Definitions


accessory olfactory bulb- the structure in the brain where neural impulses from the vomeronasal organ are processed.

action potential- a brief fluctuation in membrane potential caused by the rapid opening and closing of voltage-gated ion channels. Action potentials sweep like a wave along axons to transfer information from one place to another in the nervous system.

Adenylyl cyclase-an enzyme that catalyzes the conversion of ATP to cAMP, a second messenger

ATP (adenosine triphosphate)- the molecule that is the cell's energy source. The hydrolysis of ATP to produce adenosine diphosphate (ADP) releases energy that fuels most of the biochemical reactions of the neuron.

chemoreceptor- any sensory receptor selective for chemicals

Cyclic adenosine monophosphate- a second messenger formed from ATP by the action of the enzyme adenylyl cyclase

depolarize - to make the membrane potential less negative.

diencephalon- a region of the brain stem including the thalamus and hypothalamus

epilethelium-see olfactory epithelium

glomerulus- a cluster of neurons in the olfactory bulb that receives input from olfactory receptor neurons

G-protein- a membrane-bound protein that binds GTP when activated by a membrane receptor. Active G-proteins can stimulate or inhibit other membrane-bound proteins.

hypothalamus- the ventral part of the diencephalon, involved in the control of the autonomic nervous system and the pituitary gland.

Korsakoff's Syndrome- A neurological syndrome resulting from chronic alcoholism, characterized by confusion, confabulations, apathy, and amnesia.

limbic system- a group of interconnected deep brain structures, common to all mammals and involved in olfaction, emotion, motivation, behavior and various autonomic function

nasal septum- the cartilage separating the nostrils

neocortex- the cerebral cortex with six or more layers, found only in mammals

olfaction- the sense of smell

olfactory bulb- a bulb-shaped brain structure derived from the telencephalon that receives input from olfactory receptor neurons

olfactory cleft- narrow cavity lying on each side of the nasal septum at the very top of the nose in which the olfactory membrane lies.

olfactory cortex- the region of the cerebral cortex connected to the olfactory bulb and separated from the neocortex by the rhinal fissure.

olfactory epithelium- a sheet of cells lining part of the nasal passages that contains olfactory receptors

proteins- a molecule constructed from amino acids according to genetic instructions

second messenger- a short lived chemical signal in the cytosol that can trigger a biochemical response. Second messenger formation is usually stimulated by a first messenger (a neurotransmitter or hormone) acting as a G-protein-coupled cell surface receptor.

thalamus- the dorsal part of the diencephalon, highly interconnected with the cerebral neocortex.

transduction- the transformation of sensory stimulus energy into a cellular signal, such as a receptor potential.

unmyelinated- lacking the membranous wrapping around axons provided by oligodendroglia in the CNS and Scwhwann cells in the PNS. Unmyelinated neurons are slower in the transduction of signals than myelinated neurons.


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