AP Biology : Understanding Other Respiratory Physiology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #2 : Understanding Respiratory Functions

What happens to the pressure of the lungs to initiate inspiration?

Possible Answers:

Pressure increases, then decreases

Pressure remains constant

 Pressure increases

Pressure decreases, then increases

Pressure decreases

Correct answer:

Pressure decreases

Explanation:

During inspiration, the lungs expand as the diaphragm contracts and internal intercostal muscles relax. As the volume of the thoracic cavity increases, its pressure decreases. This creates a pressure gradient, driving air from an area of high pressure (the environment) into the area of low pressure (the lungs).

Example Question #3 : Understanding Respiratory Functions

What phenomenon occurs in the blood when an individual holds their breath for an extended period?

Possible Answers:

Auto-immune disease

Combustion

Decreased heart rate

Alkalosis

Acidosis

Correct answer:

Acidosis

Explanation:

When you are not breathing, your respiratory system cannot perform its function. Unwanted gases, such as carbon dioxide, cannot be removed from the system and necessary gases, such as oxygen, cannot enter the system. This causes a buildup of carbon dioxide in the body, which leads to acidosis. Carbon dioxide is converted to carbonic acid via carbonic anhydrase. This carbonic acid builds in the blood, lowering its pH.

Example Question #1 : Understanding Other Respiratory Physiology

 

Which of the following answers lists the correct order of respiratory structures that air moves through as it is drawn into the lungs?

Possible Answers:

Alveoli, trachea, bronchi, bronchioles

Bronchi, bronchioles, alveoli, trachea

Trachea, bronchi, bronchioles, alveoli

Trachea, bronchioles, bronchi, alveoli

Correct answer:

Trachea, bronchi, bronchioles, alveoli

Explanation:

Air enters the body of most terrestrial vertebrates through the nose or the mouth; the air then passes through the trachea to narrower tubes called the bronchi, to still narrower tubes called the bronchioles. The bronchioles "dead end" into structures called alveoli, which is where gas exchange of oxygen and carbon dioxide takes place with the blood in adjacent capillaries.

Example Question #2 : Understanding Other Respiratory Physiology

Which of the following structures is not found within the lungs?

Possible Answers:

Alveoli

Bronchioles

Trachea

Bronchi

Correct answer:

Trachea

Explanation:

The lungs contain the bronchioles, the alveoli, and part of the bronchi. The trachea carries inhaled air into the bronchi, but it is not actually enclosed by the bronchi— the lungs only enclose structures that arise after the bronchi branch away from the trachea.

Example Question #3 : Understanding Other Respiratory Physiology

Terrestrial animals must combat the drying out of respiratory surfaces due to evaporation. What is one strategy they use?

Possible Answers:

Folding the respiratory surface into the body

Having very low respiratory rates

Increased perspiration of cells on respiratory surface

Excretion of fluids from walls of lungs

Increased metabolism

Correct answer:

Folding the respiratory surface into the body

Explanation:

By folding the respiratory surface into the body, terrestrial animals increase the humidity of the environment of the respiratory surface, which will minimize evaporation and maintain moisture. Note that water loss via evaporation and perspiration accounts for the majority of water loss in terrestrial mammals.

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