Exam 4 Flashcards
(261 cards)
1
Q
Which muscle: Compresses oral cavity and tightens cheek
A
Buccinator
2
Q
Which muscle: Elevates and retracts mandible to close jaw
A
Temporalis
3
Q
Which muscle: Closes eye, squinting
A
Orbicularis oculi
4
Q
Which muscle: Pulls scalp posteriorly
A
Occipitalis
5
Q
Which muscle: Closes mouth and purses lips
A
Orbicularis oris
6
Q
Which muscle: Elevates corner of mouth
A
Zygomaticus
7
Q
Which muscle: Raises eyebrows and pulls scalp anteriorly
A
Frontalis
8
Q
Which muscle: Elevates mandible to close the jaw
A
Masseter
9
Q
Which muscle: Depresses and everts lower lip
A
Depressor labii inferioris
10
Q
Which muscle: Depresses angle of mouth
A
Depressor anguli oris
11
Q
Which muscle: Wrinkles chin and everts lower lip
A
Mentalis
12
Q
Which muscle: Pulls angle of mouth laterally
A
Risorius
13
Q
True or False: A neuron receives information on its axons and delivers it to other neurons through its dendrites.
A
FALSE
14
Q
Which of the following neuron shapes would you expect to be associated with olfaction?
A
bipolar
15
Q
What is the action of the masseter?
A
chewing
16
Q
True or False: Excitatory post-synaptic potentials must be depolarizing action potentials.
A
FALSE
17
Q
The rhomboid major and minor muscles are deep to the ________.
A
Trapezius
18
Q
Which of the following structures would send information on proprioception to structures within the brain?
A
Spinocerebellar tract (next guess)
19
Q
What is the function of the erector spinae?
A
Postural support
20
Q
Which of the following structures (lobes) is primarily responsible for processing visual information?
A
Occipital lobe
21
Q
Which muscle: Rotates thigh laterally and stabilizes coxofemoral joint
A
Quadratus femoris
22
Q
Which muscle: Extends thigh, flexes and medially rotates leg
A
Semitendinosus
23
Q
Which muscle: Abducts and medially rotates thigh, important in walking
A
Gluteus medius
24
Q
Which muscle: Extends thigh, flexes and laterally rotates leg
A
Biceps femoris
25
Which muscle: Adducts, flexes, and medially rotates thigh
Pectineus
26
Which muscle: Extends leg and flexes hip
Rectus femoris
27
Which muscle: Prime mover for thigh extension in addition to abduction
Gluteus maximus
28
Which muscle: Prime mover of flexing the hip
Iliacus
29
Which muscle: Adducts, medially rotates, and flexes thigh and involved in thigh extension
Adductor magnus
30
Which muscle: Flexes hip and lateral flexion of lumbar vertebrae, important postural muscle
Psoas major
31
Which muscle: Rotates and extends the thigh laterally, abducts thigh, stabilizes coxofemoral joint
Piriformis
32
Which muscle: Extends and laterally rotates thigh
Obterator internis
33
Which muscle: Stabilizes the leg and trunk by moderating tension in iliotibial tract, flexes and abduct thigh
Tensor fascia latae
34
Which muscle: Flexes, abducts, and laterally rotates the thigh
Sartorius
35
Analogs are chemicals which:
Similar chemical structure to neurotransmitter
36
Which of the following structures would send information for complex muscle movements and unskilled movements?
Extrapyramidal tract
37
Which of the following receptor types would detect stimuli resulting from pain?
Chemoreceptors
38
What type of glial cell is the resident macrophage behind the blood-brain barrier?
Microglia
39
Your friend is poking your skin with two pins a few millimeters apart at the same time. Visually, you can see there are two pins, but you can only feel a single pen poke. This is probably because:
the receptors in both skin areas utilize the same afferent neuron.
40
If a thermoreceptor is sensitive to temperature sensations, what would a chemoreceptor be sensitive to?
Molecules
41
The limbic system is best characterized as:
Brain regions associated with learning, memory, and behavior
42
Which of the following receptor types would detect stimuli resulting from a change in temperature?
Thermoreceptors
43
True or False: Inhibitory post-synaptic potentials must be hyperpolarizing action potentials.
FALSE
44
All indolamines are synthesized from what amino acid?
Tryptophan
45
Complete the sentence:
A threshold stimulus applied to an excitable membrane is one that is just sufficient to ______
trigger an action potential.
46
Which of the following statements concerning the properties of action potentials is TRUE?
The rate of propagation of an action potential down an axon is independent of stimulus strength.
47
Voltage-gated Na+ channels open upon reaching what state?
Threshold
48
True or False: Electrical synapses are slower than chemical synapses.
FALSE
49
Which muscle: Compresses the abdomen, depresses ribs, flexes and rotates vertebral column
External oblique
50
Which muscle: Posterior abdominal wall, prime mover of lateral flexion
Quadratus lumborum
51
Which muscle: Laterally flex vertebral column
Intertransversarii
52
Which muscle: Raise and expand the rib cage
External intercostals
53
Which muscle: Bilaterally flex neck, tilt and rotate head to the side
Sternocleidomastoid
54
Which muscle: Compresses the abdomen
Transversus abdominis
55
Which muscle: Compresses the abdomen, depresses the ribs, flexes the vertebral column
Rectus abdominis
56
Which muscle: Stabilize vertebral column
Segmental group
57
Which muscle: Primary extensors of vertebral column
Erector spinae group
58
Which muscle: Prime mover for compression and expansion of the thoracic cavity and associated changes in abdominal cavity
Diaphragm
59
Which muscle: Draw the ribs together and constrict the thoracic cage for forced exhalation
Internal intercostals
60
Which muscle: Extends vertebral column
Interspinales
61
Agonists are chemicals which:
Binds to the same receptors as a neurotransmitter and mimics the effects
62
True or False: Sensory information travels in ascending tracts in the spinal cord
True
63
Which of the following structures would send information for voluntary motor movement used in skilled motions
Pyramidal tract
64
True or False: Efferent is a term that is synonymous with sensory
FALSE
65
Which of the following neurotransmitters is associated with inhibition exclusively?
GABA
66
Which of the following receptor types would detect stimuli resulting from stretch?
Mechanoreceptor
67
Which muscle produces movement that allows you to cross your legs?
The Sartorius
68
Which muscle: Rotates arm laterally and extends arm
Infraspinatus
69
Which muscle: Abducts arm and extends arm
Supraspinatus
70
Which muscle: Adducts and stabilizes scapula
Rhomboid major
71
Which muscle: Prime mover of arm extension, adducts arm, medially rotates arm, important in power stroke of lowering arm
Latissimus dorsi
72
Which muscle: Prime mover for medial rotation of the arm and extends arm
Subscapularis
73
Which muscle: Extends, medially rotates, and adducts arm
Teres major
74
Which muscle: Adducts and elevates scapula
Levator scapulae
75
Which muscle: Stabilizes, elevates, retracts and rotates scapula and extends head
Trapezius
76
Which muscle: Prime move of arm abduction, flexes and medially rotates arm, extends and laterally rotates arm
Deltoid
77
Which muscle: Flexes and adducts arm
Coracobrachialis
78
Which muscle: Adducts, flexes and rotates arm medially
Pectoralis major
79
Which muscle: Abducts and rotates scapula, important in horizontal arm movements
Serratus anterior
80
Which muscle: Flexes forearm
Brachialis
81
Which muscle: Extends hands and fingers
Extensor digitorum
82
Which muscle: Flexes hand and tenses fascia of palm
Palmaris longus
83
Which muscle: Pronates forearm (and hand)
Pronator teres
84
Which muscle: Flexes and adducts hand
Flexor carpi ulnaris
85
Which muscle: Supinates forearm (and hand)
Supinator
86
Which muscle: Prime move of forearm extension
Triceps brachii
87
Which muscle: Extends and adducts hand
Extensor carpi ulnaris
88
Which muscle: Flexes and supinates forearm and weakly flexes arm
Biceps brachii
89
Which muscle: Extends and abducts hand
Extensor carpi radialis longus
90
Which muscle: Flexes and abducts hand
Flexor carpi radialis
91
Which muscle: Flexes forearm and stabilizes elbow
Brachioradialis
92
Which of the following is a function of the cerebellum?
Coordinate bodily movements to maintain posture
93
What is the name for the topographical representation of the sensory input to the somatosensory cortex?
homunculus
94
True or False: Generally speaking, serotonin is excitatory in motor pathways
True
95
What type of glial cell is responsible for filtering blood to produce CSF at the choroid plexus?
Ependymal cell
96
An EPSP
is a direct result of the opening of ligand-gated channels permeable to both Na + and K + ions.
97
What specialized structure of the arachnoid mater allows cerebrospinal fluid to return to venous blood supply?
Arachnoid granulations
98
All catecholamines are synthesized from what amino acid?
Tyrosine
99
True or False: A sensory modality refers to the specific stimuli/information that a receptor can encode
True
100
Which muscle: Prime mover of inversion and plantarflexes foot
Tibialis posterior
101
Which muscle: Flexes and rotates leg medially (unlocks extended knee)
Popliteus
102
Which muscle: Extends leg and stabilizes knee
Vastus lateralis
103
Which muscle: Extends leg
Vastus intermedius
104
Which muscle: Plantarflexes foot and flexes knee
Gastrocnemius
105
Which muscle: Plantarflexes and inverts foot, flexes hallux
Flexor hallucis longus
106
Which muscle: Prime mover of dorsiflexion, inverts foot
Tibialis anterior
107
Which muscle: Plantarflexes foot and important in locomotion and posture
Solus
108
Which muscle: Extends digits 2-5
Extensor digitorum longus
109
Which muscle: Extends hallux and dorsiflexes foot
Extensor hallucis longus
110
Which muscle: Plantarflexes and everts foot
Fibularis longus (with brevis)
111
Which muscle: Plantar flexes and inverts foot, flexes toes
Flexor digitorum longus
112
True or False: Inhibitory post-synaptic potentials must be hyperpolarizing graded potentials.
True
113
A channel opens on a postsynaptic membrane that causes a negative ion to enter the cell. What type of graded potential is this?
Hyperpolarizing
114
Point of communication-
Synapse
115
Receptive process-
Dendrite
116
Biosynthetic and metabolic center-
Soma
117
Conducting processes-
Axon
118
Which of the following structures (lobes) is primarily responsible for processing auditory information?
Temporal lobe
119
What two types of macromolecules are the main components of myelin?
lipids and proteins
120
Which is NOT an example of a graded potential?
A depolarizing action potential
121
What type of glial cell provides myelin for the axons in a tract?
Oligodendrocyte
122
Which of the following structures would send information on discriminative touch to the thalamus
Dorsal column medial meniscal tract
123
What is the best description of electric current?
The net movement of charged particles
124
The semimembranosus, semitendinosus, and biceps femoris (long head) all belong to what muscle group?
Hamstrings
125
Using a micropipette, a neuroscientist injects an axon with enough Na + ions to move the membrane potential +25mV (from resting).
Voltage-GATED Na + channels will be TRIGGERED TO OPEN.
126
Which term describes a bundle of axons in the peripheral nervous system?
nerve
127
An action potential in a neuronal membrane differs from a graded potential in that
an action potential is propagated without decrement, whereas a graded potential decrements with distance.
128
What type of input do afferent neurons carry?
Sensory
129
Nicotinic receptors are expressed on skeletal muscle cells. Which of the following would likely be a side-effect of the use of nicotine, an agonist for those receptors?
Muscle cell twitches (contractions)
130
Antagonists are chemicals which:
Blocks the receptor site
131
Which of the following is a prime mover in head flexion?
Sternocleidomastoid
132
Which functional division of the nervous system would be responsible for the physiological changes seen during exercise (e.g., increased heart rate and sweating)?
Autonomic
133
Which of the following substances is least able to cross the blood-brain barrier?
White blood cells
134
Which structure provides lateral stabilization of the spinal cord?
Denticulate ligament
135
Which is not a function of the cerebrospinal fluid?
Redistributing neurotransmitters
136
Which of the following structures is primarily responsible for planning the movement of skeletal muscle?
Premotor cortex
137
Which is TRUE about typical, resting neurons?
The permeability of the plasma membrane to potassium ions is much greater than its permeability to sodium ions.
138
True or False: Strong stimuli are encoded as an increased frequency in action potentials.
True
139
What region of the spinal cord contains motor neurons that direct the movement of skeletal muscles?
Ventral horn
140
Which is one of the major inhibitory neurotransmitters in the CNS?
GABA
141
Which region of gray matter in the spinal cord contains motor neurons that innervate skeletal muscles?
Ventral horn
142
Two stimuli occur on the same neuron more than a minute apart. The second stimulus is more than ten times greater than the first. If we compare the two resulting action potentials, which is TRUE?
The second stimulus will lead to an action potential with a longer duration.
143
Which of the following would NOT be categorized as a "somatic" sensation?
Sound
144
The spinal cord passes through which landmark of the vertebral column?
Vertebral foramen
145
Why type of input do efferent neurons carry?
Motor
146
Smile – you are on the multiple choice. Which muscle has an action that could be described as helping you smile by elevating the angle of the mouth?
Zygomaticus major
147
True or False: Generally speaking, all nicotinic receptors illicit an excitatory response on the postsynaptic neuron
True
148
Visual signals travel on myelinated axons. While most pain signals travel on unmyelinated axons. If you get a paper cut, will you see the cut happen or feel the pain first?
You will experience the visual sensation before the pain sensation.
149
Which of the following neurotransmitters would you expect to find active in the synapses activated during your study sessions devoted to learning the neurotransmitters?
Glutamate
150
Cerebrospinal fluid is produced by which structure?
Choroid plexus
151
Which of the following statements regarding the determination of stimulus intensity is true?
The frequency of action potentials increases with increasing stimulus intensity.
152
Which of the following structures (lobes) is primarily responsible for processing motor information?
Frontal lobe
153
Which of the following structures would send motor information to skeletal muscle?
Ventral horn
154
The relative refractory period of an axon coincides with the period of
increased K + permeability of the cell.
155
Endorphans belong to which class of neurotransmitters?
Neuropeptides
156
What category of receptors do Pacinian corpuscles belong to?
Mechanoreceptors
157
True or False: Drug Z is an agonist for a neurotransmitter receptor. It has a much higher affinity for the receptor and binds four times longer than the endogenous neurotransmitter. If you compare drug Z with the endogenous neurotransmitter, it's likely that drug Z will cause more frequent action potentials than the endogenous ligand.
True
158
What is required for neurotransmitters to be released?
Calcium has to enter the axon terminal
159
What is the best description of depolarization?
The net movement of ions across a cell membrane resulting in the interior becoming LESS NEGATIVE respective to the extracellular fluid
160
What is the best description of hyperpolarization?
The net movement of ions across a cell membrane resulting in the interior becoming MORE NEGATIVE respective to the extracellular fluid
161
Which of the following cavities contains a component of the central nervous system?
Cranial
162
Which of the following is probably going to propagate an action potential fastest?
a thick, myelinated axon
163
Inside a neuron, calcium binding sites are likely found on
proteins associated with synaptic vesicles.
164
All metabotropic receptors:
Generate metabolic changes in the cell
165
Select all of the following which are structures of the central nervous system (CNS)
- Ventral, Dorsal, and Lateral horns
- Ventral, Dorsal, and Lateral columns
- Gray commissure
166
Select all of the following which are structures of the peripheral nervous system (PNS)
- Ventral root
- Dorsal root
- Dorsal root ganglion
167
Which of the following describes action potential
Long distance, voltage-dependent, and initiated only at the axon hillock
168
The vastus intermedius muscle is deep to which of the following muscles?
rectus femoris
169
Receptors transduce ___________ into a _________ potential which can then cause an ___________ potential which travels through the ________ order neuron.
stimuli ; graded ; action ; first
170
What neurotransmitter is released at the neuromuscular junction?
acetylcholine
171
What type of receptor cell is responsible for transducing pain stimuli?
nociceptor
172
True or False: Myelinated structures appear white due because myelin is rich in carbohydrates
FALSE
173
Which part of a neuron contains the nucleus?
Soma
174
Which muscle pair plays a role in respiration?
diaphragm, intercostals
175
Which of the following structures would send information on crude touch to the thalamus
Spinothalamic tract
176
True or False: Neuroglia are the cells that form the basis of signaling within the nervous system?
FALSE
177
Which muscle originates on the transverse process of vertebrae and laterally flexes the vertebral column?
Intertransversarii
178
Select all that apply:
What processes are involved in the electrochemical gradients involved with membrane potentials
Active transport of ions
Diffusion based on concentration gradients
Diffusion based on charge
179
Which muscle originates on the transverse process of vertebrae and laterally flexes the vertebral column?
Intertransversaii
180
Which of the following structures can be classified as postsynaptic?
Glands
Skeletal muscles
Neurons
181
Nicotine is
a cholinergic agonist.
182
Which is one of the most abundant excitatory neurotransmitters in the CNS?
Glutamate
183
The activity of acetylcholinesterase is an example of:
Neurotransmitter degradation by an enzyme
184
Which of the following abdominal muscles is not a part of the anterior abdominal wall?
quadratus lumborum
185
How much of a change in the membrane potential is necessary for the summation of postsynaptic potentials to result in an action potential being generated?
+15 mV
186
Which of the following neuron shapes would you expect to be associated with general senses
Unipolar
187
What does a ligand-gated channel require in order to open?
binding of a neurotransmitter
188
Procaine (Novocain) is a drug that blocks voltage-gated Na + channels. When present, what would happen in a neuron?
Graded potentials are possible, but the neuron will not have the depolarizing phase of the action potential
189
True or False: Sensory information is invested with emotional significance in association areas in the frontal lobes and limbic system.
True
190
What is the largest muscle in the lower leg?
gastrocnemius
191
True or False: If a graded potential on a dendrite results in a 5mV depolarization, the depolarization at the axon hillock of the axon might be less than 5mV.
True
192
Select all of the following which are gray matter structures within the spinal cord
Gray commissure + Dorsal, Ventral, and Lateral horns
193
Which of the following is unique to the muscles of facial expression?
They insert into the skin.
194
Which layer of the meninges surrounds and supports the sinuses that form the route through which blood drains from the CNS?
dura mater
195
True or False: Afferent is a term that is synonymous with motor
FALSE
196
(In membrane potential) What event happens at the point labeled 3?
Voltage-gated sodium channels are opening in a positive feedback loop known as depolarization
197
Which of the following structures can be classified as presynaptic?
Neurons
198
Which is incorrect for Flexion and Crossed Extensor Reflexes
Noxious/painful stimuli must be received from both limbs results in both excitatory and inhibitory signals on BOTH sides of the spinal cord
199
In which dural septum would you expect to find the superior sagittal sinus
Falx cerebri
200
What type of receptor requires an effector protein to initiate a signal?
metabotropic receptor
201
Which of the following structures would send motor information to glands?
Lateral horn
202
Which is TRUE about the Na+, K+ ATPase (sodium-potassium) pump in neurons?
It generates a small electrical potential such that the inside is made negative with respect to the outside.
203
Which of the following is not a muscle of the rotator cuff
Teres major
204
How is the strength of a stimulus encoded by neurons?
By the frequency of action potentials
205
True or False: Ligand gated channels will open in response to a change in voltage.
FALSE
206
Which of the following structures (lobes) is primarily responsible for processing olfactory information?
Temporal lobe
207
Where is the inferior oblique muscle located?
in the eye socket
208
Select all of the following which are white matter structures within the spinal cord
Ventral, Dorsal, and Lateral column
209
From which meningeal layer would you attempt to withdraw cerebrospinal fluid circulating around the spinal cord?
Arachnoid mater
210
All ionotropic receptors:
Directly allow the movement of ions across the cell membrane
211
Which part of a neuron transmits an electrical signal to a target cell?
axon
212
True or False: Electrical synapses can send transmissions in both directions.
True
213
True or False: GABA is a neurotransmitter which generally has inhibitory activity.
True
214
Spinal nerves exit from which landmark of the vertebral column?
Intervertebral foramen
215
The large muscle group that attaches the leg to the pelvic girdle and produces extension of the hip joint is the ________ group.
gluteal
216
What ion enters a neuron causing depolarization of the cell membrane?
sodium
217
Which of the following structures is primarily responsible for initiating the movement of skeletal muscle?
Precentral gyrus
218
Which of these locations is where the greatest level of integration is taking place in the example of testing the temperature of the shower?
cerebral cortex
219
When you eat a spicy pepper, such as a jalepeño, why do you perceive heat in your mouth?
A chemical within the jalepeño acts as a stimulus for thermoreceptors.
220
At which point does the spinal cord typically end?
L1-L2
221
True or False: Generally speaking, all nicotinic receptors illicit an excitatory response on the presynaptic neuron
FALSE
222
(In membrane potential) What event happens at the point labeled 5?
Voltage-gated potassium channels are open and repolarizing the membrane
223
Which structure provides longitudinal stabilization of the spinal cord?
Coccygeal ligament
224
Which structure predominates in the white matter of the brain?
myelinated axons
225
Which of the following structures (lobes) is primarily responsible for processing somatosensory information?
Parietal lobe
226
What type of cellular junctions would you expect to find in electrical synapses?
Gap junctions
227
True or False: Ligand gated channels will open in response to the binding of a neurotransmitter.
True
228
True or False: Excitatory post-synaptic potentials must be depolarizing graded potentials.
True
229
True or False: Motor information travels in descending tracts in the spinal cord
True
230
What type of reflex can protect the foot when a painful stimulus is sensed?
withdrawal reflex
231
What does a mechanically gated channel respond to?
physical stimulus
232
A postsynaptic neuron has three presynaptic inputs—from neurons X, Y, and Z.
- Stimulation of neuron X causes the postsynaptic neuron to depolarize by 0.5 mV.
- When X and Y are stimulated simultaneously, the postsynaptic neuron depolarizes by 1 mV.
- When X and Z are stimulated simultaneously,there is no change in the membrane potential of the postsynaptic neuron.
What is most likely true about presynaptic neurons Y and Z?
Y is excitatory and Z is inhibitory.
233
True or False: The pelvic diaphragm is a set of muscles which divide the thoracic and abdominopelvic cavities
FALSE
234
Which is most directly responsible for the falling (repolarizing) phase of the action potential?
The permeability to K + increases greatly while permeability to Na + decreases.
235
True or False: Continuous conduction requires myelin sheath gaps for transmission
FALSE
236
What is the linea alba?
a long tendon that runs down the middle of the rectus abdominis
237
Which region of the frontal lobe is responsible for initiating movement by directly connecting to cranial and spinal motor neurons?
primary motor cortex
238
Which describes the response of the voltage-gated channels when an axon is stimulated to threshold?
Na + channels are activated and then inactivated.
239
Where is the temporalis muscle located?
on the side of the head
240
True or False: Generally speaking, serotonin is excitatory in sensory pathways
FALSE
241
Which of the following structures is primarily responsible for somatosensation?
Postcentral gyrus
242
Inverse agonists are chemicals which:
Binds to the same receptors as a neurotransmitter and has the opposite effect
243
What specialized structure of the arachnoid mater allows cerebrospinal fluid to flow around structures of the central nervous system
Subarachnoid space
244
Which muscles stabilize the pectoral girdle?
axial and scapular
245
Which muscle originates on the spinous process of vertebrae and extends the vertebral column?
Interpinales
246
What is the origin of the wrist flexors?
the medial epicondyle of the humerus
247
True or False: Saltatory conduction requires myelin sheath gaps for transmission?
True
248
Which is the only meningeal layer in direct contact with the structures of the central nervous system
Pia mater
249
Which of the following receptor types would detect stimuli resulting from vibration?
Mechanoreceptor
250
Which location on the body has the largest region of somatosensory cortex representing it, according to the sensory homunculus?
lips
251
Which of the following structures would receive sensory information from the dorsal root
Dorsal horn
252
Which of the following neuron shapes would you expect to be associated with motor impulses
Multipolar
253
Which lobe of the cerebral cortex is responsible for generating motor commands?
frontal
254
True or False: Chemical synapses can send transmission in both directions.
FALSE
255
You are drinking hot chocolate on a cold morning. Which of the following receptors will detect the temperature of the beverage?
Thermoreceptors
256
True or False: Your fingertips are highly sensitive, yet geographically small areas of your body. You expect the area of the somatosensory cortex that receives afferent stimuli from them to be quite small as well.
FALSE
257
Which of the following structures is primarily responsible for speech?
Broca's area
258
Which of the following neuron shapes would you expect to be associated with vision
Bipolar
259
Which muscle abducts and medially rotates the femur?
Gluteus medius
260
Select all that apply:
Cholinergic systems are characterized as having:
- Nicotinic receptors
- Muscarinic receptors
- Acetylcholine as a neurotransmitter
- Acetylcholinesterase
261
The conversion of graded potentials to action potentials requires which of the following processes (select all that apply)
- Opening of ligand-gated CATION channels
- A strong enough stimulus to cause the axon hillock to sum the DEPOLARIZING graded potentials to reach threshold
