Exam 2 Flashcards
1
Q
Structural region on MyoD that is required for activity
A
BHLH (basic helix loop helix)
2
Q
Binding site in DNA for myogenic factors
A
E-box
3
Q
Physiological process of converting an electrical stimulus to the muscle into a contraction.
A
Excitation-contraction coupling
4
Q
Molecular interactions between actin and myosin that lead to muscle contraction
A
Power stroke
5
Q
Molecular interactions between actin and myosin that lead to muscle contraction
A
Power stroke
6
Q
Stem cells found in skeletal muscle fibers that promote repair and regeneration
A
Satellite cells
7
Q
Pump located in the endoplasmic reticulum that transports calcium from the cytoplasm into the SR
A
SERCA
8
Q
Short duration contraction caused by continuous stimulation
A
Summation contraction
9
Q
Steady, prolonged contraction caused by continuous stimulation
A
Tetanus contraction
10
Q
Single muscle contraction caused by one action potential
A
Twitch contraction
11
Q
Single cell myoblasts fuse to form
A
Multinucleated myotubes
12
Q
Transcription factors determine if cells become myogenic
A
MyoD
Myogenin
Myf-5
MRF-4/herculin/myf-6
13
Q
This section of myogenic regulatory structure is responsible for dimerization (active form)
A
Helix loop helix
14
Q
This region of myogenic factors is important in allowing the dimerized myogenic factors to bind to the DNA
A
Basic region
15
Q
Myogenic factors, after dimerizing bind to this section on the DNA
A
E-box
16
Q
Two early myogenic determination factors
A
MyoD and Myf5
17
Q
Two late myogenic determination factors
A
Myogenin
RF4
18
Q
Mutations in this lead to increase in muscle mass
A
Myostatin
19
Q
Acts as a negative regulator of muscle growth.
Inhibits myoblast proliferation
Inhibits progression of myoblasts from G1 to S
TGF-beta family of signaling proteins
MyoD binds to the E-box of this things’ promoter, activating transcription
A
Myostatin
20
Q
These are recruited to supply myoblasts for repair and regeneration
A
Satellite cells
21
Q
Heavy chains of myosin consist of:
A
Globular head
Filamentous tail
22
Q
Acts as an ATPase, releasing energy for contraction.
Binds to actin
A
Globular head of myosin thick filaments
23
Q
Lies in the groove between the two strands of actin
Has a regulatory function and provides structural rigidity to actin
A
Tropomysin
24
Q
Serves to bind troponin to tropomyosin
A
Troponin T
25
Contains two high and two low affinity sites for Ca
Troponin C
26
Inhibits interaction between actin and myosin
Troponin I
27
One molecule of this extends from M line to Z disc.
Acts as a spring to keep myosin filaments centered in sarcomere and maintain resting tension that allows muscle to snap back if overextended
Titin
28
Associated w/ actin
Regulates assembly and alignment of actin filaments
Nebulin
29
Calcium binds to what protein to initiate contraction?
Troponin C
30
Energy from skeletal muscle contraction is derived from _____
The cleavage of ATP by the myosin head
31
Layer of connective tissue that surrounds a muscle fiber
Endomysium
32
Muscle fiber that is a single, long, multinucleated cell w/ flattened nuclei on the periphery
Skeletal muscle.
33
Groups of several muscle fibers
Fasicle
34
Outer covering of the fasicle
Perimysium
35
Basic functional unit of the myofibril
Repeating units of sarcomeres run the length of the muscle
Composed of thick and thin filamentss
Overlapping of filaments creates banding pattern
Sarcomere
36
Thick fliaments
Myosin
37
Thin filaments
Actin
38
Type of muscle with cells joined end to end by intercalated disks to make fibers. Cross striations from sarcomere, rounded nuclei often centrally located
Cardiac muscle
39
Eosinophilic cytoplasm, minimal endomysium. Speckled hot dog central nucleus, fiber is a single cell w/ a single nucleus
Smooth muscle
40
Type of muscle that does not contain sarcomeres
Smooth muscle
41
Region of sarcomere with only actin
I band
42
Represents the full length of the thick filaments (myosin)
A band
43
This initiates chromatin remodeling in regulatory regions of muscle-specific genes
MyoD
44
Loss of myostatin function causes what?
Muscle hypertrophy
45
What activated process of satellite cell repair?
Immune response to injury
46
T-tubule Voltage gated calcium channel that mediates long lasting calcium currents
DHP (dihydropyridine)
47
Sarcoplasmic reticulum releases calcium through this
Ryanodine receptor 1 (RyR1)
48
Conformational change in DHP causes this channel to open
RyR1
49
When no ATP is available to let actin be released from myosin
Rigor mortis
50
Cyclic myosin-actin interactions will continue as long as _____
There are calcium ions in the sarcoplasms
51
Stabilizes resting membrane potential preventing false action potentials
Important in repolarizing the membrane after contraction
Chloride channel (CIC-1)
52
A glycoprotein that binds calcium ions and acts to reduce SR concentration of free calcium
Calsequestrin
53
Order of sources used to generate ATP in skeletal muscle?
1. Phosphocreatine + ADP --(creatine phosphokinase)--> ATP + creatine
2. Glycolysis
3. Oxidative phosphorylation
54
Which of the 3 means of skeletal muscle to obtain ATP is the most abundant?
Oxidative phosphorylation
55
Force generated by formation of actin-myosin crossbridge
Active tension
56
Dramatic muscle atrophy seen in patients w/ chronic illness
Cachexia
57
Length stays constant but tension changes
Isometric contraciton
58
Tension stays constant but the length changes
Isotonic contraction
59
Single motor neuron and all muscle fibers it innervates
Motor unit
60
Dz of skeletal muscle not caused by nerve disorders
Myopathy
61
Inflammation of skeletal muscles
Myositis
62
Force generated by stretching of skeletal muscle
Passive tension
63
Rapid destruction of skeletal muscle
Rhabdomyolysis
64
Age related reduction in skeletal muscle mass and strength
Sarcopenia
65
Force generated by both cross bridge formation and satretching muscle
Total tension
66
Type of isotonic contraction; muscle decreases in length against opposing load (such as lifting weight up)
Concentric contraction
67
Type of isotonic contraction; muscle increases in length as it resists a load, such as pushing something down
Eccentric contraction
68
Length of muscle where maximum force is generated
Optimal length
69
Slow twitch fibers
Type I
70
Type of fibers with slow myosin ATPase, high in mitochondria, dependent on cellular respiration for ATP, rich in myoglobin, resistant to fatigue, activated by small motor neurons
Type I fibers (slow twitch)
71
Type of fiber w/ fast myosin ATPase
Fast twitch fibers (type II)
72
```
Type of fast twitch
Loaded w/ mitochondria
Cellular respiration and glycolysis for ATP.
High myoglobin
Moderately fatigue resistant
Large motor neurons
```
Type IIa fibers
73
```
Type of fast twitch
Few mitochondria
High glycogen
Glycolysis for ATP production
Low myoglobin
Easily fatigued
```
Type IIb fibers
74
Group of muscle fibers innervated by same motor neuron
Motor unit
75
Defects in dystrophin gene which leads to instability of sarcolemma and then to damage of the muscle during contractions
Duchenne muscular dystrophy
| Becker's muscular dystrophy
76
Breakdown of muscle fibers leading to release of contents (especially myoglobin).
Some of these fibers toxic to kidney
Most are caused by crush injury, overexertion, ETOH abuse, certain drugs (statins), and toxic substances
Rhabdomyolysis
77
Defect in RYR1 channel which causes it to open more easily and close slower. Activated by some anesthetics and muscle relaxers
Leads to uncontrolled release of calcium.
Muscles contract abnormally leading to rigidity and heat prodction
Malignant hyperthermia
78
Conversion of a physical signal (energy) into a neural signal
Transduction
79
Representation of qualitative and quantitative aspects of the stimulus
Encoding
80
Conscious awareness of stimulus
Perception
81
The quality of the stimulus, determined by the nature of the energy
Modality
82
5 sensory modalities
Touch, taste, smell, hearing, vision
83
The unique form of energy that activates a specific receptor at low energy level. (Light for photreceptors)
Adequate stimuluas
84
The lowest stimulus that can reliably (at least 50% of the time) be detected
Sensory threshold
85
A decrease in sensitivity raises the threshold and shifts the intensity-response curve to the ___
Right
86
Receptors that provide information about static properties of a stimulation
Slowly adapting receptors
87
Receptors that provide information about dynamic aspects of a stimulus
Rapidly adapting receptors
88
The specific spatial location w/in the sensory organ where stimulus energy is effective (for tactile, this is like a topographical map of the skin)
Receptive field.
89
Cold receptors are stimulated by temperature in this range ___
12-35C
90
Warm receptors are stimulated in this range
30-47C
91
Activated by extremes of heat or cold (less than 12C or more than 47C)
Thermal pain receptors
92
Two types of mechanisms of adaptation
Sensory mechanism
Membrane mechanism
93
Free nerve endings, merkel endings, hair follicle receptors
Nonencapsulated receptors
94
Formed by fine branches of sensory axons. These nerve endings lose any myelination before termination. Found throughout the body, no specialized structures. Can be mechanical, thermal, pain, or itch receptors
Free nerve endings.
95
Formed by myelinated axons of sensory receptor neurons that branch into flattened, disk shaped endings
Contain stretch-gate ion channels and function as mechanoreceptors.
Merkel receptors
96
Mechanoreceptors formed by the endings of sensory axons (thin myelinated) that wrap around the hair. Bending of the hair stretches the axon membrane, opening stretch gated channels
Hair follicle receptors
97
Class of receptors that includes Meissner corpuscles, pacinian corpuscles, and Ruffini endings.
All are mechanoreceptors w/ stretch gated channels
Encapsulated receptors
98
Contain a layered stack of Schwann cells w/in a capsule. They are oriented perpendicularly to the long axis of the capsule. One or more axon endings wind between the schwann cell layer.
Located just under the epidermis in hairless skin
Meissner corpuscles
99
Subcutaneous
Contains concentric layers of epithelial cells w/ fluid filled spaces between. A single axon ending lies in the center
Pacinian corpuscles
100
Located in the dermis and subQ and CT
Capsule contains a core of longitudinally oriented collagen strands w/ interspersed sensory endings.
Respond to drag or shearing forces
Ruffini endings
101
Most sensitive to fast vibrations
Pacinian corpuscle
102
Responds to lower frequencies of vibrations
Meissner corpuscles
103
What type of adapting receptors are pacinian corpuscles, meissner corpuscles and hair follicle receptors
Fast adapting receptros
104
What type of adaptation do merkel and ruffini receptors do?
Slow adaptation
105
Respond to skin indentation
Merkel receptors
106
Respond to the stretching of the skin that is aligned w/ the capsule of the receptor
Ruffini receptors
107
Conscious awareness of body position and movement. Dependent on signal from muscle sensory receptors
Kinesthesia
108
Detection of position and movement of body itself
Proprioception
109
Detection of the outside world
Exteroception
110
Specialized muscle cells that have both sensory and motor innervation.
Sensory neurons are sensitive to muscle stretch
Muscle spindles
111
Located in muscle tendons or CT attachments. Sensitive to tension in tendon
Golgi tendon organs
112
Specific motor neuron for muscle spindles
Gamma motor neurons
113
Three things that muscle spindles signal
Muscle length
Movement
Velocity
114
Motor neurons that fire action potentials allowing skeletal muscle contraction
Alpha motor neurons
115
Muscle tension at rest
Due to activities in alpha motor neurons at rest
Muscle tonus
116
Where is highest density of muscle spindles?
Muscles used in fine control.
117
Muscle cells inside spindle
Intrafusal cells
118
All regular muscle cells that are outside the muscle spindle
Extrafusal
119
Neurons that innervate only spindle muscle cells.
Gamma motor neurons
120
Innervate fast contracting muscle cells
Gamma dynamic motor neurons
121
Innervate slow contracting muscle cells
Gamma static motor neurons
122
Is able to encode how fast a muscle stretch is
Group Ia sensory neurons
123
Encodes the force developed by a muscle contraction
Golgi Tendon organ
124
Larger action potential generated by many individual action potential's firing at once
Compound action potential
125
If axon diameter increases, current threshold _____
Decreases
126
Current threshold varies ____ with axon diameter
Inversely
127
The amount of stimulus current required to excite an action potential in a single axon
Current threshold
128
Compound action potentials evoked in low current thresholds reflect function in ____
Large diameter (myelinated) axons
129
Type of action potential recorded if the reference electrode is located far away from the extracellular recording site along the nerve
Monophasic
130
Type of action potential recorded if the indifferent electrode is located nearby, along the same nerve
Diphasic
131
What are the chemical senses
Smell and taste
132
Site of olfactory transduction?
Odorant receptor proteins on the cilia of the olfactory receptor neurons
133
Allows humans to detect many more odors than we have receptor proteins for
Population coding
134
Each receptor neuron can be activated by several different odorants w/ varying sensitivities, with the pattern of responses across the entire population of receptors being responsible for the perceived odor.
Population coding
135
Modified epithelial cells with distinct apical and basolateral membranes that are clustered into papillae
Taste receptor cells (taste buds are what actually cluster into the papillae)
136
5 types of basic tastes that humans can recognize
```
Sweet
Sour
Bitter
Salt
Umami
```
137
Bitter, sweet, and umami tastes use what for neurotransmission
G proteins
138
Type of gustatory receptor that uses TRP channels to allow the influx of H+ ions
Sour
139
Two ways that the sweet taste transductor gets Ca to release the transmitter?
Activation of Ca permeable TRP channel
Release of Ca from the IC organelles.
140
Type of receptor that is used in the metabotropic response of bitter taste transduction
Gustducin
141
Types of gustatory responses that are metabotropic
Umami
Bitter
Sweet
142
Things that supplement taste in food identification
Temperature, texture, and odor
143
About how many olfactory receptors / receptor genes are there in humans?
500
144
About how many odors can humans detect?
Over 20000
145
Where are satellite cells located?
On surface of muscle fiber, beneath basal lamina
146
Mediates the events between muscle excitation and contraction
Calcium
147
In a powerstroke, what direction does actin move in relation to a sarcomere
Towards the center
148
Type of muscle w/ multiple flattened nuclei on the periphery
Skeletal
149
Type of muscle with round, centrally located nucleus. (Sometimes has 2 nuclei)
Cardiac
150
Type of muscle with speckled hotdog looking nucleus that is centrally located
Smooth
151
Contains the entire thick filament and part of the thin filament
A band
152
Only contains the thin filament and the Z band. Does not contain the entire thin filament
I band
153
Only contains Thick filament (not the entire thick filament)
H band
154
Yellow pigment granules in the soma
Liposfuscin
155
Cell that can myelinate multiple axons
Oligodendrocytes
156
Cell that responds to tissue injury and immune responses in the brain.
Phagocytic
Smallest glial cell w/ irregular shape dark nucleus
Microglia
157
Gray matter is outside of the ___
Brain
158
Gray matter is on the inside of the ___
Spinal cord
159
White matter is on the inside of the ___
Brain
160
White matter is on the outside of the ___
Spinal cord
161
Type of matter that is primarily neurons, unmyelinated axons, and neuroglia.
Densely packed region of cell processes called the neuropil
Gray matter
162
Primarily myelinated axons, oligodendrocytes, and blood vessels
NO neuronal cell bodies
White matter
163
Connective tissue coverings of the brain and spinal cord
Meninges
164
How many layers of cells are there in the gray matter of the cerebrum
6 layers
165
A specialized cell transmitting nerve impulses
Neuron
166
3 layers of the cerebellum
Molecular
Purkinje
Granular
167
Distinguishable large dendritic tree
Layer of cerebellum
Large cell bodies in a single layer
Middle layer of cerebellum
Purkinje Cells
168
Found in the hypodermis
Senses pressure, vibration, touch
Pacinian corpuscle
169
Found in the dermal papilla of thick skin
Senses touch
Meissner corpuscles
170
A dense layer of CT that surrounds multiple fasicles of peripheral nerves
Epineurium
171
Bundles of axons (fascicles) are surrounded by a thinner layer of connective tissue called the _____
Perineurium
172
Muscle tension can be increased in what two ways?
Recruitment (increased # motor units contracting)
| Summation (increased freq of single motor unit contracting)
173
Defects in dystrophin leading to instability in sarcolemma?
DMD
| Becker's muscular dystrophy
174
Signal joint position and movement by monitory muscle length
Muscle spindles
175
Specialized skeletal muscle cells w/ both motor and sensory innervation. Sensitive to stretch & signal changes in muscle length. Some also indicate velocity.
Adjusted by gamma motor neurons that innervate it
Muscle spindles
176
Peripheral neuropathies, loos of axons in peripheral nerves. Loss of propioception, no sense of body position, Use vision (exteroception) to compensate for proprioceptive loss
Guillain - Barre Syndrome
177
Located in muscle tendons or connective tissue attachments; sensitive to tension in tendon. Signal force produced by muscle.
Golgi tendon organs
178
Activation of alpha motor neurons
Shortens in length and generation of force
Muscle contraction
179
Contraction against moderate load, changes length, tension on tendon and force are relatively constant. Movement and position detected by muscle spindles. Force detected by golgi tendon organs
Isotonic contraction
180
Contraction against a large load. Muscle length remains constant and larger forces are generated. No movement, no change in muscle spindles. Large increased force detected by golgi tendon organs
Isometric contraction
181
Amount of tension in a muscle at rest
Muscle tonus
182
what does passive stretch test?
Tests the muscle tonus
By having pt relax and then slowly stretch the muscle by mving limb at joints.
Compare this tonus to normal muscle strength
183
Muscle spindles are found most densely in muscles that are used for
Fine control
184
Muscle cells inside the spindle
Intrafusal cells
185
Part of the muscle spindle that are able to contract
Polar regions (contain contractile filaments)
186
Part of muscle spindle that is unable to contract
Equatorial region. (Contains sensory nerve endings)
187
Muscle spindles are innervate by?
Gamma motor neurons
188
Neurons that innervate only spindle muscle cells.
Gamma motor neurons
189
Innervate fast contracting muscle cells
Gamma dynamic neurons (Ia)
190
Innervate slow contracting muscle cells
Gamma static neurons (II)
191
Spindle sensory neurons have what type of ion channels?
Stretch-sensitive
192
Secondary sensory neurons ony encode _____ of the change in length
Magnitude
193
(Ia) discharge intensely when stretch is occurring, encode velocity of the stretch, and encode the magnitude of the change in length.
Primary sensory neurons
194
Small rapid change in length produces ____ from _____.
Large discharge from Group Ia
195
Used to adjust spindle length to muscle length
Gamma motor neurons
196
Clinical significance of tonus test?
Tonus is increased in upper motor neuron disorders
197
How are muscle spindles oriented in comparison to regular muscle cells?
Parallel
198
Respond best to fast vibrations or changes in pressure. Respond robustly to the change in pressure when an object is initially grasped in hand.
"Event detectors"
Pacinian corpuscles
199
Signal the weight, form, and surface features of objects contacting skin. Sustained response allows singaling of steady pressure exerted by the edges of objects held in hand
Merkel cells
200
Most abundant receptor type in hand
Rapid adaptation - no info about static pressure
Readily detect textures and edges as the hand is moved over surfaces
Helps to provide sensory info w/ high spatial and temporal resolution.
Meissner corpuscles
201
Two cell types involved with reading braille
Meissner and merkel
202
Responds to stretch of the skin. Signaling posture and movements of the body including the hand and mouth
Ruffini
203
Cells that line the lumen of the spinal canal
Ependymal cells
204
Cells that respond to tissue injury and participate in immune responses. Phagocytic in nature. In the brain
Microglia
205
Dispersion of Nissl substance to periphery
Chromatolysis
206
Outer surface of the cerebrum and cerebellum
Central region of spinal cord
Consists of neurons , unmyelinated axons, and neuroglia
Densely packed region of cell processes called the neuropil
Gray matter
207
Primarily myelinated axons, oligodendrocytes and blood vessels.
No neuronal cell bodies.
Outside of spinal cord
Inside of brain
White matter
208
Consists of dura mater, arachnoid mater, and pia mater
Meninges
209
Network of collagen and elastic fibers filled w/ cerebrospinal fluid that acts as a shock absorber
Sub-arachnoid spaace
210
Dense connective tissue in meninges
Dura mater
211
Inner layer of loose CT that carries blood vessels (in meninges)
Pia mater
212
How many layers are there of gray matter in the cerebral cortex
6
213
Purkinje cells are middle layer of
Cerebellum
214
Pyramidal cells are found in the
Cortex
215
Key feature of cerebellum tissue
Purkinje cells
216
Plexus's that control motility and secretion in the intestinal tract
Meisners's and auerbach's plexus.
217
Fluid from this gland dissolves odor molecules so they can bind to receptors on the non-motile cilia of bipolar neurons
Bowman's gland
218
Anchor point for thick filaments
M Line
219
Location of T tubule in skeletal muscle
A-I junction
220
T tubule is at the Z line in
Cardiac sarcomere (makes diad)
221
Majority of calcium for cardiac muscle comes from?
Extracellular
222
Inner layer of smooth muscle around intestine runs
Circularly
223
Outer layer of smooth muscle around intestines runs
Longitudinally
224
Binds intermediate filaments and actin to the membrane in smooth muscle
Dense bodies
225
Actin connects to intermediate filament cytoskeleton and _____ in smooth muscle
Dense bodies
226
Are there t tubules in smooth muscles?
No
