Topic 3 - The Skeletal System (V-VI [end])

Question 1

Types of bone growth

Answer 1

• intramembranous (dermal) bone

- endochondral (cartilaginous) bone

Question 2

Intramembranous bone is also known as

Answer 2

Dermal bone

Question 3

Bones at the top of the skull + clavicle are

Answer 3

Intramembranous (dermal) bone

Question 4

Bones of the skull base + all postcranial bones, including parts of the clavicle

Answer 4

Endochondral (cartilaginous) bone

Question 5

What is the ontogenetic process in endochondral bone?

Answer 5

• cartilaginous model forms (composed of hyaline cartilage)

- ossification begins

Question 6

What composes the cartilaginous model in the ontogenetic process i endochondral bone

Answer 6

Hyaline cartilage

Question 7

Stages of ossification

Answer 7

• internally, cartilage disintegrates and excavates interior of the bone
• externally, periosteum forms

Question 8

When ossification begins, what do the blood vessels do?

Answer 8

They invade, bringing undifferentiated mesenchymal cells

Question 9

What do the mesenchymal cells differentiate into?

Answer 9

Osteoprogenitor cells, then osteoblasts, which start forming spongy bone

Question 10

What happens externally when ossification begins?

Answer 10

The periosteum forms.

• osteoprogenitor cells within the cellular layer of the periosteum mature into osteoblasts
• osteoblasts start forming compact bone

Question 11

Further growth takes place in 2 directions. What are they?

Answer 11

• interstitial growth

- appositional growth

Question 12

What is interstitial growth?

Answer 12

Growth between the diaphysis and epiphysis

Question 13

What happens during interstitial growth?

Answer 13

• blood vessels invade ends of bone as well, which become secondary centers of ossification (epiphyses)
• epiphyseal plate
• growth ceases when plate ossifies

Question 14

The epiphyseal plate is what?

Answer 14

Zone of hyaline cartilage remaining between primary and secondary ossification centers, site of active growth

Question 15

Appositional growth does what?

Answer 15

Increases in over-all size

Question 16

How is new compact bone deposited in appositional growth>

Answer 16

By osteoblasts, just below the periosteum

Question 17

In appositional growth, what do osteoclasts do?

Answer 17

Destroy bone tissue and enlarge the medullary cavity (if. Present) at the inner bone surface; remodel compact bone/spongy bone interface

Question 18

Appositional growth ceases when?

Answer 18

When the plate ossifies

Question 19

What are the 4 steps of the ontogenetic process in intramembranous bone?

Answer 19

• membranous layer forms around the blood vessels
• ossification begins
• remaining growth takes place via mechanism similar to appositional growth of endochondral bone
• process ends concurrently with endochondral growth

Question 20

When ossification begins, where does it occur?

Answer 20

Internally and externally

Question 21

During internal ossification, what happens?

Answer 21

Undifferentiated connective tissue cells around blood vessels differentiate into osteoprogenitor cells, then osteoblasts, which start forming spongy bone

Question 22

During external ossification, what happens?

Answer 22

Periosteum forms; cells within the cellular layer differentiate into osteoprogenitor cells, then osteoblasts, which start forming compact bone below periosteum.

Question 23

What is Wolff’s law?

Answer 23

bone remodels its shape according to the way force is transmitted through it

Question 24

What are the clinical considerations with the skeletal system?

Answer 24

• chemical disorders
• trauma and injury: fracture
• infectious disease
• neoplasms
• aging

Question 25

Subcategories of chemical disorders

Answer 25

nutritional and hormonal

Question 26

What are the forms of nutritional disorders?

Answer 26

Vit. C and Vit. D

Question 27

Why is Vit C important for the skeletal system?

Answer 27

- necessary for proper collagen formation | - deficiency leads to scurvy

Question 28

Where is Vit. D synthesized?

Answer 28

within the skin or ingested as part of the diet

Question 29

What are the stages of vit. D synthesization? Which one do we really need?

Answer 29

- 7-dehydrocholesterol in the skin (in the presence of ultraviolet radiation [UVR] becomes - cholecalciferol [vit. D3] goes to - liver to become 25-hydroxycholeclciferol, which goes to - kidneys to become 1,25-dihydroxycholecalciferol - really need cholecalciferol (Vit. D3)

Question 30

What does Vit. D do for bone growth?

Answer 30

Facilitates proper bone mineralization by increasing absorption of calcium within the small intestine and reabsorption of calcium in the kidneys

Question 31

Deficiency of Vit. D leads to what in children? To what in adults?

Answer 31

- rickets (soft bones) d/t being less heavily mineralized | - osteomalacia (fatigued, joint aches, bone aches)

Question 32

What are the hormonal clinical considerations with the skeletal system?

Answer 32

- parathyroid hormone (PTH) | - pituitary growth hormone (GH)

Question 33

What does PTH do?

Answer 33

Increases amount of calcium in blood by indirectly stimulating osteoclasts activity

Question 34

What happens when parathyroid hormone binds to receptors ion the osteoblasts?

Answer 34

The osteoblasts release osteoprotegerin ligand (OPGL)

Question 35

What happens when OPGL activates receptors o n the preosteoclast cells?

Answer 35

causes them to mature into osteoclasts

Question 36

What do the osteoclasts?

Answer 36

Start breaking down bone tissue

Question 37

Excess parathyroid hormone leads to what?

Answer 37

bone thinning

Question 38

Excess pituitary growth hormone (GH) leads to what in children? Leads to what in adults?

Answer 38

- gigantism | - acromegaly

Question 39

Deficit of pituitary growth hormone (GH) leads to what in children

Answer 39

Dwarfism

Question 40

What are the different types of fractures?

Answer 40

- comminuted - compression - greenstick

Question 41

What are the stages of healing a fracture?

Answer 41

- fracture hematoma formed from ruptured blood vessels - soft callus forms (mixture of spongy bone and fibrocartilage) - hard callus forms by mineralization and remodeling of soft callus - remodeling of hard callus to mature (compact and spongy) bone

Question 42

What are the infectious disease of bone?

Answer 42

- osteitis - periostitis - osteomyelitis - tuberculosis

Question 43

What is osteitis?

Answer 43

Inflammation of bone tissue caused by injury or infection

Question 44

What is perriostitis?

Answer 44

Inflammation of periosteum caused by trauma or infection

Question 45

What is osteomyelitis?

Answer 45

Inflammation of bone interior caused by bacteria, usually initially entering the bone via wound or via bloodstream

Question 46

What does tuberculosis spread to?

Answer 46

The spongy bone (particularly of the vertebral bodies [Pott's disease]), resulting in bone nad joint destruction.

Question 47

What are the 2 types of neoplasms (tumors) of bone?

Answer 47

Benign and malignant

Question 48

What are the 2 types of benign neoplasms?

Answer 48

Osteochondroma and osteoma

Question 49

What are the 2 types of malignant neoplasms?

Answer 49

Osteogenic sarcoma (osteosarcoma) and multiple myeloma

Question 50

Which kind of neoplasms can kill you?

Answer 50

The malignant (osteogenic sarcoma and multiple myeloma)

Question 51

What happens to the skeletal system when one ages?

Answer 51

- The repair/healing process is slowed | - osteoperosis

Question 52

What can osteoporosis result from?

Answer 52

Hyperthyroidism, hyperparathyroidism, prolonged vitamin C deficiency

Question 53

Who is osteoporosis most prevalent in?

Answer 53

Older women

Question 54

Why are women more prevalent with osteoporosis?

Answer 54

- women have less bone mass than men | - women lose bone mass sooner and faster than men

Question 55

What kind of man would it be common to see osteoporosis in?

Answer 55

One being treated for prostate cancer

Question 56

What is bone density?

Answer 56

Mass / vol.

Question 57

When do women start losing bone mass?

Answer 57

After age 35

Question 58

When do men start losing bone mass?

Answer 58

In 60's