Neuro 3000 Exam 2 Questions

Classify molecules as neurotransmitters

1) Synthesized and stored in presynaptic neurons 2) Released by presynaptic terminal in response to stimulation - Ca2+ dependent 3) Molecule must produce a response in postsynaptic cell receptors

What is the neural groove

17 days from conception brain is flat sheet of cells then the formation of a groove in the neural plate that runs rostral to caudal is called the neural groove

Most transmitter-gated ion channels have what in common:

4 hydrophobic segments that span the neuronal membrane

What is a ligand?

A chemical compound that binds to a specific site on a receptor

Describe how a "population code" could provide neural coding for taste?

A large number of broadly tuned neurons specify the properties of each taste stimulus

What is the function of cAMP in olfactory transduction?

Activates cAMP-gated cation channels

What leads to the difference in ion concentration b/t the fluid in the perilymph and the fluid in the endolymph?

Active transport processes taking place at the stria vascularis - Perilymph has low K+ and high Na+ concentrations, and the endolymph has high K+ and low Na+. The difference in ion contact b/t the endolymph and the perilymph is generated by active transport processes at the stria vascularis, which result in a reabsorption of sodium and secretion of potassium against their concentration gradients

What is the neural crest?

As the neural folds come together, some ectoderm is pinched off and lays laterally to the neural tube

When does signal amplification occur in GPC 2nd messenger cascade?

At several stages of the cascade

Why is the auditory system different from the vestibular system?

Auditory info operates at conscious level, where as the vestibular system is unconscious level

Central taste (fancy name: "gustatory") pathway

Axons of Face nerve (VII) --> glossopharyngeal nerve (IX) --> Vagus nerve (X) --> synapse in gustatory nucleus of brain stem Then goes to - VPM nucleus of thalamus --> PGC (Brodmann's 36)

What is acoustic radiation?

Axons that interconnect the MGN to the auditory cortex

What is a Fornix?

Bundle of axons that connect to hippocampus on each side of brain with mammillary bodies of hypothalamus

Catecholamines in the cleft are terminated how?

By selective reuptake of neurotransmitters back into the axon terminal via Na+ dependent transporters

Endocannabinoids act on what voltage-gated ion channel

Ca2+

Catecholaminergic neurons are transmitters that contain what chemical structure?

Catechol

Why does bathing brain slices in concentrated K+ soon stimulate neurotransmitter release?

Causes a large membrane depolarization when stimulate transmitter release from axons. Ca2+ must be present/entering in order for transmitter to be released. The release of candidate from tissue after depolarization occurs only when Ca2+ ions are present, too.

what is a good marker for cholinergic cells?

ChAT

What effect does choline have on ACh synthesis?

Choline availability limits how much ACh can by synthesized in terminal

When does convergence in neurotransmitters mean?

Convergence occurs when multiple transmitters (each with own receptor type) converge to affect the same effector system

If a person is deaf in only one ear, what probably happened?

Destruction of cochlear nucleus - ipslateral

what part of they developing NS is the retina formed by?

Diencephalon

Tell me about eye development

Diencephalon --> optic vesicle --> optic cup --> retina & optic stalk (-becomes optic nerve). And part of CNS

olfactory receptor cells are mapped onto glomeruli of the olfactory bulb in what manner of organization?

Each glomerulus receives input only from receptor cells expressing the same receptor gene

Nervous system develops from which layer?

Ectoderm

What is AChE?

Enzyme that degrades ACh into choline and acetic acid, removing it from the cleft

What is ChAT?

Enzyme that transfers the acetyl group from acetyl CoA to choline to synthesize ACh

Bending of the stereocilia on hair cells causes Na+ to enter and depolarize the cells: (T/F)

False

Cells that make epinephrine and dopamine always contain dopamine B hyroxyase (T/F)?

False

Cells that make only epinephrine or only dopamine always contain PNMT. T/F

False

Loudness (intensity) is determined only by the firing rate of spiral ganglion cells (T/F)

False

Olfactory information is conveyed only by one type of olfactory receptor cell for each odor (T/F)

False

Specific taste receptor cells (ie. salt)are distributed in specific areas on the tongue: (T/F)

False

Vescular and membrane transporter both use H+ gradients to drive transport (T/F)

False

all sweets are detected by a family of sweet receptors.. (T/F)?

False

the tegmentum is dorsal to the tectum (T/F)

False

G proteins are used in the detection of salt? (T/F)

False - transmitter gated

Cells that make epinephrine and dopamine always contain dopamine B-hydroxyase

False...

neurons in the cochlear nucleus receive input from both ears (T/F)?

False.... because the cochlear nuclei are two heterogeneous collections of neurons in the brain stem that receive input from the cochlear nerve

All neurotransmitters are packaged into vesicles (T/F)

False...?

Which of the following is the definition of phase locking?

Firing of a cell at the same phase as that of a sound wave - Phase locking is the consistent firing of a cell at the same phase of a sound wave, even if the neuron does not fire at every cycle of the sound wave

Which taste receptors are for bitter?

G protein coupled receptors

Do G-proteins stimulate or inhibit effector proteins?

G-protein can stimulate (Gs) or inhibit (Gi) effector proteins

Major source of inhibition in the NS?

GABAergic neurons

what is the tonotopic map?

In physiology, tonotopy is the spatial arrangement of where sounds of different frequency are processed in the brain.

AchR are coupled to what ion channel via GCPR's

K+ channels - Muscarinic receptors are activated when Ach binds that then activate Gby subuints which directly gates K+ channel

An unusual thing about receptor binding proteins in beginning of olfactory transduction pathway?

Large number of odorant receptor proteins

TRPA 1 channel on the tips of stereo cilia and does what to the hair cell?

Moving hair cells in one direction opens K+ channel and inc. inward K+ current and depolarizes the cell. moving in opposite direction closes TRPA1 channels and prevent inward K+. Thus, moving back and forth causes hyperpolarize and depolarize cell ==> receptor potential!

How do Na+ channels in the taste receptor differ from voltage-gated Na+ channels in neurons?

Na+ channel is insensitive to voltage - amiloride-sensitive channel is open all the time

What part of NS develops from neural crest?

Neurons with cell bodies in the PNS

What is ACh?

Neurotransmitter at NMJ and is produced by all motor neurons in spinal cord, brain stem, many CNS neurons

The CNS contains 2 of the 12 pairs of carinal nerves - what are they?

Olfactory and optic

What are the cell types of the olfactory epithelium?

Olfactory receptors, supporting cells, basal cells - Olfactory receptors are the site of transduction. They are genuine neurons. Supporting cells similar to glia help produce the mucus in which odorants are dissolved. Basal cells are a source of new receptor cells

What is a sensory map?

Orderly arrangement of neurons

What is unusual about the olfactory projections to cortex?

Other sensory systems pass through the thalamus before projecting to cortex, but some olfactory connections to cortex are direct

Name 3 catecholamine neurotransmitters and their precursor molecule.

Precursor - Tyrosine 3 catecholamines - DA, NE, epinephrin aka adrenaline

What happens when AChE is inhibited

Prevents ACh breakdown

Amphetamines and cocaine do what to DA and NE synapses?

Prolong presences of neurotransmitter in the cleft

What cells provide the scuffling for cell migration in the developing cortex?

Radial glial cells

How do papillae response when stimulus concentration is just above threshold value?

Selective for one basic taste

Thalamus is the gateway to the neocortex, why?

Sensory pathways all relay in the thalamus before terminating in cortex

What is the structure of most GCPR's?

Single polypeptide containing 7 membrane spanning alpha helices. 2 of the extracellular loops on polypeptide form the transmitter binding sites.

The diencephalon becomes the:

Thalamus and Hypothalamus

What is meant by divergence in neurotransmitter systems?

The ability of 1 transmitter to activate more than 1 subtype of receptor

When someone pushes us aside, what type of sensory information do we use to reorient ourselves in space?

The position of our head and body and information about how they are moving in space

What is Differentiation?

The process by which structures become more complex and functionally specialize during development

What is neurulation?

The process by which the neural plate becomes the neural tube.

Which of the following describes the shortcut pathway for G-protein-coupled effector systems?

The shortcut pathway includes 3 elements, the receptor, the G-protein, and the ion channel

Which of the following is incorrect? a. The entire CNS is derived from the walls of the neural tube b. Failure of the neural tube to close can result in anencephaly or spina bifida c. The three primary vesicles formed after neurulation are the telencephalon, the mesencephalon, and the rhombencephalon d. Skeletal muscles are derived from the mesoderm

The three primary vesicles formed after neurulation are the telencephalon, the mesencephalon, and the rhombencephalon

What is the rate limiting step in ACh synthesis?

The transport of choline into the neuron

Sweet and bitter receptors have what in common?

They are both G-protein coupled receptors

Why are auditory receptors called hair cells?

They have hairy-looking stereocilia

Different transporter families are used to load neurotransmitters into synaptic vesicles and to remove them from the synaptic cleft (T/F)

True

Glutamate is a major excitatory neurotransmitter in brain. (T/F)

True

Glutamate is removed from the synaptic cleft by cells other than neurons (T/F)?

True

the sound frequency or pitch is determined by signals from hair cells at specific locations along the basilar membrane (T/F)?

True

Most of the parasympathetic innervation of the viscera originate in what nerve?

Vagus - which emerges from the medulla

What fibers are contained w/in the spinal nerve of the spinal cord?

Ventral and dorsal roots

What system helps coordinate head and eye movements?

Vestibular system

Define receptor potential

a change in membrane potential in a receptor in response to an appropriate stimulus

What is the Longitudinal cerebral fissure?

a fissure that separates the 2 cerebral hemispheres

Define in situ hybridization

a method for localizing mRNA transcripts for specific proteins or peptides

Umami taste is produced by....

amino acids and glutamate

what is the function of the outer hair cells?

amplify sound (inner hair cells: sound to nerve signal)(outer hair cells: acoustical preamplifiers)

what is the function of the ossicles (small bones) in ear?

amplify the force of the tympanic membrane at the oval window

A bundle is defined as:

axons that run together but may not have same origin and destination

The dorsal roots that connect to the spinal cord carry __________ _________ information. a. Afferent, motor b. Afferent, sensory c. Efferent, motor d. Efferent, sensory

b. Afferent (carrying into brain from Periphery), sensory

Difference b/t sulcus and fissure?

both are grooves b/t the gyri but fissures are deeper than sulci

How is sound localized in the vertical plane?

by using the differential reflections of the sound by the curves, bumps, and ridges of the pinna

What is the composition of a taste bud?

c) Taste receptor cells, basal cells, and gustatory afferent axons

Which of the following statements is false? a) 2 different neurotransmitters don't bind to the same receptor b) Each neurotransmitter can bind to different subtypes c) nicotinic acetylcholine receptors are G-protein linked d) Agonist and antagonist can be used to classify receptor subtypes

c) nicotinic acetylcholine receptors are G-protein linked - they are transmitter-gated

Which of the following is FALSE regarding G protein coupled receptors : a. Signal slower than ligand-gated receptors b. Signaling through the same receptor can have multiple actions c. Always present only on postsynaptic cells d. Have four transmembrane regions

c. Always present only on postsynaptic cells

What is the function of the muscles attached to the ossicles? a.Transmit the majority of the sound information to eardrum b. Amplify sounds c. Attenuate loud sounds d. Vibrates the round window

c. Attenuate loud sounds

Someone with a stroke in the right primary auditory cortex will be: a. Completely deaf b. Deaf in right ear c. Normal hearing but trouble with sound localization d. None of the above

c. Normal hearing but trouble with sound localization

Which is FALSE about olfactory reception: a. Signals sent to the cortex before going to the thalamus (major relay center) b. Use population coding to convey information c. Olfactory receptor cells expresses multiple types of receptors d. All of the above are true

c. Olfactory receptor cells expresses multiple types of receptors

during the period of neural proliferation, which cells remain in the ventricular zone and continue to divide?

cells which divide vertically

Dorsal view - order of brain?

cerebrum, cerebellum, brain stem, spinal cord

if the basilar membrane became less stiff, what would be the consequence?

change in ability to detect sound frequencies

which of the following regarding olfaction is false? odorants bind to olfactory receptors on celia golf activation occurs after odorant binding to receptor ca enters cl enters

cl actually exits

The shape of the pinna influences the response of the auditory system to sound?

collect sound from a wide area

What is dopa decarboxylase?

converts dopa into DA

Which major fiber bundle connects the 2 cerebral hemispheres?

corpus callosum

G protein coupled receptors do what?

create amplified responses to neurotransmitter binding & exert long-lasting effects on the cell

Molecules are classified as neurotransmitters: a. By being released by postsynaptic cells - Nope, released by presynaptic cell b. Being released by presynaptic cells in Ca dependent way c. Must be made in presynaptic neuron d. Two of the above e. All of the above

d) 2 of the above - b. Being released by presynaptic cells in Ca dependent way c. Must be made in presynaptic neuron

List 3 important structures of the basal telencephalon, collectively known as the basal ganglia.

d) Caudate nucleus, putamen, and the globes pallidus - The cerebral cortex forms the surface of the brain and although it is telencephalic, is not part of the basal telencephalon, which is deep to the cortex. The septal area contributes axons to the fornix and is involved in memory. The caudate nucleus, putamen, and the globes pallidus are 3 important structures of the basal telencephalon, collectively known as the basal ganglia. They are important for brain control of movement.

Which of the following is involved in generating changes in the hair cell receptor potential when stereo cilia bend? a) Equilibrium potential of -80 mV for K+ ions b) Opening the Na+ channels c) High conc. of K+ in perilymph d) TRPA1 channel on the tips of the sterocilia

d) TRPA1 channel on the tips of the sterocilia - TRPA1 Channels are mechanically gated channels found on the tips of the sterocilia. When sterocilia are straight, the TRPA1 channels are partially open and allow only a small leak of K+ from the endolymph into the hair cells. Diplacement in one direction opens the channel and increases the inward K+ current and depolarizes the hair cell' displacing the cilia in the opposite direction closes the TRPA1 Channel completely, preventing inward K+ movement. When a should wave causes the sterocilia to bend back and forth, the hair cells generate receptor potentials that alternately hyper polarize and depolarize the cell membrane relative to the resting potential of -70mV

Why does yawning or swallowing at high elevations reduce the pressure in the ear?

d) The eustachian tube opens

Which of the following is false: a. Transmitter gated channels usually have five subunits b. Gate either anions or cations but not both c. Structure influences function d. All are true

d. All are true

Which of the following is incorrect? During forebrain differentiation: a. Cells form distinct layers in the cortex with the 'oldest' cells being most interior b. Neural cells use other support cells to help migrate to their final destination c. Neurogenesis continues even into adulthood d. Most CNS cells are already fully differentiated prior to migrating to the external surfaces of the forebrain

d. Most CNS cells are already fully differentiated prior to migrating to the external surfaces of the forebrain

Why are we able to detect bitter substances so well? a. Many types of receptors b. Uses labeled lines c. Sensitive to low levels of bitter d. Two of the above e. All of the above

d. Two of the above - a. Many types of receptors b. Uses labeled lines

To stimulate signaling at a synapse one would: a. Apply agonist b. Apply antagonist c. Use reuptake inhibitor d. Two of the above e. All of the above

d. Two of the above - a. Apply agonist b. Apply antagonist

Which is FALSE regarding the vestibular system: a. Controls eye movement b. Uses hair cells c. Detects head tilt, linear and rotational acceleration d. Uses cranial nerve VII (vestibular nerve) to transmit signals

d. Uses cranial nerve VII (vestibular nerve) to transmit signals

What is the quality of the taste called umami?

delicious

A neurite might

developing neuron may turn into an axon or a dendrite

the optic vesicles are derived from the:

diencephalon

Which of the following can act through G protein coupled receptors: a. Peptide neurotransmitters b. Dopamine c. Acetylcholine d. Serotonin e. All of the above

e. All of the above

The ventral root that connects to the spinal cord carry what information?

efferent motor

What is heroine hydroxylase?

enzyme that catalyzes 1st step in catecholamine synthesis - the conversion of tyrosine --> dopa

Which of the following taken back up by the presynaptic cell: a. Acetylcholine b. Epinephrine c. Dopamine d. Serotonin e. All are taken back up f. All but one

f. All but one - a. Acetylcholine - is destroyed in the synaptic cleft by AChE

The olfactory tracts connect to the thalamus before the cortex as in other sensory systems (T/F)?

false... olfactory cilia - olfactory neuron- olfactory nerves to olfactory bulb- mitral cells - olfactory tract - ipsilateral cerebral hemisphere (piriform cortex) - lateral olfactory Stria - medial olfactory stria... skips thalamus!!!

G proteins are used in the detection of salt, bitter, and umami?

false..sweet, bitter, umami

how is sound intensity (loudness) determined?

firing rate of spiral ganglion cell neurons, tonotopic map

why does the composition of endolymph need to be different from that of perilymph in the cochlea?

higher K+ concentration needed to depolarize hair cells - Big difference here: K+ goes into cell, not out of it - (Endolymph = High K+, Low Na+ vs. Perilymph = Low K+, High Na+)

Absence of the gene that encodes the protein T1R1 causes what?

inability to taste glutamate

odorants a) signal using multiple mechanisms b) inhibit G-proteins c) increase cAMP d) Bind to glia in the olfactory epithelium

increase cAMP.... this initiates learning. odorants can elicit inhibitory responses as well as excitatory responses...

nerve gas paralyzes the muscles of the respiratory system by....

inhibiting acetylcholinesterase which leads to desensitization of acetylcholine receptors

sound localization in the horizontal plane uses....

interaural time delay

Comparing the times at which the same phase of the sound wave reaches each ear can help determine the...

location of a continuous tone source

Are all transmitter (or ligand) gated channels excitatory?

nope... Inhibitory. (acetylcholine can be both... excitatory in nicotinic PNS receptors and inhibitory is muscarinic CNS receptors)

The olfactory pathway is unique b/c it has a direct and heavy influence on parts of forebrain which has roles in:

odor discrimination, emotion, motivation, some memory

Which tastes use H+ sensitive TRP channels?

only sour (book is wrong)

What are the 2 structures of the vestibular labyrinth?

otolith organs and semicircular canals

How does the attenuation reflux help us understand speech better in a noisy environment?

reflex suppresses low-frequency sounds

Serotonergic neurons do what

regular mood, emotional behavior, and sleep - not inhibitory

Catecholaminergic neurons are found in regions of the NS involved with

regulation of movement, mood, attention, and visceral function

Weird thing that endocannabinoids do?

retrograde signaling

which of the following is NOT part of the vestibular system? hair cells semicircular canals otolith organ round window

round window

IN what layer of the meninge's will you find arterial vasculature?

subarachnoid space

the cerebral aqueduct connects:

the third ventricle with the fourth ventricle

what is the function of the inner hair cells?

transmit the majority of the sound information to the spiral ganglion

what is the function of the oval window?

transmit vibrations to the perilymph. oval window directly contacted by stapes; by the time vibrations reach the oval window they're amplified.

Odor quality may be represented by temporal patterns of neural firing (T/F)?

true

Olfactory information can be represented by population coding (T/F)

true

Olfactory information is input to brain areas involved with memory (T/F)

true

Olfactory receptor proteins are 7 transmembrane proteins (T/F)?

true

Olfactory receptor proteins are expressed in zones (T/F)

true

Olfactory system forms a spatial map of odors even though not clear how this information is used (T/F)?

true

Transmitter or ligand gated channels are usually closed until igand binds

true

Transmitter or ligand gated channels are usually closed until ligand binds...

true

what is immunochemistry?

using antibodies to localize channels or receptors

in the human brain, the temporal lobe is _____ to the parietal lobe.

ventral