Group 8/9/19

Question 1

general structure of cartilage

Answer 1

avascular, no nerves or lymphatics

tough, durable form of connective tissue

Question 2

perichondrium structure and function

Answer 2

sheath of dense connective tissue that surrounds cartilage in most places (not in articular cartilage)
functions to grow and maintain cartilage
structure has type 1 collagen and fibroblasts on the outside, and mesenchymal stem cells on the inside

Question 3

cells of cartilage, and their function

Answer 3

chondrocytes, these synthesize and maintain the components in the ECM

Question 4

location of chondrocytes

Answer 4

lacunae, which are matrix cavities

Question 5

matrix of cartilage

Answer 5

extracellular matrix (ECM) has high concentration of GAGs and proteoglycans that interact with collagen and elastic fibers

Question 6

aggrecan

Answer 6

a proteoglycan that binds a large amount of water

functions to bind to type 2 collagen fibrils

Question 7

types of cartilage

Answer 7

hyaline, elastic, fibrocartilage

Question 8

location of hyaline cartilage

Answer 8

upper respiratory tract, articular ends and epiphyseal plates of long bones, fetus

Question 9

location of elastic cartilage

Answer 9

external ear, external acoustic meatus, auditory tube, epiglottis and other laryngeal cartilages

Question 10

location of fibrocartilage cartilage

Answer 10

intervertebral discs, pubic symphysis, meniscus, other joints, and insertion of tendons

Question 11

functions of hyaline cartilage

Answer 11

resists compression
cushioning, smooth, low-friction surfaces for joints
structural support for respiratory system
forms foundation for development of fetal skeleton and bone growth

Question 12

functions of elastic cartilage

Answer 12

flexible support for soft tissues

Question 13

functions of fibrocartilage

Answer 13

resists deformation under stress

Question 14

presence of perichondrium in hyaline cartilage

Answer 14

yes, except articular cartilage and epiphyseal plates

Question 15

presence of perichondrium in elastic cartilage

Answer 15

yes

Question 16

presence of perichondrium in fibrocartilage

Answer 16

no

Question 17

which types of cartilage undergo calcification?

Answer 17

hyaline cartilage calcifies in endochrondal bone formation during the aging process
fibrocartilage calcifies the callus during bone repair

Question 18

what cells is aggrecan secreted by?

Answer 18

chondrocytes

Question 19

what cells is versican secreted by?

Answer 19

fibroblasts

Question 20

typical arrangement of chondrocytes in hyaline cartilage

Answer 20

small isogenous groups

Question 21

typical arrangement of chondrocytes in elastic cartilage

Answer 21

isolated or small isogenous groups

Question 22

typical arrangement of chondrocytes in fibrocartilage

Answer 22

isolated or in isogenous groups, arranged axially

Question 23

osteoarthritis

Answer 23

chronic, during aging, loss of hyaline cartilage lining articular ends of bones

Question 24

chondronectin

Answer 24

a structural mutliadhesive glycoprotein

functions to bind to GAGs, collagen and integrins, so that chondrocytes can adhere to the ECM

Question 25

chondrocytes location and function

Answer 25

``` located at the edge of cartilage in lacunae function to synthesize sulfated GAGs and secrete proteoglycans ```

Question 26

hormone that regulate hyaline cartilage growth

Answer 26

somatotropin

Question 27

chondrogenesis

Answer 27

process by which cartilage forms from mesenchyme 1. mesenchymal cells multiply and pack 2. chondroblasts created 3. ECM encloses chondroblasts to separate them 4. embryonic development 5. become chondrocytes

Question 28

types of cartilage growth processes

Answer 28

interstitial and appositional

Question 29

interstitial growth

Answer 29

enlarges cartilage, uses mitosis for division, important for long bone development

Question 30

appositional growth of cartilage

Answer 30

takes progenitor cells from perichondrium, and differentiates them into chondroblasts

Question 31

repair of cartilage

Answer 31

cells from the perichondrium invade the injured area and produce new cartilage slow and incomplete, except in young produces a scar of dense connective tissue

Question 32

bone development name

Answer 32

osteogenesis

Question 33

types of bone development*

Answer 33

intramembranous ossification and endochondral ossification

Question 34

process of intramembranous ossification

Answer 34

1. in condensed mesenchyme, incomplete layers of osteoblasts form in ossification centers 2. osteoblasts secrete osteoid, forms woven bone with osteocytes in lacunae and canaliculi 3. neighboring ossification centers fuse 4. woven bone is replaced by compact bone 5. if there's no ossification centers, the mesenchymal regions become endosteum and periosteum

Question 35

process of endochondral ossification

Answer 35

1. osteoblasts produce a bone collar around the cartilage model diaphysis 2. causes chondrocytes to hypertrophy and die, the ECM is compressed and calcifies 3. blood vessels from the perichondrium (now periosteum) penetrate the bone collar 4. vessels and new osteoblasts move in and produce woven bone 5. primary ossification center is formed during the 1st trimester 6. secondary ossification centers develop similarly, later in time, at epiphyses of the cartilage model

Question 36

epiphyseal cartilage

Answer 36

connects the epiphysis to the diaphysis and is involved in long bone growth disappears once bones are formed

Question 37

epiphyseal plates

Answer 37

these separate the primary ossification center in the diaphyses and the secondary ossification center in the epiphyses disappear via epiphyseal closure by age 20

Question 38

types of endochondral ossification

Answer 38

longitudinal and appositional growth

Question 39

longitudinal growth process of endochrondral ossification

Answer 39

1. cartilage cells in epiphyseal plates proliferate 2. chondrocytes in the diaphysis cells hypertrophy, and the matrix calcifies and dies 3. osteoblasts lay down a new bone layer 4. epiphyseal plates are displaced away from the center, and the bone length increases

Question 40

appositional growth process of endochondral ossification

Answer 40

1. a bone collar is formed on the cartilaginous diaphysis 2. new bone is added at the periosteal surface while bone is removed at the endosteal surface 3. the central marrow cavity expands, so bone circumference grows

Question 41

zones of activity in epiphyseal growth plate from farthest from ossification center to closest

Answer 41

1. zone of reserve (resting) cartilage 2. proliferative zone 3. zone of hypertrophy 4. zone of calcified cartilage 5. zone of ossification

Question 42

zone of reserve (resting) cartilage

Answer 42

composed of hyaline cartilage

Question 43

proliferative zone

Answer 43

cartilage cells multiply, secrete type 2 collagen and proteoglycans, into columns

Question 44

zone of hypertrophy

Answer 44

chondrocytes swell, secrete type X collagen which stiffens the matrix and promotes vascularization

Question 45

zone of calcified cartilage

Answer 45

chondrocytes begin matrix calcification

Question 46

zone of ossification

Answer 46

bone tissue appears. Capillaries and osteoprogenitor cells go to the lacunae, osteoblasts secrete osteoid, woven bone develops into lamellar bone

Question 47

bone repair process

Answer 47

1. blood vessels at the fracture site release blood that clots and forms a hematoma 2. macrophages remove the hematoma, periosteum and endosteum replaces it with procallus tissue 3. blood vessels and osteoblasts replace the procallus, new woven bone forms a hard callus 4. woven bone becomes compact and cancellous bone

Question 48

***LEARNING ISSUES AND LOOK-UPS

Answer 48

Here are the learning issues we decided on for the next group meeting: - Histology of cartilage - Histology of development vs healing bones - Anatomy of the upper arm (muscles, bones, tendons, ligaments)

Question 49

muscle and nerve for 0-15 degree arm abduction*

Answer 49

supraspinatus muscle; suprascapular nerve

Question 50

muscle and nerve for 15-100 degree arm abduction*

Answer 50

deltoid muscle; axillary nerve

Question 51

muscle and nerve for >90 degree arm abduction*

Answer 51

trapezius muscle; accessory nerve

Question 52

muscle and nerve for >100 degree arm abduction*

Answer 52

serratus anterior muscle; long thoracic (SALT) nerve

Question 53

which shoulder muscles form the rotator cuff muscles, and what are their innervations?*

Answer 53

SItS: supraspinatus (suprascapular nerve), infraspinatus (suprascapular nerve), teres minor (axillary nerve), subscapularis (upper and lower subscapular nerves)

Question 54

action of supraspinatus muscle*

Answer 54

- abducts arm initially, 0-15 degrees | - most common rotator cuff injury, can be assessed with the empty/full can test

Question 55

action of infraspinatus muscle*

Answer 55

externally rotates the arm

Question 56

action of teres minor muscle*

Answer 56

adducts and externally rotates arm

Question 57

action of subscapularis muscle*

Answer 57

internally rotates and adducts arm

Question 58

greenstick fracture*

Answer 58

incomplete fracture extending partway through width of bone following bending stress. The bone fails on the tension side while the compression side is intact. Bent like a green twig.

Question 59

Torus (buckle) fracture*

Answer 59

cause: axial force applied to the immature bone effect: cortex buckles on compression side and fractures, while tension side remains intact