Chapter 7: Muscular System Flashcards Preview

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Flashcards in Chapter 7: Muscular System Deck (91):
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Functions of muscles

1. Movement
2. Maintain posture
3. Respiration
4. Production of body heat
5. Communication
6. Heart beat
7. Contraction of organs and vessels

1

Cardiac muscle

Heart- involuntary
Has 1 centrally located nuclei
Rich in mitochondria
Contract heart to propel blood through the body

2

Smooth muscle

Located in walls or hollow organs, blood vessels, and glands
Function: to compress organs, ducts, tubes, and so on.
Has less actin and myosin
1 centrally located nucleus
Involuntary

3

Skeletal muscle

Voluntary
Attached to the bone
Many nuclei per cell
Longest type of muscle
40% of body weight

4

Abilities of the skeletal muscles

1. Contractibility: shorten
2. Excitability: respond to stimuli
3. Extensibility: stretch
4. Elasticity: recoil

5

Coverings of the skeletal muscle

Endomysium
Perimysium
Epimysium

6

Endomysium

Fine connective tissue sheath that surrounds each muscle fiber.
Many nuclei

7

Muscle fiber

Skeletal muscle cells

8

Perimysium

Connective tissue that surrounds each muscle fasciculus

9

Muscle fasciculus

Bundle of muscle fibers

10

Epimysium (fascia)

Connective tissue that surround entire skeletal muscle (outside)

11

Myofibril

Thread like proteins that make up muscle fibers

12

Myofilament

Proteins that make up myofibrils
Ex. Actin and myosin

13

Sarcoplasm

Cytoplasm of muscle fiber

14

Sarcolemma

Cell membrane
-contains T-tubules

15

T-tubules (transverse)

Wrap around sarcomeres at A band
Associated with sarcoplasmic reticulum

16

Sarcoplasmic reticulum

Type of smooth ER (SER)
Surrounds myosin
Stores and releases Ca2+

17

Motor neuron

Nerve cells that carry action potentials to muscle fibers

18

Neuromuscular junction
(Synapse)

Stupid hoe couldn't just say that. Shiet.

Where nerve cell and fiber meet.


I'm gonna leave random shit places now to bug you while you study. Holla.

19

Presynaptic terminal

End of nerve cell.

The axon bitch.

20

Postsynaptic membrane

Muscle fiber membrane

21

Synaptic cleft

Space between presynaptic terminal and postsynaptic membrane.

22

Synaptic vesicle

In presynaptic terminal (nerve side)
Store and release neurotransmitters
Ex. ACh

23

Resting membrane potential

Charge difference across the membrane of a resting cell.

Outside cell Inside cell
Na+ K+
+ charge - charge
No channels closed. Some K+ open

The inside of the cell is negative even though K+ is positive because it is able to diffuse out the cell freely but other larger negative molecules can't.

24

Action potential

"Electricity"
Causes muscles to contract
Stimulus that causes rapid depolarization and repolarization

25

Depolarization

Change in charges
Inside becomes more positive and outside more negative
Na+ channel is open

26

Repolarization

Na+ channels close
Change back to resting potential

27

Hyperpolarization

To increase polarization of membranes of muscle cells

28

Neurotransmitter

Chemical that stimulates or inhibit a muscle fiber

29

ACh

Acetylcholine

30

Motor unit

Group of muscle fibers that motor neuron stimulates

31

Actin

Thin myofilament
Contain myosin binding sites

32

Troponin

Attachment site on actin for Ca2+

33

Tropomyosin

Filament on grooves of actin
Attachment site on actin for myosin (head)

34

Myosin

Thick filament
Resemble golf clubs
Have 3 properties:
1. Bind to attachment sites
2. Bend and straighten during contraction
3. Break down ATP

35

Sarcomeres

1 contractile unit
Contains actin and myosin

36

Z disk

Protein fibers that form attachment site for actin

37

H zone

Center of sarcomere
Contains only myosin

38

I band

Contains only actin

39

A band

Where actin and myosin overlap

40

M line

Where myosin are anchored

41

Isometric contraction

The length of the muscle doesn't change but the amount of tension increases. (Weight)

42

Orgin

The non movable end of the muscle

43

Insertion

The movable end of the muscle

44

Synergist

Muscles that work together to produce a movement.

45

Antagonist

Muscles that oppose each other

46

Occipitofrontalis

Move scalp and forehead

47

Orbicularis oculi

Close eyes

48

Orbicularis oris

Close lips

49

Zygomaticus major/minor (lips)

Elevate and abduct

50

Masseter

Elevate and protracted mandible

51

7th step of sliding filament model

Myosin heads bind to actin (cross-bridge)

52

8th step of sliding filament model

P is released from myosin heads and heads bend toward center of sarcomere

53

9th step of sliding filament model

Bending forces actin to slide over myosin (powerstroke)

54

10th step of sliding filament model

Acetylocholinesterase (Ach-E: enzyme breaks down ACh) is released, Na+ channels close, muscle contraction stops

55

All or None Law

Either muscle contacts or it doesn't no inbetween.

56

Threshold

weakest stimulus needed to produce a response

57

Twitch

Rapid contraction and relaxation of a muscle

58

Tetanus

Muscle remains contracted

59

Isometric

Amount of tension increases (weight)

60

Isotonic

Amount of repetitions increases (shorten)

61

Tone

Constant tension over a long period of time

62

Orgin

non moveable end of muscle

63

Insertion

movable end of muscle

64

Belly

Middle of muscle

65

Synergist

muscles that work together

66

Antagonist

muscles that oppose each other

67

Skeletal muscles are named according to:

1. Location
ex. tibialis anterior
2. Orgin/Insertion
ex. Sternocleidomastoid
3. Size
ex. Gluteus maximus
4. Shape
ex. deltoid
5. Function
ex. masseter

68

Occipitofrontalis

move scalp and forehead

69

Orbicularis oculi

Close eyes

70

Orbicularis oris

Close lips

71

Zygomaticus major/ minor (lips)

Elevate and abduct

72

Masseter

elevate and protracts mandible

73

External intercostals

elevate ribs for inspiration (inhale)

74

Internal intercostals

depress ribs during forced expiration (exhale)

75

Diaphragm

moves during quiet breathing

76

Rectus abdominis

center of abdomen
compress abdomen

77

External abdomen oblique

side of abdomen
compresses abdomen

78

Internal abdominal oblique

compresses abdomen
runs perpendicular to external abdominal oblique

79

Transverse abdominis

compresses abdomen

80

Trapezius

very superficial
shoulders and upper back
extends neck and head

81

Pectoralis major

Chest
flex shoulder,

82

Serratus anterior

Between ribs
elevates ribs

83

Deltoid

Shoulder
abductor of upper limbs

84

Rectus abdominis

Center of abdomen
Compress abdomen

85

External abdominal oblique

Sides of abdomen
Compress abdomen

86

Internal abdominal oblique

Compresses abdomen
Runs perpendicular to external abdominal oblique

87

Transverse abdominis

Compresses abdomen

88

Quadriceps femoris

4 thigh muscles. Primary extensors of the knee.
1. Rectus femoris
2. Vastus medialis
3. Vastus lateralis- used as a muscular injector site
4. Vastus intermedius

89

Hamstring

Posterior of thigh
Flexes knee rotates leg, extends hip

90

3 hamstring muscles

Biceps femoris
Semimembranosus
Semitendinosus