Chapter 47-The Musculoskeletal Systems Flashcards Preview

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Flashcards in Chapter 47-The Musculoskeletal Systems Deck (21):
1

3 Types of Skeletal Systems

1. Hydrostatic Skeletons
2. Exoskeletons
3. Endoskeletons

2

Hydrostatic Skeletons

-soft body invertebrates
-fluid filled central cavity

3

Exoskeletons

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

4

Endoskeletons

-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

5

Bone

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

6

osteoblasts

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

7

osteocytes

bone maintaining cells

8

osteoclasts

cells that break down bone tissue

9

Bone structure

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

10

Joints

-locations where one bone meets another, cartilage and fluid

11

4 basic movement patterns of joints

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

12

Periosteum

tendon attaches to this on bones and to muscles

13

Origin vs. Insertion

-origin=stationary during contraction
-insertion=attached to a bone that moves when muscle moves

14

Sarcolemma

-skeletal muscle cell
-cell membrane, contains acetylcholine receptors

15

T-tubules

-skeletal muscle cells
-connect sarcolemma with sarcoplasmic reticulum

16

sarcoplasmic reticulum

-skeletal muscle cell
-type of endoplasmic reticulum surrounding each myofibril

17

tropomyosin

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

18

Toponin

removes tropomyosin from binding sites and allows myosin to attach

19

High vs. low Ca2+ levels

-low means tropomyosin inhibits the binding of myosin
-high means Ca2+ binds with troponin to displace tropomyosin

20

How is Ca2+ released

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

21

motor unit

-motor neuron and all the muscle fibers it innervates