Chapter 47-The Musculoskeletal Systems

Question 1

3 Types of Skeletal Systems

Answer 1

1. Hydrostatic Skeletons
2. Exoskeletons
3. Endoskeletons

Question 2

Hydrostatic Skeletons

Answer 2

• soft body invertebrates

- fluid filled central cavity

Question 3

Exoskeletons

Answer 3

• surrounds body as rigid hard case
• composed of chitin in arthropods
• periodically shed (molting)
• found in arthropods

Question 4

Endoskeletons

Answer 4

• form bodys framework for support and offer surfaces for muscle attachment
• echinoderms have calcite skeletons in skin
• vertebrates have skeleton within body wall
• unlike chitin, bone and cartilage are living tissue

Question 5

Bone

Answer 5

• unique to vertebrates
• hard connective tissue
• composed of cells

Question 6

osteoblasts

Answer 6

bone making cells-synthesize collagen and enzymes needed tomake the matrix

Question 7

osteocytes

Answer 7

bone maintaining cells

Question 8

osteoclasts

Answer 8

cells that break down bone tissue

Question 9

Bone structure

Answer 9

1. compact bone-outer dense layer
2. medullary bone-lines internal cavity
3. spongy bone-forms epiphyses inside a thick shell of compact bone
   - bones retain internal blood vessels

Question 10

Joints

Answer 10

-locations where one bone meets another, cartilage and fluid

Question 11

4 basic movement patterns of joints

Answer 11

1. ball and socket joints-movement in all directions
2. hinge joints-allow movement in only 1 plane
3. gliding joints-permit sliding of one surface over another
4. combination joints-movement characteristics of 2 or more joint types

Question 12

Periosteum

Answer 12

tendon attaches to this on bones and to muscles

Question 13

Origin vs. Insertion

Answer 13

• origin=stationary during contraction

- insertion=attached to a bone that moves when muscle moves

Question 14

Sarcolemma

Answer 14

• skeletal muscle cell

- cell membrane, contains acetylcholine receptors

Question 15

T-tubules

Answer 15

• skeletal muscle cells

- connect sarcolemma with sarcoplasmic reticulum

Question 16

sarcoplasmic reticulum

Answer 16

• skeletal muscle cell

- type of endoplasmic reticulum surrounding each myofibril

Question 17

tropomyosin

Answer 17

-attachment sites for myosin heads are blocked by this, cant attach

Question 18

Toponin

Answer 18

removes tropomyosin from binding sites and allows myosin to attach

Question 19

High vs. low Ca2+ levels

Answer 19

• low means tropomyosin inhibits the binding of myosin

- high means Ca2+ binds with troponin to displace tropomyosin

Question 20

How is Ca2+ released

Answer 20

• motor neurons release acetylcholine at junction to depolarize sarcolemma
• depolarization conducted down transverse tubules to sarcoplasmic reticulum
• stimulates release of Ca2+

Question 21

motor unit

Answer 21

-motor neuron and all the muscle fibers it innervates