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33 terms

Olfaction and Taste

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Receptors for olfaction and taste
Chemoreceptors
Taste buds
structures on the tongue that contain the receptor cells for taste
papillae
rough, bumpy elevations on the dorsal surface of the tongue
types of papillae
Cicumvellate, filiform, and fungiform
each taste bud consists of two types of cells which include
gustatory, basal
serves the anterior two-thirds of the tongue
facial nerve (VII)
serves the posterior third of the tongue
glossopharyngeal nerve (IX)
carries a few fibers from the pharyngeal region
vagus nerve (X)
5 types of taste
Sweet, Salty, Sour, Bitter, Umami
Sweet taste
signals sugars and carbohydrates
Unami taste
elicited by L-amino acids and nucleotides
Salty taste
generated by Na
Bitter taste
thought to protect against ingesting poisons
Sour taste
Citric acid, tartaric acid, acetic acid
Why can't you taste sugar immediately on a dry tongue?
because no saliva is present to respond to the nose
Describe the location and cellular composition of the olfactory epithelium.
The olfactory epithelium occupies an area of about 5 cm2 in the roof of the nasal cavity. The specialized receptor cells in the olfactory epithelium are surrounded by supporting cells, non-sensory epithelial cells. The olfactory receptor cells are bipolar neurons whose olfactory cilia extend outward from the epithelium.
How and why does sniffing improve your sense of smell?
It directs more air containing the substance being smelled through the nose to the tongue, which is where the smell is processed.
five sites where receptors for taste are found.
Most are located on the dorsal surface of the tongue. A few are found on the soft palate, epiglottis, pharynx, and inner surface of the cheeks.
Describe the cellular makeup and arrangement of a taste bud (diagrammatic representation).
Taste buds consist of both gustatory cells and basal cells. They are located deep between circumvallate papilla
Why is it impossible to taste substances with a dry tongue?
Because there is no saliva present in the mouth.
How palatable is food when you have a cold?
Food is less palatable when you have a cold because your nose is blocked up and you cannot smell the food. The smell of food is a big factor affecting your perception of the flavor. When you have a cold, most foods taste rather bland because you cannot smell them.
Outer ear
The portion of the ear consisting of the pinna and the external auditory canal. The outer ear is separated from the middle ear by the tympanic membrane (the eardrum).
Middle ear
the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window.
Inner ear
The part of the ear where sound is transduced into neural impulses; consists of the cochlea and semicircular canals.
Decibels
loudness of sound
Conductive hearing loss
results from diseases or disorders that limit the transmission of sound through the outer of middle ear. This hearing loss can usually be treated medically or surgically.
Sensorineural hearing loss
Affects the inner ear or neural pathways. In this case, sound is transmitted through the outer and middle ears, but the inner ear is less efficient in transmitting the sound, usually due to damages to the fine nerve endings inside the cochlea. This leads to reduced perception of sound intensity and quality. This type of hearing loss is usually compensated with a hearing instrument that amplifies sound to overcome the decrease in hearing sensitivity.
Combination hearing loss
Is the simultaneous occurrence of conductive and sensorineural hearing loss, which is also referred to as mixed haring loss.
If Conduction deafness is present
sound will be heard more strongly in the ear in which there is a hearing loss due to sound conduction by the bone of the skull.
Nystagmus
involuntary rolling of the eyes in any direction or the trailing of the eyes slowly in one direction, followed by their rapid movement in the opposite direction.
vertigo
condition in which one feels that one's surroundings are turning about; dizziness
Equilibrium depends on input from a number of sensory receptors, these are
Vestibular receptors, Visual receptors, Somatic receptors.
What effect does alcohol consumption have on balance?
Alcohol depresses the neurons and enhances the inhibition of coordination and causes a loss of equilibrium reflexes.