Question 1

Which group of animals has one-way flow of air through its lungs,whereas all the others have tidal flow?

Accepted Answer

Birds have a unique respiratory system where the air flows in one direction through the lungs, unlike other animals where the air flows in and out through the same paths (tidal flow).

Question 2

Humans cannot survive long at altitudes greater than 6000 m because ________.

Accepted Answer

As altitude increases, the atmospheric pressure decreases, which results in a decrease in the partial pressure of oxygen. At high altitudes above 6000 m, the partial pressure of oxygen can become less than half that at sea level, which can lead to hypoxia and negatively affect the human body's vital functions.

Question 3

Most phyla of aquatic invertebrates have improved the rate of gas exchange by creating a water current over their respiratory surfaces,thereby ________.

Accepted Answer

Creating a water current over respiratory surfaces increases the concentration difference of gases, enhancing the rate of diffusion according to Fick's law of diffusion.

Question 4

Major evolutionary changes have resulted in anatomical and physiological adaptations that optimize the rate of gas exchange in animals by each of these factors except ________.

Accepted Answer

Increasing the diffusion constant for each gas is not a major evolutionary change that has resulted in optimizing the rate of gas exchange in animals. The diffusion constant is a physical constant for each gas and cannot be changed by evolution. The other options (A, B, and C) are all major evolutionary changes that have resulted in optimizing the rate of gas exchange in animals.

Question 5

The primary advantage of gills versus the body surface for gas exchange in aquatic animals is that ________.

Accepted Answer

Gills have a much greater diffusion surface area than the body surface, allowing for more efficient gas exchange. This is because gills are composed of many thin, flattened filaments or plates with many small projections called lamellae, which greatly increase surface area.

Question 6

What change would increase the rate of oxygen diffusing from lung alveoli into the blood?

Accepted Answer

An increase in the hemoglobin concentration of the red blood cells would increase the rate of oxygen diffusing from lung alveoli into the blood because hemoglobin binds oxygen, thus maintaining a gradient for oxygen to continue diffusing from the alveoli into the blood.

Question 7

Which blood vessels carry oxygenated blood?

Accepted Answer

Pulmonary veins carry oxygenated blood from the lungs to the heart.

Question 8

Tom is choking on a piece of steak that is stuck in his trachea,and he signals for his young son to call 911.It takes the paramedics four minutes to reach his house.Will this be in time to save Tom (and why),or will Tom already be dead (and why)?

Accepted Answer

When Tom started choking, he had a reserve of about three-quarters of his hemoglobin still bound to oxygen. Hemoglobin is responsible for carrying oxygen in the blood, and having this reserve oxygen allowed Tom to continue to have oxygen circulated throughout his body despite the blockage in his trachea. Therefore, the paramedics arriving four minutes later should still be in time to save Tom's life.

Question 9

In the future,it may be possible to screen for a number of different types of cancer by a simple blood test.If a blood test indicates a very early stage of lung cancer,where is the most likely place that the tumor will be growing?

Accepted Answer

Lung cancer commonly arises in the bronchial epithelium, and if detected at an early stage, the tumor is likely to still be confined to the wall of a large bronchus rather than having spread to other areas such as the alveoli or pulmonary veins.

Question 10

Soft-shelled turtles can remain submerged underwater for several hours without ventilating their lungs because ________.

Accepted Answer

Soft-shelled turtles can remain submerged for extended periods due to their ability to perform cutaneous respiration, particularly through the highly vascularized soft lining of their throats, allowing them to exchange gases directly with the water.

Question 11

During your dissection of a fish,what structure would you have to remove to see the gills?

Accepted Answer

The operculum is the bony covering on the fish's gill that protects and helps with water flow over the gills. Removing it will expose the gills.

Question 12

The gas exchange surfaces in a mammalian lung are organized into structures that look like clusters of hollow grapes.The hollow,grape-like structures are the________.

Accepted Answer

Alveoli are the gas exchange structures in mammalian lungs that are organized into clusters of hollow grapes. Spiracles are openings on the surface of some insects for gas exchange, lamellae are found in fish gills, papulae are small projections on the surface of some animals, and bronchi are the main branches of the airway in the respiratory system.

Question 13

The respiratory systems of fish and birds are similar in that both________.

Accepted Answer

Both fish and birds have a unidirectional flow of the environmental medium (water or air) over their gas exchange surfaces (gills or lungs, respectively), allowing for efficient gas exchange. While some fish may use countercurrent exchange, not all fish do, and birds do not utilize this mechanism. Birds do have air sacs, but this is not a defining similarity between the respiratory systems of fish and birds. The partial pressure of oxygen in the environmental medium can vary widely, so it is not a reliable similarity between the respiratory systems of fish and birds.

Question 14

During an asthma attack,allergens trigger the release of histamine,which causes severe constriction of the ________.

Accepted Answer

During an asthma attack, allergens trigger the release of histamine, which causes severe constriction of the bronchi, leading to difficulty in breathing. The other options do not play a significant role in asthma attacks.

Question 15

What is the likely outcome if you were able to force water through fish gills in the opposite direction to how it normally flows over the gills?

Accepted Answer

The answer of What is the likely outcome if you...

Question 16

Which of these animals uses positive pressure breathing?

Accepted Answer

Amphibians, such as frogs and salamanders, use positive pressure breathing. They fill their mouth with air and then close their mouth and push the air into their lungs, rather than relying on negative pressure created by expanding their ribcage like mammals, birds, and reptiles.

Question 17

One possible reason that there are not any really large insects currently living on Earth is that

Accepted Answer

The bulk flow of air through the tracheal tubes of insects is passive and relies on the diffusion of gases. As the body size of an insect increases, the distance that oxygen needs to diffuse through the tracheal tubes also increases, leading to a decrease in oxygen supply to tissues. This limits the maximum size that insects can attain. Therefore, the correct answer is D - the bulk flow of air through their tracheal tubes would be more difficult the larger the body and longer the tracheal tubes.

Question 18

In the countercurrent exchange in a fish's gills,the oxygen concentration is always ________ in the water than the blood along the entire pathway of each lamella.

Accepted Answer

In countercurrent exchange in a fish's gills, the design ensures that the water flowing past the blood has a higher oxygen concentration. This gradient facilitates efficient oxygen transfer from the water to the blood throughout the entire pathway of each lamella.

Question 19

Which dissolved gas cannot be transported by hemoglobin?

Accepted Answer

Nitrogen is the correct answer because, under normal physiological conditions, it is not transported by hemoglobin. Hemoglobin primarily transports oxygen, carbon dioxide, and can also bind to carbon monoxide and nitric oxide, but it does not carry nitrogen in a significant amount. Nitrogen is mostly dissolved in the plasma and is not actively transported by hemoglobin.

Question 20

What respiratory adaptation was important for the invasion of land by arthropods?

Accepted Answer

Arthropods needed to evolve the ability to close their spiracles, small openings in their exoskeleton that allow for gas exchange, in order to prevent water loss in the terrestrial environment. This adaptation allowed them to conserve water while still being able to obtain oxygen for respiration.

Quiz 47: The Respiratory System