Chapter Nine: Muscular System Flashcards
(166 cards)
1
Q
What kind of Muscle Tissue?
- Responsible for locomotion, facial expressions, posture respiratory movements, other types of body movement
- voluntary
A
Skeletal Muscle Tissue
2
Q
What kind of Muscle Tissue?
- walls of hollow organs, blood vessels, eye, glands, skin
- some functions: propel using, mix food in digestive tract, dilating/constricting pupils, regulating blood flow
- controlled involuntarily by endocrine and autonomic nervous systems
- autorhythmic in some locations
A
Smooth Muscle Tissue
3
Q
What kind of Muscle Tissue?
- heart: major source of movement of blood
- authorhythmic
- controlled involuntarily by endocrine and autonomic nervous systems
A
Cardiac Muscle Tissue
4
Q
What are the seven functions of the Muscular System?
A
- Movement of the body
- Maintenance of posture
- Respiration
- Production of body heat
- Communication
- Constriction of organs and vessels
- Contraction of the heart
5
Q
Ability of a muscle to shorten with force
A
Contractility
6
Q
Capacity of muscle to respond to an electrical stimulus (from our nerves)
A
Excitability
7
Q
Muscle can be stretched beyond its normal resting length and still be able to contract
A
Extensibility
8
Q
Ability of muscle to recoil to original resting length after stretched
A
Elasticity
9
Q
____________ Muscle Anatomy
- composed of muscle cells (fibers), connective tissue, blood vessels, nerves
- fibers are long, cylindrical, multinucleated
- striated appearance due to light and dark banding
A
Skeletal
10
Q
What is the layer of connective tissue that surrounds a whole muscle?
A
Epimysium
11
Q
What is the layer of connective tissue that surrounds a group of muscle fibers?
A
Perimysium
12
Q
Each group of muscle fibers is called a…
A
fascicle
13
Q
What is the layer of loose connective tissue with reticular fibers?
A
Endomysium
14
Q
The connective tissue sheet is also known as the…
A
Muscular Fascia
15
Q
The Muscular fascia goes from external to epimysium and holds muscles together as well as separates them into…
A
Functional Groups
16
Q
Motor neurons stimulate muscle fibers to…
A
Contract
17
Q
Motor neurons: nerve cells with cell bodies in brain or spinal cord; ________ extend to skeletal muscle fibers through nerves
A
Axons
18
Q
Axons branch so that each muscle fiber is…
A
Innervated
19
Q
Motor neurons: contact is __________________ junction
A
Neuromuscular Junction
20
Q
Skeletal Muscle Fiber Anatomy: several nuclei just inside…
A
Sarcolemma
21
Q
Invaginations that connect extracellular environment to interior of muscle fibers
A
Transverse Tubules (T-tubules)
22
Q
Skeletal Muscle Fiber cells are packed with _________ within cytoplasm (sarcoplasm)
A
Myofibrils
23
Q
Myofibrils are composed of myofilaments: thin filaments (_________) and thick filaments (____________)
A
actin
myosin
24
Q
Highly ordered repeating units of myofilaments in skeletal muscle fiber
A
Sarcomeres
25
Calcium regulation and storage within skeletal muscle fibers
Sarcoplasmic Reticulum
26
Actin (thin) Myofilaments:
Two strands of _______ actin form a double helix extending the length of the myofilament; attached at either end of the sarcomere to the Z disc
fibrous actin
27
Actin (thin) Myofilaments:
Composed of G (__________) actin monomers, each of which has an active site
globular
28
Actin (thin) Myofilaments:
Active site can binds ________ during muscle contraction
myosin
29
an elongated protein winds along the groove of the F actin double helix
Tropomyosin
30
Troponin has three subunits, each subunit binds to one of these three…
1. Actin
2. Tropomyosin
3. Calcium Ions
31
Troponin holds tropomyosin over the active sites on…
actin
32
The tropomyosin/troponin complex regulates the interaction between what two things?
Actin and Myosin
33
Myosin (thick) Myofilament:
Many elongated ____________ molecules shaped like golf clubs
myosin
34
Myosin (thick) Myofilament:
Molecule consists of myosin heavy chains wound together to form a ______ portion lying parallel to the myosin filament and _______ heads that extend laterally
rod
two
35
Myosin heads can bind to active sites on the actin molecules to form…
cross-bridges
36
Myosin heads are attached to the _____ portion by a hinge region that can bend and straighten during contraction
rod
37
Myosin heads are ATPase enzymes: break down _____, releasing energy
adenosine triphosphate (ATP)
38
Basic functional unit of muscle fiber
Sarcomere
39
Filamentous network of protein; serves as attachment for actin myofilaments
Z disk
40
Elastic chains of amino acids; make muscles extensible and elastic
Titin filaments
41
What four things create the striated appearance in Sarcomeres?
1. I Bands
2. A bands
3. H zone
4. M. Line
42
Sarcomeres Striated Appearance:
form Z disks to ends of thick filaments
I bands
43
Sarcomeres Striated Appearance:
length of thick filaments
A bands
44
Sarcomeres Striated Appearance:
region in A band where acting and myosin do not overlap
H zone
45
Sarcomeres Striated Appearance:
middle of H zone; delicate filaments holding myosin in place
M line
46
Sliding Filament Model:
actin myofilaments sliding over myosin to shorten…
sarcomeres
47
Sliding Filament Model:
what two things do not change the length?
actin and myosin
48
Sliding filament model:
shortening sarcomeres responsible for skeletal muscle…
contraction
49
During relaxation, ______________ lengthen because of some external force, like contraction of antagonistic muscles
sarcomeres
50
Muscles that produce the opposite effect of lengthening during relaxation due to external force
Antagonistic muscles
51
axon terminal resting in an invagination of the sarcolemma
Synapse
52
What are the three parts of a neuromuscular junction?
1. Presynaptic Terminal
2. Synaptic Cleft
3. Postsynaptic Membrane
53
What part of the neuromuscular junction?
- axon terminal with synaptic vesicles
- synaptic vesicles contain neurotransmitters
Presynaptic terminal
54
What part of the neuromuscular junction?
- space
Synaptic cleft
55
What part of the neuromuscular junction?
- sarcolemma of the muscle cell
Postsynaptic membrane
56
What are the four parts of the “Big Picture”
1. Action Potential in Neuron
2. Stimulation of muscle fiber at the Neuromuscular Junction
3. Action Potential in Muscle
4. Sarcomere Contraction via Cross-Bridge Movement
57
All excitable cells are…
polarized
58
Polarized cells possess a difference in _________ between inside and outside
charge
59
Charge difference between inside and outside of the cell is known as a…
Membrane Potential
60
Nervous system controls muscle contractions through…
action potentials
61
Resting Membrane Potentials:
Membrane voltage difference across membranes (_________)
polarized
62
Resting Membrane Potentials:
Inside cell is more ___________ due to accumulation of large protein molecules
negative
63
Resting Membrane Potentials:
More ______ on inside than outside
K+
64
Resting Membrane Potentials:
______ leaks out but not completely because negative proteins hold some back
K+
65
Resting Membrane Potentials:
Outside of cell is more positive and more ______ on outside of the cell than the inside of the cell
Na+
66
What two kinds of pumps maintains resting membrane potentials?
Na+ and K+ pumps
67
What type of ion channel?
- gate is closed until neurotransmitter attaches to receptor molecule
- EX: neurotransmitters
Ligand-gated
68
molecules that bind to receptors
Ligands
69
Protein or Glycoprotein with a receptor site
Receptor
70
What type of ion channel?
- open and close in response to small voltage changes across plasma membrane
Voltage-gated
71
What inside the plasma membrane is higher than that outside the plasma membrane?
K+
72
What outside the plasma membrane is higher than that inside the plasma membrane
Na+
73
Plasma membrane is more permeable to what?
K+
74
More leaky ____ channels than leaky Na+ channels, so ____ diffuses out of the cell -> inside becomes even more negative
K+
75
________ __________ of Na+ and K+ maintains the uneven distribution of Na+ and K+ across plasma membrane
Active Transport
76
What are the six steps of action potential?
1. Excitation
2. Ion channels open
3. change in membrane permeability
4. ions diffuse through channels
5. change in charge across plasma membrane
6. action potential
77
What are the two phases of action potential?
Depolarization and Repolarization
78
What phase of action potential?
- inside of plasma membrane becomes less negative
- if change reaches threshold, depolarization occurs
Depolarization
79
What phase of action potential?
- return to resting membrane potential
Repolarization
80
What principle?
- if threshold is reached, a full action potential is generated; if not, no signal is produced?
All-or-none principle
81
What part of action potentials?
- spread from one location to another
- action potentials does not move along the membrane: new action potentials at each successive location
Propagate
82
What part of Synaptic vesicles?
- substance released from a presynaptic membrane that diffuses across the synaptic cleft and stimulates (or inhibits) the production of an action potential in the postsynaptic membrane
- EX: Acetylcholine
Neurotransmitter
83
What part of Synaptic vesicles?
- a degrading enzyme in synaptic cleft that prevents accumulation of ACh
Acetylcholinesterase
84
The first function of neuromuscular junction:
Action potential arrives and opens voltage-gated _______ channels
Ca2+
85
The second function of neuromuscular junction:
Ca2+ initiates release of ___________ __________
synaptic vesicles
86
The third function of neuromuscular junction:
______ released into synapse
Ach
87
The fourth function of neuromuscular junction:
Ach opens ligand-gated _______ channels
Na+
88
The fifth function of neuromuscular junction:
Na+ enters cell —> depolarization —> ____________ _____________
action potential
89
The sixth function of neuromuscular junction:
Ach detaches and NA+ channels…
close
90
The seventh function of neuromuscular junction:
Acetylcholinesterase breaks down…
Ach
91
The eighth function of neuromuscular junction:
___________ transported to presynaptic terminal
Choline
92
The ninth function of neuromuscular junction:
Ach is reformed from recycled choline and packaged into…
synaptic vesicles
93
What disease of the neuromuscular junction?
- muscles contract and cannot relax
- can be caused by poisons that inhibit acetylcholinesterase
Spastic Paralysis
94
What disease of the neuromuscular junction?
- caused when Ach cannot bind to receptors
- muscle is incapable of contracting
- EX: Myasthenia Gravis
Flaccid Paralysis
95
Mechanism where an action potential causes muscle fiber contraction
Excitation-Contraction Coupling
96
Excitation-Contraction Coupling involves what seven things?
1. Sarcolemma
2. Transverse (T) tubules
3. Terminal Cisternae
4. Sarcoplasmic Reticulum
5. Triads
6. Ca2+
7. Troponin
97
invaginations of sarcolemma
Transverse (T) tubules
98
sarcoplasmic reticulum near T tubule
Terminal Cisternae
99
What part of excitation-contraction coupling goes with the smooth ER?
Sarcoplasmic Reticulum
100
What part of excitation-contraction coupling is T tubule, two adjacent terminal cisternae
Triad
101
Action potential produces at the ______________ ____________ is propagates along sarcolemma (including T tubules)
neuromuscular junction
102
Depolarization of ____ ___________ opens voltage-gated Calcium channels in sarcoplasmic reticulum and Ca2+ diffuses into sarcoplasm
T tubule
103
Calcium ions bind to _______ —> ________ molecules bound to actin are released —> tropomyosin is moved —> active sites on actin are exposed
troponin
104
_______ ________ bind to exposed active sites on actin to form cross bridges
Myosin heads
105
Muscle Relaxation:
Ca2+ moves back into the __________ _________ by active transport (requires energy)
sarcoplasmic reticulum
106
Muscle Relaxation:
_________ moves away from troponin-tropomyosin complex
Ca2+
107
Muscle relaxation:
complex re-establishes its position and blocks…
binding sites
108
Muscle _________
- muscle contraction in response to a stimulus that causes an action potential in one or more muscle fibers
Muscle Twitch
109
What are the three phases of a muscle twitch?
1. Lag/latent
2. Contraction
3. Relaxation
110
a single motor neuron and all muscle fibers innervated by it
Motor Units
111
Large muscles have motor units with _________ muscle fibers
many
112
Small muscles that make delicate movements contain motor units with _____ muscle fibers
few
113
what law for muscle fibers?
- individual muscle fibers contract with equal force in response to each action potential
All-or-none
114
What stimulus?
- no action potential; no contraction
Sub-threshold stimulus
115
What stimulus?
- action potential; contraction
Threshold stimulus
116
What threshold?
- action potential; contraction equal to that with threshold stimulus
Stronger than threshold
117
Strength of whole muscle contraction is graded: ranges from ________ to _________ depending on stimulus strength
weak to strong
118
strength of contraction depends upon recruitment of motor units
Multiple Motor Unit Summation
119
What kind of stimuli?
- increasing number of motor units responding
Submaximal Stimuli
120
What kind of stimuli?
- all motor units respond
Maximal Stimulus
121
What kind of stimuli?
- all motor units respond; same as maximal stimulus
Supramaximal Stimuli
122
Trapped is a ________ response
graded
123
Treppe occurs in muscle ___________for prolonged period
rested
124
Each subsequent contraction is __________ than previous until all equal after few stimuli
stronger
125
More and more Ca2+ remains in ____________ and is not all taken up into the sarcoplasmic reticulum
Sarcoplasm
126
As the frequency of action potentials increase, the frequency of contraction…
increases
127
What kind of tetanus?
- muscle fibers partially relax between contraction
Incomplete Tetanus
128
What kind of tetanus?
- no relaxation between contractions
Complete Tetanus
129
What kind of summation?
- muscle tension increases as contraction frequencies increase
Multiple-wave summation
130
force applied to an object to be lifted when a muscle contracts
Active Tension
131
what kind of muscle with active tension: not enough cross-bridging
stretched muscle
132
what kind of muscle with active tension: myofilaments crumpled, cross-bridges can’t contract
Crumpled muscle
133
tension applied to load when a muscle is stretched but not stimulated
Passive Tension
134
Active tension + Passive tension
Total tension
135
What type of muscle contraction?
- no change in length but tension increases
EX: postural muscles of body
Isometric
136
What type of muscle contraction?
- change in length but tension constant
Isotonic
137
What type of Isotonic muscle contraction?
- overcomes opposing resistance and muscle shortens
Cocentric
138
What type of Isotonic muscle contraction?
- tension maintained but muscle lengthens
Eccentric
139
What type of muscle fiber?
- contract more slowly, smaller in diameter, better blood supply, more mitochondria, more fatigue-resistant than fast-twitch, large amount of myoglobin
- postural muscles, more in lower than upper limbs, dark meat of chicken
Slow-twitch oxidative (Type 1)
140
What type of muscle fiber?
- respond rapidly to nervous stimulation, contain myosin that can break down ATP more rapidly than that in Type 1, leads blood supply, fewer and smaller mitochondria than slow-twitch
- lower limbs in sprinter, upper limbs of most people, white meat
- comes in oxidative (Type 2a) and glycolytic (Type 2b) forms
Fast-twitch (Type 2)
141
Hypertrophy: increase in…
muscle size
142
Hypertrophy has an increase in what 4 things other than muscle size?
1. Myofibrils
2. Nuclei due to fusion of satellite cells
3. Strength due to better coordination of muscles
4. Production of metabolic enzymes, better circulation, less restriction by fat
143
Atrophy is the decrease in…
muscle size
144
Atrophy is reversible except in severe situations where…
cells die
145
During exercise, both the metabolic rate and heat production…
increase
146
Post exercise, metabolic rate stays _______ due to oxygen debt
high
147
Excess heat is lose because of vasodilation and…
sweating
148
Uncoordinated concentration of muscle fibers resulting in shaking and heat production
Shivering
149
ATP provides immediate energy for muscle contractions; produced from what three sources?
1. Creatine Phosphate
2. Anaerobic Respiration
3. Aerobic Repsiration
150
What ATP producer?
- during resting conditions stores energy to synthesize ATP
Creatine phosphate
151
What ATP producer?
- occurs in absence of oxygen and results in breakdown of glucose to yield ATP and lactic acid
Anaerobic respiration
152
What ATP producer?
- requires oxygen and breaks down glucose to produce ATP, carbon dioxide and water
- more efficient than anaerobic
Aerobic Respiration
153
Decreased capacity to work and reduced efficiency of performance
Muscle fatigue
154
What are the two types of muscle fatigue?
Psychological and Muscular
155
What type of muscle fatigue?
- depends on emotional state of individuals
Psychological
156
What type of muscle fatigue?
- results from ATP depletion
Muscular
157
Muscular muscle fatigue: Acidosis and aTP depletion due to either an increased ATP consumption or a…
decreased ATP production
158
Muscular muscle fatigue: Oxidative stress, which is characterized by the build-up of excess reactive…
oxygen species
159
Muscular muscle fatigue: local _______________ reactions
inflammatory
160
state of fatigue where due to lack of ATP neither contraction nor relaxation can occur
Physiological Contracture
161
Development of rigid muscles several hours after death
Rigor Mortis
162
Rigor mortis: Ca2+ leaks into sarcoplasm and attaches to ___________ _________ and cross bridges form
myosin heads
163
Rigor mortis: absence of _________ —> cross bridges cannot be broken down
ATP
164
Rigor mortis: rigor ends as tissues start to…
deteriorate
165
insufficient oxygen consumption relative to increased activity at the onset of exercise
Oxygen Deficit
166
Oxygen taken in by the body, above that required for resting metabolism after exercise
- repays the oxygen deficit
Recovery Oxygen Consumption
