Muscle Flashcards

1
Q

Every cell in the human body is ________ to some extent.

A

Contractile

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2
Q

In muscle tissue, contractility is highly ________.

A

Developed

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3
Q

Muscles convert _______ energy into ________ energy.

A
  • Chemical

- Mechanical

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4
Q

Three categories of muscle

A
  • Smooth
  • Skeletal
  • Cardiac
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5
Q

Smooth muscle cells are fu_____, un______, responsive to _____, in_______, and found in _______.

A
  • Fusiform
  • Uninucleate
  • ANS
  • Involuntary
  • Viscera
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6
Q

Skeletal muscle is associated with ________, vo______, and innervated by _____.

A
  • Skeleton
  • Voluntary
  • CNS
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7
Q

In skeletal muscle, the cells are lo____, cy_____, mu_______, nuclei ______, contain large # of packed filaments called _______, and cells are called _______.

A

-long
-cylindrical
-multinucleate
-nuclei peripheral
myofibrils
-muscle fibers

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8
Q

In cardiac muscle, cells are similar to skeletal muscle cells but _____ and nuclei _____. It is found only in ______, in______, and au______.

A
  • uninucleated
  • central
  • heart
  • involuntary
  • autorhythmic
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9
Q

Muscle cell

A

Muscle fiber

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10
Q

Cell membrane (plasmalemma)

A

Sarcolemma

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11
Q

Cytoplasm

A

Sarcoplasm

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12
Q

Endoplasmic reticulum

A

Sarcoplasmic reticulum

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13
Q

Longitudinal endoplasmic reticulum tubules

A

Sarcotubule

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14
Q

Bundle of myofibrils

A

Sarcomere

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15
Q

Histological unit of skeletal muscle is a ______.

A

Fiber

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16
Q

A fiber is a long, cylindrical __________ cell.

A

Multinucleate

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17
Q

Large numbers of muscle fibers are grouped into ________.

A

Fascicles

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18
Q

Fascicles are arranged in several forms to form different ______, such as _______, _______, etc.

A
  • Muscles
  • Bipennate
  • Unipennate
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19
Q

CT surrounding the entire muscle is called _______.

A

Epimysium

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20
Q

CT surrounding the fascicles is called ________.

A

Perimysium

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21
Q

CT surrounding individual muscle fibers is called _________.

A

Endomysium

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22
Q

CT allows ______ and individual ______ of movement.

A
  • Firmness

- Freedom

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23
Q

Skeletal muscle is richly supplied with ______.

A

Blood

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24
Q

Normal thickness of muscle fiber is _______ micrometers.

A

10-70

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25
Q

Uninucleate mesenchymal cells differentiate into ______ which fuse to form multinucleate ______, which lengthen and incorporate more ______.

A
  • Myoblasts
  • Myotubes
  • Myoblasts
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26
Q

Some myoblasts fail to fuse and form _____ or _______ cells.

A
  • Satellite

- Myosatellite

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27
Q

Myotubules then synthesize _________ (actin and myosin).

A

Myofilaments

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28
Q

In adults, further growth of muscles is either ________ of use or ______ of disuse.

A
  • Hypertrophy

- Atrophy

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29
Q

Repair is by ________ which are a residual population of myoblasts.

A

-Satellite cells

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30
Q

All muscle fibers in a muscle are ______.

A

Not identical

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31
Q

Muscle fibers vary in _______ and _______ and physiological properties.

A
  • Diameter

- Cytochemical

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32
Q

Most muscles contain a ______ of three kinds of fibers. The ____ of each depends on type of muscle activity.

A
  • Mixture

- Percent

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33
Q

Muscles of low intensity contractions such as muscles of back and legs that support body weight have ________.

A

Red muscles

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34
Q

Contraction time for:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • Slow
  • Fast
  • Very Fast
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35
Q

Size of motor neurons for:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • Small
  • Large
  • Very Large
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36
Q

Resistance to fatigue for:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • High
  • Intermediate
  • Low
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37
Q

Activity used for:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • Aerobic
  • Long term anaerobic
  • Short term anaerobic
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38
Q

Force production for:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • Low
  • High
  • Very high
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39
Q

Mitochondrial density of:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • High
  • High
  • Low
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40
Q

Capillary density of:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • High
  • Intermediate
  • Low
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41
Q

Oxidative capacity of:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • High
  • High
  • Low
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42
Q

Glycolytic capacity of:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • Low
  • High
  • High
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43
Q

Major storage fuel of:

  • Type I or Red Fibers
  • Type IIA or Intermediate Fibers
  • Type IIB or White Fibers
A
  • Triglycerides
  • Glycogen
  • Glycogen
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44
Q

The structural components of a typical skeletal muscle fiber are:

  • sa_______, sa_____, sa_______
  • myo_______, ________ bands or _______
  • ________ and _______ cells
  • ________ nuclei
  • ______ nucleoli per nucleus
A
  • Sarcolemma, sarcoplasm, sarcoplasmic reticulum
  • Myofibrils, transverse bands or striations
  • Multinucleate and elongated cells
  • Peripheral nuclei
  • 1-2 nucleoli per nucleus
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45
Q

Sarcolemma inside is coated with ________ for mechanical reinforcement.

A

Dystrophin

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46
Q

Genetic disorder due to dystrophin deficiency

A

Duchenne muscular dystrophy

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47
Q

Duchenne muscular dystrophy affects ________ who are unable to walk and die before age 20. It’s manifestation is also reported in ________ muscle.

A
  • Only boys and young men

- Cardiac

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48
Q

_____ droplets, ______ particles, and oxygen binding ______ are present in sarcoplasm.

A
  • Lipid
  • Glycogen
  • Myoglobin
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49
Q

Myoglobin is of little significance in humans, but is important in ______ and ________.

A
  • Birds

- Diving animals

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50
Q

In transverse sections, muscle fibers appear in polygonal shape termed __________.

A

Fields of Conheim

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51
Q

Anisotrophic or A bands

A

Dark bands

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52
Q

Isotrophic or I bands

A

Light bands

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53
Q

Length of A bands is _________ in all phases of contraction.

A

Constant

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54
Q

Length of I bands ______ during contraction.

A

Changes

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55
Q

Muscle fibers also contains __ and __ lines, __ zone, and ______.

A
  • Z and M lines
  • H zone
  • Sarcomeres
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56
Q

SKM fiber contains all common ________, and the mitochondria are _______.

A
  • Organelles

- Peripheral

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57
Q

SR is a system of membrane limited _______.

A

Sarcotubules

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58
Q

Sarcotubules from a close ________ canalicular network occupying narrow spaces between ________.

A
  • Meshed

- Myofibrils

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59
Q

Sarcotubules are _________ in A band region but ________ in H region.

A
  • Longitudinal

- Anastamose

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60
Q

In the ultrastructure of SKM fibers, ______ tubules, _______ cisternae, and _______ are present.

A
  • Transverse tubules
  • Terminal Cisternae
  • Triads
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61
Q

______ are specialized complexes consisting of a narrow central T tubule flanked (bordered) on each side by the terminal cisternae.

A

Triads

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62
Q

Triads are located at the _____ junction in skeletal muscles and help provide ______ contractions.

A
  • A-I

- Uniform

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63
Q

Transverse tubules do not belong to _________.

A

Sarcoplasmic Reticulum

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64
Q

Transverse tubules are invaginations of ________ and are continuous with extracellular space.

A

Sarcolemma

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65
Q

Longitudinal sarcotubules and terminal cisternae regulate _____ concentration in the microenvironment of myofibrils.

A

Ca++

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66
Q

Myofibrils are the _______ units of contractile material in a muscle fiber.

A

Smallest

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67
Q

Each myofibril consists of _____ or myosin filaments (A bands) and ____ or actin filaments (I bands).

A
  • Thick

- Thin

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68
Q

Myosin filaments are ____ micrometers long, have a _____ central segment, but ends are projected by ________.

A
  • 1.5
  • Smooth
  • Cross fibers
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69
Q

Myosin molecules are _____ shaped with ______ projections.

A
  • Rod

- Globular

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70
Q

The two components of myosin filaments are __________ and ________.

A
  • Heavy meromyosin

- Light meromyosin

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71
Q

Heavy meromyosin contains ______ (120KD), _______ (60KD), and heads with ______ activity.

A
  • HMM1
  • HMM2
  • ATPase
72
Q

A large protein _____ holds myosin filament in position and attaches to Z line

A

Titin

73
Q

Actin filaments are ___ micrometers long and located on either sides of ______.

A
  • 1

- Z line

74
Q

The ____ varies in different muscles.

A

Z line

75
Q

The Z line contains a protein ______ which plays an important role in actin binding.

A

-alpha actinin

76
Q

At the level of Z band, actin filaments are surrounded by a honeycomb like structure called _______.

A

Z filaments

77
Q

Filamentous actin is composed of ______ actin subunits.

A

Globular

78
Q

Actin filaments are oriented in ______.

A

Double helix

79
Q

Associated with double helix are ______ filament and a complex of three _____: ___, ___, and ___.

A
  • Tropomyosin
  • Troponin
  • TnT, TnC, TnI
80
Q

Tropomyosin filaments are located in grooves of _____.

A

Helix

81
Q

The complex of three troponin molecules are located at _______.

A

Regular intervals

82
Q

TnT attaches ___ to ____.

A

Troponin to Tropomyosin filament

83
Q

TnC has a binding site for ____.

A

Ca++

84
Q

TnI inhibits interaction between _____ and ____ filaments.

A

Actin and myosin

85
Q

Decreased ___ levels in sarcoplasm: Actin filament binding sites to myosin filaments are ______.

A

Unexposed

86
Q

Increased ___ levels in sarcoplasm: Actin filament binding sites to myosin filaments are ______.

A

Exposed

87
Q

Function of titin

A

Anchors thick filament to Z line

88
Q

Function of alpha-actinin

A

Anchors thin filaments to Z line

89
Q

Function of nebulin

A

Helps alpha-actinin anchor thin filaments to Z line

90
Q

Function of tropomodulin

A

Maintains length of actin filament

91
Q

Function of desmin

A

Stabilizes crosslinks between neighboring sarcomere myofibrils

92
Q

Function of myomesin and C proteins

A

Holds thick filaments at M-line

93
Q

Function of dystrophin

A

Mechanical reinforcement of sarcolemma

94
Q

Excitation-Contraction Coupling:

_____ Impulse –> ________ –> ______ Tubules –> ________ Reticulum –> ____ release –> Muscle ______

A
  • Nerve Impulse
  • Sarcolemma
  • Transverse Tubules
  • Sarcoplasmic Reticulum
  • Ca++ release
  • Muscle Contraction
95
Q

In relaxed muscle, Ca++ is stored in _________ and there is very low Ca++ in ________.

A
  • Sarcoplasmic reticulum

- Sarcoplasm

96
Q

In relaxed muscle, ____ is attached to ______ heads on cross bridges, and myosin heads cannot bind to actin filaments because of _________ and ______ complex.

A
  • ATP
  • Myosin
  • Tropomyosin and troponin
97
Q

During the nerve impulse at the neuromuscular junction, ______ along nerve membrane reach synaptic knobs.

A

Action potentials

98
Q

In response to the action potential, Ca++ enters the nerve membrane at synaptic knobs and causes release of _______ into the synapse.

A

Acetylcholine

99
Q

Acetylcholine diffuses across the synapse and binds to ______ located on the ______ of the muscle cell.

A
  • ACh receptors

- Sarcolemma

100
Q

Interaction of ACh with sarcolemma generates ______ in the sarcolemma, which travels to ______ and then to ______ of sarcoplasmic reticulum.

A
  • Action potential
  • Transverse tubules
  • Terminal cisternae
101
Q

In response to the action potential, the terminal cisternae release Ca++ which in turn:

  • Binds to ____ and exposes active sites on _____
  • Activates ____ to function as _____
  • Allows binding of _____ with _____
A
  • TnC; Actin filaments
  • Myosin heads; ATPase
  • Myosin heads; actin filaments
102
Q

Energy from _____ drives the power stroke to pull actin filaments over myosin filaments; _____ are brought closer together. This causes ______ of sarcomere, muscle fiber, and then the muscles as a whole.

A
  • ATP hydrolysis
  • Z lines
  • Contraction
103
Q

After contraction, ACh rapidly diffuses or is hydrolyzed by _________ and impulse stops; Ca++ is actively transported back to sarcoplasmic reticulum by a transport protein _______ and ATP.

A
  • Acetylcholinesterase

- Calsequesterin

104
Q

After contraction, low Ca++ in sarcoplasm results in detachment of ____ and ____ which slip back; Z lines move apart and muscle _____.

A
  • Actin filaments
  • Myosin filaments
  • Relaxes
105
Q

ATP is resynthesized after contraction by ______.

A

ATPase

106
Q

Skeletal muscles are innervated by nerves containing axons from ________ in the spinal cord.

A

Motor neurons

107
Q

At the muscle, the nerve divides into ______ that penetrate muscle through ___________.

A
  • Branches

- Perimysial septa

108
Q

Individual axons then branch into the endomysium to form ________ - a few to several hundred.

A

Endings

109
Q

A single motor neuron, its axon and the muscle fiber it innervates, constitutes a ________.

A

Motor unit

110
Q

Activity of motor unit is ________.

A

All or none

111
Q

At the site of contact with muscle fiber, axon loses _________ and forms several short axons terminals.

A

Myelin sheath

112
Q

Axon terminals occupy a shallow depression of the muscle fiber membrane called ___________.

A

Primary synaptic cleft

113
Q

Sarcolemma then forms several ____________ to increase surface area.

A

Secondary synaptic clefts

114
Q

Axoplasm has mitochondria and synaptic vesicles which are the sites of ______ (10,000 molecules/vesicle)

A

Acetylcholine

115
Q

Acetylcholine is released by _______.

A

Exocytosis

116
Q

Nerve impulse –> ________ –> Sarcolemma –> _________ –> Sarcoplasmic Reticulum –> ___________ –> Muscle Contraction

A
  • Action Potential
  • Transverse Tubules
  • Ca++ Release
117
Q

Action potentials increase _________ of sarcolemma to Na+

A

Permeability

118
Q

Sarcolemma has ________ for degradation of ACh

A

Acetylcholinesterase

119
Q

An autoimmune disease - antibodies against sarcolemma - causes weakness, fatigue, paralysis

A

Myasthenia gravis

120
Q

Myasthenia gravis involves reduction of _________ at the neuromuscular junction.

A

ACh receptors

121
Q

Normally 30-40 million receptors/NMJ; in Myasthenia gravis _______% reduction; anti AChE chemicals help

A

70-90

122
Q

Neuromuscular spindles are complex _______ organs, _______ shaped, and encapsulated with striated muscle fibers with their endings enclosed in a sheath.

A
  • Sensory

- Fusiform

123
Q

Capsules of Neuromuscular Spindles are continuous with _____ and _________.

A

Peri- and Endomysium

124
Q

Muscle fibers of Neuromuscular Spindles are called __________.

A

Intrafusal fibers

125
Q

Central portion of intrafusal fibers have no ________ and cannot stretch.

A

Myofibrils

126
Q

Intrafusal fibers are categorized as either __________ or __________.

A
  • Nuclear bag fibers

- Nuclear chain fibers

127
Q

Two categories of Special Nerve Endings of Neuromuscular Spindles

A
  • Sensory or afferent

- Motor or efferent

128
Q

Sensory or afferent nerve endings are primary to _________ and secondary to _______ on two sides of primary.

A
  • Nuclear bag or chain

- Nuclear chain

129
Q

Motor of efferent nerve endings are gamma to _______ and alpha to ________.

A
  • Intrafusal fibers

- Extrafusal fibers

130
Q

Sensory Nerve Endings in Tendons are called _________, and encapsulated and sense _______ stress by _______, and consist of collagen fibers.

A
  • Tendon organs
  • Tensional
  • Muscle pull
131
Q

Cardiac muscle fibers are separate cellular units joined ________ by specializations called _________ with traverse across the fiber.

A
  • End to end

- Intercalated discs

132
Q

Cardiac muscle fibers ______ or ______ to form a network.

A

Bifurcate or converge

133
Q

Cardiac muscle fibers contain ______ nuclei, elongate and situated deep centrally, abundant cytoplasm, numerous mitochondria, and sarcoplasm rich in glycogen.

A

Single

134
Q

Cardiac muscle fibers beat spontaneously and exhibit _______ control.

A

Involuntary

135
Q

Myofibrils of cardiac muscle fibers are NOT in discrete ______ in cross sections as in skeletal muscles.

A

Bundles

136
Q

In cardiac muscle fibers, mitochondria appear ________ in myofibrils.

A

Enclosed

137
Q

Cardiac muscle transverse tubules are ______ than those in skeletal muscle and are at the level of z lines, not at _________ junctions as in skeletal muscle.

A
  • Thicker

- A-I junctions

138
Q

Intercalated discs are deeply _______, appear wavy, and important in cell to cell adhesions.

A

Sculptured

139
Q

Intercalated discs have fascia ______, gap _______, and de_______.

A
  • Adherens
  • Junctions
  • Desmosomes
140
Q

Intercalated discs are rich in _______ and ______.

A
  • Alpha-actinin

- Vinculin

141
Q

Myocardial Endocrine Cells are located in _____.

A

Atria

142
Q

Myocardial Endocrine Cells have membrane bound ________ granules with a family of biologically active polypeptides called ca________ or ________________ (ANP) or ________________.

A
  • Atrial-specific granules
  • Cardiodilatins
  • Atrial natriuretic peptides
  • Atrial natriuretic hormone
143
Q

ANP is a ________ and a strong ______ or natriuretic.

A
  • Vasodilator

- Diuretic

144
Q

The effects of ANP are mediated by inhibition of _________ (ADH) from posterior pituitary and _________ from adrenal gland.

A
  • Vasopressin

- Aldosterone

145
Q

The Sinoatrial Node is located beneath __________ at the junction of superior _________ and right _______.

A
  • Epicardium
  • Vena Cava
  • Atrium
146
Q

The Atrioventricular Node is located beneath ________ in the lower part of the _______ septum.

A
  • Endocardium

- Interatrial

147
Q

The Atrioventricular Bundle originates anteriorly from ________ and divides into right and left _____.

A
  • Atrioventricular Node

- Branches

148
Q

The Purkinje Fibers are fine branches of ______________.

A

Atrioventricular Bundle

149
Q

Nodal cells are smaller than cardiac muscle fibers and seldom have ____________.

A

Intercalated discs

150
Q

There is ___ direct connection between Sinoatrial Node and Atrioventricular Node.

A

No

151
Q

The conducting system of the hear is richly innervated with _____________. Sympathetic ANS _____ heart rate and parasympathetic ANS _____ heart rate.

A
  • Autonomic Nervous System
  • Increases
  • Decreases
152
Q

Initiation of heart beat is ____ dependent on nervous system. It is __________.

A
  • Not

- Autorhythmic

153
Q

Smooth muscle fibers form _______ portions of walls of ____ tract, ____ of glands, ____ and ____ ducts, _____ passages, and _____ vessels.

A
  • Contractile
  • Digestive
  • Ducts
  • Urinary and genital
  • Respiratory
  • Lymphatic
154
Q

Smooth muscle fibers are also found in ____ (Arrectores pilorum), _____ glands, ____ and ____ of eye, _____ and _____.

A
  • Hair
  • Mammary
  • Iris
  • Ciliary body
  • Testes and uterus
155
Q

Smooth muscle fibers are ____, ____ shaped or _____, closely associated in bundles. Length and diameter are highly ______.

A
  • Long
  • Spindle
  • Fusiform
  • Variable
156
Q

Smooth muscle fibers have _____, elongate nuclei with _____ nucleoli.

A
  • Single

- 1 or 2

157
Q

Smooth muscle fibers are thick portions of fibers ________ to thin portions of adjacent fibers.

A

Juxtaposed

158
Q

The sarcoplasm of smooth muscle fibers is _________, containing mitochondria, Golgi complex, centrioles, glycogen and longitudinal fibrils called myofibrils.

A

Homogenous

159
Q

Smooth muscle fibers can be organized in _____ patterns.

  • ________ in loose connective tissue
  • In slender ______ as in hair, iris of eye
  • Oriented ________ - arterioles, arteries
  • _____ or _____ layers - intestinal walls
  • ______ defined layers - hollow organs (bladder, uterus)
A
  • Various
  • Singly
  • Fascicles
  • Circumferentially
  • Circular or longitudinal
  • Poorly
160
Q

Variations in form of smooth muscle fibers:

  • Smooth _____ or _____: bladder uterus
  • ___________ cells of mammary glands - several radiating processes
  • ______ - in certain capillaries - rounded cells with several tapering processes
A
  • Fusiform or branched
  • Myoepithelial
  • Pericytes
161
Q

The smooth muscle fibers have sarcoplasm with _______ (actin, myosin, intermediate) ________ to axis.

A
  • Myofibrils

- Parallel

162
Q

Scattered in the cytoplasm of smooth muscle fibers are cytoplasmic _______ (analogous to z lines of skeletal muscle) - these bodies contain a protein called __________.

A
  • Dense bodies

- Alpha actinin

163
Q

Along sarcolemma of smooth muscle fibers are subplasmalemmal _______ made of _____ and ____.

A
  • Dense plaques
  • Vinculin
  • Talin
164
Q

Sarcolemma of smooth muscle fibers between plaques has _______ called ______ which are believed to store ____ for release during muscle contraction.

A
  • Inpocketings
  • Caveolae
  • Ca++
165
Q

Contraction of smooth muscle is ____ than skeletal muscle and sustains forceful contraction for _____ periods.

A
  • Slower

- Longer

166
Q

Contraction of smooth muscle may be initiated by ______ impulse, _______, or local ______ (stretching).

A
  • Nerve
  • Hormones
  • Changes
167
Q

In the smooth muscle, the tropomyosin complex of skeletal muscle is ______.

A

Absent

168
Q

In smooth muscle, extracellular Ca++ diffuses from _____ or ___________.

A
  • Caveolae

- Subplasmalemmal reticulum

169
Q

In smooth muscle, Ca++ binds to ______ which activates ______ in myosin heads.

A
  • Calmodulin

- ATPase

170
Q

ATP ______ and induces a conformational change which causes ________.

A
  • Hydrolyzes

- Muscle contraction

171
Q

Two kinds of smooth muscle

A
  • Visceral or unitary

- Vascular or multiunit

172
Q

Visceral or unitary smooth muscle has _________ and impulses travel through gap junctions - responsible for peristalsis in GI, ureter, bile duct etc.

A

Autorhythmicity

173
Q

Vascular or multiunit smooth muscle in found in large _______, ciliary body, iris of eye, walls of male reproductive tract.

A

Blood vessels

174
Q

Vascular or multiunit smooth muscle impulses are _____ through gap junctions. Each fiber is innervated _________.

A
  • Not

- Separately

175
Q

Vascular or multiunit smooth muscle fibers in blood vessels maintain a muscle _____; blood vessels have receptors for:

  • ___________: Norepinephrine, Vasopressin, Oxytocin
  • ___________: Bradykinin, Prostaglandins
A
  • Tone
  • Vasoconstriction
  • Vasodilation