neuroscience 2

a small conical elevation on the soma of a neuron that does not contain Nissl substance; the site of the generation of action potentials in a neuron.

cytoplasmic component of the neuron that is the main determinant of its shape

formed by two strands of polymerized globular actin monomers. play an important role in the motility of growth cones during development

material consisting of RNA granules (ribosomes)

glial cell that supports neurons in the brain and regulates the chemical and extracellular environments

modified astrocytes found in the retina

specialized ependymal cells found in the floor of the third ventricle; their processes extend into the brain tissue, where they are juxtaposed to blood vessels and neurons. They are implicated in the transport of hormones from the cerebrospinal fluid to capillaries of the portal system and from hypothalamic neurons to the CSF

supporting cells responsible for myelination of axons in the central nervous system.

connective tissue sheath that encloses each bundle of nerve fibers

Positively charged ion

Negatively charged ions

• protein that transports a specific substance or group of substances through intracellular
• compartments or in extracellular fluids (in the blood) or else across the cell membrane.

difference in concentrations of a solute during transport; solute moves from high to low areas of concentration

process by which substances are moved across the cell membrane without chemical energy

reduction in the negative charge inside a neuron

increase in the negative charge inside a neuron

channels that allow some ions to cross the membrane in the direction of their concentration gradients

receptor in which four to five protein subunits are arranged in such a way that the recognition site for the neurotransmitter is part of the ion channel; a transmitter binds to its receptor and brings about a conformational change that results in the opening of the ion channel.

a membrane potential at the trigger zone at which action potentials become self-propagating

allosteric protein that is mostly in the closed state at rest and opens in response to a stimulus

time required for the sodium channel to revert from inactivated to resting state (de-inactivation) of the neuron

is an area where two neurons are apposed to each other at an electrical synapse

each hemichannel in a gap junction channel

fluid filled gaps which separate the cells of the presynaptic terminal and postsynaptic neuron

are brief local changes in membrane potential that occur in neuronal dendrites and cell bodies, but not axons

the synapse of the axon terminal of a neuron with the motor end-plate.

occurs when the postsynaptic membrane is on the cell body (soma) of another neuron

synaptic arrangement in which postsynaptic and presynaptic membranes are similar in thickness (inhibitory synapse)

occurs when the postsynaptic membrane is on the axon of another neuron

• electrical potential generated at the muscle
• end-plate; elicited by activation of nicotinic cholinergic receptors located at
• the end-plate by acetylcholine

the site where action potentials are generated; the axon hillock is the trigger zone in neurons.

process in which there is fusion of the neurotransmitter-containing vesicle with the presynaptic terminal membrane, resulting in an opening through which the neurotransmitter is released into the synaptic cleft.

protein involved in endocytosis; forms a basket-like lattice on the remnants of a fused vesicle giving the appearance of a coated pit

contain small-molecule neurotransmitters; found at fast synapses

pre-peptide from which the signal sequence of amino acids is removed

serves as a neurotransmitter at the terminals of preganglionic neurons in the sympathetic as well as parasympathetic ganglia, at the terminals of parasympathetic post-ganglionic neurons.

major excitatory amino acid neurotransmitter in the central nervous system synthesized from glutamine in presence of the enzyme glutaminase.

small-molecule inhibitory neurotransmitter synthesized from glutamate by the enzyme, glutamic acid decarboxylase

small-molecule, inhibitory neurotransmitter synthesized from serine

chemical compound that contains a catechol (benzene ring with two adjacent hydroxyl groups [e.g., dopamine, norepinephrine, and epinephrine])

a small-molecule catecholamine neurotransmitter synthesized from tyrosine