1C Skeletal System

Question 1

Skeletal System

Answer 1

System of the body, which forms a solid framework around which the body is built

Question 2

Functions of Skeletal System

Answer 2

• Structural support of the body
• Attachment fro skeletal muscles (origin, insertion)
• Protection of certain vital organs
  ex: brain by skull and heart and lungs by thoracic cage
• Manufacture certain blood cells: hemopoiesis (red bone marrow)
• Storage of certain chemical substances (calcium, phosphate)

Question 3

Long bone

Answer 3

A bone in which the length exceeds the width, and is characterized by having a medullary (marrow) canal
ex: humerus, radius, ulna, tibia, fibula

Question 4

Short bone

Answer 4

A bone in which the length equals the width

ex: carpal bones

Question 5

Flat bone

Answer 5

A bone expanded into 1 plane

ex: scapula

Question 6

Irregular bone

Answer 6

A bone that does not fit into any of the other 3 categories

ex: vertebrae

Question 7

Axial Skeleton

Answer 7

Part of the skeleton that occupies the central axis of the body

1. Skull and hyoid (23)
2. Vertebral column ( 7 cervical, 12 thoracic, 5 lumbar, 1 saccrum, 1 coccyx = 26)
3. Ribs and Sternum (12 pairs of ribs + sternum) = 25
4. Bones of the middle ear (6, 3 per side)

Question 8

Appendicular Skeleton

Answer 8

Part of the skeleton that comprises the appendages

Question 9

Bones of the upper limb (64)

Answer 9

1. Clavicle: collar bone
2. Scapula: shoulder blade
3. Humerus: arm
4. Ulna and radius: forearm
5. 8 carpal bones: wrist
6. 5 metacarpal bones: forming the palms
7. Fourteen phalanges: fingers (28 total)

Question 10

Bones of the lower limb (62)

Answer 10

1. Hip bone
2. Femur: thigh
3. Patella
4. Tibia an Fibula: leg
5. 7 tarsal bones: ankle (14 total)
6. 5 Metatarsal bones: foot
7. 14 phalanges

Question 11

Total Number of Bones

Answer 11

206

Question 12

Sesamoid bone

Answer 12

Bone located in tendons

*aside from 206 bones

Question 13

Ectopic bone

Answer 13

Pathological bone formation within tissue

*aside from bone formation within tissue

Question 14

Epiphysis

Answer 14

The two ends of the long bone, which are wider than the shaft and take part in the formation of a joint

Question 15

Diaphysis

Answer 15

Shaft of the long bone

Question 16

Compact bone

Answer 16

Laid down in concentric layers making it appear solid

1. Forms the outer surface of all bones
2. Thicker in Diaphysis (shaft) and thinner in the Epiphysis (ends)

Question 17

Spongy bone

Answer 17

Composed of very thin plates of bone at various angles, leaving spaces between them

Question 18

Periosteum

Answer 18

Connective tissue sheath composed of two layers

1. Outerlayer: tough fibrous layer that serves as a place of insertion for muscle tendons
2. Inner layer: delicate cellular layer responsible for producing growth in the diameter of bone

Question 19

Endosteum

Answer 19

Thin, cellular layer found lining the medullary cavity and the cavities of spongy bone

1. Its primary function is to destroy bone, thus allowing for growth in the diameter of the marrow cavity, which prevents bone from becoming too solid and heavy as it increases in size

Question 20

Medullary (marrow) cavity

Answer 20

Cavity running the length of the diaphysis that contains either red marrow (blood cells), yellow marrow (fat cells), or combinations of the two.

Question 21

Articular cartilage

Answer 21

Thin layer of hyaline cartilage covering the articular surface of each epiphysis

1. Resiliency of this material cushions the joint during movement

Question 22

Articular capsule

Answer 22

Connects together the 2 bones and completely encircles the joint, thus enclosing a cavity hat is called the joint cavity or synovial cavity

1. Outer fibrous layer: continuous with the periosteum of bone
2. An inner layer: lines the inside of the fibrous layer
   - Also called synovial membrane
   - Vascular and produces synovial fluid that fills the joint cavity, lubricates the joint, and nourishes the articular cartilage

Question 23

Epiphyseal disc

Answer 23

• In puberty of a growing child, it is a cartilaginous plated
• Located at the junction of epiphysis and diaphysis that allows for growth in the length of bone

Question 24

Metaphysis

Answer 24

Spongy bone tissue located at the junction of the diaphysis and the epiphyseal disc

-In adults, the bony tissue of the metaphysis is continuous with the epiphysis

Question 25

Cartilage

Answer 25

A tough connective tissue, which is composed of cells embedded in a firm, gel-like intercellular substance

Question 26

Cartilage 1-6

Answer 26

1. It is not as hard as bone, and exhibits some degree of flexibility 2. It is called gristle by laymen 3. It lacks nerves 4. It lacks blood vessels - Nutrients diffuse through the intercellular substance 5. The entire embryo skeleton is initially cartilage, but is replaced by bone during growth (ossification) 6. The classification of cartilage is via the histologic appearance of the intercellular matrix

Question 27

Hyaline Cartilage

Answer 27

Glass-like, translucent appearance ex: - Embryo skeleton - Epiphyseal discs - Articular cartilages - Costal cartilages (between ribs and sternum) - Larynx, trachea, and bronchi (respiratory) - Nasal cartilages

Question 28

Fibrocartilage

Answer 28

- Interpubic disc (symphysis pubis) | - Intervertebreal discs (between adjacent vertebrae)

Question 29

Elastic cartilage

Answer 29

- Auricle (part of external ear) - Auditory tube (connects ear and pharynx) - Epiglottis (flap that keeps food from entering lungs)