Question

Order the steps of the chemoreceptor reflex pathway:

Intra-alveolar pressure equilibrates with atmospheric
Plasma oxygen decreases
Pressure in lung decreases
Chemoreceptor cell in carotid body depolarizes
Sensory neuron firing increases
Diaphragm and other inspiratory muscles contract
Message sent to RCC in pons/medulla
Air moves in down pressure gradient
Output is sent via somatic motor neurons
Potassium channels close
Excitatory neurotransmitter released onto sensory neuron
Volume of thoracic cage increases

Answer 1

Here is the ordered sequence of steps in the chemoreceptor reflex pathway:

Plasma oxygen decreases

Chemoreceptor cell in carotid body depolarizes

Excitatory neurotransmitter released onto sensory neuron

Sensory neuron firing increases

Message sent to RCC (respiratory control centers) in pons/medulla

Diaphragm and other inspiratory muscles contract

Volume of thoracic cage increases

Intra-alveolar pressure equilibrates with atmospheric pressure

Pressure in lung decreases

Air moves in down pressure gradient

Output is sent via somatic motor neurons

Potassium channels close

Please note that this is a generalized sequence, and additional feedback loops and regulatory mechanisms may also be involved in the overall control of respiration.