Chapter 9.3 - The Olfactory System
Limbic system
Action potentials for smell and taste propagate to the ______ ______
Rapidly
Adaptation (decreasing sensitivity) to odors occurs ______
Decreasing
Another mechanism of adaptation (decreasing sensitivity) occurs by _________ the opening of cAMO-gated cation channels, causing the olfactory transduction process to be less responsive to odorant
Nonmotile cilia
Extending from the dendrite of an olfactory cell receptor are several _____ _____, which are the sites for olfactory transduction
Neurons
Olfactory receptor cells are ______
Olfactory (I) nerves
On each side of the nose, bundles of axons of olfactory receptor cells form the right and left ____ (__) ______
Limbic system
Other axons of the olfactory tract project to the _____ _____; these neural connections account for our emotional responses to odors
Temporal
Some of the axons of the olfactory tract project to the olfactory cortex in the _______ lobe, where conscious awareness of smell occurs
Olfactory epithelium
The receptors for olfaction, the sense of smell, are located in a 5-cm^2 patch called the ______ ______ in the upper part of the nasal cavity
Phosphorylation
At the receptor level, adaptation seems to involve the _______ of odorant receptor proteins by a protein kinase This reduces the sensitivity of the olfactory receptor to odorant binding
Odorants
Chemicals that bind to and stimulate the receptors in the olfactory cilia are called _______
Olfactory receptor
Each glomerulus receives input from only one type of ______ ______ This allows the mitral cells of a particular glomerulus to convey information about a select group of odorants to the remaining parts of the olfactory pathway
Orbitofrontal cortex
From the olfactory cortex, a pathway extends via the thalamus to the _______ ______ in the frontal lobe, where odor identification and discrimination occur
Frontal
From the olfactory cortex, a pathway extends via the thalamus to the orbitofrontal cortex in the _______ lobe, where odor identification and discrimination occur
Low
Olfaction, like all of the special sense has a _____ threshold Only a few molecules of certain substances need be present in air to be perceived as an odor
Thalamus
Olfactory sensations are the only sensations that reach the cerebral cortex without first synapsing in the _________
Receptor
Only one type of ______ is found in any given olfactory receptor cell
Olfactory cortex
Some of the axons of the olfactory tract project to the ______ _____ in the temporal lobe, where conscious awareness of smell occurs
Olfactory receptor cells
The _____ _____ _____ are the first-order neurons of the olfactory pathway
Olfactory tract
The axons of the mitral cells form the _____ ______
Olfactory glands
The olfactory epithelium also contains ____ _____ which produce mucus that moistens the surface of the olfactory epithelium and dissolves odorants so that transduction can occur
Olfactory receptor cells
The olfactory epithelium consists of three types of cells: 1.) 2.) Supporting cells 3.) Basal cells
Supporting cells
The olfactory epithelium consists of three types of cells: 1.) Olfactory receptor cells 2.) 3.) Basal cells
Basal cells
The olfactory epithelium consists of three types of cells: 1.) Olfactory receptor cells 2.) Supporting cells 3.)
Olfactory bulbs
The olfactory nerves extend to parts of the brain known as the ______ _____, which contain ball-like arrangements called glomeruli
Glomeruli
The olfactory nerves extend to parts of the brain known as the olfactory bulbs, which contain ball-like arrangements called _______
Mitral cells
The olfactory nerves extend to parts of the brain known as the olfactory bulbs, which contain ball-like arrangements called glomeruli Within each glomerulus, axons of olfactory receptor cells converge onto _____ ______ - the second-order neurons of the olfactory pathway
Olfactory cilia
Within the plasma membranes of the ______ ____ are olfactory receptor proteins that detect inhaled chemicals
Olfactory receptor proteins
Within the plasma membranes of the olfactory cilia are ______ ______ ______ that detect inhaled chemicals
Olfactory receptor cells
______ ____ _____ are sensory neurons that respond to olfactory stimuli
Supporting cells
______ _____ provide physical support to the olfactory receptor cells and help detoxify chemicals that come in contact with the olfactory epithelium
Basal cells
______ ______ are stem cells that continually undergo cell division to produce new olfactory receptor cells, which live for only about two months before being replaced
Olfactory
_______ sensations are the only sensations that reach the cerebral cortex without first synapsing in the thalamus