How Adrenaline and Acetylcholine Affect Heart Rate

In this episode, Leslie Samuel discusses how adrenaline and acetylcholine affect heart rate. Adrenaline, released from the adrenal gland, increases heart rate by enhancing sodium and calcium conductance, leading to faster action potentials. Conversely, acetylcholine increases potassium conductance, causing hyperpolarization and slower depolarization, which decreases heart rate. The episode also recaps the pacemaker potential and spontaneous signals in the heart, and concludes with a mention of additional resources available on the Interactive Biology website.

What is the primary function of the SA node in the heart?

• To store oxygen

• To pump blood throughout the body

• To generate spontaneous signals for heartbeats

• To filter blood

How does adrenaline affect the conductance in pacemaker cells?

• It increases conductance for sodium and calcium ions

• It decreases conductance for sodium and calcium ions

• It decreases conductance for potassium ions

• It increases conductance for potassium ions

What happens to the heart rate when adrenaline is released?

• The heart rate remains unchanged

• The heart rate decreases

• The heart stops

• The heart rate increases

What effect does acetylcholine have on potassium conductance?

• It increases sodium conductance

• It has no effect on potassium conductance

• It increases potassium conductance

• It decreases potassium conductance

How does acetylcholine affect the depolarization process?

• It slows down depolarization

• It has no effect on depolarization

• It stops depolarization

• It speeds up depolarization