by htyrey


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Most physiological control systems are
negative feedback systems
The Na+/K+ ATPase uses energy to move Na+ ions ____ the cell and K+ ions ___ the cell.
out of; into
The normal flow of information in mammalian neurons is
dendrites, soma, axon.
An ion X+ is distributed across the cell membrane in such a way the Ex+ = -85 mV.  Vr in this cell is - 80 mV.  If we increase gx+, there will be a net movement of X+ ____ the cell and Vm will become _____.
out of; more negative
The voltage gated Na+ channels that open during the action potential are inactivated by
depolarization of the cell membrane.
Making the axonal membrane thicker with myelin _____ the capacitance of the axonal membrane in the myelinated portions and increases the conductino velocity of the axon.
decreases
Most synapses in mammals utilize
chemical transmission of information
If we could stimulate a mechanoreceptor chemically, the conscious perception of the stimulus by the animal would be
mechanical
A postsynaptic cell receives inputs from two different presynaptic cells.  This is an example of ____.  Activation of either presynaptic input alone produces a subthreshold EPSP in the postsynaptic cell.  However, when both presynaptic inputs are activated at the same time, the postsynaptic cell reaches threshold and an action potential results.  This is an example of ____ summation.
convergence; spatial
If you give a normal animal an IV injection of a muscarinic cholinergic antagonist such as atropine, you would expect to see an increase in heart rate.  This would indicate that before the atropine injection, there was ongoing ____ nerve activity directed at the heart.
parasympathetic
In a normal skeletal muscle cell, Cl- permeability (gcl-) is quite high at rest.  In addition, the equilibrium potential for Cl- (Ecl-) is more negative than Vr.  If we decrease gcl-, the muscle cell will be ___ excitable, and Vm will be ______.
more; depolarized
The axons of alpha motor neurons (i.e. the final common pathway for motor activity) exit the spinal cord in the ____.
ventral roots
In a typical neuron, the voltage difference across the cell membrane ____ movement of K+ ions into the cell.
favors
The adrenal medulla releases more _____.
epinephrine
If you block voltage gated K+ chennels with tetraethylammonium, you will alter the ______ phase of the action potential.
repolarization
In a myelinated axon, ions are exchanged btwn the extracellular fluid and the intraxonal fluid only in the _____ portions of the axon.
unmyelinated
An action potential reaches the presynaptic terminal.  If we block Ca++ entry into the terminal, the size of the postsynaptic response would ____.
decrease
If stimulation of a sensory receptor by its adequate stimulus results in a decrease in gna+, the resulting receptor potential will be a _____.
hyperpolarization
In testing the stretch (i.e. myotatic) reflex in a muscle, increasing the amount of stretch will ____ the size of the receptor potential in the stretch receptor.
increase
An animal will be confronted with situations that require increases and decreases in heart rate.  From our class discussion, an animal could increase heart rate by ____ sympathetic activity or by _____ parasympathetic activity.
increasing, decreasing
If an ion X+ is actively pumped against its concentration gradient, increasing the activity of the pump will ____ the difference btwn Ex+ and Vm.
increase
Reuptake of norepinephrine after release by sympathetic nerves is an important part of sympathetic neurotransmission.  If we block reuptake of norepinephrine, we would expect to blood vessels to be more ____ than before blockade.
constricted
A dog is brought to your clinic because of a general lack of muscle coordination.  As part of you examination, you measure the conduction velocity in a peripheral nerve.  The distance btwn your stimulating and recording electrodes is 2 meters (it's a big animal).  You find that the latency to the first peak in the recorded compound action potential is 0.02 sec.  The conduction velocity of the nerve fibers responsible for this first peak is approximately ____.  This conduction velocity indicates that this first peak is due to firing in ____ fibers.
100 meters/sec; myelinated
Local anesthetics like lidocaine block nerve conduction by blocking entry of ___ ions into the axon.  They do this by blocking ____ channels.
Na+; voltage gated
Blockade of breakdown of acetylcholine with an acetylcholinesterase inhibitor such as phyosostigmine (e.g. as in treatment of myesthenia gravis) would ____ its postsynaptic effects.
prolong
The effects of parasympathetic stimulation on cardiac muscle are mediated via cholinergic _____ receptors.
muscarinic
What two types of muscle are affected by the efferent limbs of the arterial baroreflex?
smooth and cardiac muscle
Neurons that modulate inputs and outputs w/in a nucleus in the central nervous system and do not project out of or into that nucleus are called ____
interneurons
One difference btwn chemical and electrical synaptic transmission is _____
electric is faster ( no delay)
A decrease in the amplitude of a receptor potential during a sustained stimulus is referred to as _____.
adaptation
We have discussed one example of a point of communication btwn two excitable cells where summation of presynaptic inputs is not required for a postsynaptic response.  What is the one example we discussed where one presynaptic action potential will normally produce one postsynaptic action potential?
neuromuscular junction
Mammalian sensory pathways all follow a common plan.  For example, they all involve a sensory receptor.  What is another one of the elements common to all sensory pathways?
What is one difference btwn somatic and autonomic reflexes?
somatic = 1 efferent fiber cell
autonomic = 2 efferent fiber cells
A receptor protein that is not directly coupled to a channel may still open or close that channel via generation of a _____.
secondary messenger
In addition to neurons, there are other types of cells in the central nervous system.  One of these is _____.
astrocytes
Membrane channels that allow ions to cross the cell membrane:
may be opened by other ions, may be opened by mechanical forces, and may be opened by a chemical or ligand
The following statement about the sensory or afferent limb of the myotatic reflex is true:
activation of this afferent limb results in muscle contraction
In a typical neuron at rest:
Ek+ is more negative than Vr
During a neuronal action potential:
voltage gated K+ channels open and the inside of the cell transiently becomes positive
Which of the following sequences related to synaptic transmission is in the correct order? (note: steps may be missing and the order can still be correct)
Presynaptic action potential, Ca++ entry, transmitter release

Presynaptic change in gion, transmitter release, postsynaptic change in gion.
Receptor potentials are
graded with the size of the sensory stimulus
The receptor for gamma aminobutyric acid (GABA):
can be affected by other drugs like benzodiazepines.
The following change would be characteristic of increased sympathetic discharge:
increased heart rate
The following is a difference btwn the action potential on one hand and synaptic and receptor potentials on the other:
the action potential has a refractory period
In a normal neuron, if a neurotransmitter binds with a receptor that opens a channel selective for Cl- ions:
Vm will become more negative (i.e. be hyperpolarized)
Considering the myotatic reflex arc (i.e. the stretch reflex), if a muscle is stretched:
we would expect to see action potentials in the afferent neurons.
The following cells release acetylcholine (ACh) as their neurotransmitter:
alpha motor neurons, preganglionic parasympathetic neurons, preganglionic sympathetic neurons
The concentration of Na+ ions is greater than that for K+ ions ____ the cell.
outside
The two most numerous chemical compounds of cell membranes are ____ and _____.
proteins and phospholipids
In a typical neuron, the dendrites represent the ___ side of the cell.
input
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