Med Physiology- Chapter 6
Acetylcholine (ACh) is ______. a) a neurotransmitter b) an enzyme that breaks down neurotransmitters at synapses c) released onto skeletal muscle cells by motor neurons d) released by neurons within the brain
-a neurotransmitter -released onto skeletal muscle cells by motor neurons -released by neurons within the brain
The following statements relate to movement of ions during an action potential. Which are true? --With repeated action potentials, concentration gradients for Na+ and K+ would eventually dissipate without the action of the Na+/K+-ATPase pump. --The number of ions that cross the membrane during an action potential is extremely large compared to the total number of ions in a cell. --Blocking the action of the Na+/K+-ATPase pump would immediately stop the ability to produce action potentials. --The number of ions that cross the membrane during an action potential is extremely small compared to the total number of ions in a cell.
--With repeated action potentials, concentration gradients for Na+ and K+ would eventually dissipate without the action of the Na+/K+-ATPase pump. --The number of ions that cross the membrane during an action potential is extremely small compared to the total number of ions in a cell.
Which of the following are purines that are co-released from neurons and act as neuromodulators? -ATP -Nitric oxide -Glutamate -Adenosine -Serotonin
-ATP -Adenosine
Which of the following are proposed functions of astrocytes? -Stimulate the production of cerebral spinal fluid -Insulate axons to increase conduction speed -Absorption of K+ from the extracellular fluid -Stimulate the formation of tight junctions between the cells that constitute the blood-brain barrier
-Absorption of K+ from the extracellular fluid -Stimulate the formation of tight junctions between the cells that constitute the blood-brain barrier
Which of the following are classified as neuropeptide neurotransmitters/neuromodulators? -Beta-endorphin -Dynorphin -Glutamate -Enkephalin -Nitric oxide
-Beta-endorphin -Dynorphin -Enkephalin
What are the two major divisions of the forebrain? -Cerebrum -Pons -Medulla oblongata -Diencephalon -Cerebellum
-Cerebrum -Diencephalon
Which of the following are layers of the meningeal membrane? -Dura mater -Whatza mater -Pia mater -Choroid mater -Arachnoid mater -Hydroid mater
-Dura mater -Pia mater -Arachnoid mater
Which of the following may be attributed to the effects of endogenous opioids? -Eating and drinking behavior -Erection of genital tissues -Excitotoxicity -Parkinson's disease -Pain relief
-Eating and drinking behavior -Pain relief
Removal of neurotransmitters from synapses occurs by which of the following mechanisms? -Enzymatic transformation into inactive substances -Active transport into nearby cells, such as glial cells -Active transport back into the presynaptic terminal -Diffusion through channels into the postsynaptic cell -Diffusion away from the synapse
-Enzymatic transformation into inactive substances -Active transport into nearby cells, such as glial cells -Active transport back into the presynaptic terminal -Diffusion away from the synapse
Which of the following are categorized as amino acid neurotransmitters? -Glutamate -Glycine -Leucine -Norepinephrine -Gamma-aminobutyric acid (GABA)
-Glutamate -Glycine -Gamma-aminobutyric acid (GABA)
Which of the following statements about norepinephrine are true? -It is a biogenic amine. -It is a neurotransmitter. -It is an amino acid. -It is a neuropeptide. -It is a catecholamine.
-It is a biogenic amine. -It is a neurotransmitter. -It is a catecholamine.
Which three are TRUE about dopamine? -It is derived from the amino acid glutamate. -It is a neurotransmitter. -It is a monoamine. -It is a catecholamine.
-It is a neurotransmitter. -It is a monoamine. -It is a catecholamine.
Which 3 of the following are true about action potential conduction in myelinated axons? -Propagation slows and amplitude decreases with distance along the length of the axon. -It is called called saltatory conduction. -Propagation occurs without a decrease in action potential size. -It is faster than in unmyelinated axons.
-It is called called saltatory conduction. -Propagation occurs without a decrease in action potential size. -It is faster than in unmyelinated axons.
Which of the options are correctly identified as lipid neurotransmitters? -Glutamate -Leukotrienes -Prostaglandins -Thromboxanes -Serotonin -Endocannabinoids
-Leukotrienes -Prostaglandins -Thromboxanes -Endocannabinoids
Velocity of action potential propagation is determined by which of the following? -Myelination -Absolute refractory period -Stimulus size -Axon diameter
-Myelination -Axon diameter
Which of the following are receptors for the neurotransmitter glutamate? -5-hydroxytryptamine-2A (5-HT2A) -Para-amino benzoic acid (PABA) -Alpha-adrenergic -N-methyl-D-aspartate (NMDA) -Alpha-amino-3 hydroxy-5 methyl-4 isoxazolepropionic acid (AMPA) -Nicotinic cholinergic
-N-methyl-D-aspartate (NMDA) -Alpha-amino-3 hydroxy-5 methyl-4 isoxazolepropionic acid (AMPA)
Which of the following are types of acetylcholine receptors? -Nicotinic -Androgenic -Muscarinic -Parthenogenic -Pathogenic
-Nicotinic -Muscarinic
Which of the following are catecholamines? -Serotonin -Norepinephrine -Acetylcholine -Dopamine
-Norepinephrine -Dopamine
Which of these are the main hormones secreted by the adrenal medulla? -Norepinephrine -Epinephrine -Estradiol -Aldosterone -Acetylcholine
-Norepinephrine -Epinephrine
What are the two major subdivisions of the efferent autonomic nervous system? -Parasympathetic -Somatic -Empathetic -Sympathetic -Sensory
-Parasympathetic -Sympathetic
Which ion species are in higher concentration in the cytosol of neurons than in the extracellular fluid? -Ca2+ -Phosphate ions -Cl- -Na+ -K+
-Phosphate ions -K+
The hindbrain develops into these three major parts. -Pons -Medulla oblongata -Melamine -Cerebellum -Diencephalon -Cerebrum
-Pons -Medulla oblongata -Cerebellum
Which are TRUE about the anatomy of efferent autonomic pathways of the autonomic nervous system? -Postganglionic neurons originating in ganglia in the PNS synapse onto smooth muscle, cardiac and gland cells. -Preganglionic neurons originating in the CNS synapse onto postganglionic neurons in a ganglion in the PNS. -Preganglionic neurons originating in the PNS synapse onto postganglionic neurons at ganglia in the CNS. -Postganglionic neurons originating in the CNS synapse onto preganglionic neurons at ganglia in the PNS.
-Postganglionic neurons originating in ganglia in the PNS synapse onto smooth muscle, cardiac and gland cells. -Preganglionic neurons originating in the CNS synapse onto postganglionic neurons in a ganglion in the PNS.
Action potentials tend to travel in only one direction along an axon for which two reasons? -Voltage-gated Na+ channels only allow one-way flow of ions--into the cell. -Ion channels are positioned at an angle in the membrane, which only directs positive current away from the axon hillock. -They begin propagating at one end of an axon, and not in the middle -Refractoriness of the region of membrane where an action potential has just occurred prevents a propagating action potential from reversing direction
-They begin propagating at one end of an axon, and not in the middle -Refractoriness of the region of membrane where an action potential has just occurred prevents a propagating action potential from reversing direction
Neurotransmitters do not stay bound to receptors indefinitely; instead, they ______. -are transported back into the presynaptic cell via reuptake -diffuse away from the synapse -are bound to carrier proteins and flushed from the synaptic cleft into the circulation for disposal -are broken down into component parts by enzymes
-are transported back into the presynaptic cell via reuptake -diffuse away from the synapse -are broken down into component parts by enzymes
A subthreshold stimulus to a neuron ______. -depolarizes the local membrane potential briefly before it returns to the resting potential -hyperpolarizes the membrane potential of the axon thus activating only a few voltage-gated ion channels -does not generate an action potential -generates a weak action potential
-depolarizes the local membrane potential briefly before it returns to the resting potential -does not generate an action potential
Which of the following neurotransmitters are categorized as biogenic amines? -dopamine -histamine -Gamma-amino butyric acid (GABA) -acetylcholine -glutamate -norepinephrine -serotonin
-dopamine -histamine -norepinephrine -serotonin
Chemical synapses ______. -have a synaptic cleft between pre- and postsynaptic cells -may contain more than one transmitter at a time -transmit local current resulting from action potentials through gap junctions directly into the next cell -use neurotransmitters released by the presynaptic cell to transmit signals to the postsynaptic cell
-have a synaptic cleft between pre- and postsynaptic cells -may contain more than one transmitter at a time -use neurotransmitters released by the presynaptic cell to transmit signals to the postsynaptic cell
Click on three of the following structures that are important interconnected structures that are part of the limbic system. -cerebellum -hypothalamus -pons -hippocampus -thalamus -medulla oblongata
-hypothalamus -hippocampus -thalamus
The four lobes that make up the cerebral hemispheres are the ________, ______, ______, and ______. -ear lobe -occipital lobe -pyramidal lobe -occidental lobe -frontal lobe -temporal lobe -parietal lobe
-occipital lobe -frontal lobe -temporal lobe -parietal lobe
Fibers from the cerebellum connect directly or indirectly with the ______, ______, and the ______. -primary motor cortex. -corpus callosum. -pons and spinal cord. -reticular formation.
-primary motor cortex. -pons and spinal cord. -reticular formation.
Electrical synapses ______. -conduct the signal to the next cell via neurotransmitters released into the junction between cells -exist only between brain cells in the human body -conduct an action potential directly between cells via connecting gap junctions -transmit signals faster than chemical synapses
-transmit signals faster than chemical synapses -conduct the signal to the next cell via neurotransmitters released into the junction between cells
Neurotransmitters categorized as ______ include dopamine, norepinephrine, serotonin, and histamine. a) purines b) biogenic amines c) catecholamines d) gases e) neuropeptides
b) biogenic amines
The ______ receptors are the targets of tetrahydrocannabinol (THC). a) serotonergic b) dopaminergic c) cholinergic d) adrenergic e) cannabinoid
e) cannabinoid
Neurotransmitters categorized as ______ include dopamine, norepinephrine, serotonin, and histamine. a) purines b) biogenic amines c) neuropeptides d) catecholamines e) gases
b) biogenic amines
When some glutamate synapses are stimulated repeatedly, presynaptic and postsynaptic mechanisms are altered so that subsequent presynaptic action potentials result in larger excitatory postsynaptic potentials. This phenomenon is called ______. a) long term potentiation b) synaptic integration c) long term depression d) synaptic amplification e) synaptic inhibition
a) long term potentiation
______ are purines that are sometimes co-released with one or more neurotransmitters at synapses, and act mainly as neuromodulators. a) ATP and adenosine b) Endorphin and enkephalin c) Nitric oxide and hydrogen sulfide d) GABA and glycine
a) ATP and adenosine
By convention, when describing a cell's membrane potential the ______ of the cell is assigned a value of zero, and the voltage is defined as the positive or negative charge on the ______ of the cell. a) outside; inside b) nucleus; cytoplasm c) inside; outside d) cytoplasm; cytosol
a) outside; inside
The permeability of a resting plasma membrane is greater for ______ than it is for ______; therefore, a net negative membrane potential develops. a) potassium; sodium b) sodium; potassium c) sodium; chloride
a) potassium; sodium
______ is the extracellular liquid that circulates through brain ventricles, the spinal canal, and the subarachnoid space. a) Cerebrospinal fluid b) Plasma c) Meningococcal fluid d) Menstrual fluid e) Braniocranial fluid
a) Cerebrospinal fluid
What type of channels in the postsynaptic membrane open when neurotransmitters bind to them? a) Ligand-gated channels b) Leak channels c) Mechanically gated channels d) Gap junctions e)Voltage-gated channels
a) Ligand-gated channels
The predominant ions in the extracellular fluid are ______, and the predominant ions in the intracellular fluid are ______. a) Na+ and Cl-; K+ and phosphate compounds b) K+ and phosphate compounds; Na+ and Cl- c) Na+ and K+; Cl- and phosphate compounds d) K+ and Mg2+; Na+ and Ca2+ e) Na+ and Ca2+; K+ and Mg2+
a) Na+ and Cl-; K+ and phosphate compounds
True or false: Action potentials in neurons are very brief events, and may repeat at high frequencies-up to several hundred per second. a) True b) False
a) True
True or false: Graded potentials can either depolarize or hyperpolarize the membrane potential. a) True b) False
a) True
True or false: In most cells, the Na+/K+-ATPase pump makes a small electrogenic contribution to creating the negative resting membrane potential. a) True b) False
a) True
True or false: Many EPSPs occurring in a short period of time are generally required to initiate an action potential in a postsynaptic neuron. a) True b) False
a) True
True or false: Most cells have resting membrane potentials that are negative on the inside compared to the outside. a) True b) False
a) True
True or false: The length of the refractory periods limit the number of action potentials an excitable membrane can produce in a given period of time. a) True b) False
a) True
An IPSP is ______. a) a graded potential in a postsynaptic cell that decreases the likelihood that the cell will reach the threshold for an action potential b) a graded potential in a presynaptic cell that decreases Ca2+ entry and decreases the release of excitatory neurotransmitter c) a graded potential in a presynaptic cell that decreases Ca2+ entry and decreases the release of inhibitory neurotransmitter
a) a graded potential in a postsynaptic cell that decreases the likelihood that the cell will reach the threshold for an action potential
The neurotransmitter used by somatic motor neurons is ______ and the effect on muscles is ______. a) acetylcholine; always excitatory b) norepinephrine; always excitatory c) norepinephrine; always inhibitory d) acetylcholine; sometimes excitatory and sometimes inhibitory e) acetylcholine; always inhibitory
a) acetylcholine; always excitatory
The glial cells that promote the formation of the blood-brain barrier are the ______. a) astrocytes b) Schwann cells c) ependymal cells d) oligodendrocytes
a) astrocytes
The ______ is like the cerebrum in that it consists of paired hemispheres with an outer layer of cortical cells and several deeper cell clusters. It does not initiate motor movements, but is an important center for coordinating movements and for coordinating posture and balance. a) cerebellum b) thalamus c) hypothalamus d) pons e) medulla oblongata
a) cerebellum
The function of interneurons is to ______. a) connect neurons within the CNS b) convey information towards the CNS c) convey information away from the CNS d) combine neurons within the PNS
a) connect neurons within the CNS
When a region of brain cells die and excessive glutamate is released, it can over-activate NMDA receptors of nearby cells, causing them to die also, in a spreading wave of damage. This phenomenon is called ______. a) excitotoxicity b) confabulation c) hyperpolarization d) suprathreshold stimuli e) tetanus toxin
a) excitotoxicity
The primary neurotransmitter at an estimated 50% of excitatory synapses in the CNS is ______. a) glutamate b) norepinephrine c) glycine d) gamma-aminobutyric acid (GABA) e) N-methyl-D-aspartate (NMDA)
a) glutamate
The portion of the diencephalon responsible for homeostatic regulation of the internal environment and for behaviors having to do with preservation of the individual (such as eating, drinking, and so on), is called the ______. a) hypothalamus b) mammillary body c) epithalamus d) thalamus
a) hypothalamus
Ganglia in sympathetic autonomic pathways are found ______; parasympathetic pathway ganglia are found ______. a) in two chains close to the spinal column; within or close to target organs b) within or close to target organs; in two chains close to the spinal column c) in the dorsal root of spinal nerves; in two chains close to the spinal column d) within or close to target organs; in the dorsal root of spinal nerves e) in the dorsal root of spinal nerves; within or close to target organs
a) in two chains close to the spinal column; within or close to target organs
The membrane potential of a postsynaptic neuron is either driven farther from threshold (hyperpolarized) or stabilized at its resting potential at an ______. a) inhibitory synapse b) excitatory synapse
a) inhibitory synapse
The resting membrane potential of body cells ______. a) is negative, with values varying from -5 to -100 mV b) is negative, with values varying from -100 to -200 mV c) is positive, with values varying from 100 to 200 mV d) is positive, with values varying from 5 to 100 mV
a) is negative, with values varying from -5 to -100 mV
Describing an action potential as "all-or-none" means that ______. a) stimuli are either suprathreshold (action potential occurs) or subthreshold (no action potential); action potentials are not graded b) if stimuli are gradually increased in size, action potentials gradually become larger in amplitude; action potentials are graded c) once an action potential begins, it will not propagate "all the way" to the end of the neuron's axon d) a second action potential cannot be generated during the time when Na+Na+ channels are inactivated from a previous action potential
a) stimuli are either suprathreshold (action potential occurs) or subthreshold (no action potential); action potentials are not graded
During the absolute refractory period of a neuronal membrane ______. a) the axon cannot undergo a second action potential, no matter how strongly it is stimulated b) All voltage-gated Na+ and K+ channels are absolutely closed c) is the only time during an action potential that the membrane potential is actually negative to its resting value d) a second action potential can be initiated, but only if a very strong stimulus is applied
a) the axon cannot undergo a second action potential, no matter how strongly it is stimulated
Limitations on the maximum action potential firing frequency of neurons are determined by ______. a) the length of the refractory periods b) the presence of myelination c) the amplitude of the action potentials d) the length of the axons
a) the length of the refractory periods
Afferent neurons convey information ______ the CNS, while efferent neurons convey information ______ the CNS. a) toward; away from b) on the outside of; on the inside of c) on the inside of; on the outside of d) away from; toward
a) toward; away from
_______ are a subclass of monoamines derived from tyrosine that include dopamine, norepinephrine and epinephrine. a) Neuropeptides b) Catecholamines c) MAOI inhibitors d) Endocannabinoids
b) Catecholamines
True or false: A fundamental physical principle is that charges of the same type (such as 2 positive charges) attract each other, while charges of opposite types (positive and negative) repel each other. a) True b) False
b) False
True or false: A large number of ions are required to cause the large fluctuation in membrane potential during an action potential; without the action of the Na+/K+-ATPase pump, the concentration gradients for Na+ and K+ would be significantly altered by a single action potential. a) True b) False
b) False
True or false: If an action potential was started in the middle of an axon it could only propagate in one direction—away from the cell body. a) True b) False
b) False
True or false: The neuronal membrane is much more permeable to sodium than potassium during rest because there are more ion channels for sodium. a) True b) False
b) False
True or false: The number of anions floating freely in the bulk solution inside of excitable cells is greater than the number of cations in the bulk solution, which is why the resting membrane potential is negative. a) True b) False
b) False
True or false: Whether a synapse is excitatory or inhibitory is determined by what neurotransmitter is released from the presynaptic cell. a) True b) False
b) False
Which is generally true regarding how postsynaptic potentials initiate action potentials at synapses between neurons? a) In order for an action potential to be generated, equal numbers of EPSPs and IPSPs must be generated, so the membrane potential rises to threshold. b) Individual EPSPs are small, so initiating an action potential requires the summation of multiple excitatory inputs within a short time period. c) EPSPs are large enough that a single excitatory input to a postsynaptic cell almost always results in generation of an action potential. d) In order for an action potential to be generated, a predominance of IPSPs must be generated within a short amount of time.
b) Individual EPSPs are small, so initiating an action potential requires the summation of multiple excitatory inputs within a short time period.
What term describes the situation in which a receptor at first responds to a neurotransmitter, but over time becomes non-responsive despite the continued presence of the neurotransmitter signal? a) Receptor hypersensitization b) Receptor desensitization c) Receptor upregulation d) Auto reception
b) Receptor desensitization
Which is a true statement regarding the voltage-gated Na+ and K+ channels that mediate neuronal action potentials? a) The K+ channels have inactivation gates, but the Na+ channels do not. b) The Na+ channels have inactivation gates, but the K+ channels do not. c) Neither Na+ nor K+ channels have inactivation gates. d) Both Na+ and K+ channels have inactivation gates.
b) The Na+ channels have inactivation gates, but the K+ channels do not.
Which of the following is true about graded potentials? a) They are only generated by voltage-gated ion channels. b) The flow of charge decreases with distance. c) They are "all-or-none," meaning they are always of the same size regardless of the size of the stimulus. d) The flow of charge is propagated the entire length of the axon.
b) The flow of charge decreases with distance.
The resting membrane potential is mainly due to ______. a) negative charges on membrane proteins associated with the outer surface of the plasma membrane b) a tiny separation of charges that collect in a thin shell tight against the inner and outer surfaces of the membrane c) a much higher cation concentration in the bulk of the extracellular fluid compared to the cation concentration in the intracellular fluid d) a significantly higher anion concentration in the intracellular fluid than in the extracellular fluid
b) a tiny separation of charges that collect in a thin shell tight against the inner and outer surfaces of the membrane
Spinal nerves exiting between vertebrae of the spinal column contain ______. a) axons of motor neurons and dendrites of sensory neurons b) axons of both afferent and efferent neurons c) only axons of efferent neurons d) only axons of afferent neurons
b) axons of both afferent and efferent neurons
The contributions of Na+, K+ and Cl- to the overall membrane potential are mainly a function of their ______. a) molecular weights and relative permeabilities b) concentration gradients and relative permeabilities c) wealth and generosity d) valences and concentration gradients e) molecular weights and valences
b) concentration gradients and relative permeabilities
The ______ provides both a structural and functional connection between the cerebral hemispheres. a) longitudinal fissure b) corpus callosum c) mesencephalic aqueduct d) central sulcus
b) corpus callosum
The pituitary gland is part of the ______. a) cerebrum b) diencephalon c) cerebellum d) brainstem
b) diencephalon
The ability of cells with voltage-gated ion channels to produce electrical signals is called ______. a) conductivity b) excitability c) impedance d) extensibility e) reactivity
b) excitability
At an ______, the membrane potential of a postsynaptic neuron is brought closer to threshold (depolarized). a) inhibitory synapse b) excitatory synapse
b) excitatory synapse
The pituitary gland is located ______ to the hypothalamus and is connected to the diencephalon by a stalk called the ______. a) dorsal; mammillary body b) inferior; infundibulum c) anterior; olfactory bulb d) superior; anterior commissure
b) inferior; infundibulum
The resting membrane potential of body cells ______. a) is positive, with values varying from 100 to 200 mV b) is negative, with values varying from -5 to -100 mV c) is negative, with values varying from -100 to -200 mV d) is positive, with values varying from 5 to 100 mV
b) is negative, with values varying from -5 to -100 mV
The closing of voltage-gated K+ channels during repolarization of an action potential is an example of ______ feedback; the opening of Na+ channels during the depolarizing phase of an action potential is an example of ______ feedback. Multiple choice question. a) negative; negative b) negative; positive c) positive; negative d) positive; positive
b) negative; positive
A collection of neuron cell bodies within the central nervous system is properly referred to as a _____. a) ganglion b) nucleus c) tissue d) lobe
b) nucleus
In ______, the amount of an excitatory neurotransmitter released from an axon is decreased by the effects of another neuron synapsing near its axon terminal. a) long term synaptic modulation b) presynaptic inhibition c) long term depression d) postsynaptic inhibition
b) presynaptic inhibition
Given the following permeabilities, extracellular fluid (ECF) concentrations, and intracellular fluid (ICF) concentrations for Na+, K+ and Cl-, calculate the resting membrane potential of a hypothetical cell: ECF: [Na+] = 145 mM; [K+] = 5 mM; [Cl-] = 100 mM ICF : [Na+] = 4 mM; [K+] = 160 mM; [Cl-] = 17 mM PK+ = 1; PNa+ = 0.05; PCl- = 10 a) +90 mV b) +60 mV c) -49 mV d) -70 mV
c) -49 mV
Which best describes a neuromodulator? a) A protein that binds to vesicles within presynaptic cells, that induces vesicles to fuse with the membrane when Ca2+ concentration increases. b) A compound released from a presynaptic cell that directly opens ligand-gated channels within the synapse on the postsynaptic cell.. c) A compound that indirectly alters the effectiveness of a synapse by altering release of, or responsiveness to, a neurotransmitter.
c) A compound that indirectly alters the effectiveness of a synapse by altering release of, or responsiveness to, a neurotransmitter.
A collection of afferent and efferent neuron axons wrapped together with connective tissue in the peripheral nervous system is called a ______. a) tract b) ganglion c) neuron d) nerve
d) nerve
Which best describes the process called "repolarization?" a) A neuron's membrane potential is becoming more positive than its resting potential. b) A neuron is becoming more negative than its resting potential. c) A neuron is returning from the peak of its action potential toward its resting potential.
c) A neuron is returning from the peak of its action potential toward its resting potential.
What enzyme is responsible for the inactivation of acetylcholine at the synaptic cleft? a) ATPase b) Kinase c) Acetylcholinesterase d) Cholecalciferol
c) Acetylcholinesterase
Which of the following has sensory receptors at one end of the cell? a) Efferent neurons b) Interneurons c) Afferent neurons
c) Afferent neurons
Two fluid-filled experimental chambers are separated by a plasma membrane that has open Cl- channels but no other ion permeability. Into side 1 you put 200 mM NaCl and into side 2 you put 100 mM KCl. Which of the following will occur? a) The higher concentration of Cl- on side 1 will make the membrane have a resting membrane potential that is negative on side 1 and positive on side 2. b) Cl- will flow from side 1 to side 2 until the two compartments have the same Cl- concentrations. c) Cl- will flow from side 1 to side 2 and the membrane will develop a membrane potential that is positive on side 1 and negative on side 2. d) No membrane potential will develop, because the electrical attraction of Na+ and K+ ions will keep Cl- from moving through the membrane.
c) Cl- will flow from side 1 to side 2 and the membrane will develop a membrane potential that is positive on side 1 and negative on side 2.
Which term is used to describe areas of the central nervous system with a high proportion of cell bodies and dendrites? a) Nerves b) Tracts c) Gray matter d) White matter
c) Gray matter
What gaseous neurotransmitter is produced from L-arginine by nitric oxide synthetase? a) CO2 b) CO c) NO d) NO2 e) N2O
c) NO
Summation occurs when ______. a) a stimulus causes the membrane potential to undergo a graded potential that moves the membrane potential in a more positive direction b) a graded potential becomes smaller in size the farther away from the stimulus site it is measured c) additional stimuli cause graded potentials to occur in a neuron before the graded potentials from previous stimuli have died away d) a stimulus causes the membrane potential to undergo a graded potential that moves the membrane potential in a more negative direction
c) additional stimuli cause graded potentials to occur in a neuron before the graded potentials from previous stimuli have died away
Receptors that respond to norepinephrine or epinephrine are called ______ receptors. a) biogenic amines b) cholinergic c) adrenergic d) beta cholinergic
c) adrenergic
The synapse between neurons A and B is categorized as an ______. a) axo-axonic synapse b) inhibitory synapse c) axo-dendritic synapse d) excitatory synapse
c) axo-axonic synapse
If a neuron releases the neurotransmitter acetylcholine, it is referred to as a(n) ______ neuron. a) androgenic b) neurotic c) cholinergic d) purinergic e) adrenergic
c) cholinergic
Threshold stimuli ______. a) cause the opening of leak K+ channels b) cause the opening of only voltage-gated K+ channels c) elevate the membrane potential sufficiently to generate an action potential d) lower the membrane potential below threshold
c) elevate the membrane potential sufficiently to generate an action potential
If the electrical resistance is high, the current flow will be ______. a)unchanged b) high c) low
c) low
The equilibrium potential of an ion is the ______. a) point at which the concentration of positive ions inside a cell is equal to the concentration of negative ions b) membrane potential at which the concentration of that ion is the same inside and outside of the cell c) membrane potential at which ion flux due to the membrane potential is equal and opposite to the flux due to the concentration gradient d) same as the resting potential of the cell
c) membrane potential at which ion flux due to the membrane potential is equal and opposite to the flux due to the concentration gradient
The subtype of acetylcholine receptor found at neuromuscular junctions and which are stimulated by plant alkaloids found in tobacco products are ______ acetylcholine receptors. a) cannabinoid b) moronic c) nicotinic d) muscarinic e) tobacanic
c) nicotinic
A difference in the amount of electrical charge between two points in space is defined as a difference in electrical ______. a) excitability b) current c) potential d) resistance
c) potential
When neurotransmitters such as GABA or ACh are released from neuron A and bind to receptors embedded in the membrane of the axon terminal of neuron B, causing a decrease in the amount of an excitatory neurotransmitter released by neuron B, it is called ______. a) long term potentiation b) presynaptic facilitation c) presynaptic inhibition d) long term depression e) postsynaptic inhibition
c) presynaptic inhibition
The period of time when only a stronger than normal stimulus can produce another action potential in a neuronal membrane is known as the ________. a) resting period b) threshold period c) relative refractory period d) absolute refractory period
c) relative refractory period
All cells under resting conditions have a voltage difference between the inside and outside of their plasma membranes, which is referred to as the ______. a) action potential b) baseline ionic permeability c) resting membrane potential d) background leak current
c) resting membrane potential
The portions of afferent neurons farthest from the CNS have ______. a) axon terminals that release neurotransmitters that bind to receptors on target cells and influence their activity b) cell bodies, with nuclei that manufacture proteins to be sent toward the CNS by axonal transport c) sensory receptors, which respond to physical or chemical changes in their environment by generating electrical signals
c) sensory receptors, which respond to physical or chemical changes in their environment by generating electrical signals
When an additional stimulus induces a graded potential before a graded potential from a previous stimulus has died away, it can result in ______. a) rectification b) piling on c) summation d) rejuvenation e) multiplication
c) summation
A synapse could be excitatory or inhibitory depending on ______. a) the type of neurotransmitter that is released from the presynaptic cell b) the frequency of presynaptic action potentials and the resulting concentration of neurotransmitter in the synapse c) the type of postsynaptic ion channel influenced by the signal transduction mechanism d) whether the postsynaptic receptors are ionotropic or metabotropic
c) the type of postsynaptic ion channel influenced by the signal transduction mechanism
An ion channel that opens in response to a change in the membrane potential of the cell is called a __________ channel. a) ligand-gated b) leaky c) voltage-gated d) fair-weather e) mechanically gated
c) voltage-gated
While K+ ions move through both leakage and voltage-gated channels, Na+ ions move predominantly through ______ during an action potential. a) leak or leakage channels b) endocytosis c) voltage-gated channels
c) voltage-gated channels
How many different lobes make up each of the cerebral hemispheres? a) 2 b) 1 c) 3 d) 4
d) 4
Which of these is NOT classified as an amino acid neurotransmitter? a) Glycine b) Glutamate c) Gamma-aminobutyric acid d) Acetylcholine
d) Acetylcholine
Ions with charges of the same type ______ each other, while ions with opposite charges ______ each other. a) attract; repel b) repel; destroy c) destroy; repel d) repel; attract
d) repel; attract
The ______ runs throughout the core of the brainstem and consists of loosely arranged nuclei intermingled with bundles of axons. Its axons release biogenic amines that are critical in regulating sleep and wakefulness. a) corpus callosum b) limbic system c) pineal gland d) reticular formation
d) reticular formation
Which of these explains why an action potential is able to propagate along the full length of an axon? a) Even though action potentials decrement with distance, axons are generally short enough for them to make it all the way to the end. b) Local currents generated in a given patch of membrane are only able to move in one direction: toward the axon terminals. c) Local currents from an action potential are so large that they can travel the full length of the axon and directly depolarize the axon terminal. d) Action potentials are regenerated in each patch of membrane by depolarizing local currents arriving from previously-depolarized patches of membrane.
d) Action potentials are regenerated in each patch of membrane by depolarizing local currents arriving from previously-depolarized patches of membrane.
Which of the following cells stimulate the formation of the blood-brain barrier? a) Schwann cells b) Satellite cells c) Oligodendrocytes d) Astrocytes
d) Astrocytes
Which is true about signaling by nitric oxide (NO)? a) It binds to and opens K+ channels in postsynaptic membranes. b) Its only function is in the body is to dilate blood vessels. c) It is released by exocytosis from presynaptic vesicles. d) It diffuses into target cells and activates guanylyl cyclase. e) It binds to receptors on target cell plasma membranes.
d) It diffuses into target cells and activates guanylyl cyclase.
In which of the following will the speed of action potential propagation be fastest? a) Large diameter, unmyelinated fibers b) Small diameter, myelinated fibers c) Small diameter, unmyelinated fibers d) Large diameter, myelinated fibers
d) Large diameter, myelinated fibers
What type of ACh receptors are located in smooth muscle cells, cardiac muscle cells and some glandular cells? a) Catecholamine b) Adrenergic c) Nicotinic d) Muscarinic e) Arsphenamine
d) Muscarinic
During action potential propagation, when an action potential is occurring in one patch of membrane what induces the neighboring patch of membrane to depolarize to threshold? a) The opening of voltage-gated K+ channels in the neighboring patch of membrane. b) The neighboring patch of membrane being is in the afterhyperpolarization phase. c) The inactivation of voltage-gated Na+ channels in the original patch of membrane. d) The flow of local positive current from the depolarized patch to the neighboring patch of membrane.
d) The flow of local positive current from the depolarized patch to the neighboring patch of membrane.
Consider an experimental set-up with two fluid-filled chambers that are separated by a plasma membrane with open K+ channels but no other ion permeability. If you were to add 100 mM of NaCl into side 1 and 100 mM of KCl into side 2, what would you expect to happen? a) No K+ will flow through the membrane because the charged Na+ on side 1 will repel any K+ from moving. b) The membrane will develop a membrane potential that is positive on side 2 compared to side 1. c) K+ will flow from side 2 to side 1 until it is in equal concentrations in the two compartments. d) The membrane will develop a membrane potential that is positive on side 1 compared to side 2.
d) The membrane will develop a membrane potential that is positive on side 1 compared to side 2.
Which is TRUE regarding the effect of the Na+/K+-ATPase pump on the membrane potential of excitable cells? a) The pump's only effect on membrane potential is via the concentration gradients for Na+ and K+ that it generates. b) Exchanging 3 Na+ for 2 K+ is the main direct cause of the resting membrane potential; ion movement through leak channels plays a minor role. c) The pump is not necessary for maintaining concentration gradients, because electrochemical forces create the gradients for Na+ and K+. d) The pump has a minor electrogenic effect that directly contributes to the negative value of the resting membrane potential.
d) The pump has a minor electrogenic effect that directly contributes to the negative value of the resting membrane potential.
Synaptic vesicles ready to be released at chemical synapses are at locations known as ________. a) dendritic spines b) postsynaptic densities c) terminal cisternae d) active zones e) gap junctions
d) active zones
Receptors that respond to norepinephrine or epinephrine are called ______ receptors. a) beta cholinergic b) cholinergic c) biogenic amines d) adrenergic
d) adrenergic
Because the voltage-gated K+ channels of an axon close relatively slowly, immediately after the action potential there is a period of time where the membrane is transiently hyperpolarized towards the K+ equilibrium potential; this portion of the action potential is called the ______. a) repolarization b) depolarization c) absolute refractory period d) afterhyperpolarization
d) afterhyperpolarization
Receptor potentials ______. a) are action potentials in afferent neurons b) are graded potentials in efferent neurons c) are action potentials in efferent neurons d) are graded potentials in afferent neurons
d) are graded potentials in afferent neurons
The glial cells of the nervous system ______. a) are neurons that are found in the outer layer of the brain b) are neurons with cell bodies in the central nervous system and long axons that extend into the peripheral nervous system c) are neurons with cell bodies in the peripheral nervous system and long axons that extend into the central nervous system d) are non-neuronal cells that provide physical and metabolic support to neurons
d) are non-neuronal cells that provide physical and metabolic support to neurons
Neurons involved in the control of voluntary movements are located in cellular clusters deep within the cerebral hemispheres called the ______. a) postcentral gyri b) hypothalamus c) thalamus d) basal nuclei
d) basal nuclei
The brain is protected from injury because it is floating on a cushion of ______. a) adipose tissue b) plasma c) air d) cerebrospinal fluid
d) cerebrospinal fluid
The structures that form an interface between the bloodstream and each ventricle of the brain that are responsible for the formation of cerebrospinal fluid are called the ______. a) aqueducts b) neural stem cells c) central canals d) choroid plexuses
d) choroid plexuses
The electrical potential difference between two areas tends to make the charges flow, thus producing a ______. a) resistance b) polarity c) potential d) current
d) current
Excitotoxicity is a phenomenon in which regions of damage in brain tissue tend to spread due to excess release of the neurotransmitter _______. a) acetylcholine b) methamphetamine c) norepinephrine d) glutamate e) serotonin
d) glutamate
Inferior to the lateral ventricles of the cerebral hemispheres is a collection of several large nuclei that are responsible for filtering out extraneous sensory information. This region of the diencephalon is called the ______. a) epithalamus b) hypothalamus c) pituitary gland d) thalamus
d) thalamus
Temporal summation within the nervous system occurs ______. a) due to divergence of neural pathways b) due to convergence of neural pathways c) when signals from several presynaptic neurons summate within one postsynaptic neuron that integrates the signal d) when successive signals arriving from a single presynaptic neuron generate postsynaptic potentials that summate with each other
d) when successive signals arriving from a single presynaptic neuron generate postsynaptic potentials that summate with each other
In an experiment with an artificial cell, the equilibrium potentials for ions X+, Y- and Z+ are +50 mV, -50 mV, and +5 mV, respectively. If the cell is equally permeable to ions X+ and Y-, but 10 times more permeable to ion Z+ than to ion Y-, which statement is most likely true? Multiple choice question. a) X+ concentration is higher outside the cell than inside, and the resting membrane potential is negative. b) Y- concentration is higher inside the cell than outside, and the resting membrane potential is positive. c) All three ions have higher concentrations outside the cell than inside, and the resting membrane potential is negative. d) All three ions have higher concentrations inside the cell than outside, and the resting membrane potential is positive. e) All three ions have higher concentrations outside the cell than inside, and the resting membrane potential is positive.
e) All three ions have higher concentrations outside the cell than inside, and the resting membrane potential is positive.
Given the concentration gradients and relative membrane permeabilities for Na+, K+, and Cl-, the resting membrane of a cell can be calculated using the ______ equation. a) Nernst b) Ohm c) Boltzmann-Feinstein-Dietz (BFD) d) Goldman-Sachs e) Goldman-Hodgkin-Katz (GHK)
e) Goldman-Hodgkin-Katz (GHK)
Masses of gray matter deep within the cerebral white matter are called ______. a) corpus callosum b) gyri c) mirror neurons d) tracts e) basal nuclei
e) basal nuclei
The exchange of substances between blood and the extracellular fluid in the CNS is different from the exchange between blood and the extracellular fluid of other tissues; it is more restrictive in the CNS due to the ______. a) mucosal barrier b) buccal membranes c) pleural membranes d) meningeal membranes e) blood-brain barrier
e) blood-brain barrier
Excitotoxicity is a phenomenon in which regions of damage in brain tissue tend to spread due to excess release of the neurotransmitter _______. a) serotonin b) acetylcholine c) methamphetamine d) norepinephrine e) glutamate
e) glutamate
The cerebral cortex is organized into sinuous ridges called ______ separated by deep grooves, called ______. a) lobes; gyri b) fissures; sulci c) fissures; lobes d) sulci; gyri e) gyri; sulci
e) gyri; sulci
Receptors found in postsynaptic densities of synapses that both bind to neurotransmitters and act as ion channels are known as ______. a) SNARES b) gap junctions c) metabotropic receptors d) synaptotagmin receptors e) ionotropic receptors
e) ionotropic receptors
Neurotransmitter receptors that act indirectly on separate ion channels through a G protein and/or a second messenger are referred to as ______. a) ionotropic receptors b) gap junction receptors c) synaptotagmin receptors d) cotransmitter receptors e) metabotropic receptors
e) metabotropic receptors
The neurons of the ______ division of the nervous system innervate skeletal muscle, whereas the neurons of the ______ division of the nervous system innervate smooth and cardiac muscle, glands, neurons in the gastrointestinal tract, and other tissues. a) parasympathetic; sympathetic b) autonomic; systematic c) autonomic; somatic d) sympathetic; parasympathetic e) somatic; autonomic
e) somatic; autonomic