True and False Questions Exams 1-3

Plaques develop when the second splice of APP is made by beta secretase, which creates longer splices that stick together thereby forming plaques.

True

Some people who have a limb amputated still vividly feel the presence of that limb.

True

Tan was a patient of Paul Broca who could only say a single word and upon his death Broca discovered that a part of his cortex was damaged. That part is now referred to as Broca's area.

True

The Ca++ that enters through NMDA receptor-channels in the dendritic spines of hippocampal and cortical cells can activate a Ca++/calmodulin dependent protein kinase.

True

The main purpose of an action potential is to transmit a signal rapidly over long distances, and with high fidelity.

True

The most recent development in prostheses for quadriplegics is the demonstration that monitoring activity from the motor cortex can be used to stimulate the muscles of a paralyzed person and allow him or her to make movements that he or she intended to make.

True

The quantal hypothesis holds that each end plate potential is the result of the simultaneous release from the nerve terminal of many quanta of ACh, where each quantum has the ACh content that produces one miniature end plate potential.

True

The quantal hypothesis was proposed by Bernard Katz who won the Nobel Prize for his studies of synaptic transmission

True

The quantal hypothesis was supported by the discovery of the presence of synaptic vesicles. Large numbers of synaptic vesicles were seen in electron micrographs of the neuromuscular junction and some were seen fused to the membrane of the axon terminal, suggesting that these vesicles were each releasing one quantum of transmitter into the synaptic cleft.

True

The representation of the body surface in the somatosensory pathway is a distorted representation since the most sensitive parts of the body receive the largest representation in the brain

True

The unit of contraction in all striated muscle is the sarcomere

True

layer 4 of the cortex is always well developed in sensory portions of the cortex

True

the cortex is a thin layer of cells that covers the telencephalon

True

the medulla is the most caudal (or posterior) portion of the hindbrain

True

One feature of some people who have neglect syndrome is that they deny that anything is wrong.

True

The representation of the body surface in the somatosensory pathway is distorted because the arms and legs receive a larger representation than do the hands and lips.

False

There are both ionotropic and metabotropic receptors for all neurotransmitters.

False

A synapse capable of generating Long Term Potentiation (LTP) is not capable of also producing (Long Term Depression) LTD.

False

Camilio Golgi is considered to be the father or modern neuroscience

False

Fibers in the corticospinal tract make their first synapse in the medulla and the axons of the cells in the medulla then cross to the opposite side before projecting to the spinal cord.

False

Phineas Gage was one of the patients whose epilepsy was relieved by surgically removing a small part of the brain.

False

Shibire flies carry mutant forms of synaptotagmin, a protein that is thought to be important for the recycling of synaptic vesicles.

False

Small unmyelinated axons utilize saltatory conduction to speed up their conduction.

False

The amount of current flow of an ion across the membrane is determined only by its driving force

False

The effects of transmitters on metabotropic receptors are to open channels that are part of the receptor and thereby generate action potentials.

False

The mapping of the body surface in the brain is hard wired and cannot change.

False

The myelin sheath slows down the conduction velocity of an axon because it prevents the movement of ions across the cell membrane.

False

The representation of the body surface in the somatosensory pathway is a distorted representation since the largest parts of the body surface receive a disproportionate amount of neural space.

False

The representation of the body surface in the somatosensory pathway is an exact representation of the size of each of the body parts

False

ACh is excitatory at the neuromuscular junction, because it generates EPSPs in skeletal muscles. This means that it is the transmitter, ACh in this case, that determines whether the postsynaptic response in any neuron will be excitatory or inhibitory.

False - ACh does not determine it, it is the kind of presynaptic neuron that releases its transmitter into that synapse. The critical factor is the response of the ligand-gated channel to the release of transmitter.

Cholinesterase is located inside the presynaptic terminal and breaks down ACh once it is reabsorbed after release.

False - ACh esterase

Amyloid precursor protein (APP) is normally spliced in two steps. The first splice is made by alpha secretase and the second by beta secretase, which produces a shorter version of the amyloid protein that does not form plaques.

False - Alpha-secretase cuts APP closer to cell membrane so APP fragment released is longer than when Beta-secretase cuts APP - Second cut by Gamma-secretase releases 40 beta-amyloid, the short version that doesn't aggregate and form plaques

Plaques form and Alzheimer's disease occurs when there is an imbalance in the short and long forms of the beta-amyloid, where the amount of short form greatly exceeds the amount of long form.

False - Plaques are formed when "sticky" 42 Beta-amyloid monomers agglutinate to form dimers which then form oligomers. These oligomers agglutinate into plaques

Synapsin is the calcium sensor that cause vesicle fusion when calcium enters the presynaptic terminal.

False - Synaptotagmin

Curare is an antagonist for muscarinic Ach receptors.

False - antagonist for nicotinic Ach receptor

Skeletal muscle fibers are interconnected by electrical synapses or gap junctions.

False - by NMJ

The quantal hypothesis holds that synaptic transmission occurs through the release of one molecule of transmitter, where each molecule constitutes a quantum of transmitter that generates a miniature end plate potential.

False - causes the simultaneous release of many quanta

the thalamus is part of the telencephalon

False - diencephalon

the cerebellum is a part of the midbrain

False - hindbrain

the pons is a part of the midbrain

False - hindbrain

Threshold for generating an action potential occurs when the influx of potassium is just slightly greater than the efflux of sodium.

False - influx of sodium and efflux of potassium

It is the transmitter that determines whether the postsynaptic response in any neuron will be excitatory or inhibitory.

False - it is the kind of presynaptic neuron that releases its transmitter into that synapse and the response of the ligand-gated channel to the release of transmitter.

Spines are found on dendrites and axons.

False - just dendrites

Anode break excitation occurs after a long period of membrane depolarization.

False - occurs when a neuron is hyperpolarized for tens of milliseconds, then quickly brought back to rest, therefore lowering the threshold and generating an action potential.

Nodes of Ranvier are plentiful on long thin dendrites

False - on axon

People who suffer a small stroke confined only to their right precentral gyrus will often deny the existence of parts of their bodies on the left side.

False - precentral gyrus is the motor cortex

The S3 segment is the voltage sensor in all voltage gated ion channels

False - s4

Muscarinic Ach receptors are metabotropic receptors.

True

Neurofibrillary tangles are formed from tau proteins liberated from microtubules when tau become hyperphosphorylated.

True

A person whose hand been amputated might still feel sensations in his or her hand when either portions of the face or arm are stimulated.

True

All striated muscle is innervated by neurons that use acetylcholine as their neurotransmitter.

True

Alternative splicing of RNA transcription is one feature that accounts for the large number of different types of potassium channels found in cells.

True

Botulinum toxin attacks proteins involved in vesicle fusion, and thus prevents transmitter release, but only in excitatory neurons.

True

CaMKII is necessary for generating Long Term Potentiation (LTP). One way that it acts is by phosphorylating AMPA receptors.

True

Calcium is stored in the sarcoplasmic reticulum in skeletal muscle.

True

Catecholamine transmitters, such as serotonin and noradrenalin, are not usually broken down by a catalytic enzyme, but instead, are retaken into the presynaptic terminal by transporters.

True

Freeing of vesicles tethered to the cytoskeleton in the storage pool is brought about by phosphorylation of synapsin by a Ca++/calmodulin dependent protein kinase.

True

GABA and glycine receptors are the two major types of ligand gated channels that produce inhibitory responses in the central nervous system.

True

If a neuron is electrically stimulated at the terminal of its axon, it should generate an action potential that propagates backward to its soma.

True

In skeletal muscle, a single action potential causes the release of sufficient amounts of calcium to occupy all troponin sites and thereby cause a maximal shortening of all sarcomeres in the fiber.

True

Just outside the active zone, a reserve pool of transmitter-filled vesicles is held anchored to actin filaments of the cytoskeleton.

True

LTP and LTD are opposite process whereby generating LTD can reverse LTP at a synapse.

True

LTP is caused by an increase in the conductance of AMPA receptors due to phosphorylation of a portion of the receptor together with the recruitment of additional AMPA receptors at the synapse.

True

Loewi's experiment on the heart was the first conclusive demonstration of chemical neurotransmission between a nerve and its target cell

True