skeletal system

Question 1

what are the three types of CELLS that make up bone?

Answer 1

1. osteoblasts
2. osteocytes
3. osteoclasts

Question 2

Function of osteoblasts

Answer 2

cells that form the bone

Question 3

function of osteocytes

Answer 3

Ossified osteoblasts that have become trapped in the matrix

Question 4

function of osteoclasts

Answer 4

“evil twins” of osteoblasts
- instead of forming bone, they eat it

Question 5

function of cancellous bone
“spongy bone”

Answer 5

• tiny spicules, the lacey network, that appear randomly arranged
• spaces between spicules contain bone marrow

Question 6

function of compact bone

Answer 6

• shafts of long bones and the outside layers of all the bones
• composed of haversian systems that run lengthwise with the bone

Question 7

yellow bone marrow

Answer 7

• primarily composed of adipose connective tissue (AKA fat)
• can revert to red bone marrow if needed

Question 8

red bone marrow

Answer 8

• hematopoietic tissue: forming blood cells

Question 9

list the three classifications of joints

Answer 9

1. fibrous: immovable - skull
2. cartilaginous: slightly movable
3. synovial: freely movable

Question 9

hinge joints

Answer 9

Ex: Elbow joint
- one joint surface swivels around the other
- only capable of flexion and extension

Question 10

synovial joint movements (6)

Answer 10

1. flexion: makes the joint smaller - bending elbow
2. extension: joint longer
3. adduction: move limb towards the midline
4. abduction: move the limb away from the midline
5. rotation: twisting movement - twisting hand up/down
6. circumduction: moving extremity so distal end moves in a circle

Question 11

gliding joints

Answer 11

Ex: carpus, wrist
- rocking motion of one joint surface on the other
- primarily capable of flexion and extension
- adduction/abduction possible

Question 12

pivot joints

Answer 12

Ex: atlantoaxial joint, neck
- one bone pivots (rotates) on another
- only capable of rotation

Question 13

ball-and-socket joints

Answer 13

Ex: shoulder and hip joints
- allow for all joint movements

Question 14

process of endochondral bone formation (hint: it’s how puppies grow!)

Answer 14

• grows and replaces cartilage
• primary growth: bones developed in diaphysis (the middle)
• secondary “growth plates”: grow in epiphysis of bones (the ends)

Question 15

process of intramembranous bone formation

Answer 15

• occurs only in skull formation
• bone forms in the fibrous tissue membranes that cover the brain in the developing fetus