Question 52 – Neuronal communication - Questions

A physiological study investigated the autonomic regulation of cardiac function in a miniature pig model. Under basal resting conditions, the mean heart rate was recorded as $bpm85\text{ bpm}$ . The researchers then performed the following experimental interventions:

Following bilateral vagotomy (severing the parasympathetic vagus nerves), the resting heart rate increased to $bpm135\text{ bpm}$ .
Following surgical cardiac sympathectomy (severing the sympathetic nerves), the resting heart rate decreased to $bpm75\text{ bpm}$ .

Suggest two conclusions about the autonomic control of resting heart rate in this model that can be drawn from these data. Support your conclusions with quantitative evidence.

Identify:

The specialised region of cardiac muscle tissue in the right atrium that acts as the primary pacemaker where these autonomic pathways synapse.
The neurotransmitter released by postganglionic parasympathetic neurones at this location.

Following bilateral vagotomy (severing the parasympathetic vagus nerves), the resting heart rate increased to $bpm135\text{ bpm}$ .
Following surgical cardiac sympathectomy (severing the sympathetic nerves), the resting heart rate decreased to $bpm75\text{ bpm}$ .

Suggest two conclusions about the autonomic control of resting heart rate in this model that can be drawn from these data. Support your conclusions with quantitative evidence.

Identify:

The specialised region of cardiac muscle tissue in the right atrium that acts as the primary pacemaker where these autonomic pathways synapse.
The neurotransmitter released by postganglionic parasympathetic neurones at this location.

Neuronal communication

Question 25

Neuronal communication

Question 25

Neuronal communication

Question 25

Neuronal communication Questions

Neuronal communication

Question 25

Neuronal communication Questions