5 Written Questions

1. Diminished olfaction.
2. Thalamic pathways projecting to the ____ convey conscious perception and discrimination of odors. Olfactory pathways leading to the ____ mediate emotional/motivational/behavioral/physiological effects.
3. A complete lack of olfaction.
4. Lowered sensitivity to a specific odorant (with intact sensitivity to other odorants) caused by lacking an odorant receptor.
5. When odorants bind to their receptor, they interact with a ____ which activates ____ increasing ____ which opens cyclic nucleotide gated cation channels causing ____ influx and a change in cilium membrane potential (____).

5 Matching Questions

1. IP3, cGMP, and CO
2. Action potential
3. bipolar; cribriform plate; olfactory bulb; one; numerous
4. Cacosmia
5. General anosmia and hyposmia

1. a What is the type of membrane potential change produced in olfactory sensory neurons that are stimulated by an odorant?
2. b List three other second messengers (besides cAMP) that may play a role in signal transduction in the olfactory system.
3. c ____ may be caused by respiratory infections (transient), head trauma, damage to the cribriform plate that heals over and severs olfactory axons, and Parkinsons.
4. d Olfactory neurons are ____ nerve cells embedded in the epithelium of the nasal cavity's dorsal posterior recess. Axons travel through the ____ and into the ____. They have ____ dendrite terminating into ____ cilia at the mucous membrane surface.
5. e Olfactory hallucinations of repugnant smells due to epileptic seizures.

5 Multiple Choice Questions

1. What are the maximum numbers of odorants and tastants that human beings can distinguish?
   1. Contribute to odorant concentration/removal
   2. Odorant and tastant
   3. Urine or glandular secretions
   4. Thousands of odorants, over a hundred tastants
2. Name the two olfactory systems in animals that sense pheromones.
   1. Main olfactory system and accessory olfactory (vomeronasal) system.
   2. orbitofrontal cortex/neocortex; amygdala/hypothalamus
   3. Urine or glandular secretions
   4. bipolar; cribriform plate; olfactory bulb; one; numerous
3. Describe the hypothetical functions of the odorant binding proteins that are contained in the mucous of the olfactory mucosa.
   1. Odorant and tastant
   2. Contribute to odorant concentration/removal
   3. Urine or glandular secretions
   4. Action potential
4. Describe one property of olfactory neurons that distinguishes them from other neuronal types.
   1. Main olfactory system and accessory olfactory (vomeronasal) system.
   2. Taste cells are short lived and replaced from stem cells at the base of the taste bud.
   3. G protein; adenylyl cyclase type III; cAMP; Na/Ca; depolarization
   4. They are short-lived (30-60 days) and continuously replaced by the basal stem cell population lining the epithelium closest to the cribriform plate.
5. Compare the turnover of taste receptor cells and neurons.
   1. Main olfactory system and accessory olfactory (vomeronasal) system.
   2. Thousands of odorants, over a hundred tastants
   3. Taste cells are short lived and replaced from stem cells at the base of the taste bud.
   4. bipolar; cribriform plate; olfactory bulb; one; numerous

5 True/False Questions

1. Influence estrus cycles, regulate the age of onset of puberty, prevent fertilized embryo implantation, and signal receptivity of females for mating. → Explain the basis for the ability of olfactory sensory neurons to detect a wide variety and large number of odorant molecules.

   True        False

2. Action potentials → What are the kinds of membrane potential changes that are produced in taste cells of the taste buds by tastants?

   True        False

3. Umami (monosodium glutamate) → What is a fifth possible taste quality that has been identified?

   True        False

4. No → ____ taste occurs by the passage of H+ through amiloride-sensitive Na+ channels or blockade of K+ channels by H+.

   True        False

5. Vision → Name another sensory modality whose receptors utilize a similar transduction mechanism to the olfactory one.

   True        False