Essay Example on The gustatory system is responsible for the taste and flavor perspective

The gustatory system is the sensory system that is responsible for the taste and flavor perspective In humans this sensory system is made up of taste cells in the mouth that are able to sense the different types of taste which are salty sweet bitter sour and umami and it is also made up of many cranial nerves and the gustatory cortex The gustatory cortex is important because it is the primary brain structure that is responsible for how differentiate taste and it includes the anterior insula on the insular lobe and the frontal operculum on the inferior frontal lobe which is what makes up this important structure that is used the taste pathway A taste receptor is a receptor that is primarily in the taste buds of the mouth which are found in structures known as papillae There are three different types of papillae that help to taste which are fungiform papillae foliate papillae and circumvallate papillae The last type of papillae which does not contain any taste buds are filiform papillae When food or drink enters the mouth the molecules mix with the saliva and are mostly bound to the taste receptors that are in the oral cavity 

Taste receptors function by using taste buds which contain super sensitive microscopic hairs that are referred to as microvilli Microvilli can function as a receptor by sending information to the brain according how things taste All tastes can be equally recognized on all parts of the tongue so that it can directly be sent to the brain The chemical substances that are responsible for taste comes into contact with nerve cells and it activates the cell by changing the specific proteins in the wall of the sensory cell This then causes the sensory cell to send messenger substances which are able to activate the nerve cells and pass information to the brain The papillae which contains several taste buds with sensory cells lie underneath the mucous membrane of the tongue and they function by increasing the surface area of the tongue to ensure that taste can be recognized to its fullest potential Every papillae on the tongue contains at least three to five taste buds The fungiform papillae are the most common are found at the tip of the tongue and the edges and these have a high sensitivity to taste as well as touch and temperature Circumvallate papillae are larger and can be found at the base of the tongue and they help to rinse the substances into the sensory nerve cells Lastly foliate papillae are found at the rear edges of the tongue 

The receptor molecules in the oral cavity mix with different components and are found on the apical microvilli parts of the taste cells The transduction portion of the oral cavity deals with ion channels that are also located on the apical and basolateral membranes of the oral cavity The ion channels are generally located in the axonal membranes that are on the basolateral parts of the receptors and they include the voltage gated channels of Na K and Ca2 that can produce the depolarizing potentials when the taste cells mix with the chemical stimulus The receptor potentials help to raise Ca2 to levels that are high enough for vesicle fusion and synaptic transmission Vesicle fusion is the merging of vesicles with other different vesicles and synaptic transmission is the process where the signaling neurotransmitters are released by the axon terminal of a neuron The greater the concentration of the taste the greater the depolarization of the taste cell will occur The apical surface of the taste cell receptor contains both channels and the G protein coupled receptors that are generally activated by chemical stimulus The basolateral surface contains the voltage gated channels and the components necessary for synaptic transmission that is mediated by serotonin which is a monoamine neurotransmitter 

The second messenger systems and the intracellular compartments that contain Ca2 are present in the basolateral surface as well An increase in intracellular Ca2 by either the activation of the voltage gated channels or the release from the intracellular compartments helps the synaptic vesicles to join together to release their neurotransmitters to receptors on the sensory neurons The receptors for salt NaCl are an epithelial type Na channel that are located on the apical membrane of taste cells The higher the NaCl concentration that is taken in through the mouth the larger the depolarization will be in the taste cells These specific Na channels are regulated by hormones that are involved with water and electrolyte balance in which can medicate the Na specific intake Another substance that can travel through this channel are protons like H but move at a slower rate than Na These protons are responsible for the sour taste that is perceived and they interact with channels on the apical membranes of the taste cells They also activate proton gated cations and Cl channels that activate to send information to the brain

The transduction of sweeter tasting substances needs the help of the activation of G protein coupled receptors which are located on the apical surface of the taste cells Saccharides activate the G protein coupled receptors which depolarizes the taste cells by activating the enzyme adenylate cyclase This then increases the cAMP concentration which is the second messengers in transduction processes that can directly or indirectly shut basolateral K channels The bitter tasting substances usually bind to the G protein coupled receptors that activate gustducin which is a G protein that is found in taste cells which causes the activation of the enzyme phosphodiesterase This action lowers the cyclic nucleotide concentration and closes the cyclic nucleotide channels that are located on the basolateral membranes of the taste cells To obtain the fullest potential of substances the receptors need to respond to the stimulus by allowing the channels to open and close with the help of saliva and other components to be able to send a response to the brain for analyzation