Level 2 - Skeletal Development 1

Question 1

What are the functions of bone?

Answer 1

-support
-protection
-movement
-mineral storage
-hematopoiesis

Question 2

Blood cell formation is carried out by myeloid tissue (red bone marrow).
In adults the myeloid tissue is found in the epiphyses of certain long bone and in flat bones of the skull, pelvis, sternum, ribs

Answer 2

Hematopoiesis

Question 3

What are the 5 major types of structural bone?

Answer 3

Long bone (femur)
Short bone (carpal)
Flat bone (scapula)
Irregular bone (vertebrae)
Sesamoid bone (patella)

Question 4

-Main long shaft of bone
-hollow, cylindrical shape and thick compact bone
-provides strong support without cumbersome weight

Answer 4

Diaphysis

Question 5

-Both ends of a long bone, made of cancellous bone filled with marrow
-bulbous shaped
-provides attachments for muscles and gives stability to joints

Answer 5

Epiphyses

Question 6

The zone of growth between the epiphysis and diaphysis during bone development

Answer 6

Metaphysis

Question 7

Where bone grows

Answer 7

Epiphyseal line

Question 8

Layer of hyaline cartilage that covers the articular surface of epiphyses
-functions to cushion jolts and blows

Answer 8

Articular cartilage

*Long bone

Question 9

-dense white fibrous membrane that covers bone
-attached tendons firmly to bones
-contains cells that form and destroy bone
-contains blood vessels important in growth and repair
-contains blood vessels that send branches into bone
-essential for bone cell survival and bone formation

Answer 9

Periosteum (surrounds bone)

*long bone

Question 10

-tubelike hollow space in the diaphysis
-filled with yellow marrow in adults
-filled with red marrow in kids

Answer 10

Medullary cavity (marrow)

*long bone

Question 11

Thin, fibrous membrane that lines the medullary cavity of long bones. Also lines the space of spongy bone

Answer 11

Endosteum

*long bone

Question 12

Cranial flat bones have an internal and external table of compact bone and an inner cancellous region called the:

Answer 12

Diploë (spongy bone in flat bones)

Question 13

T/F
Spaces inside the cancellous bone of short, flat, irregular and sesamoid bones are filled with red marrow
Ex. Sternum

Answer 13

True

Question 14

-most distinctive form of connective tissue
-extracellular components are hard and calcified
-rigidity of bone gives it supportive and protective functions
-tensile strength nearly equal to that of cast iron at less than 1/3 the weight

Answer 14

Bone tissue

Question 15

-extra cellular components are hard and calcified
-rigidity of bone gives it supportive and protective functions
-tensile strength nearly equal to the of cast iron at less that 1/3 of weight

Answer 15

Characteristics of bone tissue

Question 16

Contains many cylinder-shaped structural units called OSTEONS or HAVERSIAN systems

Answer 16

Compact bone

Question 17

-surround central (Haversian) canals (containing blood/lymphatic vessels and nerves) that run lengthwise through bone and are connected by transverse (volkmann)

Answer 17

Osteon

Question 18

Where are living bone cells located?

Answer 18

Osteons
*constitute the structural framework of compact bone
*osteons permit delivery of nutrients and removal of waste products

Question 19

What are the 3 structures of the lamellae?

Answer 19

-concentric
-interstitial
-circumferential

Question 20

Lamellae

Cylinder-shaped layers of calcified matrix around central canal

Answer 20

Concentric

Question 21

Lamellae

Layers of bone matrix between the osteons; leftover from previous osteons

Answer 21

Interstitial
*between tissue

Question 22

Lamellae

Few layers of bone matrix that surrounds all osteons; run along the outer circumference of a bone and inner circumference (boundary of medullary cavity) of a bone
*surrounds several osteons

Answer 22

Circumferential

Question 23

What structures make up the osteon?

Answer 23

-lamellae
-lacunae
-canaliculi
-central (osteonal or Haversian) canal

Question 24

Small spaces containing tissue fluid in which bone cells are located between hard layers of the lamella
*hallow spaces/blue spots on osteon model

Answer 24

Lacunae

Question 25

Ultra small canals radiating in all directions from the lacunae and connecting them to each other and to the central canal

Answer 25

Canaliculi *hair like structures, red on osteon model

Question 26

Extends lengthwise through the Center of each osteon; contains blood vessels and lymphatic vessels and nerves. Nutrients and oxygen move from the central canal through the cancliculi to the lacunae and their bone cells inside

Answer 26

Central (ostenonal or Haversian) canal

Question 27

T/F Compact bone, in addition to bone marrow and blood vessels from the periosteum penetrates the bone and then, by way of transverse (Volkmann) canals, connects with vessels in the central canals of osteons

Answer 27

True

Question 28

T/F Bone cells are metabolically active and need a blood supply, which comes from the bone marrow in the internal medullary cavity of cancellous bone

Answer 28

True

Question 29

T/F Cancellous bone does not have osteons

Answer 29

True *has trabeculae instead -nutrients are delivered and waste products removed by diffusion through tiny canaliculi similar to compact bone

Question 30

Bony branches arranged along lines of stress to enhance the bones strength

Answer 30

Trabeculae *cancellous bone

Question 31

Where is spongy bone (traveculae) found?

Answer 31

-between compact bond in: Flat bones Irregular bones Seamus bones Long bone (inside epiphysis and lining the medullary cavity)

Question 32

What are the 3 types of bone cells?

Answer 32

-osteoblasts -osteoclasts -osteocytes

Question 33

-bone forming cells found in all bone surfaces -small cells synthesize and secrete osteons, an important part of the ground substance

Answer 33

Osteoblasts

Question 34

-giant multinucleated cells -responsible for active erosion of bone minerals -contain large numbers of mitochondria and lysosomes

Answer 34

Osteoclasts

Question 35

T/F Osteoblasts, osteoclasts, osteocytes are found in both compact and spongy bone

Answer 35

True

Question 36

-mature non-dividing osteoblasts surrounded by matrix and lying within lacunae

Answer 36

Osteocytes

Question 37

-type of soft, diffuse connective tissue; called myeloid tissue -site for production of blood cells -found in medullary cavity of long bone and in spaces in spongy bone

Answer 37

Bone marrow

Question 38

What bones in adults still contain red marrow?

Answer 38

Ribs Vertebrae (bodies) Humerus Pelvis Femur Scapula Clavicle Sternum

Question 39

T/F Red marrow can change to yellow marrow during times of decreased blood supply, such as anemia, radiation exposure, disease

Answer 39

True

Question 40

-found in virtually all bones in an infant or child body -produces red blood cells

Answer 40

Red marrow

Question 41

-As individuals age, red marrow is replaced -marrow cells become saturated with fat and are no longer active in blood cell production

Answer 41

Yellow marrow

Question 42

T/F The skeletal system is a storehouse for about 98% of body calcium reserves

Answer 42

True

Question 43

Osteoblasts remove calcium from blood and lower circulating levels

Answer 43

During bone formation

Question 44

Osteoclasts release calcium into blood and increase circulating levels

Answer 44

During breakdown of bone

Question 45

Homeostasis of calcium ion concentration is essential for:

Answer 45

-bone formation, remodelling, repair -blood clotting -transmission of nerve impulses -maintenance of skeletal and cardiac muscle contraction

Question 46

-primary regulator of calcium homeostasis -stimulates osteoclasts to initiate breakdown of bone matrix and increase blood calcium levels -increase renal absorption of calcium from urine -stimulates vitamin D synthesis

Answer 46

Parathyroid hormone *mechanisms of calcium homeostasis

Question 47

-protein hormone produced in thyroid gland -produced in response to high blood calcium levels -stimulates bone deposition by osteoblasts -inhibits osteoclast activity -far less important than parathyroid hormone

Answer 47

Calcitonin