special sences Flashcards
What type of receptors do olfactory cells have?
Chemoreceptors
Where are Olfactory (Chemoreceptors) located?
In the nasal Epithelium lining the nasal cavity.
The cell bodies of the olfactory cells lye between supporting cells of the epithelium.
In order to stimulate olfactory cells for us to smell something the substance must be two things. What are they?
converted to a gaseous state and
water soluble
Axons leaving the olfactory cells penetrate the… what?
cribriform plate (ethmoid bone)
The fibers from the olfactory nerve travel to the brain via which cranial nerve?
Cranial nerve I
sensations of smell are experienced when impulses reach the…… in the temporal lobe.
olfactory cortex
The sense of taste is called what?
gustation
What cells are responsible for taste and where are they located?
Gustatory epithelial cells.
Located in taste buds mainly on the surface of the tongue in projections called lingial papillae.
Gustatory cells have fine projections called what that function as the actual taste receptors?
Microivilli
What are the three different types of lingual papillae, where are they located and how many taste buds to they have?
- Filiform papillae provide friction do not contain taste buds located to the back on the sides - Fungiform papillae contain 5 taste buds each located on the front - Circumvallate papillae contain 100 taste buds each located towards the back
There are 4 primary taste sensations. What are they and what are they stimulated by?
sweet - stimulated by sugars, saccharin
sour - stimulated by H+ (acids)
salt - stimulated by metallic salts, eg. Na+, K+
bitter - stimulated by alkaloids, e.g. quinine,
nicotine, morphine
In which regions of the tongue are the 4 primary taste sensations detected?
tip - sweet, salty
sides - sour
back - bitter
There are two additional taste sensations other than sweet, sour, bitter and salty. What are they?
Umami - amino acids, small peptides and nucleotides.
Water - water receptors in pharynx
Impulses from taste receptors travel into the medulla in a number of cranial nerves. What are the two primary ones?
Cranial Nerve VII - Facial
Cranial Nerve IX - Glossopharyngeal
Trace the pathway of light through the eye and to the visual cortex
cornea –> Anterior segment (aqueous humor) –> Pupil –> Lens –> Posterior segment (vitreous humor) –> Retina (rods and cones) –> Optic nerve –> optic chiasma –> optic tract –> Primary visual cortex