Chapter 11: The Skeletal System

Question 1

What are the functions of the skeletal system?

Answer 1

Support framework, movement anchor, protection, mineral storage, fat storage, blood cell production.

Question 2

Compact Bone

Answer 2

Highly organized and composed of tubular units called osteons.

Question 3

Osteocytes

Answer 3

Bone cells lie in tiny chambers arranged in concentric circles around a central canal (Lacunae)

Question 4

Matrix

Answer 4

Fills the space between the rows of the lacunae (cells), hard from mineral salts, flexible from collagen.

Question 5

Spongy Bone

Answer 5

Unorganized appearance, contains thin plates (trabeculae) separated by unequal spaces, lighter but designed for strength, lattice work, spaces often filled with red bone marrow.

Question 6

Cartilage

Answer 6

Less strength than bone but more flexible, cells are scattered in a gel-like matrix, no nerves or blood vessels, three types.

Question 7

Hyaline Cartilage

Answer 7

Firmer with a lot collagen, found at the ends of bones, nose, larynx, and trachea.

Question 8

Fibrocartilage

Answer 8

Strong from rows of thick collagen fibers, found where a lot of support is needed (disks of spine and knee).

Question 9

Elastic Cartilage

Answer 9

More flexible with a lot of elastin fibers in the matrix. Found in the ear flaps and the epiglottis.

Question 10

Five Major Steps of Ossification or Bone Development

Answer 10

Cartilage model, bone collar, primary ossification center, secondary ossification, growth plate.

Question 11

1st step in ossification: Cartilage model

Answer 11

In the embryo, chondrocytes lay down hyaline cartilage, which is shaped like the future cells. (cartilage models of future bones)

Question 12

2nd Step of Ossification: Bone Collar

Answer 12

Osteoblasts secretes the organic matrix, and the matrix undergoes calcification. Bone collar is composed of compact bone.

Question 13

3rd Step of Ossification: The Primary Ossification Center

Answer 13

First center for bone formation, blood vessels bring osteoblasts to the interior and start to lay down spongy bone.

Question 14

4th Step of Ossification: The Medullary Cavity and Secondary Ossification Sites

Answer 14

The spongy bone of the diaphysis is absorbed by osteoclasts and creates the medullary cavity. Shortly after birth, the second site is formed in the epiphyses.

Question 15

5th Step of Ossification: The epiphyseal (growth) Plate

Answer 15

A band of cartilage called a growth plate remains between the primary and secondary ossification center. Bones continue to grow as long as the plate is present. The growth plate eventually disappears from the cartilage thinning.

Question 16

Hormones

Answer 16

Regulate bone growth with GH in childhood and sex hormones in puberty.

Question 17

How are bones maintained by BONE REMODELING?

Answer 17

Renewal and recycling, old cells broken down and new cells formed, allows regulation of Ca2+ in blood, thickens and strengthens bones that get a lot of use or stress, bone loss can occur with older age.

Question 18

What are the 4 steps of bone repair and the functions?

Answer 18

1. Hematoma: Clotted blood forms within hours
2. Fibrocartilage callus: fills the space between the ends of the broken bone for about 3 weeks
3. Bony callus: convert fibrocartilage callus to bony callus that joins broken bones together (lasts 3-4 months)
4. Remodeling: Osteoblasts build new compact bone. osteoclasts absorb the spongy bone, creating a new medullary cavity. (last for years).

Question 19

Axial Skeleton

Answer 19

Skull, backbone, and rib cage.

Question 20

Appendicular Skeleton

Answer 20

Pectoral girdle, pelvic girdle, arms, legs.

Question 21

Fibrous Joint

Answer 21

Fibrous connective tissue, immoveable. (cranial joints)

Question 22

Cartilaginous Joint

Answer 22

Hyaline or fibrocartliage, slightly moveable. (ribs to sternum, intervertebral disks)

Question 23

Synovial Joint

Answer 23

Flexible and moveable, cavity with synovial liquid that cushions and lubricate, cartilage decreases friction, reinforced with ligaments, hinge joints, ball and socket joints.

Question 24

Flexion

Answer 24

Joint angle decreases

Question 25

Extension

Answer 25

Joint angle increases

Question 26

Adduction

Answer 26

Body part moves toward midline

Question 27

Abduction

Answer 27

Body part moves away from midline

Question 28

Rotation

Answer 28

Body part moves around its own axis

Question 29

Circumduction

Answer 29

Body part moves so that a cone shape is outlined

Question 30

Enversion

Answer 30

Sole of foot turns outwards

Question 31

Inversion

Answer 31

Sole of foot turns inward

Question 32

Osteoporosis

Answer 32

Decreased bone mass, sex hormones maintain mass, decline with age, calcium, vitamin D and weight bearing exercise all help prevent

Question 33

Arthritis

Answer 33

Inflammation of joints

Question 34

Osteoarthritis

Answer 34

From wear and tear over time, direct grinding of bones

Question 35

Rheumatoid Arthritis

Answer 35

Arthritis from immune response, replacement of cartilage with fibrous connective tissue, limiting movement.