Muscle/Autonomic Nervous System Flashcards
1
Q
the muscle used for posture and locomotion
A
Skeletal muscle
2
Q
The muscle that enables out arms and legs to contract, under our conscious control
A
Skeletal muscle
3
Q
The muscle responsible for the rhythmic contractions of the heart
A
Cardiac muscle
4
Q
The muscle that causes involuntary contraction in blood vessels, gut, bronchi, and the uterus
A
Smooth muscle
5
Q
Muscle is attached at each end to
A
Tendons
6
Q
Tendons connect … to …
A
muscle to bone
7
Q
Contraction of skeletal muscle pulls on the …. resulting in the …. of the joints
A
Contraction of skeletal muscle pulls on the tendons resulting in flexion of the joints.
8
Q
Skeletal muscle is composed of
A
bundles of long (up to 1 ft) thin cells called muscle fibers.
9
Q
bundles of long (up to 1 ft) thin cells
A
muscle fibers.
10
Q
Mature muscle fibers
A
long thin cells with many nuclei
11
Q
appearance of the fiber
A
striped
12
Q
Muscle fibers are generated during development by the
A
fusion of a large number of small precursor cells called myoblasts
13
Q
small precursor cells of muscle
A
myoblasts
14
Q
Each myobast is a single/multi nucleated cell
A
single
15
Q
Each muscle fiber is a single/multi nucleated cell
A
multi
16
Q
Skeletal muscle fibers consist of
A
cylindrical bundles called
myofibrils
17
Q
cylindrical bundles in muscle fibers
A
myofibrils
18
Q
The striations within each myofibril are caused by
A
alternating light I-bands and dark A-bands
19
Q
I bands
A
light region of myofibril
20
Q
A bands
A
dark region of myofibril
21
Q
Z-line
A
dark line in the center of each light band
22
Q
sarcomere
A
distance from Z line to Z line
Contractile unit of skeletal muscle
23
Q
M line
A
line in the center of each dark band
24
Q
H zone
A
region of non overlapping A bands, just thick filament
25
Each sarcomere consists of two sets of
parallel and partially overlapping protein filaments
| thick and thin
26
(thick/thin) filaments: extending from one end
| of the A band to the other
Thick
27
(thick/thin) filaments: attached to the Z lines and extending across the I band and part way into the A band
Thin
28
Cross bridges
Attach the thick filaments to the thin filaments
29
The myofibril is a lattice of thick/thin/both filaments
the myofibril is a lattice of thick and thin filaments.
30
H Zone has thick/thin/both filaments
thick filaments
31
I Zone has thick/thin/both filaments
thick filaments
32
A band has thick/thin/both filaments
both filaments
| overlap of thick and thin filaments
33
Thin filaments are made of
actin
34
each actin filament is formed from
two chains of globular actin subunits, twisted into a helix.
35
Thick filaments are made of
myosin
36
Thicks filaments consist of ______ bundles
myosin bundles
37
Sliding filament reaction is driven by
ATP hydrolysis
38
What occurs in the sliding filament model?
The thin filaments are pulled over the thick filaments by the myosin head groups, which repeatedly grab, pull and release the thin filaments.
39
What occurs when thin filaments slide over thick filaments
the sarcomere contracts
40
Contraction of the sarcomeres results in
the shortening of the entire myofibril
41
The amount of tension a muscle fiber can develop depends on
fiber length
42
length-tension relation reflects
the degree overlap between thick and thin filaments
43
The cross-bridge cycle is driven by
ATP binding and hydrolysis by the myosin head groups
44
How does the cross bridge release from the actin?
binding of ATP
45
Motor unit
A motor neuron and the group of muscle fibers it innervates.
46
Number of fibers innervated by a single motor neuron
Range from 10 to 100 to several thousand
47
Muscles with 10 fibers innervated by a single motor neuron
extraocular muscles
48
Muscles with 100 fibers innervated by a single motor neuron
muscles of the hand
49
Muscles with several thousand fibers innervated by a single motor neuron
large flexor and extensor muscles of leg
50
Neuromuscular transmission steps (5)
1. Action potential in motor neuron
2. Acetylcholine release at presynaptic terminal.
3. 3. Na+ influx through activated nicotinic acetylcholine receptors.
4. Endplate potential.
5. Fiber action potential
51
size of the motor synapse vs brain synpase
Motor synapse are much larger than brain synpase
52
What does. the action potential cause muscle to do?
contract
53
Sarcoplasmic reticulum
filled with calicum
| intercellular component inside muscle fiber
54
T-tubles
extensions of the cell membrane that penetrate into the centre of the muscle fibers
55
Activation of the Ryanodine Receptor
Causes Ca2+ efflux from the SR
| Moves calcium into the cytoplasm
56
What does the released calcium from the SR bind to
troponin on the thin filaments
57
The binding of calcium to troponin causes
a conformation change
58
Conformation change of troponin allows the
myosin binding site on actin to be free and the heads of the thick filaments can bind
59
Contraction of muscle fiber in response to a single action potential is called a
twitch
60
Why does the twitch lags behind the muscle action potential?
-because of the delays associated with excitation-contraction coupling
61
the delays associated with excitation-contraction coupling are due to
the time it takes for the calcium concentration in the muscle cell to return to baseline
62
Force generated by a muscle is called
tension
63
The tension exerted by a whole muscle is controlled by (2)
recruitment and summation
64
an increase in the number of active fibres with the addition of motor units
recruitment
65
the additive effects of several closely spaced twitches.
summation
66
Motor neurons typically fire in bursts, resulting in, sustained contraction of the muscle fiber, called
tetanus
67
Muscle fiber activity requires large amounts of
energy
68
There is only enough premade ATP in a muscle fiber to last for
a few twitches
69
Transfer of a P from creatine phosphate to ADP creates
enough ATP for a few seconds of muscle activity
70
Levels of ATP are sustained during prolonged muscle activity by
glycolysis and oxidative phosphorylation
71
What provides the fuel?
Glycogen in the muscle and glucose and fatty acids from the blood
72
Muscle fibers store energy in the form a
glycogen
73
a polysaccharide comprising long chains of glucose molecules.
glycogen
74
Types of skeletal muscle fibers
Fast glycolytic fibers, Slow oxidative fibers, Fast oxidative fibers
75
Fast glycolytic fibers, Slow oxidative fibers, Fast oxidative fibers: Myosin with high ATPase activity.
Fast glycolytic fibers
76
Fast glycolytic fibers, Slow oxidative fibers, Fast oxidative fibers: For generation of large force over short periods of time.
Fast glycolytic fibers
77
Fast glycolytic fibers, Slow oxidative fibers, Fast oxidative fibers: no myoglobin (“white muscle”)
Fast glycolytic fibers
78
Fast glycolytic fibers, Slow oxidative fibers, Fast oxidative fibers:
Myosin with low ATPase activity.
Slow oxidative fibers
79
Fast glycolytic fibers, Slow oxidative fibers, Fast oxidative fibers:
Myoglobin to facilitate oxygen transport from blood (“red muscle”).
Slow oxidative fibers
80
Fast glycolytic fibers, Slow oxidative fibers, Fast oxidative fibers:
For generation of low levels of force over long periods of time.
Slow oxidative fibers
81
Fast glycolytic fibers, Slow oxidative fibers, Fast oxidative fibers:
Intermediate properties. “Fast” myosin and oxidative metabolism.
Fast oxidative fibers
82
protects muscle from damage
Fatigue
83
T/F Fatigue is caused by depletion of ATP
F
84
Responsible for muscle fatigue
number of complex mechanisms
85
Which of the following would not muscle fatigue?
- changes in ion gradients
- reduction in pH due to build up of lactic acid
- depletion of glycogen
- damaged tissue
- Failure of command signals from the CNS
damaged tissue
86
Changes in muscle physiology depend on the type
of excerise
87
Low intensity, exercise causes
increased ability of muscle fibers to extract ATP energy through oxidative metabolism.
muscles more efficent
88
High-intensity, short-duration exercise causes
increase in the diameter of fast glycolytic fibers and muscle hypertrophy.
89
What does inflammation in response to muscle damage result in?
Muscle soreness
90
Released by damaged tissues
Factors that may be involved in muscle changes in response to exercise
91
Muscles that have a contraction that involves myosin thick filaments pulling on actin thin filaments
Smooth and skeletal muscle
92
Muscles that have actin and myosin have highly ordered structure
skeletal and cardiac muscle
93
What muscle lacks striations?
smooth muscle
94
Calcium in smooth vs skeletal muscle
Calcium can come from many different places in smooth muscle
95
The activity of the smooth muscle is regulated by many types
of extracellular signals, including hormones and neurotransmitters of the autonomic nervous system
96
a sensory and motor system, innervating visceral tissues and organs.
autonomic nervous system
97
The autonomic nervous system is trying to maintain a relatively stable internal environment known as
homeostasis
98
The autonomic nervous system has three major divisions:
the sympathetic system, the parasympathetic system and the enteric system.
99
innervate cardiac and smooth muscle and glandular tissue,
the sympathetic system, the parasympathetic system
100
controls the digestive tract
enteric system
101
The sympathetic and parasympathetic systems typically have _______ effects on target tissues
opposing
102
governs emergency fight-or-flight reactions
sympathetic system
103
responsible for rest-and-digest processes
parasympathetic system
104
The autonomic motor neurons are located
| - in groups called
outside the spinal cord in cell groups called the autonomic ganglia
105
autonomic motor neurons are activated by
preganglionic neurons
106
preganglionic neurons have cell bodies located in the
spinal cord or brainstem
107
Sympathetic preganglionic neurons release
acetylcholine
108
acetylcholine activates ...
| through...
- postganglionic neurons
| - nicotinic acetylcholine receptors
109
sympathetic postganglionic neurons release
norepinephrine
110
modulates target tissues through interaction with a-adrenergic and b-adrenergic receptors
norepinephrine
111
Parasympathetic preganglionic neurons
acetylcholine
112
Parasympathetic postganglionic fibers release
acetylcholine
113
—- afferents modulates the target tissue through activation of muscarinic acetylcholine receptors
Excitatory ACh
114
emerge from the brainstem (cranial nerves III, VII, IX and X) and the sacral spinal cord
Preganglionic parasympathetic fibers
115
emerge from the thoracic and lumbar chord
Preganglionic sympathetic fibers
116
form interconnected chains on either side of the chord
sympathetic ganglia
| known as sympathetic trunks
117
increases heart rate and the strength of heart contraction
Sympathetic stimulation
118
decreases heart rate and contraction
Parasympathetic stimulation
119
Most sensory information from visceral organs reaches the brain by way of the
cranial nerve
120
integrates visceral sensory inputs and autonomic outputs and projects to higher brain centres involved in homeostasis
The brainstem
121
Controls the gastrointestinal tract, the pancreas and the gallbladder
Enteric Nervous System
122
control smooth muscle in the gut as well as local blood vessels and secretion by the mucosa.
Enteric motor neurons
123
how many neurons does the human enteric system contains
100 million neurons,
124
T/F: The human enteric system can not function normally in the absence of external neuronal input
F: highly autonomous and can function normally in the absence of external neuronal input.
125
plays a critical role in integrating autonomic responses and endocrine function with behavior, to maintain basic homeostatic requirements of everyday life.
The hypothalamus
126
hypothalamus regulates
1. Blood pressure and electrolyte balance.
2. Body temperature.
3. Energy metabolism
4. Reproduction
5. Emergency responses to stress
127
hypothalamus receives sensory information from
the entire body, and from brain regions involved in cognition, emotion and memory
128
The hypothalamus compares sensory information with
biological set points
129
When it detects a deviation from a set point
restore homeostasis: it coordinates autonomic, endocrine and behavioural responses
130
The autonomic nervous system and hypothalamus
| interact with other brain regions, including
amygdala and ventromedial prefrontal cortex
131
Brain parts that relate visceral responses to conscious
| feelings and connect emotions to memories.
amygdala and ventromedial prefrontal cortex
