Question 1

The sense of smell requires that the odorant molecule has some water solubility because

The nasal mucosa is composed of lipids
The receptors are embedded in an aqueous environment
Odorants must pass through ion channels
All odorants are charged ions
Cells are 90% water

Question 2

The detection of an odorant occurs

When the odorant molecule diffuses through the membrane of the receptor cell
By the kinetic vibrational energy of the odorant molecule's side group bonds exciting the receptors
When the odorant molecule binds to a specific receptor allowing energy loss by electron tunnelling
When an odorant binds to beta-carotenes in the pigment granules and causes a semi-conductor current
When the odorant binds to one of seven different shaped receptor sites

Question 3

Olfactory receptor cells are

Bipolar neuro-epithelial cells
Epithelial cells which synapse with the primary afferent olfactory nerve
Specialised nerve endings
Typical sensory neurones

Question 4

The olfactory receptors are

Located within the receptor cells
Situated on cilia projecting from the receptor cell
Located in pits in the olfactory mucosa
Found on the surface of olfactory papillae
Freely diffusing binding proteins in the olfactory mucosa

Question 5

Which one of the following statements is NOT true

The olfactory receptor cells are linked directly to the olfactory bulb
Olfaction in humans is under descending inhibition
The olfactory system is linked to the limbic system
The olfactory system connects directly to the cerebellum
Olfactory cells project to the thalamus

Question 6

In olfaction

The larger the odorant molecule the less it smells
Charged molecules have no smell
Charged molecules only smell if they pass through ion channels
The size of the odorant molecule plays no role in its smell
An odorant must have transferrable electrons in order to smell

Question 7

Olfactory receptor cells

Exhibit graded receptor potentials in response to stimulation
Hyperpolarise in response to stimulation
Fire action potentials in response to stimulation
Change their rate of firing in response to stimulation
Cannot fire action potentials