PCB exam 2

What is the passive electrical property of a neuron that can be described as the ability of the neuron to store an electric charge?

Capacitance

What is the active electrical property of a neuron that can be described as a loss in signal strength?

Decrement

What is defined as the difference in the electrical potential between the external and the internal environments of the cell?

Membrane Potential

What is defined as a measure of a membrane’s permeability to ions/charge?

Membrane Conductance

What describes the relationship between resistance, voltage, and current across a membrane?

Ohm’s Law

What states that the equilibrium potential depends on the absolute temperate, the charge on the ion in question, and the ratio of ionic concentrations on the two sides of the membrane?

Nernst Equation

What is the resting potential of a standard mammalian neuron?

-70mv

The resting potential is due to an uneven exchange of cations by a transmembrane sodium-potassium pump. What is the exchange?

3 Na+ are pumped out of the cell for 2 K+ being pumped into of the cell

What happens when the interior voltage of a neuron becomes more negative relative to the resting potential?

Hyperpolarization

What change from the resting potential will cause an action potential?

Depolarization

What is the region on the axonal hillock where the neuron will integrate incoming signals to determine if it will generate an action potential?

Spike Initiating Zone

During which phase of the action potential will the membrane depolarize and Na+ channels open allowing sodium to flood into the cell?

Rising Phase

When does the depolarization of the cell stops? The membrane potential is at its maximum.

Peak Phase

During which phase of the action potential will the membrane potential temporarily become more negatively charged than when at rest (hyperpolarized)?

Undershoot Phase

During which phase of the action potential will the membrane potential temporarily become more negatively charged due to the opening of voltage-gated K+ channels) which allows K+ to exit the cell?

Falling Phase

Which supporting cells will remove excess K+ from the surrounding interstitial space during the refractory period?

Astrocytes

Which type of potential cannot be propagated and is prone to decrement the further you get from the site of stimulation?

Graded Potential

Myelin will insulate the neurons and affect the length constant of the neuron. How does myelin affect the length constant of an axon?

greatly increases it which increases the efficiency at which the longitudinal current spreads.

Which of the following is not a characteristic of an electrical synapse?

The response will have a different sign than the source (ex, hyperpolarization of the presynaptic neuron causes depolarization of the postsynaptic neuron)

The flow of what ion into the axon terminal will signal the synaptic vesicles to move to the Active Zones on the presynaptic membrane near the synaptic cleft?

Ca+2

Once the neurotransmitter has bound to receptor proteins on the post-synaptic membrane what type of ion channels will open up to allow for the continuation of a Fast Chemical Synapse?

ligand-gated

The key difference in a Slow Chemical Synapse (from a Fast Chemical Synapse) is that their neurotransmitters alter the level of signal molecules within the postsynaptic cell which will eventually modify its ion channels.

True

What characteristic describes a postsynaptic potential?

subject to decrement

What type of postsynaptic potential does the neurotransmitter Glutamate trigger?

Excitatory Postsynaptic Potential

What type of postsynaptic potential is able to control the generation of an impulse by the postsynaptic cell through the summation of their voltage effects?

Both

What is the only essential element in synaptic transmission (at an NMJ)?

Ca+2

What is the term for the folds of the (postsynaptic) sarcolemma in an NMJ?

Junctional Folds

What is the neurotransmitter between the motor neuron and skeletal myofiber in an NMJ?

Acetylcholine

What is the neurotransmitter between the presynaptic and postsynaptic neuron in fast excitatory postsynaptic potential neurons of the vertebrate CNS?

Glutamate

What do the neurotransmitters bind to on the postsynaptic membrane in a Slow Chemical Synapse?

metabotropic receptors

The activity of the G Proteins of a Slow Chemical Synapse is regulated by factors that control their ability to bind to and hydrolyze GTP into GDP. What is their state when they bind GDP?

they are turned off

What are the transmembrane proteins that will activate G proteins (in a Slow Chemical Synapse) after a neurotransmitter binds to them?

G protein coupled receptors

What is the limiting factor in the synthesis of acetylcholine?

choline

What is the general term for a diverse group of small peptide molecules synthesized and released by neurons? They include vasopressin.

Neuropeptides

In which mechanism for the recycling of synaptic vesicles do we see the vesicular membrane fuse with the presynaptic membrane and be retrieved through endocytosis?

Classical Pathway

What is considered to be the most primitive reflex arc in most animal species?

Monosynaptic Reflex Arc

What has evolved from the ganglia and their connectives in Annelids and Arthropods?

ventral nerve cord

What is the tapering, caudalmost portion of the vertebrate spinal cord?

conus medullaris

What type of information is processed by the dorsal horns of spinal cord grey matter?

both visceral and somatic sensory

What is considered to be the most primitive portion of the typical vertebrate brain?

medulla oblongata

Which of the following brain regions does not contain the reticular formation?

hippocampus

Which region of the diencephalon is the main visceral control center of the body?

hypothalamus

Which region of the diencephalon plays a major role in the endocrine system since it influences the actions of the pituitary gland?

hypothalamus

Which division of the Autonomic Nervous System uses a two-neuron relay system?

both do

Which division of the Autonomic Nervous System uses epinephrine/norepinephrine to communicate with the target organ?

Sympathetic

Which division of the Autonomic Nervous System causes the “flight-fright-fight response”?

Sympathetic

Which division of the Autonomic Nervous System arises craniosacrally from the CNS?

Parasympathetic

Which division of the Autonomic Nervous System has both chain and prevertebral ganglia?

Sympathetic

What is the term for the process by which a receptor cell will change stimulus energy into the energy of a nerve impulse?

Transduction

Which stage of the event described in question #49 often involves the use of G proteins?

amplification of stimulus

Which type of sensory receptors will fire action potentials continuously during the duration of the stimulus?

Tonic Receptors

Which type of sensory receptor will have a receptor potential traveling down the neuron until it gets to the spike initiating zone? At the spike initiating zone it will directly modulate the production of action potentials and is now called a Generator Potential.

sensory neuron receptor

What is the term for the range over which an animal’s particular sensory system will be able to encode the stimulus?

Dynamic Range

Which form of gustatory reception uses the G protein Gustducin?

bitter

What are the taste receptors of insects called?

uniporous sensilla

What enzyme in olfaction will be activated by a G protein and in turn will catalyze an increase in cAMP in the receptor cell? This will result in an impulse forming and traveling to the CNS.

Adenylate Cyclase

What does the pheromone bind to in the receptor cells of the vomeronasal organ to cause the depolarization of these pheromone receptor cells?

seven-transmembrane-helix-receptor proteins

What ion is very abundant in the endolymph of an insect mechanoreceptor?

K+

What is the term for the “hair-like” projections of the statocysts (equilibrioceptors found in many invertebrates)? They project into the statolith membrane.

setae

In the vertebrate macula the otoliths will be pulled by gravity in one direction or another causing a deformation of the neuroepithelial stereocilia. What does this deformation cause?

an increase in ion permeability resulting in depolarization

What causes the differences in the degree of depolarization between the outer and inner hair cells in the Organ of Corti which results in the ability to detect different pitches and tones?

the degree of deformation of their associated stereocilia (“hairs”)

What ion is very abundant in the endolymph of the membranous labyrinth of the cochlea?

K+

What is the term for the photoreceptor units of the invertebrate compound eye?

ommatidia

Which layer of the vertebrate retina has the retinal ganglion cells which organize the visual signal and send them to the brain?

Ganglion Layer

What is the second amplification step in the vertebrate eye?

each cGMP-specific phosphodiesterase hydrolyzes 1000 cGMP molecules

What is the term for the movement of cations into the vertebrate photoreceptor causing the membrane potential to be at -40mv when the cells are not being stimulated by light?

Dark Current

What causes activation of the vertebrate rods and cones?

hyperpolarization