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Flashcards in Muscles (KT) Deck (118)
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1
Q

The scientific study of muscles

A

Myology

2
Q

How much total body mass does muscle account for?

A

45%- responsible for most of the work generated by the body

3
Q

Functions of Muscles (5)

A
  1. Maintain posture and body position
  2. Movement
  3. Heat production
  4. Guard orifices
  5. Support visceral organs
4
Q

Properties of Muscle Tissue (4)

A
  1. Excitability
  2. Contractility
  3. Extensibility
  4. Elasticity
5
Q

The ability to receive and respond to electrical or chemical stimuli

A

Excitability

6
Q

The ability to shorten forcibly when stimulated

A

Contractility

7
Q

The ability to be stretched without damaging the tissue

A

Extendibility

8
Q

The ability to return to original shape after being stretched

A

Elasticity

9
Q

Muscle composition (5)

A

Muscles are organs… The consist of…

  1. Connective Tissue
  2. Arteries/Veins
  3. Nerves
  4. Lymphatics
  5. Contractile muscle cells
10
Q

Skeletal Muscle Characteristics (7)

A
  1. Attaches to bone, skin, or fascia
  2. Striated with light and dark bands
  3. Voluntary control
  4. Long, thin, and multinucleate fibers
  5. Arranged into packages that attach to and cover the bony skeleton
  6. Contracts rapidly, but tire easily
  7. Exert great force
    Fiber= 1 muscle cell
11
Q

The main portion of a muscle

A

Belly/Gaster

12
Q

Where is the belly of the muscle attached?

A

Belly is attached to tendons, and then tendons are attached to bones

13
Q
  • Dense irregular connective tissue that is around muscle

- Holds it in place and separates it from other muscles

A

Deep Fascia

14
Q
  • Loose connective tissue beneath skin

- Surrounds several muscles

A

Subcutaneous Fascia

15
Q

How are skeletal muscles organized? (General)

A
  • Many muscle fibers are bundled together into groups called fascicles
  • 10-100 muscles fibers per fascicles
  • Several fascicles make up a muscle
16
Q

Skeletal muscle connective tissue that surrounds the whole muscle

A

Epimysium

17
Q

Skeletal muscle connective tissue that surrounds the fascicles

A

Perimysium

18
Q

Skeletal muscle connective tissue that separates individual muscle fibers (cells)

A

Endomysium

19
Q

All connective tissue extends beyond the muscle belly to form the….

A

Tendon

20
Q

Tendons that from thick flattened sheets are called…

A

Aponeuroses

21
Q

Embryonic cells that fuse to form muscle fibers… (this is why they are long and multinucleate)

A

Myoblasts

22
Q

Myoblasts that do not fuse become…

A

Myosatellite cells

23
Q

What is the function of Myosatellite cells?

A

Assist in repair of damaged cells

24
Q

Fiber cytoplasm

A

Sarcoplasm

25
Q

Plasma membrane in a fiber

A

Sarcolemma

26
Q

Extensions of the sarcolemma into the sacroplasm

A

Transverse (T) Tubule

27
Q

Contractile organelles that…

  • Extend the length of fiber
  • Surrounded by the sarcoplasmic reticulum
A

Myofibrils

28
Q
  • Surround the myofibrils
  • Similar to the ER
  • Contain calcium ions
A

Sarcoplasmic Reticulum

29
Q

What is the functional unit of a myofibril

A

Sarcomere

30
Q

What are the 2 components of sarcomeres?

A
  1. Thick Filaments

2. Thin Filaments

31
Q

What is the component of Thick Filaments?

A

-Myosin

32
Q

What is the component of myosin?

A
  • Twisted protein with globular heads
  • 1.6 um long
  • 500 per thick filament
33
Q

What are the components of Thin Filaments? (2)

A
  1. Actin

2. Regulatory Proteins

34
Q

Components of Actin… (2)

A
  1. Structural Proteins

2. Coiled “beads”

35
Q

Components and function of Regulatory Proteins… (3)

A
  1. Allow/Prohibit attachment between actin and myosin
  2. Tropomyosin
  3. Troponin
36
Q

Cause the striated appearance

A

Sarcomere bands

37
Q

What are the 4 kinds of sarcomere bands?

A
  1. A Band
  2. I Band
  3. H Band
  4. Zone of Overlap
38
Q

Type of band that includes the entire thick filament range

A

A Band

39
Q

Type of band that includes only thin filaments

A

I Band

40
Q

Type of band that includes only thick filaments

A

H Band

41
Q

Type of band that includes both filaments

A

Zone of Overlap

42
Q

These structures divide and flank the sarcomere

A

Sarcomere Lines

43
Q

What are the 2 types of sarcomere lines?

A
  1. Z line

2. M Line

44
Q

This type of sarcomere line…

  • Is at the end of the sarcomere
  • Made of actinin protein
  • Anchors thin filaments
A

Z Line

45
Q

This type of sarcomere line…

  • Is in the middle of the sarcomere
  • Stabilizes thick filaments
A

M Line

46
Q

Structural Protein that…

  • Anchors a thick filament to a Z line
  • Accounts for elasticity and extensibility
A

Titin

47
Q

Structural Protein that…
-Holds the F actin together on
thin filaments

A

Nebulin

48
Q

Structural Protein that…

-Makes up the Z line

A

Actinin

49
Q

The process of the actin sliding over the myosin

A

Sliding Filament Theory

50
Q

What happens during the Sliding filament theory? (5 steps)

A
  1. Zone of overlap enlarges
  2. H band shrinks
  3. I band shrinks
  4. A band remains the same
  5. The Z line moves closer to the A band
51
Q

The 6 components of the neuromuscular junction

A
  1. Motor Unit
  2. Neuromuscular Junction
  3. Synaptic Terminal
  4. Motor end plate
  5. Synaptic cleft
  6. Neurotransmitters
52
Q

Part of the neuromuscular junction that…

-Neuron + all the muscle cells stimulated by the neuron

A

Motor Unit

53
Q

Part of the neuromuscular junction that…

-Point of contact between the neuron and the muscle

A

Neuromuscular Junction

54
Q

Part of the neuromuscular junction that…

-End of the axon that contacts motor end plate

A

Synaptic Terminal

55
Q

Part of the neuromuscular junction that…

-Point on the muscle fiber that contacts synaptic terminal

A

Motor End Plate

56
Q

Part of the neuromuscular junction that…

-Gap between the neuron and the muscle

A

Synaptic Cleft

57
Q

Part of the neuromuscular junction that…

  • Chemical released into the synaptic cleft
  • In this case it is acetylcholine
A

Neurotransmitter

58
Q

Events of Muscle Contraction (9)

A
  1. Ach stored in the synaptic vesicles
  2. Impulse reaches end of the neuron–> Ach is released
  3. Ach crosses the gap and binds to the receptors
  4. Impulse travels through motor end plate down the T- tubules to the sarcoplasmic reticulum
  5. Ca+2 ions fiffuse out of the sarcoplasmic reticulum into the sarcoplasm
  6. Ca+2 exposes the active site
  7. Myosin then binds to active site
  8. ATP is used and contraction occurs
  9. Contraction continues as long as Ca+2 concentration is high
59
Q

Events of Muscle Relaxation (5)

A
  1. Ach decomposed by acetylcholinesterase (AChe)
  2. Ca ions transported back to SR
  3. Actin and myosin links broken
  4. Cross bridges move back
  5. Active site is blocked once again
60
Q

This is determined by the frequency of stimulation and the number of neurons stimulated

A

Tension

61
Q

Tension in which…

-All fibers in a motor unit fully contract if stimulated

A

All or None Law

62
Q

Tension in which…

-Steady increase in tension by increasing the number of contracting motor neurons

A

Recruitment

63
Q

Tension in which…

  • Muscle never begins to relax
  • Continuous fused contraction
A

Tetanus

64
Q
  • Motor untis contract randomly

- Tension but no movement

A

Muscle Tone

65
Q

Muscle tone can… (3)

A
  1. Stabilizes joints
  2. Holds objects in place
  3. Maintains posture
66
Q
  • Constant, exhaustive stimulation increases the number of organelles/proteins in a fiber
  • Increases the overall enlargement of the muscle
A

Hypertrophy

67
Q

Hypertrophy increases the number of… (4)

A
  1. Mitochondria
  2. Glycolytic enzyme reserves
  3. Myofibrils
  4. Filaments within myofibrils
68
Q

During hypertrophy, muscle cells (do/do not) reproduce

A

DO NOT

69
Q

The lack of constant motor neuron stimulation reduces organelles ad proteins

A

Atrophy

70
Q

Atrophy can be due to… (4)

A
  1. Age
  2. Hormones
  3. Lack of use
  4. Nerve damage
    * Is reversible as long as the fiber isn’t dead
71
Q

Attachment site that doesn’t move

A

Origin

72
Q

Attachment site that moves

A

Insertion

73
Q

Tension=

A

Force

74
Q

Fascicle arrangement varies based on…

A

Position of the muscle

75
Q
  • Fascicles parallel to long axis

- Unidirectional force

A

Parallel Muscles

76
Q

Example of parallel muscles

A

Biceps brachii

77
Q
  • Fan shaped muscles
  • Multidirectional force
  • Versatility
  • Generates least amount of force
A

Convergent Muscles

78
Q

Example of Convergent Muscles

A

Pectoralis major

79
Q
  • Feather shaped muscle
  • Fascicles oblique to long axis
  • Tendon passes through the muscle
  • Greatest force
A

Pennate Muscle

80
Q

Example of pennate muscle

A

Deltoid

81
Q
  • Concentric fascicles around an opening

- Contraction decreases lumen diameter

A

Circular muscles

82
Q

Example of circular muscles

A

Orbicularis oculi

83
Q

-Rotation around one axis

A

Uniaxial

84
Q

Uniaxial Movements

A

Rotation- atlantoaxial and pivot joints

Angular- knee and IP joints

85
Q

Movement along 2 axes

A

Biaxial

86
Q

Angular movement of biaxial articulations

A

Angular-

  • flexion/extension
  • Abduction/Adduction
87
Q

Examples of biaxial Joints (4)

A
  1. Ellipsoidal Joint
  2. Radiocarpal
  3. Metacarpal Phalange
  4. Carpometacarpal (2-5)
88
Q

Movement on all axes

A

Mutliaxial Movement

89
Q

Multiaxial Movement

A

Angular-

  • Flexion/Extension
  • Abduction/Adduction

Rotation-
-Circumduction

90
Q

Example of Multiaxial Movement

A

Ball and socket

91
Q
  • Main muscle causing directional force

- This can be any muscle of interest

A

Agonist

92
Q

-Muscle that contracts to oppose agonist
Ex. Bicep brachii
Tricep brachii

A

Antagonist

93
Q

-Muscle that assists/modifies movement

Ex. Brachialis and pronator teres

A

Synergist

94
Q

-Muscle that stabilizes elements associated with agonist

Ex. Deltoid stabilizes glenohumeral joint

A

Fixator

95
Q

This type of system modifies movement

A

Levers

96
Q

Levers can change… (4)

A
  1. Magnitude of force
  2. Speed
  3. Direction
  4. Distance of limb movements
97
Q

The 4 components of the Lever System…

A
  1. Lever (L)
  2. Effort (E)
  3. Fulcrum (F)
  4. Resistance (R)
98
Q

Skeletal Element

A

Level

99
Q

Applied force

A

Effort

100
Q

Joint

A

Fulcrum

101
Q

Body part or object moved

A

Resistance

102
Q

3 types of levers

A
  1. First Class
  2. Second Class
  3. Third Class
103
Q

Type of lever that…

-R opposite of E with central F

A

First Class

104
Q

E, F, and R of neck extension

A

E- neck extensions
F- atlanto-occipital joint
R- Skull

105
Q

Type of lever that…

  • E is opposite of F to move R
  • Example is plantar flexion
A

Second Class

106
Q

E, F, and R of plantar flexion

A

E- calf
F- MP joint
R- Weight of body

107
Q

Type of lever that…

  • E is in between F and R
  • Example is elbow flexion
A

Third Class

108
Q

E, F, R of elbow flexion

A

E- biceps brachii
F- elbow joint
R- weight distal to joint

109
Q

Types of Skeletal Muscle Fibers (3)

A
  1. Fast Fibers
  2. Slow Fibers
  3. Intermediate Fibers
110
Q

Characteristics of Fast Fibers (7)

A
  1. Fast acting, high energy requirements
  2. Anaerobic
  3. Large diameter
  4. Densely packed myofibrils
  5. Large glycogen reserves
  6. Few mitochondria
  7. Rapid, powerful and brief contractions
111
Q

Characteristics of Slow Fibers (5)

A
  1. More myoglobin, slower sustained contraction
  2. Aerobic
  3. Smaller diameter
  4. Longer to contract
  5. Contract for longer time
112
Q

Characteristics of Intermediate Fibers

A
  • Has attributes of both
  • Similar to fast fibers
  • Greater resistance to fatigue
  • Exercise or lack of can change one muscle type to another
113
Q

Smooth Muscle characteristics (7)

A
  1. Attached to hair follicles
  2. In walls of hollow organs and blood vessels
  3. Nonstriated
  4. Involuntary control
  5. Contractions are slow and sustained
  6. Spindle shaped
  7. Very elastic
114
Q

Smooth muscles are stimulated by… (4)

A
  1. Nervous System
  2. Hormones
  3. Ions
  4. Stretching
115
Q

Smooth muscle types (2)

A
  1. Single Unit

2. Multi Unit

116
Q

-Many gap junctions
-Sheets of spindle shaped cell
-Contract together (syncytial contraction)
Ex. BV’s, digestive tract, resp. tract, and urinary tract

A

Single Unit

117
Q

-Few/No gap junctions
-Separate fibers that contract independently
-Only contract when stimulated by motor nerve
Ex. walls of large BV’s, uterus, and iris of eye

A

Multi Unit

118
Q

Characteristics of Cardiac Muscles

A
  • striated in appearance
  • involuntary control
  • network of fibers with intercalated disks at the ends
  • only found in heart