Session 2h

To say that a drug has an affinity for a particular type of receptor is to imply that the drug:

binds to that receptor.

endorphins

block the locus coeruleus (responds to arousing or stressful stimuli by releasing norepinephrine).

endorphin

blocks the locus coeruleus, that responds to arousal/stressful stimuli

cocaine

blocks the reuptake of dopamine, norepinephrine, and serotonin, thus prolonging their effects (synapse).

What is the most unusual thing about the neurotransmitter nitric oxide (NO)? a. It is found only in sensory neurons. b. It is both excitatory and inhibitory. c. It is normally a poisonous gas. d. It is also known as "laughing gas."

c. It is normally a poisonous gas.

The primary difference between an EPSP and an action potential is that: a. the magnitude of an action potential decreases as it travels along the membrane. b. EPSPs occur without sodium ions entering the cell. c. action potentials are always hyperpolarizations. d. EPSPs are subthreshold events that decay over time and space.

c. They operate on an all-or-none principle.

Which of the following is NOT true about EPSPs? a. They decay over time. b. Their strength decreases with distance. c. They operate on an all-or-none principle. d. They are depolarizations.

c. They operate on an all-or-none principle.

On the basis of what evidence were the properties of synapses first inferred? a. the electron microscope b. single-neuron recordings c. behavioral observations d. PET scans

c. behavioral observations

When an action potential reaches the end of an axon, it evokes the release of neurotransmitters by opening ____ channels in the axon terminal. a. chloride b. bicarbonate c. calcium d. oxygen

c. calcium

Large neurotransmitters are synthesized in the: a. postsynaptic terminal. b. presynaptic terminal. c. cell body. d. dendrites.

c. cell body.

Which of the following would most likely result in an IPSP? a. potassium ions entering the cell b. sodium ions entering the cell c. chloride ions entering the cell d. chloride ions leaving the cell

c. chloride ions entering the cell

Vesicles are located: a. in postsynaptic terminals. b. in dendrites. c. in presynaptic terminals. d. outside of the neuron in the extracellular fluid.

c. in presynaptic terminals.

When a vertebrate animal contracts the flexor muscles of a leg, it relaxes the extensor muscles of the same leg. Sherrington considered this evidence for the existence of: a. spatial summation. b. temporal summation. c. inhibitory messages. d. the delay in transmission at synapses.

c. inhibitory messages.

What ordinarily prevents extensor muscles from contracting at the same time as flexor muscles? a. the ligaments and tendons that bind them together b. learned patterns of coordination in the cerebral cortex c. inhibitory synapses in the spinal cord d. control of both muscles by different branches of the same axon.

c. inhibitory synapses in the spinal cord

The "spontaneous firing rate" of a neuron refers to: a. its resting potential. b. its rate of energy consumption. c. its rate of producing action potentials even when it is not stimulated. d. the velocity of its action potentials under normal conditions.

c. its rate of producing action potentials even when it is not stimulated.

Spatial summation refers to: a. multiple weak stimulations that occur in rapid succession. b. a decrease in responsiveness after repeated stimulation. c. multiple weak stimulations that occur at the same time. d. an increase in the strength of action potentials after repeated stimulation.

c. multiple weak stimulations that occur at the same time.

In addition to influencing other neurons, ____ dilates the nearby blood vessels, thereby increasing blood flow to that area of the brain. a. endorphins b. glycine c. nitric oxide d. acetylcholine

c. nitric oxide

Which of the following neurotransmitters is released by active neurons to dilate the blood vessels and increase blood flow? a. endorphins b. glycine c. nitric oxide d. acetylcholine

c. nitric oxide

A certain weak stimulus produces no reflexive response, but a rapid repetition of that stimulus may produce such a response. What is this phenomenon called? a. spatial summation b. temporal summation c. saltatory conduction d. synaptic combination

c. saltatory conduction

After a meal that was rich in the amino acid tryptophan, which neurotransmitter level would be increased the most? a. dopamine b. endorphin c. serotonin d. nitric oxide

c. serotonin

The amino acid tryptophan is the precursor to which neurotransmitter? a. dopamine b. endorphin c. serotonin d. nitric oxide

c. serotonin

Simultaneous weak stimuli at different locations produce a greater reflexive response than one of the stimuli by itself. What is this phenomenon called? a. Sherrington's law b. temporal summation c. spatial summation d. the all-or-none law

c. spatial summation

What determines whether a neuron has an action potential? a. only the number of EPSPs impinging on an axon b. only the number of IPSPs impinging on the dendrites c. the combined effects of EPSPs and IPSPs d. summation effects of IPSPs

c. the combined effects of EPSPs and IPSPs

Sherrington deduced that transmission at a synapse must be slower than conduction along an axon. This was based on what kind of evidence? a. temporal summation b. drugs that increase or inhibit activity at synapses c. the speed of reflexive responses d. differences in diameter between axons and dendrites

c. the speed of reflexive responses

dopamine

can be released in many situations that do not require attention

presynatic

cannabinoid receptors are found in the _______ terminals

amphetamine on dopamine transporter

causes cells to excrete dopamine than reabsorb it

Gray matter in the brain and spinal cord is mainly composed of what structures?

cell bodies and dendrites

Large neurotransmitters are synthesized in the:

cell body.

A fluid-filled channel in the center of the spinal cord is called the:

central canal.

If a person has difficulty determining which of two rhythms is faster, it is likely that she suffered damage to the:

cerebellum.

The major disadvantage of a blood-brain barrier is that:

certain required chemicals must be actively transported.

lysergic acid diethylamide

chemically resembles serotonin and stimulates serotonin type 2 receptors (5-HT₂). stimulate recpetors not serotonin itself

true

cocaine users have high risk of stroke, epilepsy and memory impairment

Myelination in the human brain

continues well into adult years

Each hemi of the cerebral cortex recieves most of its input from the ____ side of the body and controls its muscles iwth the ___

contralateral; contralateral

The medulla controls a number of reflexes through:

cranial nerves.

What was the first evidence reported by T. R. Elliott suggesting that synapses operate chemically? a. Adrenaline mimics the effects of the parasympathetic nervous system. b. Adrenaline decreases heart rate. c. Adrenaline produces a hormone which decreases heart rate. d. Adrenaline mimics the effects of the sympathetic nervous system.

d. Adrenaline mimics the effects of the sympathetic nervous system.

What do temporal summation and spatial summation have in common? a. Both involve the activity of only two neurons. b. Both require a response from the brain. c. Both depend on a combination of visual and auditory stimuli. d. Both enable a reflex to occur in response to weak stimuli.

d. Both enable a reflex to occur in response to weak stimuli.

A graded depolarization is known as an: a. EPIP b. IPSP c. ESPN d. EPSP

d. EPSP

____ are a category of chemicals including adenosine and several of its derivatives. a. Neuropeptides b. Acetylcholine c. Monoamines d. Purines

d. Purines

Which of the following is NOT a catecholamine? a. Dopamine b. Epinephrine c. Norepinephrine d. Serotonin

d. Serotonin

An IPSP represents: a. the location where a dendrite branches. b. a gap in a myelin sheath. c. a subthreshold depolarization. d. a temporary hyperpolarization.

d. a temporary hyperpolarization.

The release of neurotransmitter from the presynaptic terminal is most dependent on the influx of what ion? a. sodium b. potassium c. chloride d. calcium

d. calcium

When an action potential reaches the end of an axon, the depolarization causes what ionic movement in the presynaptic cell? a. sodium out of the cell b. lithium out of the cell c. iron into the cell d. calcium into the cell

d. calcium into the cell

Dopamine and norepinephrine are classified as: a. second messengers. b. purines. c. proteins. d. catecholamines.

d. catecholamines.

Insulin increases the entry of tryptophan into the brain by: a. weakening the blood-brain barrier. b. converting tryptophan into a compound that more easily enters the brain. c. increasing metabolic activity only in those areas of the brain that use tryptophan. d. causing certain competing amino acids to enter other cells, outside the brain.

d. causing certain competing amino acids to enter other cells, outside the brain.

The catecholamines include: a. epinephrine, norepinephrine, dopamine, and serotonin. b. epinephrine, serotonin, and dopamine. c. dopamine, serotonin, and acetylcholine. d. epinephrine, norepinephrine, and dopamine.

d. epinephrine, norepinephrine, and dopamine.

In a reflex arc, the coordination between contraction of certain muscles and relaxation of others is mediated by: a. glial cells. b. motor neurons. c. sensory neurons. d. interneurons.

d. interneurons.

An action potential causes the release of neurotransmitters by: a. blocking potassium pores in the membrane. b. opening chloride pores in the membrane. c. blocking iron pores in the membrane. d. opening calcium pores in the membrane.

d. opening calcium pores in the membrane.

Temporal summation most likely occurs with: a. infrequent, subthreshold excitation. b. rapid succession of stimuli that each exceed threshold. c. infrequent, inhibitory stimuli. d. rapid succession of subthreshold excitation.

d. rapid succession of subthreshold excitation.

The "decision" for a neuron to fire is determined by the: a. number of EPSPs only. b. spontaneous firing rate. c. number of IPSPs only. d. ratio of EPSPs to IPSPs.

d. ratio of EPSPs to IPSPs.

To measure temporal summation in single cells, researchers: a. attach electrodes to the scalp. b. insert an microelectrode into the scalp. c. collect sodium and potassium ions from nearby glial cells. d. record depolarizations of the postsynaptic neuron.

d. record depolarizations of the postsynaptic neuron.

The proper order of a reflex arc is: a. motor neuron, sensory neuron, interneuron. b. sensory neuron, motor neuron, interneuron. c. motor neuron, interneuron, sensory neuron. d. sensory neuron, interneuron, motor neuron.

d. sensory neuron, interneuron, motor neuron.

Specialized junctions between neurons are called: a. nodes of Ranvier. b. spines. c. dendrites. d. synapses.

d. synapses.

Which of the following is NOT a factor in determining whether or not two EPSPs combine to reach threshold? a. size of the EPSPs b. timing between them c. threshold of the postsynaptic cell d. threshold of the presynaptic cell

d. threshold of the presynaptic cell

Which of the following is the correct order of transmission of information within a neuron?

dendrite, cell body, axon

Which of the following is the correct order of transmission of information within a neuron?

dendrite, cell body, axon...

After the migrating neuron reaches its destination ___ behin to form

dendrites

A neuron can have any number of ____, but no more than one ____.

dendrites; axon

A nueron can have any number of ____, but no more than one_____.

dendrites; axon

The sodium gates in the axon are usually closed. Which of the following opens them?

depolarization of the membrane

At high doses, MDMA

destroys axons that release serotonin.

The formation of a neurons distinctive shape occurs during the _____ stage of neurogenesis

differentiation

marijuana

dissolve in body fats and leave body very slowly so it does not produce intense withdrawal effects

The brain has an enormous number of ____ and ____.

divisions; subareas

Most habit-forming drugs activate which type of synapse?

dopamine

predominant

drugs are categorized based on ________ action

false - unpleasant

drugs dominate the attention even if drug experience is unpleasant

false - any stimulus

drugs that reminds someone of past drug experiences can trigger a craving

The effectiveness and side-effects of a drug vary from one person to the next. One reason for this is that:

each drug tends to affect more than one kind of synapse.

When do the ventricles and the central canal of the spinal cord form?

early in embryonic development

amhetamine and cocaine

effects are intense but short-lived

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.

Differentiation is the:

formation of dendrites and an axon

The choroid plexus:

forms the cerebrospinal fluid.

nicotinic receptors

found in the CNS and nerve muscular junction but abundant in nucleus accumbens

cannabinoid receptors

fround in the hippocampus, basal ganglia and cerebellum none in the medulla and brainstem

true

fully expected event draws little attention

Which type of explanation describes the advantages provided by a particular structure or behavior?

functional

The anterior pituitary is composed of ____ and the posterior pituitary is composed of ____.

glandular tissue; neural tissue

Main source of nutrition for vertebrate neurons?

glucose.

The erections of hairs on the body, most often around arms and shoulders are called:

goose bumps.

An EPSP is a(n):

graded depolarization.

alcohol

greater amounts of ______ cause damage to liver, impairs judgment and ruin lives

Radial glia:

guide the migration of neurons during the embryonic stage.

marijuana

has cannabinoids that decrease gaba and glutamate

nucleus accumbens

has many nicotinic acetylcholine receptors

If a drug binds to a particular receptor, it is said to:

have an affinity for that type of receptor.

.55

heritability of alcholism

dopamine

high _____ activity reduces background noise and increase signal-to-noise ratio

A chemical is called a _____ when it flows throuhg the blood to targets throughout the body

hormone

no dopamine

if a stimulus predicts food, ___ ______

Chemicals known as ___ and ___ guide neuron migration:

immunoglobins; chemokines

Sex-limited genes are present:

in both sexes.

stimulant drugs

increase activity at dopamine receptors, d2, d3, d4

endorphins

increase dopamine release by inhibiting an inhibitor, gaba and norepinephrine

Dendrites often contain additional short outgrowths. These are believed to:

increase the surface area available for synapses.

The ascending portion of the reticular formation:

increases arousal and attention.

nicotine

increases dopamine release in the nucleus accumbens.

methylphenidate

increases serotonin release, which has calming effects for people with ADD

Saltatory conduction ____ the velocity of action potentials and _____ the amount of energy used by the neuron ____.

increases, decreases.

alcohol

inhibits the flow of sodium across the membrane, expands the surface of membranes, decreases serotonin activity, facilitates response by the GABAA receptor, blocks glutamate receptors, and increases dopamine activity.

If a sympathetic nervous system axon does not receive enough nerve growth factor, the nueron

kills itself

cocaine

mainly increasing dopamine effects, secondly, increasing serotonin effects

A certain drug user experiences intensified sensations and the illusion that time is passing slowly. He also experiences problems with attention and memory. These symptoms are most characteristic of the use of which drug?

marijuana

attention deficit disorder

marked by impulsiveness and poor control or attention

norepinephrine

memory storage

After cells have differentiated as neurons or gila they:

migrate

Molecules that can cross the blood-brain barrier are usually:

molecules that can dissolve in the fats of the capillary walls.

opiates

morphine heroin methodone

true

most researchers believe that genetics contribute to alcoholism (.55 heritability for alcoholism). t/f

true

nearly all drugs increase the activity at dopamine synapses

Of the following, which person is MOST likely to deal exclusively with brain disorders?

neurologist

What are the two kinds of cells in the nervous system?

neurons and glia

Most ____ have a mixture of psychological and medical training, and they work in hospitals and clinics.

neuropsychologists

Goose bumps ____ in humans.

no longer serve a purpose

The results of several studies of facial expressions in people who were born blind suggest:

no role of genetics but a major role of environment in the control of facial expressions.

Gaps in the insulating material that surrounds axons are known as:

nodes of Ranvier.

Sympathetic is to ____ as parasympathetic is to ____.

norepinephrine; acetylcholine

The structure that contains the chromosomes is called the:

nucleus.

What type of glial cells myelinate axons in the brain and spinal cord?

oligodendrocytes

A stereotaxic instrument would most likely be used for:

placing an electrode in the brain.

dopamine

pleasure chemical

Knowing that it is appropriate to tackle people on the football field, but not in the classroom, is dependent on the functioning of the:

prefrontal cortex

stimulant drugs

produce excitement, alertness, elevated mood, decreased fatigue, sometimes increased motor activity

serotonin

produces hallucinogenic effect at high doses of ______

cocaine

prolongs the effect of norepinephrine, serotonin and dopamine

The ____ of neurons most strongly differentiate them from other cells in the body.

shape.

Compared to ionotropic effects, metabotropic effects are:

slower and longer-lasting.

nucleus accumbens

small subcortical area rich in dopamine receptors

If depolarization is less than the cell's threshold:

sodium crosses the membrane only slightly more than usual.

The action potential of a neuron depends mostly on what movement of ions?

sodium ions entering the cell

Nerves from the central nervous system convey information to the muscles and glands by way of the:

somatic nervous system.

Simultaneous weak stimuli at different locations produce a greater reflexive response than one of the stimuli by itself. What is this phenomenon called?

spatial summation

In humans, myelination first occurs in the

spinal cord

Even at rest, most neurons have periodic production of action potentials known as the

spontaneous firing rate.

methylphenidate ritalin

stimulant drug that is prescribed for people with ADD/ attention deficit disorder

LSD

stimulate serotonin type 2 receptors

nicotine

stimulates one type of acetylcholine receptor known as nicotinic receptor (found in the CNS and nerve-muscle junction of skeletal muscles)

ecstacy MDMA

stimulates release of dopamine at low doses stimulates the release of serotonin at high doses

Methylenedioxymethamphetamine

stimulates the release of dopamine at low doses; at higher doses, it stimulates serotonin synapses giving hallucinogenic effects.

One currently popular hypothesis about the binding problem is that binding depends on:

synchronized activity in different brain areas.

true

t/f Moderate amounts of alcohol helps people relax. May help prevent heart attacks

false - does not , true

t/f being an alcoholic requires severe deterioration (__) and should interfere with persons life (__)

Monkeys with Kluver-Bucy syndrome fail to show normal fears and anxieties after damage to the:

temporal lobe

If the spinal cord is cut at a given segment, the brain loses sensation at:

that segment and all segments below it.

In general, when biologists speak of sex-linked genes they are referring to genes on:

the X chromosome.

What determines whether a neuron has an action potential?

the combined effects of EPSPs and IPSPs

d

the difference between the good and bad use of drugs: a. amount taken b. reason for taking it c. social settings d. all of the above

Electrical gradients lead to what kind of movements?

the movement of ions to areas having the opposite electrical charges

Evolution improves the fitness of the population, which is defined as:

the number of copies of one's genes that endure in later generations.

Which two factors affect the speed of an action potential?

the presence of myelin and the diameter of the axon

What is the point from which an axon releases chemicals into the synapse?

the presynaptic terminal

role of dopamine synapses and nucleus accumbens

they relate to the arousal or attention-getting potential of an event

The sodium-potassium pump repeatedly transports ____ sodium ions out of the cell while drawing ____ potassium ions into it.

three; two

amphetamine and cocaine

two drugs that increase dopamine activity and has the same behavioral effects

2

type _ early onset

1

type _ late onset

The risk of having part of the brain unprotected by the blood-brain barrier is that:

viruses or toxic chemicals are more likely to damage it.

The superior colliculus is to ____ as the inferior colliculus is to _____.

vision; hearing

unpredictable

we enjoy almost any event that is ________

neural Darwinism

we start with more neurons and synapses than we keep. selection process occurs where we keep others and reject others. the most successful axons and combinations survice, while others fail

reinforcer

whatever causes an individual to repeat an act not something enjoyable

e

which of the ff is not an effect of alcohol a.inhibits the flow of sodium across the membrane b. expands the surface of membranes c. blocks glutamate receptors d. facilitates response by the GABAA receptor e. decreases dopamine activity f. increases dopamine activity. g.decreases serotonin activity

c

which of the ff is not an effect of alcohol a.inhibits the flow of sodium across the membrane b. expands the surface of membranes c. increase serotonin activity d. facilitates response by the GABAA receptor e. blocks glutamate receptors f. increases dopamine activity. g.decreases serotonin activity

c

which of the ff is not the effect of stimulant drugs on the body? a.produce excitement b. elevated mood c. decrease attention d. decreased fatigue

Chalmers' fundamental "hard problem" is:

why and how brain activity is associated with consciousness.

Which bests represents Lamarckian evolution?

"If you don't use it, you lose it."

Which best describes the concept of evolution?

"Reproduction of the fittest."

What is it called when some animals are selectively bred because they possess some desirable characteristic?

Artificial selection

The human central nervous system:

Begins to form when the embryo is about 2 weeks old

Session 2

Bio Pysch

Enzymes serve as...

Biological catalysts that regulate chemical reactions in the body.

More people would be born without an appendix if...

If more people without and appendix reproduce than people who have an appendix.

After cells have differentiated as neurons or glia, they:

Migrate

marijuana

a drug that does not fit in any categorization

Which type of glia remove waste material in the NS?

astrocytes

Which division of the NS consists of neurons that control the heart, intestines and other organs

autonomic

cocaine

blocks the reuptake of norepinephrine, serotonin and dopamine

What are the two parts of the central nervous system?

brain and spinal cord

What makes nitric oxide unique among neurotransmitters? a. It is released before the action potential occurs. b. It is taken back up into the presynaptic neuron. c. It is a gas. d. It is composed of amino acids.

c. It is a gas.

Biological catalysts that regulate chemical reactions in the body are called:

enzymes.

nicotine

excites acetylcholine receptors that release dopamine in the nucleus accumbens

autoreceptors

exerts negative feedback that reduces further release of dopamine

informative events

food and shock ---attention-getting

Individuals afflicted with PKU need to avoid:

foods high in phenylalanine.

Kin selection as an explanation for altruistic behavior would argue that:

individuals spread their genes by helping their relatives.

dopamine

inhibitory neurotransmitter that decrease activity in much of the brain

cocaine

interferes with the reuptake of released dopamine

In a reflex arc, the coordination between contraction of certain muscles and relaxation of others is mediated by:

interneurons

The neurotrans GABA exerts ____ and it's affects are almost always ____

iontropic; inhibitory

alcoholism or alcohol dependence

is the continued use of alcohol despite medical or social harm, even after people decide to quit or decrease their drinking.

What is one factor in determining whether a drug that readily attaches to a receptor will have agonistic or antagonistic effects?

its efficacy

Massive cell death in the brain during prenatal development is:

normal.

addiction

not product of the drug

The basal ganglia are a related cluster of cell bodies in the central nervous system. Technically, the basal ganglia should have been name the basal:

nuclei.

Sensory information that is not processed by the thalamus includes:

olfactory information.

Brain areas where new neurons form

olfactory receptors, neurons in hippocampus, and neurons in song-producing areas of some bird species

false-can still continue

once a strong habit is formed, it cannot continue even with weak or erratic reinforcement

A(n) ____ explanation describes how a structure or behavior develops, including the influences of genes, nutrition, experiences, and their interactions.

ontogenetic

endorphins

peptides in the brain

A(n) ____ explanation would describe eating in terms of the hypothalamus affecting insulin production, which affects the availability of glucose in cells.

physiological

By both neural and hormonal pathways, the hypothalamus regulates activity of the:

pituitary gland.

nucleus accumbens

pleasure area

The only area of the cerebral cortext known to recieve input from ALL sensory modalities is the:

prefrontal cortex

Local anesthetic drugs attach to the sodium channels of the membrane, which:

prevents sodium ions from entering and stopping action potential.

Temporal summation most likely occurs with:

rapid succession of sub-threshold excitation

Temporal summation most likely occurs with:

rapid succession of subthreshold excitation.

The primary feature of a nueron that prevents the action potential from traveling back from where it just was is the:

refractory period

dopamine release

reinforces behavior among gamblers, sports fan video game players

true

repeated use of cocaine releases less dopamine

Compared to passive transport, the major disadvantage of active transport is that it:

requires expenditure of energy.

Adrenocorticotropic hormone (ACTH) controls:

secretions of the adrenal cortex.

The spinal cord communicates with:

sense organs and muscles below the level of the head.

nucleus accumbens

sexual excitement,strong habits, habitual video game playing, drugs use, classical condition

Early in development, the nervous system begins as a

tube surrounding a fluid filled cavity

Damage to the basil ganglia would most likely result it...

... a movement disorder.

Reuptake is the absorption of ...

... neurotransmitters by the presynaptic neuron

According to Bell-Magendie Law ...

... ventral roots carry motor information, while dorsal roots carry sensory information

The term "pons" is named as such because...

...axons within the pons cross over from one side to the other.

Across mammalian species, the most constrant structure is the...

...cerebellum.

The branching fibers that form the information-receiving pole of the nerve cells are called...

...dendrites.

An impairment of eating, drinking, temp regulation and sexual behavior suggests possible damage to the...

...hypothalamus

Dendrites often contain additional short outgrowths. These are believed to:

...increase the surface area available for synapses.

The hippocampus plays a major role in...

...memory.

The brain area most often linked to drug addiction is the...

...nucleus incumbens

One function of the thalamus is to...

...relay sensory information to the cerebral cortex.

Besides problems with balance and coordination, a person with damage to the cerebellum, would also likely have problems with...

...shifting attention between auditory and visual stimuli.

Compared to iontropic effects, metobotropic effects are...

...slower and longer lasting

Human central nervous system (CNS)

1. begins to form when the embryo is 2 weeks old. 2. dorsal surface thickens and then long thin lips rise, curl, and merge, forming a neural tube that surrounds a fluid-filled cavity 3. tube sinks under skin surface, forward end enlarges and differentiates into hind mid and forebrain (rest becomes spinal cord) 4. Fluid filled cavity becomes central canal of spinal cord and 4 ventricles of brain, containing CSF

How many pairs of cranial nerves to humans have.

12.

1

2

2

3

4

5

Neurotrophin

A chemical that promotes survival and activity of neurons (i.e. NGF) Neurons that fail to receive NTs, fail to receive these things and so they die out

substance abuse

A maladaptive pattern of substance abuse leading to clinically significant impairment or distress

Migration requires:

A precise chemical environment

Which of the following would produce spatial summation

A rapid sequence of weak stimuli

Migration

After cells differentiate into neurons or glia they migrate or move, some faster than others, slowest don't reach their destination till adulthood

false -more

After nicotine use, nucleus accumbens cells become more responsive

acetaldehyde,

Alcohol is metabolized by the body through converting it to _________ then converts it to acetic acid which the body can use as a source of energy.

acetic acid, energy

Alcohol is metabolized by the body through converting it to acetaldehyde, then converts it to ______ which the body can use as a source of ____.

acetic acid

Alcohol is metabolized by the body through converting it to acetaldehyde, then converts it to ______ which the body can use as a source of energy.

Which group is most likely to suffer from a thiamine deficiency?

Alcoholics

True

Almost any substance can be abused

Which of the following would most likely interfere with migration of neurons during development?

Altering the chemical paths

Why is a genetic explanation for altruism problematic?

Altruistic behaviors rarely benefit the individual performing them.

What causes hydrocefalus.

An obstruction in the flow of cerebral spinal fluid.

Proliferation occurs:

Around the ventricles

Which of the following would be a functional explanation for why birds sing?

Birds sing to defend territories and attract mates.

Average human brain

Birth = 350 gs End of first year = 1,000 gs Adult = 1,200 to 1,400 gs

How does the method of transcranial magnetic stimulation of brain areas differ from magnetic inactivation?

Brain activation results from mild, brief magnetic stimulation.

Plasticity of brain

Brain is constantly changing, within limits - it changes rapidly in early development and continues changing throughout life

dopamine

Brain stimulation is reinforcing only if it stimulates axons releasing ____________-

dopamine

Brain stimulation is reinforcing only if it stimulates axons that release

Growth of brain

Changes when you are really young, but when you are older it doesn't (more about dendrites growing and making new connections) ---- Think about all the things a one year old can do that they couldn't at birth = brain growth ----Think about all the things you couldn't do a few years ago like analyze stats. etc.. = dendrites have grown new branches

dangerous drugs

Cocaine,morphine, amphetamine

Marijuana

Contains the chemical ∆⁹-tetrahydrocannabinol and other cannabinoids. Absorbed by the body through smoking or eating the leaves.

Sperry experiment

Cut optic nerve of frog and rotated 180 degrees Axons from what originally was dorsal retina (now ventral) grew back to area for dorsal - axons from what had once been ventral (now dorsal) grew back to original target - frog saw world upside down

dopamine and serotonin

Damage to moderate number of ______ and ______ neurons could increase risk of depression or Parkinson's disease.

depression or parkinson's disease.

Damage to moderate number of dopamine and serotonin neurons could increase risk of _________ or ___________

marijuana

Decrease the brain damage caused by stroke

Which of the following would be the most likely affect of taking a drug that blocks sympathetic NS activity?

Decreased heart rate

After the migrating neuron reaches its destination, ______ begin to form

Dendrites

Whether or not a transplanted immature neuron adopts the properties of neurons in the new location or retains at least some properties of neurons from where it was taken from depends largely on how much the transplanted neuron has:

Differentiated

What is the process called when a primitive neuron begins to develop dendrites and an axon?

Differentiation

hallucinogenic Drugs

Distorts perceptions.

habit-forming

Drugs, gambling, video games, powerful habits

endorphins

EFFECT: Decreased response to stress and decreased memory storage.

The primary difference between an EPSP and an action potential is that:

EPSPs are subthreshold events that decay over time and space.

Results of Sperry's experiment

Each axon regenerated to the area of the tectum where it had originally been presumably by following a chemical trail - helped by chemical gradients (page 127)

Effects of being active

Enhances growth of axons and dendrites, even for rats in isolation Improves learning and memory Neuronal changes in humans Being mentally active help fight the declining brain volume and activity characteristic of elderly people

What supports the argument that humans have NOT stopped evolving?

Evolution is based on reproduction rates, so as long as some people have more children than others to, their genes will spread.

marijuana

Excites negative-feedback receptors on presynaptic cells; thereby puts the brakes on release of either glutamate or GABA

Vulnerable developing brain

Fetal alcohol syndrome "Crack baby" Impaired thyroid production produces lethargy in adults but retardation in infants (page 131)

Synaptogenesis

Final stage where synapses form - starts before birth but throughout life neurons form new synapses and discard old ones

Which lobe contains the primary motor cortex and the prefrontal cortex?

Frontal

What is the name given to a cluster of neurons outside the CNS?

Ganglion

Which of the following statements about evolution is TRUE?

Genes in the previous generation may not be adaptive in future generations.

dopamine synapses

Habit-forming or addictive behaviors have something to do with ________

Suppose that adopted children are more similar to their biological parents than their adoptive parents in their preferences for a flavor of ice cream. Which of the following would be true?

Heritability of this trait is high.

As the neural tube sinks under the surface of the skin, the forward end enlarges and differentiates into the:

Hindbrain, midbrain, and forebrain.

Recessive genes manifest their effects only when the individual is ______ for them.

Homozygous

What is the result if a stimulus shifts the potential inside a neuron from the resting potential to a more ____ potential?

Hyper-polarization

Why is that all neurons in a health adult brain have made appropriate connections?

If an axon does not make the appropriate connections by a certain age, it dies

Chemicals that guide migration

Immunoglobulins and chemokines - defecit in these leads to impaired migration, decreased brain size, decreased axon growth, and mental retardation Also, extreme excesses of immuno has been linked to schizo

Chemicals known as _____ and _____ guide neuron migration.

Immunoglobulins; chemokines

marijuana

Increase lung cancer risk and Parkinson's disease.

Marijuana

Intensification of sensory experience and an illusion that time is passing very slowly. impair cognition increase appetite

If all of a neuron's dendrites or axons were contained within the spinal cord, it would be considered what type of neuron?

Intrinsic

methlyphenidate

It blocks the dopamine uptake in the same way (similar to Cocaine) but more gradually (dose and time) than Cocaine does

Color vision deficiency is more common in males than females because...

It is a recessive X-linked gene.

Which of the following is NOT a characteristic of a dendrite?

It is in contact with the dendrites of other neurons. Dendrites do: 1. Taper as it gets further from the body 2. Its surface may be lined with synaptic receptors 3. It receives information from other neurons or the environment.

In what way is a myelinated axon that has lost its myelin (through disease) different from an axon that was never myelinated?

It lacks sodium gates along parts of its surface.

Which of the following is TRUE about genetic drift?

It occurs more often in small populations.

What does it mean to say that acetylcholine exerts ionotropic effects?

It opens gates for a particular ion.

What happens to a virus that manages to cross the blood-brain barrier and enter the brain?

It stays in the nervous system the rest of that person's life.

Following damage to the temporal lobe, monkeys that fail to display normal fear of snakes most likely have which of the following?

Kluver-Bucy syndrome

stimulant drugs

Known for their short-term effects, but repeated use of high doses can produce long-term problems.

The phrase "If you don't use it, you lose it" best represents ____.

Lamarckian evolution

Which of the following theories would support the idea that by taking out a peoples' wisdom teeth, eventually fewer people will be born with them?

Lamarckian evolution

The theory of evolution through the inheritance of acquired characteristics is known as:

Lamarckian evolution.

Myelination

Later and slower stage (continues gradually for decades) - the process by which glia produce the insulating fatty sheaths that accelerate transmission in many vertabrae axons Myelin forms first in spinal cord, then hind, mid, and forebrain

Rest of chapter

Look at Online Assignment 2

Suppose a virus damaged the dorsal roots of the spinal cords, but not the ventral roots. What would happen to the sensory and motor abilities of the affected area?

Loss of sensation but preserved motor control.

Damage to which hindbrain structure would be most life-threatening?

Medulla

Reflexive changes in heart rate and breathing when you are exercising, for example, are regulated by which of the following?

Medulla

Immunoglobulins and cheekiness play an important role in neural:

Migration

What term describes the movement of primitive neurons and glia within the developing nervous system?

Migration

Where do the metabolic activities occur that provide energy for all of the other activities of the cell?

Mitochondria

Migration is the:

Movement of primitive neurons and glia

For some axons, glial cells produce an insulating sheath that makes rapid transmission possible. What is this process called?

Myelination

Differentiation

Neuron forms its axon and dendrites

What are two kinds of cells in the nervous system?

Neurons and gila.

____ in the brain and spinal cord and ___ in the periphery are specialized types of glia that build the sheaths that surround neurons.

Oligodendrocytes; Schwann Cells

nucleus accumbens

Only in the _______ is the nicotine has more effect because if has plenty of nicotinic receptors

Someone who suddenly loses the ability to identify objects by feeling them has probably suffered damage to which area of the cortex?

Parietal Lobe

What is one important difference between people who are blind because of cortical blindness and others who are blind because of problems with their eyes:?

People with damage to their eyes can still imagine visual scenes

If you were to stub your toe and feel the pressure a second or two before you feel the pain, then which of the following statements is most likely true:

Pressure sensitive neurons are large and myelinated.

Proliferation is the:

Production of new cells

Proliferation

Production of new cells. Early in develop., the cells lining ventricles divide - some cells remain as stem cells , continuing to divide - others become primitive neurons and glia that begin migrating to other locations

Apoptosis

Programmed mechanism of cell death

Stem cells are important for which of the following developmental processes?

Proliferation

What is the production of new neurons called?

Proliferation

A strand of DNA serves as a template for the synthesis of...

RNA

Which of the following activities does NOT stimulate dopamine release in the nucleus incumbens...

RUNNING What does: Gambling, sex, video games

Which of the following actions is most likely to be dependent on ionotropic events

Rapid muscle contractions

Stem cells in nose

Remain immature throughout life - periodically divide with one remaining immature and other differentiating

Which of the following statements regarding reflexes would Charles Sherrington most likely agree with?

Repeated stimuli occurring within a brief time can have a cumulative effect.

What is the difference in voltage called that typically exists between the inside and the outside of a [missing word... neuron?]

Resting potential

After a meal that was rich in ammino acid tryptophan, which neurotransmitter level would increase the most

Serotonin

The _____ of neurons most strongly differentiate them from other cells in the body.

Shape

cocaine

Similar behavioral effects with Amphetamine.

Neurons in humans

Skin - turn over rapidly (less than yr) Skeletal - 15 years Cerebral cortex - from birth (form no or few new neurons after birth)

What happens to the ion gates when the membrane of a neuron starts to be depolarized?

Sodium gates open.

An axon in your hand causes contraction of a muscle fiber in your finger as you write. This neuron belongs to which branch of the nervous system?

Somatic

Myelination is a process common to:

Some vertebrae axons

What is the primary difference between temporal summation and spatial summation?

Spatial summation depends on contributions from more than one sensory neuron.

opiates

Stimulates endorphin (endo-genous morphins) receptors.

Seeing a snake coming out of the drain in the bathtub may dilate your pupils, make your hair stand on your neck and cause you to sweat. These are due to the ______ NS.

Sympathetic

Which lobe seems to be especially involved in the comprehension of spoken language in humans?

Temporal

Which of the following would be a physiological explanation for why birds sing?

Testosterone causes the growth of certain brain areas which control singing in certain birds.

Plasticity

The ability of the brain to change its anatomy over time, within limits.

Which of the following is an advantage of having a resting potential?

The cell is prepared to respond quickly to a stimulus.

false-increase

The drugs amphetamine and cocaine decrease accumulation of dopamine in synaptic cleft but washes away faster than presynaptic cell can synthesize

A group of forebrain structures is important for motivated and emotional behavior. What is the name given to this group?

The limbic system.

Breathing, heart rate, vomiting, coughing, sneezing, are all controlled by which structure?

The medulla

Religious affiliation is...

The one exception to a behavior due to heritability.

Which two factors affect the speed of an action potential?

The presence of myelin and the diameter of the axon.

nerve growth factor

The protein that is delivered and that promotes survival and growth, when a neuron of the SNS forms a synapse onto a muscle (muscle does delivering) - an axon that doesn't receive NGF degenerates and its cell body dies

The neuron will produce an action potential only if the depolarization exceeds what level?

The threshold of excitation.

Prior to the work of Santiago Ramon y Cajal, what did many investigators believe?

The tip of an axon physically merged with the next neuron.

Which of the following is a characteristic of glial cells in the human brain?

They are more numerous than neurons.

What do the corpus collosum and anterior comissure have in common?

They both are made of gray matter.

Which of the following is NOT true of axons?

They carry information toward the soma. True: They can vary in length, they release chemicals that cross the synapse, and some of them are covered in myelin sheaths.

Which of the following best characterizes how axons arrive at the correct target cells?

They follow chemical gradients from the target cell

What generally is the relationship between the activity of the sympathetic NS and the parasym NS

They usually have opposite affects on each other

What are two requirements for the brain to metabolize glucose?

Thiamine and oxygen

Which one of Sherrington's inferences about the synapse was WRONG?

Transmission at the synapse is primarily an electrical process.

Why is the speed of conduction through a reflex arc slower than the speed of a conduction of an action potential along an axon?

Transmission between neurons at synapses is slower than along axons.

Which is NOT performed by a glia?

Transmitting information. True: They remove waste materials, build myelin sheaths, guide the growth of axons and dendrites.

Early in the development, the nervous system begins as a:

Tube surrounding a fluid-filled cavity

When researchers try to estimate the heritability of a human behavior, what are the main kinds of individuals they consider?

Twins and adopted children.

marijuana

Used medically to relieve pain, nausea, and combat glaucoma.

The fluid-filled cavity of the developing neural tube becomes the:

Ventricular system

The main feature that distinguishes a neuron from other animal cells is that a neuron has:

a distinctive shape.

According to David Chalmers, consciousness is

a fundamental property of matter.

Any estimate of the heritability of a particular trait is specific to:

a given population.

The results of several studies of facial expressions in people who were born blind suggest:

a major role for genetics as well as environment in the control of facial expressions.

The all-or-none law states:

a neuron produces an action potential of maxiamal strentgth, or none at all.

amphetamine

a stimulant drug that increases the release of dopamine from the presynaptic terminal

An IPSP represents:

a temporary hyperpolarization.

Which of the following is TRUE about the spontaneous firing rates of neurons? a. EPSPs increase the frequency. b. EPSPs decrease the frequency. c. IPSPs increase the frequency. d. One EPSP equals the effect of two IPSPs.

a. EPSPs increase the frequency.

Which of the following would produce spatial summation? a. Present two or more weak stimuli at the same time. b. Start action potentials at both ends of one axon at the same time. c. Do not allow a flexor muscle to relax before stimulating it again. d. Present a rapid sequence of weak stimuli.

a. Present two or more weak stimuli at the same time.

A new drug is discovered that affects the activity of enzymes. Which of the following stages of synaptic transmission is most likely to be affected? a. Synthesis b. Diffusion c. action potential d. Release

a. Synthesis

After one frog's heart has been stimulated, 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? a. Transmission at synapses is a chemical event. b. The sympathetic and parasympathetic nervous systems are antagonistic. c. Transmission at heart muscle synapses is electrical. d. Hormones facilitate the actions of the nervous system.

a. Transmission at synapses is a chemical event.

Why is the speed of conduction through a reflex arc slower than the speed of conduction of an action potential along an axon? a. Transmission between neurons at synapses is slower than along axons. b. The longer an axon, the slower its velocity. c. Interneurons have thicker axons than other neurons. d. There are greater amounts of myelin involved in the reflex arc.

a. Transmission between neurons at synapses is slower than along axons.

A normal, healthy animal never contracts the flexor muscles and the extensor muscles of the same leg at the same time. Why not? a. When the interneuron sends excitatory messages to one, inhibitory messages go to the other. b. They are mechanically connected in a way that makes it impossible for both to contract at the same time. c. Such coordination is learned through prenatal movement. d. Both muscles are controlled by branches of the same axon.

a. When the interneuron sends excitatory messages to one, inhibitory messages go to the other.

The circuit from sensory neuron to muscle response is called: a. a reflex arc. b. a synapse. c. flexion. d. extension.

a. a reflex arc.

Avoiding foods with lecithin, such as eggs and peanuts, would affect which neurotransmitter level the most? a. acetylcholine b. serotonin c. GABA d. endorphin

a. acetylcholine

The basic building blocks for the majority of neurotransmitters are: a. amino acids. b. nitric oxide. c. sugars. d. carbohydrates.

a. amino acids.

Depolarization is to ____ as hyperpolarization is to ____. a. excitation; inhibition b. inhibition; excitation c. increasing the threshold; decreasing the threshold d. decreasing the threshold; increasing the threshold

a. excitation; inhibition

Exocytosis is the process by which neurotransmitters are: a. excreted into the synaptic cleft. b. synthesized. c. destroyed. d. secreted into synaptic vesicles.

a. excreted into the synaptic cleft.

An EPSP is a(n): a. graded depolarization. b. depolarization with a rebounding hyperpolarization. c. graded hyperpolarization. d. action potential in a reflex arc.

a. graded depolarization.

Inhibitory synapses on a neuron: a. hyperpolarize the postsynaptic cell. b. weaken the cell's polarization. c. increase the probability of an action potential. d. move the potential closer to the cell's threshold.

a. hyperpolarize the postsynaptic cell.

Nitric oxide's value is that it: a. increases blood flow to certain areas of the brain. b. restricts blood flow to certain areas of the brain. c. increases growth of microglia. d. decreases growth of microglia.

a. increases blood flow to certain areas of the brain.

effects drugs on dopamine synapses

a. increasing release of dopamine b. decreasing reuptake by presynaptic cell

High concentrations of all neurotransmitters, except for NO, are stored in the: a. presynaptic terminals. b. postsynaptic terminals. c. axon. d. cell body.

a. presynaptic terminals.

Which of the following patterns of post-synaptic excitation will most likely result in an action potential? a. rapid sequence of EPSPs b. rapid sequence of IPSPs c. large number of simultaneous IPSPs d. large number of simultaneous IPSPs and EPSPs

a. rapid sequence of EPSPs

amphetamine

a. reverses the dopamine transporter (protein) b. blocks synapses that inhibit dopamine release

Like an action potential, an EPSP results from: a. sodium ions entering the cell. b. potassium ions entering the cell. c. sodium ions exiting the cell. d. potassium ions exiting the cell.

a. sodium ions entering the cell.

Even at rest, most neurons have periodic production of action potentials, known as the: a. spontaneous firing rate. b. excitatory firing rate. c. all-or-none law. d. Dale's principle.

a. spontaneous firing rate.

What provides the building blocks for synthesizing all neurotransmitters? a. substances found in the diet b. breakdown products of DNA c. breakdown products formed from other transmitters d. methane and ethanol

a. substances found in the diet

Charles S. Sherrington was the first to infer the properties of which of the following? a. synapses b. the refractory period c. the sodium-potassium pump d. dendrites and axons

a. synapses

Sherrington found that repeated stimuli within a brief time have a cumulative effect. He referred to this phenomenon as: a. temporal summation b. spatial summation c. synaptic summation d. saltatory summation

a. temporal summation

Although slower than an action potential, synaptic transmission is still relatively fast because: a. the synaptic cleft is very narrow. b. sodium ions are transported quickly. c. neurotransmitters diffuse faster than electricity. d. EPSPs travel faster than IPSPs.

a. the synaptic cleft is very narrow.

Temporal summation is to ____ as spatial summation is to ____. a. time, location b. EPSP, IPSP c. location, time d. depolarization, hyperpolarization

a. time, location

The tiny packets that contain neurotransmitters in the presynaptic neuron are called: a. vesicles. b. bags. c. sacs. d. terminals.

a. vesicles.

false- nearly all

all addicting drugs release dopamine in nucleus accumbens

Which of the following would most likely interfere with migration of neurons during development?

altering the chemical paths

The basic building blocks for the majority of neurotransmitters are:

amino acids.

classical conditioning

an event that do not require attention can cause release of dopamine

A drug that blocks the effects of a neurotrans is a _____; a drug that mimics or increases effects is a _____

antagonist; agonist

If a drug has high affinity and low efficacy, what effect does it have on the postsynaptic neuron?

antagonistic

drugs

are able to dominate a user's attention

Compared to dendrites, axons usually:

are covered in myelin

Compared to dendrites, axons usually:

are covered with myelin.

nucleus accumbens

are stimulated by sexual activity, video games, and gambling

"Second messengers" carry their messages to:

areas within the postsynaptic cell.

The term pons (meaning "bridge") is named as such because:

axons within the pons cross over from one side to the other.

A temporary hyperpolarization is known as an: a. EPSP. b. IPSP. c. ISPS. d. EPIP.

b. IPSP.

The research that firmly established synaptic communication as chemical was: a. Elliot's adrenaline mimicking sympathetic activation. b. Loewi's transfer of fluid from stimulated frog hearts. c. Sherrington's study of reflexes. d. Eccles's measurement of IPSPs.

b. Loewi's transfer of fluid from stimulated frog hearts.

Which of the following statements regarding reflexes would Charles Sherrington most likely agree with? a. The overall speed of conduction through a reflex arc is faster than conduction along an axon. b. Repeated stimuli occurring within a brief time can have a cumulative effect. c. Each neuron physically merges with the next one. d. Excitatory synapses are more important than inhibitory synapses.

b. Repeated stimuli occurring within a brief time can have a cumulative effect.

What is the primary difference between temporal summation and spatial summation? a. Only spatial summation can produce an action potential. b. Spatial summation depends on contributions from more than one sensory neuron. c. Temporal summation produces a hyperpolarization instead of a depolarization. d. Spatial summation alters the response of more than one postsynaptic cell.

b. Spatial summation depends on contributions from more than one sensory neuron.

____ are specialized junctions between neurons. a. Nodes of Ranvier b. Synapses c. Dendrites d. Spines

b. Synapses

What do dopamine, norepinephrine, and epinephrine share in common? a. They all affect the same receptors. b. They are all synthesized from the same amino acids. c. They are all released by the same neurons. d. They all are gases.

b. They are all synthesized from the same amino acids.

Which of the following is TRUE about EPSPs? a. It takes two to produce an action potential. b. They decay over time and space. c. They can be either excitatory or inhibitory. d. They occur because potassium gates open.

b. They decay over time and space.

Which one of Sherrington's inferences about the synapse was WRONG? a. Transmission at a synapse is slower than transmission of impulses along an axon. b. Transmission at the synapse is primarily an electrical process. c. Synapses can be either excitatory or inhibitory. d. Synapses make spatial summation and temporal summation possible.

b. Transmission at the synapse is primarily an electrical process.

If you eat a food containing tryptophan, what can you consume with it to increase its entry to the brain? a. phenylalanine b. carbohydrates c. fats d. thiamine

b. carbohydrates

Loewi demonstrated that synapses operate by the release of chemicals. He did this by: a. applying adrenaline directly to the heart muscle. b. collecting fluid from a stimulated frog's heart, transferring it to another frog's heart, and measuring that heart rate. c. measuring the speed of a dog's reflexes while the dog was under the influence of various drugs. d. applying an extract of marijuana in eye drops and discovering that it dilated the pupils.

b. collecting fluid from a stimulated frog's heart, transferring it to another frog's heart, and measuring that heart rate.

An EPSP is to ____ as an IPSP is to ____. a. hyperpolarization; depolarization b. depolarization; hyperpolarization c. spatial summation; temporal summation d. temporal summation; spatial summation

b. depolarization; hyperpolarization

The neuron excretes neurotransmitter through its membrane by a process called: a. Dale's principle. b. exocytosis. c. endocytosis. d. voltage-dependent flow.

b. exocytosis.

Increased permeability to ____ would most likely result in an IPSP. a. sodium b. potassium c. calcium d. bicarbonate

b. potassium

Increased permeability to which of the following ions would most likely result in an IPSP? a. sodium b. potassium c. calcium d. bicarbonate

b. potassium

Acetylcholine is synthesized in the: a. postsynaptic terminal. b. presynaptic terminal. c. cell body. d. dendrites.

b. presynaptic terminal.

All of the following are catecholamines EXCEPT: a. dopamine. b. serotonin. c. norepinephrine. d. epinephrine.

b. serotonin.

The correct sequence of chemical events at a synapse is: a. reuptake, release, transport, synthesis b. synthesis, transport, release, reuptake c. transport, release, reuptake, synthesis d. recycle, reuse, release, return

b. synthesis, transport, release, reuptake

What causes an EPSP? a. the deactivation of cytoplasmic enzymes b. the opening of sodium channels c. the opening of potassium channels d. inherited paranormal psychic abilities

b. the opening of sodium channels

The presynaptic terminal stores high concentrations of neurotransmitter molecules in: a. axons b. vesicles c. peptides d. dendrites

b. vesicles