Anatomy & Physiology Respiratory #12

Question

Which circumstance stimulates the medulla oblongata to send a message to the respiratory system to increase the frequency of breathing?

Answers

  1. Increased oxygen levels.
    • Rationale:

      Increased levels of oxygen do not stimulate the medulla oblongata to change the rate of respiration.

  2. Decreased oxygen levels.
    • Rationale:

      Decreased levels of oxygen do not stimulate the medulla oblongata to change the rate of respiration.

  3. Decreased carbon dioxide levels.
    • Rationale:

      While carbon dioxide levels do stimulate the medulla oblongata to change the rate of breathing, it is not decreased levels of this gas that initiate this process.

  4. Increased carbon dioxide levels.
    • Rationale:

      Increased serum levels of carbon dioxide stimulate the medulla oblongata to increase the rate of respiration thereby decreasing the levels of this gas in the blood.

Overview

The human species has a complex system of respiration which transports oxygen to the cells and rids the body of waste products, including carbon dioxide.

Explanation

Learning Outcomes

The medulla oblongata controls the rate of breathing. It does so by monitoring serum carbon dioxide levels. An increased carbon dioxide level stimulates the medulla which sends a message to the diaphragm and the rib muscles to increase the rate of breathing which assists in ridding the blood of carbon dioxide.

Test Taking Tip

Think about the function of the brain and gas exchange when choosing the correct answer choice for this question.

Video Rationale