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
Nissl Substance or Bodies
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.
Gamma aminobutyric Acid (GABA)
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