question: why are my taste buds off when I’m sick?
comment: Your taste buds aren't off, your nose is. Most of what you think of as taste is actually from your sense of smell. When you're sick your nose is stuffed up and you can't smell stuff so your sense of taste doesn't work as well.
passages: Dysgeusia, or an alteration in taste perception, is common, especially for those who are receiving concomitant radiation therapy to the neck and mouth area. "Taste blindness", or an altered sense of taste, is a temporary condition that occurs because of effects on taste buds that are mostly located in the tongue. Sometimes, only partial recovery of taste occurs. Common complaints are of food tasting too sweet or too bitter or of a continuous metallic taste.
  
  Section::::Signs and symptoms.:Complications.
   The tongue is covered with thousands of small bumps called papillae, which are visible to the naked eye. Within each papilla are hundreds of taste buds. The exception to this is the filiform papillae that do not contain taste buds. There are between 2000 and 5000 taste buds that are located on the back and front of the tongue. Others are located on the roof, sides and back of the mouth, and in the throat. Each taste bud contains 50 to 100 taste receptor cells.
   Taste in the gustatory system allows humans to distinguish between safe and harmful food, and to gauge foods’ nutritional value. Digestive enzymes in saliva begin to dissolve food into base chemicals that are washed over the papillae and detected as tastes by the taste buds. The tongue is covered with thousands of small bumps called papillae, which are visible to the naked eye. Within each papilla are hundreds of taste buds. The exception to this are the filiform papillae that do not contain taste buds. There are between 2000 and 5000 taste buds that are located on the back and front of the tongue. Others are located on the roof, sides and back of the mouth, and in the throat. Each taste bud contains 50 to 100 taste receptor cells.
   Distortions in the taste buds may give rise to dysgeusia. In a study conducted by Masahide Yasuda and Hitoshi Tomita from Nihon University of Japan, it has been observed that patients suffering from this taste disorder have fewer microvilli than normal. In addition, the nucleus and cytoplasm of the taste bud cells have been reduced. Based on their findings, dygeusia results from loss of microvilli and the reduction of Type III intracellular vesicles, all of which could potentially interfere with the gustatory pathway. Radiation to head and neck also results in direct destruction of taste buds, apart from effects of altered salivary output.
   The tongue can also feel other sensations not generally included in the basic tastes. These are largely detected by the somatosensory system. In humans, the sense of taste is conveyed via three of the twelve cranial nerves. The facial nerve (VII) carries taste sensations from the anterior two thirds of the tongue, the glossopharyngeal nerve (IX) carries taste sensations from the posterior one third of the tongue while a branch of the vagus nerve (X) carries some taste sensations from the back of the oral cavity.
   On average, the human tongue has 2,000–8,000 taste buds.
  
  Section::::Types of papillae.
  
  The taste buds on the tongue sit on raised protrusions of the tongue surface called papillae. There are three types of lingual papillae that contain taste buds present on the human tongue:
  
  BULLET::::- Fungiform papillae - as the name suggests, these are slightly mushroom-shaped if looked at in longitudinal section. These are present mostly at the dorsal surface of the tongue, as well as at the sides. Innervated by facial nerve.
   The tongue is covered with thousands of small bumps called papillae, which are visible to the naked eye. Within each papilla are hundreds of taste buds. The exception to this is the filiform papillae that do not contain taste buds. There are between 2000 and 5000 taste buds that are located on the back and front of the tongue. Others are located on the roof, sides and back of the mouth, and in the throat. Each taste bud contains 50 to 100 taste receptor cells.
   If the flavor has been encountered before the subject becomes ill, the effect will not be as strong or will not be present. This quality is called latent inhibition. Conditioned taste aversion is often used in laboratories to study gustation and learning in rats.
  
  Aversions can also be developed to odors as well as to tastes.
   Some people with HSAN2 experience a diminished sense of taste due to the loss of a type of taste bud on the tip of the tongue called lingual fungiform papillae.
   Section::::Structure.:Blood supply and innervation.
  
  The nerves supplying the palatine tonsils come from the maxillary division of the trigeminal nerve via the lesser palatine nerves, and from the tonsillar branches of the glossopharyngeal nerve. The glossopharyngeal nerve continues past the palatine tonsil and innervates the posterior 1/3 of the tongue to provide general and taste sensation. This nerve is most likely to be damaged during a tonsillectomy, which leads to reduced or lost general sensation and taste sensation to the posterior third of the tongue.
   The gustatory system consists of taste receptor cells in taste buds. Taste buds, in turn, are contained in structures called papillae. There are three types of papillae involved in taste: fungiform papillae, foliate papillae, and circumvallate papillae. (The fourth type - filiform papillae do not contain taste buds). Beyond the papillae, taste receptors are also in the palate and early parts of the digestive system like the larynx and upper esophagus. There are three cranial nerves that innervate the tongue; the vagus nerve, glossopharyngeal nerve, and the facial nerve. The glossopharyngeal nerve and the chorda tympani branch of the facial nerve innervate the TAS1R and TAS2R taste receptors. Next to the taste receptors in on the tonge, the gut epithelium is also equipped with a subtle chemosensory system that communicates the sensory information to several effector systems involved in the regulation of appetite, immune responses, and gastrointestinal motility 
   The main causes of taste disorders are head trauma, infections of upper respiratory tract, exposure to toxic substances, iatrogenic causes, medicines, and glossodynia ("Burning Mouth Syndrome (BMS)").
  
  Head trauma can cause lesions in regions of the central nervous system which are involved in processing taste stimuli, including thalamus, brain stem, and temporal lobes; it can also cause damage to neurological pathways involved in transmission of taste stimuli.
  
  Section::::Causes.:Neurological damage.
   The existence of neglect and/or extinction in taste is less explored than olfaction, even though in humans the ability to localize taste stimuli presented on the tongue has been previously described. In the case of a patient with a wide parietal-occipital tumor, tactile extinction on the upper limbs and extinction of taste sensations on the left part of the tongue where seen when two tastes were presented simultaneously on each hemitongue. The results of the assessment revealed there is unimodal taste extinction and displacement of taste sensations under crossmodal taste-tactile stimulation. In particular, when a touch was delivered to the right hemi-tongue and a taste was applied on the left hemi-tongue, the patient repeatedly reported bilateral taste stimulation, thus surprisingly extinguishing the right touch and partially misplacing the left taste stimulus. Gustatory extinction also seems to occur consequently to a severe tactile extinction.
   The central process passes toward the deep extremity of the bud, and there ends in single or bifurcated varicosities.
  
  The nerve fibrils after losing their medullary sheaths enter the taste bud, and end in fine extremities between the gustatory cells; other nerve fibrils ramify between the supporting cells and terminate in fine extremities; these, however, are believed to be nerves of ordinary sensation and not gustatory.
  
  The average lifespan of the cells of a taste bud is estimated to be 10 days.
  
  Section::::See also.
  
  BULLET::::- Tongue map
  
  Section::::External links.
  
  BULLET::::- Taste Perception: Cracking the Code
   Individual variation in the volume of EC is linked to taste perception. People with a larger EC in the left hemisphere found quinine, the source of bitterness in tonic water, less bitter. 
  
  Section::::Clinical significance.
  
  Section::::Clinical significance.:Alzheimer's disease.
   The chorda tympani innervates the fungiform papillae on the tongue. According to a study done by Sollars et al. in 2002, when the chorda tympani has been transected early in postnatal development some of the fungiform papillae undergo a structural change to become more “filliform-like”. When some of the other papillae grow back, they do so without a pore.
  
  Section::::Dysfunction.
  
  Loss of taste from anterior 2/3 of tongue. However, taste from the posterior 1/3 of tongue (supplied by the glossopharyngeal nerve) remains intact.
   Sores or ulcerations can become infected by virus, bacteria or fungus. Pain and loss of taste perception makes it more difficult to eat, which leads to weight loss. Ulcers may act as a site for local infection and a portal of entry for oral flora that, in some instances, may cause septicaemia (especially in immunosuppressed patients). Therefore, oral mucositis can be a dose-limiting condition, disrupting a patient’s optimal cancer treatment plan and consequentially decreasing their chances of survival.
  
  Section::::Pathophysiology.
   More evidence that suggests the relationship between tactile and taste extinction in the tongue comes from a patient with a right parieto-occipital glioblastoma, tested with local applications of the four basic tastants (bitter, salty, sour, sweet), or with touch and pin prick stimuli to the two sides of the tongue. The patient missed most of the left hemitongue stimuli on bilateral stimulation, or less frequently wrongly attributed to them the quality of the concurrent right stimulus. Combinations of taste and mechanical stimuli showed an interference of left side stimuli on the perception of right stimuli, suggesting a complex alteration of the central tactile and gustatory representations of both sides of the tongue. Given that taste perception is usually co-mingled with tactile sensations, it is possible that left-sided gustatory extinction in severe left buccal hemineglect was secondary to left-sided lingual tactile extinction.
   The upper surface of the tongue is covered in masticatory mucosa a type of oral mucosa which is of keratinized stratified squamous epithelium. Embedded in this are numerous papillae that house the taste buds and their taste receptors. The lingual papillae consist of filiform, fungiform, vallate and foliate papillae. and only the filiform papillae are not associated with any taste buds.
   This particular sensation, called chemesthesis, is not a taste in the technical sense, because the sensation does not arise from taste buds, and a different set of nerve fibers carry it to the brain. Foods like chili peppers activate nerve fibers directly; the sensation interpreted as "hot" results from the stimulation of somatosensory (pain/temperature) fibers on the tongue. Many parts of the body with exposed membranes but no taste sensors (such as the nasal cavity, under the fingernails, surface of the eye or a wound) produce a similar sensation of heat when exposed to hotness agents. Asian countries within the sphere of, mainly, Chinese, Indian, and Japanese cultural influence, often wrote of pungency as a fifth or sixth taste.
   Studies on conditioned taste aversion which involved irradiating rats were conducted in the 1950s by Dr. John Garcia, leading to it sometimes being called the Garcia effect.
  
  Conditioned taste aversion sometimes occurs when sickness is merely coincidental to, and not caused by, the substance consumed. For example, a person who becomes very sick after consuming vodka-and-orange-juice cocktails may then become averse to the taste of orange juice, even though the sickness was caused by the over-consumption of alcohol. Under these circumstances, conditioned taste aversion is sometimes known as the "Sauce-Bearnaise Syndrome", a term coined by Seligman and Hager.
  
  Section::::Garcia's study.
   Like the olfactory system, the taste system is defined by its specialized peripheral receptors and central pathways that relay and process taste information. Peripheral taste receptors are found on the upper surface of the tongue, soft palate, pharynx, and the upper part of the esophagus. Taste cells synapse with primary sensory axons that run in the chorda tympani and greater superficial petrosal branches of the facial nerve (cranial nerve VII), the lingual branch of the glossopharyngeal nerve (cranial nerve IX), and the superior laryngeal branch of the vagus nerve (Cranial nerve X) to innervate the taste buds in the tongue, palate, epiglottis, and esophagus respectively. The central axons of these primary sensory neurons in the respective cranial nerve ganglia project to rostral and lateral regions of the nucleus of the solitary tract in the medulla, which is also known as the gustatory nucleus of the solitary tract complex. Axons from the rostral (gustatory) part of the solitary nucleus project to the ventral posterior complex of the thalamus, where they terminate in the medial half of the ventral posterior medial nucleus. This nucleus projects in turn to several regions of the neocortex which includes the gustatory cortex (the frontal operculum and the insula), which becomes activated when the subject is consuming and experiencing taste.
   Concerning hearing, Lussana argues that auditory vertigo, a disorder of the movements of the head and body, is due to a lesion of the semicircular canals, because the victim cannot perceive the direction of sounds ("The semicircular canals and the vertigo of Meniere", Naples 1891). 
  
  As for flavors, Lussana notes that the bitter taste is perceived on the back of the tongue, sweet on the tip, sour and salty at its edges ("innervation of taste".)
  
  Section::::Work.:Maize and pellagra.
   The registry analysed the effects of Caphosol in head and neck cancer patients along with the frequency of patient dosing, adherence to treatment, and patient and physician global satisfaction assessments. Patients at risk of oral mucositis were given Caphosol and instructed to rinse 4-10 times daily depending on the severity of the mucositis. Patients and physicians completed questionnaires on the symptoms of oral mucositis, mucositis severity and satisfaction with the treatment.
   These bumps are small, white bumps on the base of the tongue. They are likely to be the result of transient lingual papillitis (TLP). This condition is limited to the upper (dorsal) surface of the tongue, affecting some of the tiny bumps on the tongue known as the fungiform papillae, what we commonly call the "taste buds." 
  
presuppositions: Taste buds don't work well when you are sick. Taste comes from your taste buds.
corrections: Your nose doesn't smell well when you are sick. Most of what you think as taste is actually from your sense of smell, and your nose gets stuffed up when you are sick.
raw_presuppositions: Taste buds don't work well when you are sick. Taste comes from your taste buds.
raw_corrections: Your nose doesn't smell well when you are sick. Most of what you think as taste is actually from your sense of smell, and your nose gets stuffed up when you are sick.