6-1. Bones and Skeletal Tissue

Question 1

What are the functions of bone?

Answer 1

1. SUPPORT (for soft body tissues, gives body shape)
2. PROTECTION (of delicate internal organs (eg. brain, heart))
3. MOVEMENT (muscles use bones as levers to move body parts)
4. MINERAL STORAGE (bones are reservoirs for calcium and phosphate)
5. BLOOD CELL PRODUCTION (hematopoiesis; most blood cells are formed in bone marrow)

Question 2

What tissues make up bones?

Answer 2

cartilage and bone tissue

Question 3

Bones themselves are ___.

Answer 3

organs

Question 4

What are the types of cartilage?

Answer 4

hyaline, elastic and fibrocartilege

Question 5

What are the primary components of cartilage?

Answer 5

chondrocytes
extracellular matrix made of a jelly like ground substance with collagen and/or elastic fibers
no blood vessels or nerves

Question 6

The embryonic skeleton is initial made of up __ and __, but most is soon replaced by ___.

Answer 6

cartilage and fibrous membranes; bone

Question 7

Where is cartilage found in the adult skeleton?

Answer 7

regions where more flexibility is required

Question 8

What are 5 places where hyaline cartilage is found in the adult skeleton?

Answer 8

1. articular cartilage - covers ends of bones at movable joints
2. costal cartilage - connects ribs to sternum
3. laryngeal cartilage - framework of voicebox
4. tracheal and bronchial cartilage - keeps airways from collapsing
5. nasal cartilage - tip of nose

Question 9

Where is elastic cartilage found in the adult skeleton?

Answer 9

external ear and epiglottis

Question 10

Where is fibrocartilage found in the adult skeleton?

Answer 10

intervertebral discs
pubic symphysis
menisci of knee

Question 11

What are some types of bone cells?

Answer 11

osteoblasts > osteocytes

osteoclasts

Question 12

osteoblast

Answer 12

bone building cells that secrete matrix around themselves

Question 13

osteocyte

Answer 13

mature bone cells that maintain bone matrix

Question 14

osteoclasts

Answer 14

break down bone matrix from areas where it’s deteriorating

Question 15

What is bone matrix made of?

Answer 15

inorganic parts - mineral salts (primarily calcium phosphate) in tightly packed crystals - make up 65% of bone by weight and give it hardness

organic parts - osteoid - made of ground substance and collagen fibers forming a framework for calcium salts

Question 16

osteoid

Answer 16

organic part of the bone matrix, made from ground substance and collagen fibers

Question 17

Why is bone porous?

Answer 17

carry blood vessels and nerves to supply nutrients

make bones lighter

Question 18

Bone can be classified as either _ or _, based on _.

Answer 18

compact or spongey; the distribution and size of the pores

Question 19

What are the classifications of bone (by shape)?

Answer 19

long bones
short bones
flat bones
irregular bones

Question 20

long bones

Answer 20

longer than they are wide, consist of a shaft with two ends (eg. humerous, femur)

Question 21

short bones

Answer 21

about equal in length and width, roughly cube shaped (eg. carpals)

Question 22

flat bones

Answer 22

thin flattened but often a bit curved (eg. sternum, cranium)

Question 23

irregular bones

Answer 23

bones that don’t fit the other categories (eg. vertebrae)

Question 24

diaphysis

Answer 24

tubular shaft; thick collar of compact bone surrounding central cavity

Question 25

medullary cavity

Answer 25

hollow cavity running length of diaphysis; filled with adipose in adults (yellow marrow)

Question 26

epiphysis

Answer 26

enlarged end, filled with spongey bone inside; have a proximal and a distal epiphysis

Question 27

periosteum

Answer 27

shiny white membrane covering outer surface except at joints

Question 28

endosteum

Answer 28

membrane lining the internal bone cavities

Question 29

articular cartilage

Answer 29

hyaline cartilage covering the epiphysis at joints

Question 30

epiphyseal line

Answer 30

between the diaphysis and each epiphysis of an adult bone. it is what remains of the epiphysial plate

Question 31

epiphysial plate

Answer 31

a region of bone growth in children

Question 32

The _ lines the outer surface of bones except at _.

Answer 32

periosteum; joints

Question 33

The _ lines the internal bone cavities.

Answer 33

endosteum

Question 34

compact bone

Answer 34

dense tissue containing few spaces - found in the diaphysis of long bones, helping them to resist stress, and covers the surface of all bones

Question 35

The diaphysis of long bones is made primarily of __.

Answer 35

compact bone

Question 36

The epiphysis of long bone is filled with __

Answer 36

spongey bone

Question 37

__ covers the surface of all bones.

Answer 37

compact bone

Question 38

Haversian System (osteon)

Answer 38

structural unit of adult compact bone; elongated cylinder ("tree trunks")

Question 39

Volkmann's Canals

Answer 39

carry blood vessels and nerves from periosteum to interior (horizontal)

Question 40

Haversian Canals

Answer 40

rung lengthwise thru center of osteons, carry blood vessels (vertical)

Question 41

lamellae

Answer 41

concentric rings of hard, calcified matrix around each Haversian Canal

Question 42

lacunae

Answer 42

small cavities between lamellae where osteocytes are housed

Question 43

canaliculi

Answer 43

tiny canals that connect osteocytes to each other and to Haversian Canals; provide routes for nutrients

Question 44

spongy bone

Answer 44

found inside short, flat and irregular bones, and within the epiphyses of long bones

Question 45

Short bones are made primarily of _.

Answer 45

spongy bone

Question 46

Flat bones are made primarily of _.

Answer 46

spongy bone

Question 47

Irregular bones are made primarily of _.

Answer 47

spongy bone

Question 48

Spongy bone / contain Haversian Systems/osteons.

Answer 48

does not

Question 49

trabeculae

Answer 49

needle like spikes of bone that form along lines of stress; spaces between are filled with red bone marrow (where blood cells are produced) Osteocytes lie in lacunae within the trabeculae and are nourished directly by blood from capillaries in the surrounding endosteum

Question 50

Short, flat and irregular bones all consist of thin plates of ____-covered ____ bone on the outside and ___-covered ____ bone within.

Answer 50

periosteum-covered compact bone | endosteum-covered spongy bone (called diploe)