Skeletal System

Question 1

What is the definition of cartilage?

Answer 1

Specialized connective tissues found in surfaces between bones and also some non-bony structures

Question 2

What is a ligament?

Answer 2

Bands of fibrous dense regular connective tissue that anchor bones to other bones

Question 3

What is a tendon?

Answer 3

Bands of fibrous dense regular connective tissue that anchor muscles to bones

Question 4

What is bone matrix composed of?

Answer 4

Collagen mixed with calcium salts

Question 5

What roles do the muscular system and the skeletal system play in the skeletomuscular system?

Answer 5

Muscles: movement, support, generates heat
Skeleton: support, protects tissues, stores minerals, forms blood clot

Question 6

Why are cartilage and bone grouped together into one?

Answer 6

They both have a very dense/solid extracellular matrix

Question 7

What is cartilage matrix made out of? What is bone matrix made out of?

Answer 7

Proteoglycans (protein +chondroitin sulfates); collagen + calcium salts

Question 8

What are the two ways that chondrocytes can grow?

Answer 8

From within (interstitial), by adding new layers at the tissue surface (appositional)

Question 9

How do chondrocytes maintain the ECM? At what stage of their life does this happen?

Answer 9

• live in lacunae and synthesize proteoglycans

- adult state

Question 10

Does cartilage grow in adulthood?

Answer 10

Only under very unusual circumstances and then only appositional

Question 11

What are the six types of bones in the skeleton?

Answer 11

Sutural, flat, irregular, short, long, sesamoid

Question 12

What are the two kinds of bone?

Answer 12

Spongy and compact

Question 13

What runs through the central canal?

Answer 13

Capillaries, venule, nerve

Question 14

What are the four different kinds of cells that live within bone tissue?

Answer 14

Osteogenic, osteocytes, osteoblasts, osteoclasts,

Question 15

What do osteogenic cells do?

Answer 15

They are stem cells that divide to maintain or increase the population of other cells

Question 16

What are osteoblasts and what do they do?

Answer 16

Produce new areas of matrix by secreting proteins and minerals (ossification)

Question 17

What are osteocytes?

Answer 17

Mature osteoblasts that occupy lacunae, maintain and turnover the mineral and protein in the bone matrix

Question 18

What do osteoclasts do?

Answer 18

Live at the surface of the medullary cavity and can dissolve bone matrix

Question 19

What are the two mechanisms for bone growth and when do they occur?

Answer 19

Appositional: osteoblasts adds layers of bone matrix to the outer surface
Endochronal: (in embryo) ossification of cartilage when blood vessels invade the cartilaginous skeletal structures
- the epiphyses ossifies, and the metaphysis remains cartilage and elongates the shaft through interstitial growth

Question 20

How do dermal and sesamoid bones ossify?

Answer 20

From non-cartilaginous connective tissue
Dermal bones: develop from dermal tissue; ossification centres within the developing dermis
Sesamoid bones: form from ossification within the tendons

Question 21

What is the feedback loop for regulating calcium levels?

Answer 21

Sensor: Parathyroid gland
Integrator: PTH (increases activity of osteoclasts)
Effector: osteoclasts
Feedback loop: negative, homeostasis

Question 22

How does bone repair itself?

Answer 22

1. Formation of blood clot (fracture hematoma)
2. Cartilage forms
3. Cartilage is replaced with spongy bone
4. Spongy bone remodels into compact bone

Question 23

What are the three types of joints/articulations?

Answer 23

1. Synarthrosis (no mvmt)
2. Ampiarthrosis (little mvmt)
3. Diarthrosis (free mvmt)

Question 24

What are the four types of synarthrosis?

Answer 24

1. Fibrous (suture)
2. Gomphosis (teeth)
3. Cartilagenous (syndechondrosis: the cartilage between the manubrium and ribs)
4. Bony (synostosis: line in frontal lobe)

Question 25

What are the two types of amphiarthrosis?

Answer 25

Fibrous (syndesmosis: fibrous tissue between tibia and fibula)
Cartilagenous (symphysis: pubic symphysis)

Question 26

What is an example of a diarthrosis?

Answer 26

Synovial joint

Question 27

What is the synovial membrane made out of? What is its function?

Answer 27

Epithelium and areolar tissue

- lubrication, absorb impacts, nourishes cartilage

Question 28

What kind of cartilage is in the synovial joint?

Answer 28

Articular (hyaline)

Question 29

What happens when articular cartilage is damaged?

Answer 29

Increases friction at the synovial joint, inflammation, more pressure on remaining cartilage

Question 30

What does osteoarthritis affect?

Answer 30

Synovial joints

Question 31

What structural features make cartilage not repair very well? What is the advantage of it not repairing easily?

Answer 31

• no blood vessels,, no nutrients to repair with
• growth would require a perichondrial layer, and this compromises the smooth surface
• improper growth would compromise joint function

Question 32

What are the two layers of periosteum and what are their three functions?

Answer 32

Cellular and fibrous

1. Isolate bone from surrounding tissues
2. Provides a route for the blood and nervous supply
3. Actively participates in bone growth and repair

Question 33

What is the purpose of perforating fibres in bone?

Answer 33

Cement tendons, ligaments, joint capsules to the circumferential lamellae with collagen fibres