Pocket Companion to Guyton & Hall Textbook of Medical Physiology E-Book (Guyton Physiology) by Hall John E

Author:Hall, John E. [Hall, John E.]
Language: eng
Format: mobi
ISBN: 9781416054511
Publisher: A Saunders Title
Published: 2011-03-01T16:00:00+00:00

Transmission of Smell Signals into the Central Nervous System (p. 651)

The olfactory bulb lies over the cribriform plate of the ethmoid bone that separates the cranial and nasal cavities. The olfactory nerves pass through perforations in the cribriform plate and enter the olfactory bulb, where they terminate in relation to glomeruli. This is a tangled knot of mitral and tufted cell dendrites and olfactory nerve fibers. Mitral and tufted cell axons leave the olfactory bulb via the olfactory tract and enter specialized regions of the cortex without first passing through the thalamus.

The medial olfactory area is represented by the septal nuclei, which project to the hypothalamus and other regions that control behavior. This system is thought to be involved in primitive functions such as licking, salivation, and other feeding behavior.

The lateral olfactory area is composed of the prepiriform, piriform, and cortical amygdaloid regions. From here, signals are directed to less primitive limbic structures, such as the hippocampus. This apparently is the system that associates certain odors with specific behavioral responses.

Another, phylogenetically newer pathway projects to the dorsomedial thalamic nucleus and then onto the orbitofrontal cortex.

Fibers that originate in the brain course centrifugally to reach granule cells in the olfactory bulb. The latter cells inhibit mitral and tufted neurons of the bulb, and in this way one’s ability to distinguish different odors is sharpened.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.