer 16

The periosteum can form new bone (osteogenesis) in response to injury or mechanical stress.

Question 17

What is Compact Bone?

Answer 17

closely packed structural units called osteons, hard and dense. Provides strength and rigidity.

Question 18

What is Cancellous bone?

Answer 18

It is spongy/ trabecular bone interspersed with marrow, less dense and more vascularized than compact

Question 19

What bones in Adults contain Hematopoietic marrow?

Answer 19

Flat bones and (skull, illium, scapula, sternum, ribs) and ends of long bones

Question 20

Wht type of Marrow is found in the medullary cavities of long bones?

Answer 20

Fatty yellow marrow

Question 21

What type of bone tissue makes the cortical layer?

Answer 21

Compact bone

Question 22

Bone (superficial to deep)

Answer 22

Periosteum–> Compact bone (cortical layer) –> Cancellous bone or medullary cavity

Question 23

Examples of short bones…

Answer 23

cuboidal bones found only in the wrist and ankles

Question 24

Examples of Irregular bones…

Answer 24

include vertebrae and bones of the cranial base and face, coxal bone

Question 25

Sesamoid bones:

Answer 25

form within tendons where they cross joints, reduce friction and increase mechanical advantage.

Question 26

What do Accessory (supernumary) bones result from?

Answer 26

result from an incomplete or abnormal fusion of ossification centers; common in cranial sutures.

Question 27

Describe Intramembranous ossification (direct ossification)

Answer 27

mesenchymal cells give rise to bone forming cells --> bone formation proceeds outward from this primary ossification center.

Question 28

Describe Endochondreal Ossification...

Answer 28

Mesenchyme gives rise to cartilage-forming cells, which replace the mesenchyme model with hyaline cartilage --> invading blood vessels then initiate ossification of the cartiliginous model. (Secondary ossification center)

Question 29

In long bones, a Primary ossification Center forms in...

Answer 29

the diaphysis (shaft)

Question 30

In long bones, Secondary Ossification Centers form later in the....

Answer 30

Epiphyses (ends) of the bone

Question 31

What is the epiphysial plate?

Answer 31

A growth plate made of Hyaline cartilage connects each epiphysis to the diaphysis in long bones

Question 32

What happens with the growth of epiphysieal cartilage?

Answer 32

the bone increases in length.

Question 33

What happens when growth stops in a long bone?

Answer 33

When growth is complete, the epiphysieal plate ossifies and fuses with the rest of the bone leaving a faint epiphyseal line.

Question 34

What are the major joint classes?

Answer 34

Fibrous joints, Cartilaginous joints, and Synovial Joints

Question 35

What are types of Fibrous joints?

Answer 35

Suture (fontanelles in infants/ syntoses in adults) | and Syndesmosis & gomphosis

Question 36

What is a Syndesmosis?

Answer 36

A type of Fibrous Joint where elements are united by a sheet of connective tissues (i.e. tibiofibular syndesmosis/ minimally flexible & radioulnar syndesmosis/ highly mobile)

Question 37

Name the types of Cartilaginous joints...

Answer 37

Synchondrosis (united by hyaline cartilage i.e. epiphyseal growth plate; growth/ no mvmt) & Symphysis (united by fibrocartilage; some mvmt i.i. pubic symphysis)

Question 38

What are Synovial joints?

Answer 38

The most mobile joint type and the most common. Elements are united by a fibrous connective tissue joint (articular) capsule, which encloses a joint cavity

Question 39

What is a Joint capsule/ Articular Capsule?

Answer 39

An outer fibrous capsule that connects the joint elements

Question 40

The Fibrous joint Capsule and all non-articular surfaces are lined by....

Answer 40

A Serous Synovial Membrane, which secretes slippery synovial fluid

Question 41

What what type of cartilage covers the articular surfaces in a synovial joint?

Answer 41

Hyaline articular Cartilage ( lubricated by synovial fluid)

Question 42

Synovial effusion results when...

Answer 42

inflammation causes excess fluid production in the synovial cavity.

Question 43

Articular discs..

Answer 43

Fibrocartilage structures that unite elements and/ or facilitate mvmt in synovial joints

Question 44

Fibrocartilaginous rings..

Answer 44

Deepen articular surfaces and increase stability (e.g. glenohumeral labrum) in a synovial joint

Question 45

Bursae (bursa s.)

Answer 45

Synovial structures that protect tendons and facilitate their mvmt

Question 46

What are the 6 major types of Synovial Joints?

Answer 46

Plane, Hinge, Pivot, Saddle, Condyloid, and Ball-and-socket joints.

Question 47

Hinge joint ex

Answer 47

Uniaxial... elbow/ knee

Question 48

Condyloid joint ex

Answer 48

Biaxial (flexion/extension & Abbduction/Adduction) | ex. metacarpal phalangeal joints and whrist

Question 49

Saddle joint ex

Answer 49

Biaxial, but also permit circumduction-like motion. i.e. thumb and sternoclavicular joint

Question 50

Pivot joint

Answer 50

Uniaxial I.e. Dens freely rotates with Atlas & proximal radioulnar joint

Question 51

Ball and Socket joints

Answer 51

Multi-axial, spherical head rotates freely about all axes i.e Hip and Shoulder

Question 52

What is the extra cellular matrix of cartilage made of?

Answer 52

Collagen, elastin, and proteoglycans

Question 53

What bones in infants contain hematopoietic marrow?

Answer 53

All bones at birth