EXAM 1-BP
Pok is measuring the resting potential of neurons. Approximately what should she measure as the resting potential?
-70 millivolts
What does the all-or-none law state?
All action potentials have same amplitude and velocity
Which type of glia release chemicals that modify the activity of neighboring neurons?
Astrocytes
When do sodium channels close?
At the peak of the AP
When an action potential reaches the end of an axon, the depolarization causes what ionic movement in the presynaptic cell?
Ca into the cell
Action potentials are produced in the dendrites of neurons (T or F)
False
Each neuron releases one and only one NT
False
Schwann cells produce the myelin sheath in the central nervous system, and oligodendrocytes do so in the periphery (T or F)
False
Which of the following cranial nerves plays a role in the sensation of taste?
Glossopharyngeal
What occurs when a stimulus shifts the potential inside a neuron from the resting potential to a more negative potential?
Hyperpolarization
What ordinarily prevents extensor muscles from contracting at the same time as flexor muscles?
Inhibitory synapses in the spinal cord
Glutamate opens sodium gates, enabling sodium ions to enter the postsynaptic cell. What type of effect is this?
Ionotropic
What is the function of the enzyme acetylcholinesterase?
It breaks acetylcholine down into components for recycling.
What is the importance of the myelin sheath?
It speeds up the AP down the length of the axon
Which type of glia remove waste material in the NS?
Microglia
What is the primary neurotransmitter of the sympathetic nervous system?
Norepinephrine
Increased permeability to which type of ion would most likely result in an IPSP?
Potassium
Which structure provides the main source of input to the cerebral cortex?
Thalamus
Which statement correctly described how the concentration and electrical gradients act on potassium when the neuron is at rest?
The concentration gradient moves potassium out, and the electrical gradient moves it in.
Which statement correctly described how the concentration and electrical gradients act on sodium when the neuron is at rest?
The concentration gradient moves sodium in, and the electrical gradient moves it in
Sherrington deduced that transmission at a synapse must be slower than conduction along an axon. This was based on what kind of evidence?
The speed of reflexive responses
What happens to voltage-gated channels when the membrane is depolarized?
They open
After one frog's heart has been stimulated to increase its rate, an extract of fluid from that heart can make a second frog's heart beat faster. What conclusion did Otto Loewi draw from these results?
Transmission at synapses is a chemical event
Whether or not a neurotransmitter is excitatory depends on the response of the postsynaptic receptor (T or F)
True
Dr. O'Reilly is trying to produce hyperpolarization in neurons. What should she do?
Use a microelectrode to apply a negative charge
Damage to the basal ganglia would most likely result in ____.
a movement disorder
Which statement about autoreceptors is accurate?
activated autoreceptors decrease neurotransmitter release
Before the action potential is initiated, when the neuron is at rest, sodium channels ____.
are closed and dont allow sodium to pass through
"Second messengers" carry their messages to ____.
areas within the postsynaptic cell
Terrance went to the dentist and was given some Novocain. This prevented him from feeling pain because the drug ____.
attached to sodium channels, blocking sodium from entering and stopping the action potential from sending a pain message
As a general rule, axons convey information ______.
away from their own cell body
"Transporter" proteins transport neurotransmitters ____.
back into presynaptic neuron
What mechanism prevents or slows some chemicals from entering the brain, while allowing others to enter?
blood-brain barrier
What do temporal summation and spatial summation have in common?
both enable a reflex to occur in response to weak stimuli.
The central nervous system is made up of _____.
brain and spinal cord
What determines whether a neuron has an action potential?
combines effects of EPSPs and IPSPs
A hormone is a chemical that is____.
conveyed by the blood to other organs, whose activity it influences
The net effect of each cycle of the sodium-potassium pump is to ____.
decrease the number of positively charged ions within the cell
Neuropeptides differ from other neurotransmitters in that they are mostly released from _____.
dendrites
The tree-like branches of a neuron that receive information from other neurons are called _____.
dendrites
The concentration gradient refers to the _____.
difference in distribution for various ions between the inside and outside of the membrane
If you were to accidentally touch a hot stove with your hand, you would quickly pull your hand away. The information carried to the muscles in your arm to make them contract was carried by ____.
efferent neurons
If Geri had disruptions to her limbic system, she would likely have problems with _____.
emotional behaviors
A neuron excretes neurotransmitters through its membrane by a process called ____.
exocytosis
Most of the brain's excitatory ionotropic synapses release ____ .
glutamate
If the prefrontal cortex is damaged, an individual may ____.
have difficulty remembering where they just placed the keys
An individual has difficulty remembering certain things after brain damage, but all memories stored before the damage are intact. The brain area most likely damaged is the ____.
hippocampus
The role of the pituitary gland is to make and release ______.
hormones into the bloodstream
Releasing hormones are synthesized in the
hypothalamus
People with damage of the parietal cortex tend to have trouble ____.
locating objects in space
An important difference between ionotropic and metabotropic effects is that _____.
metabotropic effects are slower and longer lasting
In which area of the brain would one find the tectum, tegmentum, superior and inferior colliculi, and substantia nigra?
midbrain
Damage to any hypothalamic nucleus leads to abnormalities in _____.
motivated behaviors
Santiago Ramon y Cajal demonstrated that _____.
neurons are separate from one another
In myelinated axons, the action potential starts at the first ____.
node of ranvier
When the potential across a membrane reaches threshold, the sodium channels ____.
open to let sodium enter the cell rapidly
temporal summation and spatial summation _____.
ordinarily occur together
Together, the somatic nervous system and the autonomic nervous system make up the ____.
peripheral NS
The membrane of a neuron is composed of ____.
phospholipids with embedded proteins
What provides the building blocks for synthesizing nearly all neurotransmitters?
proteins found in the diet
The primary feature of a neuron that prevents the action potential from traveling back from where it just passed is the ____.
refractory period
After damage to the dorsal roots of the spinal cord, an individual will suffer what kind of loss?
sensation from the affected body area
What is the proper order of neurons in the reflex arc, from first to last?
sensory neuron, interneuron, motor neuron
Hormones exert their effects ____.
similarly to metabotropic neurotransmitters
Most of the neuron's metabolic work occurs in the _____.
soma
Desirae touched a plate, and it was hot. Which part of her nervous system conveyed this sensory information?
somatic
Karissa is in the lab working and was able to produce a reflexive response by stimulating several different locations all at one time. She successfully demonstrated ______.
spatial summation
You are walking after dark when a sudden noise frightens you. Your heart pounds, your pulse races, and your breathing rate increases. These responses are due to your ____.
sympathetic NS
The sweat glands, adrenal glands, and muscles that constrict blood vessels have input from only the ____.
sympathetic nervous system
Dr. Andrus has demonstrated that a certain reflex doesn't occur in response to a single stimulus but will occur if multiple stimuli are presented in rapid succession. What has Dr. Andrus demonstrated?
temporal summation
Kimiko has been diagnosed with cortical blindness. She has had damage to _____.
the occipital cortex
Acetylcholine is the only neurotransmitter released by ___.
the parasympathetic nervous system's postganglionic axons
After the peak of an action potential, what prevents sodium ions from continuing to enter the cell?
the sodium gates in the membrane close.
A membrane produces an action potential whenever the potential across it reaches what level?
the threshold of excitation
What do the corpus callosum and anterior commissure have in common?
they both connect the 2 hemispheres
Which statement is true of EPSPs?
they decay over time and space.
How do EPSPs affect the firing rate of neurons?
they increase it above the spontaneous firing rate
The resting potential of a neuron is the ____.
total amount of negative charge inside the neuron relative to the outside
Why is the speed of conduction through a reflex arc slower than the speed of conduction of an action potential along an axon?
transmission between neurons at synapses is slower than transmission along axons
Prior to their release, NTs are typically stored in ____.
vesicles in the presynaptic neuron