Join thousands of students who trust us to help them ace their exams!Watch the first video
Multiple Choice
What is the primary physiological response if there is an increase in carbon dioxide ($\mathrm{CO_2}$) levels in the blood?
A
The kidneys stop filtering waste products.
B
The breathing rate increases to expel more $\mathrm{CO_2}$.
C
The heart rate decreases to conserve energy.
D
Oxygen levels in the blood increase immediately.
Verified step by step guidance
1
Step 1: Understand the role of carbon dioxide ($\mathrm{CO_2}$) in the blood. Carbon dioxide is a waste product of cellular respiration and is transported in the blood to be expelled through the lungs. High levels of $\mathrm{CO_2}$ can lead to a condition called hypercapnia, which disrupts the blood's pH balance.
Step 2: Recognize the physiological mechanism for detecting $\mathrm{CO_2}$ levels. Specialized chemoreceptors in the body, such as those in the medulla oblongata and carotid bodies, detect elevated $\mathrm{CO_2}$ levels and send signals to the respiratory control centers in the brain.
Step 3: Analyze the body's response to increased $\mathrm{CO_2}$ levels. The respiratory control centers stimulate the diaphragm and intercostal muscles to increase the breathing rate (ventilation). This helps expel excess $\mathrm{CO_2}$ from the lungs and restore normal blood pH.
Step 4: Evaluate why the other options are incorrect. The kidneys do not stop filtering waste products in response to $\mathrm{CO_2}$ levels. The heart rate typically does not decrease in this scenario, and oxygen levels in the blood do not increase immediately as a direct response to elevated $\mathrm{CO_2}$.
Step 5: Conclude that the primary physiological response to increased $\mathrm{CO_2}$ levels in the blood is an increase in the breathing rate to expel more $\mathrm{CO_2}$ and maintain homeostasis.