Chapter 45: Systems and Locomotion

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1

What are the three things a skeleton provides structure for?

Support, Locomotion, and Protection

2

What are the two major types of skeletons?

Endoskeleton adn Exoskeleton

3

What does the exoskeleton surround and protect?

Internal organs, environment, and predators

4

What is the exoskeleton made of?

Chitin - polysaccharide (Some use calcium)

5

What is segmentation in the exoskeleton helpful for?

Movement

6

What is ecdysis?

Molting for growing

7

What organisms inhabits all ecological niches?

Arthropods

8

What are the differences in exoskeleton due to survival?

Flight and Protection

9

What is the endoskeleton function?

Internal support and protection

10

What is. bone?

Living, dynamic tissue with both organic and mineral components

11

What are the bone forming cells?

Osteoblasts and Osteocytes

12

What are Osteoblasts and osteocytes composed of providing strength and flexibility?

Collagen

13

What are the cells that break down bone?

Osteoclasts

14

What are the two mineral ions provided through an animals diet?

Ca2+ and PO4 2-

15

What are the 3 functions of the vertebrate skeleton?

Support, Protection. of internal surfaces, and Movement

16

What are the two parts of the vertebrate skeleton?

Axial Skeleton and Appendicular skeleton

17

What is the axial skeleton?

Main longitudinal axis

18

What is the appendicular skeleton?

Limb bones and girdles

19

What is a joint?

Where two or more bones come together

20

What are three types of movement?

Pivot, Hinge, Ball and Socket

21

What is formed in marrow of bones?

Blood cells and platelets

22

When supply is low, what mineral do the bones supply for the body?

Ca2+

23

What do bones. provide?

Framework for skeletal muscles

24

How many types of muscle vertebrates have and how are they classified?

Three

They a re classified according to structure, function, and control mechanisms

25

What are the three types of muscle and where are they located?

1. Cardiac Muscle - only found in the heart

2. Smooth muscle - surrounds. and forms part of the lining hollow organs and tubes

3. Skeletal muscle - directly involved in. locomotion

26

What kind of tissue bonds skeletal muscle together?

Connective

27

What are tendons?

Linkage of muscles to bones

28

As bone moves, muscle (shortens or extends)?

Shortens

29

What happens. to the bones when a muscle is contracted?

Attached bones pulled toward or away from each other (ONLY a pulling force)

30

What is a flexor?

Bending a limb at a joint

31

What is an extensor?

Straightening of a limb

32

What are antagonists?

Groups of muscles that produce oppositely directed movements at a joint

33

Where do skeletal muscle fibers arise from?

Cells that fish to form a single cell with. multiple nuclei

34

What are myofibrils?

Cylinidrical bundles in. muscle fibers

35

What does each myofibril contain?

Repeating until of filaments (sarcomeres)

36

What are thick filaments made of?

Myosin

37

What are thin filaments made of?

Actin and other proteins

38

What 2 types of bands on up a sarcomere?

A and I

39

What is the A band?

Wide. formed by thick filaments

40

What is the Z line?

Network of proteins to which thin filaments are attached

41

How many successive Z lines define a sarcomere?

Two

42

What is the I band?

Contains portions of thing filaments that fo not overall thick filaments

43

What is the. H zone?

Narrow region in center of A band, space between the 2 sets of thin. filaments

44

What is M line?

In the center of H zone, proteins the think central regions of adjacent thick filaments

45

What are cross-bridges?

Spaces between overlapping thick and think filaments that are bridged together

46

What are thin filaments?

Actin molecules that form two intertwined helical chains

47

What two proteins are chains closely associated with? And, what are they important for regulation of?

Tropomyosin and Troponin

They are important in regulating contractions

48

What kind of structure does Myosin have and what does it mean?

Three domain structure

  • Composed of two intertwined tails, two hinges, and two heads
49

What are thick filaments made of?

Many myosin proteins, with hinges and heads extending out to sides and forming cross-bridges

50

Each head of myosin contains bonding sites for ________ and _______?

Actin and ATP

51

When do sarcomeres shorten?

As thin filaments slide past stationary thick filaments (Z line towards the M line)

52

When myosin cross-bridges attach to thin filaments, what happens?

Thin filaments are formed toward center of sarcomere

53

What is the first step of the cross-bridge cycle?

Cross-bridge binds to actin in response to increase in Ca2+ concentration

54

What is the second step of the cross-bridge cycle?

Cross-Bridge and thin filaments move "power stroke"

55

What is the third step of the cross-bridge cycle?

ATP binds to myosin, and cross-bridge detaches

56

What is the fourth, and final step of the cross-bridge cycle?

ATP hydrolysis reenergizes and resets the cross-bridge

57

How is Tropomyosin arranged?

Rod-shaped molecule composed of two intertwined proteins

Arranged. along length of actin thin filament

58

What happens with tropomyosin in the absence of Ca2+?

It covers myosin-binding sites and prevents cross-bridges from making contact with actin

59

What is the structure of troponin?

Smaller protein bound to tropomyosin and actin

Binds Ca2+ and moves tropomyosin off of myosin-binding site - permits cross-bridge cycling to occur

60

What happens with Troponin when Ca2+ is removed?

The process is reversed and contraction stops

61

What do skeletal muscle cell action potentials cause rises in and releases from?

They cause rises in cytosolic Ca2+ and is released from sarcoplasmic reticulum

62

What are invaginations of the plasma membrane?

Transverse (T-tubles) Tubules

63

What is the role of ion pumped in the excitation and coupling of skeletal muscle cells?

They return calcium to the sarcoplasmic reticulum, resulting in muscle relaxation

64

What is the neuromuscular junction?

Junction of motor neuron's axons and muscle fibers

65

The axon divides into terminals containing vesicles of what?

Acetylcholine (ACh)

66

What is the region of muscle fiber under an axon terminal called?

Motor end plate (It is folded into junctional folds to increase surface area)

67

What Na+ flows into a muscle cell, what happens?

Depolarization and an action potential travels through T-tubles

68

Overstimulation of muscle fiber is prevented by?

Acetylcholinesterase (which removes acetylcholine)

69

What are slow fibers?

Have myosin with a low ATPase activity

70

What are fast fibers?

Contain myosin with higher ATPase activity

71

If the maximal force produced by each kind of fiber is the same, what varies (making them different)?

The rate of cross-bridge cycling

72

What are oxidative fibers?

Contain numerous mitochondria and have a high capacity for oxidative phosphorylation

73

What do oxidative fibers contain large amounts of?

Myoglobin as an intracellular reservoir of oxygen

74

What are glycolic fibers?

Few mitochondria but a high concentration of glycolic enzymes and large stores of glycogen

75

Why are glycolic fibers pale or white?

They contain little myoglobin

76

What are the three major types of skeletal muscle fibers?

Slow-oxidative, Fast-oxidative, and Fast-glycotic

77

What are slow-oxidative fibers?

Low rates of myosin ATP hydrolysis but makes large amounts of ATP

78

What are slow-oxidative fibers used for?

Prolonged, regular activity (Posture, flight)

79

What are fast-oxidative fibers?

High myosin activity, makes large amounts of ATP

80

What are fast-oxidative fibers used for?

Suited for rapid actions (Bird song, rattlesnake tail)

81

What are fast-glycotic fibers?

High myosin activity but cannot make as much ATP

82

What are fast-glycotic fibers used for?

Suited for rapid, intense actions but fatigue quickly (Cheetah sprints)

83

An increased amount of exercise can produce an increase in what?

The size of muscle fibers and their capacity for ATP production

84

What is Atrophy?

Reduction in size of a muscle

85

When does Atrophy occur?

As a result of decline or cessation of muscular activity

86

What are two constraints to animal locomotion?

Must overcome drag

Energy is required for thrust and/or lift

87

What does locomotion result from?

Muscular contractions exerting force on the skeleton

88

What is the greatest challenge for locomotion in water?

The density of water

89

What is an energetic advantage of locomotion in water?

Do not need to overcome gravity

90

What is the main way aquatic animals produce locomotion?

By swimming

91

What is the most energetically cost way of locomotion?

Locomotion on land

92

What must be overcome at every step when moving on land?

Gravity

93

Most animals limit ground contact to reduce what?

Friction

94

What are the only four occasions where locomotion is involved in air?

Ptersosaurs, insects, birds, and mammals (bats)

95

What are the numerous advantages of locomotion in air?

Escape, scan large areas, inhabit inaccessible ares

96

What are two things you must overcome when flying?

Gravity and air resistance

97

What is the lift and thrust in vertebrates provided by?

Pectoral and back muscles

98

What are rickets?

Improper mineral deposition (Vitamin D)

99

What is Osteoporosis?

Occurs when normal balance between bone formation and breakdown is disrupted

100

What is muscular dystrophy?

Progressive degeneration of skeletal and cardiac muscles, ultimately leading to death