Olfactory and Gustation Flashcards
What senses are complementary?
Sense and taste
How do smell and taste work together?
Choose the right food
physiological responses involved in digestion
recognition of other animals
Both sense are strongly tied to primitive emotional and behavioural functions of the nervous system
What does the olfactory consist of
Olfactory bulb
Olfactory tract
Lateral olfactory gyrus
Piriform
Why is the olfactory system essential
localization of food
reflex stimulation secretion of digestive enzymes.
detection of danger
What are the olfactory cells are part of?
the specialized epithelium found on the ethmo-turbinate bones of the nasal cavity
What do the olfactory give rise to?
to the olfactory nerves that terminate in the olfactory bulb
What are the receptor cells for smell sensation?
Olfactory cells
- BIPOLAR NEURONS derived originally from the CNS
What are the receptor cells for smell sensation?
Olfactory cells
- BIPOLAR NEURONS derived originally from the CNS
What are the spaces among the olfactory cells
olfactory glands
What do the olfactory glands secrete?
mucus from the nasal cavity
Where are the olfactory cells located?
in the olfactory epithelium interspersed amoung supporting cells
Have cilia projecting into the mucus that coats the inner surface of the nasal cavity
The cilia reacts to odors in the air and stimulate the olfactory cells
What is the stimulation of the olfactory cells
The olfactory cilia responds to olfactory chemical stimuli
Describe the steps of the olfactory response to olfactory chemical stimuli
- odorant molecules that enter nasal cavity diffuse into the mucus
- bind to GPCR in the membrane of each cilium
- the alfa subunit activates adenylyn cyclase which produces cAMP
- cAMP activates A gated Na/C ion channels and allow influx of cations (mostly Ca+)
- Influx of Ca Actiavtes Cl- channels to open an Cl leaves the cell
Describe the steps of the olfactory response to olfactory chemical stimuli
- odorant molecules that enter nasal cavity diffuse into the mucus
- bind to GPCR in the membrane of each cilium
- the alfa subunit activates adenylyn cyclase which produces cAMP
- cAMP activates A gated Na/C ion channels and allow influx of cations (mostly Ca+)
- Influx of Ca actiavtes Cl- channels to open an Cl leaves the cell
- Membrane depolarizes and generates an excitatory post synaptic potential (EPSP) in the cilia
- EPSP travels from the cilia to the trigger zone of the olfactory cell to generate an AP
What is the central pathway for olfaction?
the olfactory nerve fibers terminate and synapse in the olfactory bulb to form the olfactory tract (CN I)
the olfactory reaches the piriform lobe as well as the non-olfactory of the brain that are part of the limbic system
What are the specific cells present in the olfactory bulb
Tufted cells
Mitral cells
Mitral cells
Dendrites of this cells synapse with terminal ends of the olfactory cells forming the glomeruli of the olfactory bulb
Neurotransmitter will excite the cells
What is the limbic system responsible for?
forming olfactory memories
* Olfaction can evoke emotional and autonomic responses
Olfactory signals do not directly project to the thalamus
Amydgala, entorhinal cortex, hippocampal formation, septal nuclei
* These areas also send olfactory signals to the hippocampus and frontal cortex
What is taste mainly functioning with
Taste bubs which contain taste receptor cell
Where are the taste receptors located
In dogs they are located in various types of papillae which are located dorsal and lateral surfaces of the tongue
What are the papillae regions
Fungiform
Vallate
Foliate
What are the sense of taste regions
Meaty Taste:Rostral 2/3 of the dorsal surface
Sweet taste: Rostral and lateral portions
Salty and sour: Caudal lateral sites
Bitter Taste: Caudal portion of the tongue
What are taste buds composed of?
Groups of columnar taste receptors cell
- bundles together like cluster of bananas
- taste receptors are arranged such that their tips form a small taste pore
- each taste cells has receptor for only one favour
How does the sense of get dissolved
Chemical molecules that trigger the sense of taste are disolved by saliva
- enter the taste buds though porse
- bind to the receptor located in the membrane of the microvilli
- the binding of molecules with receptors depolarizes the membrane of the taste cells - the mechanism depends on the tase molecule that binds to their specific receptor
