BIO202 CORRECT EXAMS SCRIPT ALL QUESTIONS
AND ANSWERS SURE A+
✔✔True or False. Both sensory receptors and sensory receptor cells have axons -
✔✔False, only sensory receptors have axons to exhibit action potentials. Sensory
receptor cells only produce graded potentials (no axon)
✔✔Answer the following about the Olfactory epithelium:
a) What is it?
b) Contains what kind of cells to properly register different smells? Each of these cells
has how many receptors?
c) From b), these cells are what kind of neuron?
d) Leads to what part of the brain? What is this structure? - ✔✔a) A specialized sensory
tissue in the roof of the nasal cavity
b) Olfactory receptor cells; each has only ONE olfactory receptor
c) Bipolar sensory neuron - fused
d) Leads to the olfactory bulb of the brain. The olfactory bulb is the first brain structure
that receives and processes smell information from olfactory receptor cells
✔✔Olfactory bulb is a spinal or cranial nerve? - ✔✔Cranial
✔✔Why are olfactory receptor cells unique among sensory receptor cells? -
✔✔Olfactory receptor cells are sensory neurons and can generate action potentials
, ✔✔What is the pathway of olfactory information from air to brain? - ✔✔Odorant in air →
olfactory epithelium → olfactory receptor neuron → holes in the bony cribriform plate →
olfactory bulb in brain
✔✔Bipolar neurons of the olfactory system contain what receptors on which part of
them? How do they make up the olfactory epithelium? - ✔✔The cilia of bipolar neurons
contain odorant receptor proteins that detect incoming chemical stimuli. These cilia
project into a mucus layer holding these proteins and coats the olfactory epithelium
✔✔Which stimulation of the 5 special senses can reach the cerebral cortex directly
without relaying through the thalamus first? - ✔✔Olfactory stimulation
✔✔Explain the steps of Chemoreception in the Olfactory system - ✔✔1) An odorant
enters the nose and dissolves in the mucus covering the olfactory epithelium
2) The odorant reaches the cilia of an olfactory receptor neuron
3) The odorant binds to a specific odorant receptor protein on the cilium. This receptor
is a G-protein-coupled receptor (GPCR)
4) Odorant binding activates the olfactory G-protein (Golf) and the activated G-protein
stimulates adenylate cyclase
5) Adenylate cyclase converts ATP → cAMP. cAMP acts as a second messenger inside
the olfactory receptor neuron
6) cAMP binds to and opens cAMP-gated cation channels, so Na⁺ and Ca²⁺ enter the
cell
7) The incoming Ca²⁺ activates Ca²⁺-activated Cl⁻ channels, so Cl⁻ leaves the cell
(Olfactory neurons have an unusually high intracellular Cl⁻ concentration, so opening
Cl⁻ channels causes Cl⁻ to flow out, not in)
8) Depolarization occurs (Na⁺ enters, Ca²⁺ enters, and Cl⁻ leaves)
9) If the depolarization is large enough, it reaches the trigger zone, so the voltage-gated
Na⁺ channels open
10) The olfactory receptor neuron fires action potentials along the axon and the signal
travels to the olfactory bulb in the brain for processing
✔✔What organ detects pheremones and where is it located in mammals vs reptiles? -
✔✔Vomeronasal Organ
AND ANSWERS SURE A+
✔✔True or False. Both sensory receptors and sensory receptor cells have axons -
✔✔False, only sensory receptors have axons to exhibit action potentials. Sensory
receptor cells only produce graded potentials (no axon)
✔✔Answer the following about the Olfactory epithelium:
a) What is it?
b) Contains what kind of cells to properly register different smells? Each of these cells
has how many receptors?
c) From b), these cells are what kind of neuron?
d) Leads to what part of the brain? What is this structure? - ✔✔a) A specialized sensory
tissue in the roof of the nasal cavity
b) Olfactory receptor cells; each has only ONE olfactory receptor
c) Bipolar sensory neuron - fused
d) Leads to the olfactory bulb of the brain. The olfactory bulb is the first brain structure
that receives and processes smell information from olfactory receptor cells
✔✔Olfactory bulb is a spinal or cranial nerve? - ✔✔Cranial
✔✔Why are olfactory receptor cells unique among sensory receptor cells? -
✔✔Olfactory receptor cells are sensory neurons and can generate action potentials
, ✔✔What is the pathway of olfactory information from air to brain? - ✔✔Odorant in air →
olfactory epithelium → olfactory receptor neuron → holes in the bony cribriform plate →
olfactory bulb in brain
✔✔Bipolar neurons of the olfactory system contain what receptors on which part of
them? How do they make up the olfactory epithelium? - ✔✔The cilia of bipolar neurons
contain odorant receptor proteins that detect incoming chemical stimuli. These cilia
project into a mucus layer holding these proteins and coats the olfactory epithelium
✔✔Which stimulation of the 5 special senses can reach the cerebral cortex directly
without relaying through the thalamus first? - ✔✔Olfactory stimulation
✔✔Explain the steps of Chemoreception in the Olfactory system - ✔✔1) An odorant
enters the nose and dissolves in the mucus covering the olfactory epithelium
2) The odorant reaches the cilia of an olfactory receptor neuron
3) The odorant binds to a specific odorant receptor protein on the cilium. This receptor
is a G-protein-coupled receptor (GPCR)
4) Odorant binding activates the olfactory G-protein (Golf) and the activated G-protein
stimulates adenylate cyclase
5) Adenylate cyclase converts ATP → cAMP. cAMP acts as a second messenger inside
the olfactory receptor neuron
6) cAMP binds to and opens cAMP-gated cation channels, so Na⁺ and Ca²⁺ enter the
cell
7) The incoming Ca²⁺ activates Ca²⁺-activated Cl⁻ channels, so Cl⁻ leaves the cell
(Olfactory neurons have an unusually high intracellular Cl⁻ concentration, so opening
Cl⁻ channels causes Cl⁻ to flow out, not in)
8) Depolarization occurs (Na⁺ enters, Ca²⁺ enters, and Cl⁻ leaves)
9) If the depolarization is large enough, it reaches the trigger zone, so the voltage-gated
Na⁺ channels open
10) The olfactory receptor neuron fires action potentials along the axon and the signal
travels to the olfactory bulb in the brain for processing
✔✔What organ detects pheremones and where is it located in mammals vs reptiles? -
✔✔Vomeronasal Organ
