Question 1

Chemoreceptors in the circulatory system detect changes in circulating pCO₂. If CO₂ concentrations get too high, the rate of ventilation increases. Why does this make sense?

Accepted Answer

CO₂ is a byproduct of cellular respiration, which occurs in tissues that are actively working. An increase in CO₂ concentration therefore indicates that these tissues require more oxygen and are producing more carbon dioxide. The chemoreceptors in the circulatory system detect this change and increase the rate of ventilation to supply the working tissues with more oxygen and remove the excess carbon dioxide.

Question 2

A man visits a doctor, and discovers that, due to tumors, he needs to have both of his carotid bodies removed. How will their removal affect his body?

Accepted Answer

The carotid bodies are responsible for sensing the oxygen concentration of blood flowing to the brain. Without them, the body will not be able to detect low oxygen levels in the brain, which can lead to a range of symptoms including dizziness, shortness of breath, and even loss of consciousness. The removal of carotid bodies does not affect the CO₂ concentration of blood, which is not sensed by the carotid bodies.

Question 3

As you read this sentence, you have breathed in and out. What you have just experienced is referred to as "gas exchange," where you have taken oxygen into your lungs and expelled carbon dioxide into the environment.

Accepted Answer

This statement is true. Gas exchange is the process of taking in oxygen and expelling carbon dioxide through the lungs.

Question 4

Terrestrial insects are large enough that diffusion through simple openings on their body surface is insufficient to supply oxygen to their tissues. Instead, insects deliver oxygen:

Accepted Answer

Insects deliver oxygen directly to their tissues through branching structures called tracheoles, which are connected to external openings called spiracles.

Question 5

During certain stressful moments, some individuals will begin to hyperventilate-that is, their breathing will be very shallow and quick. A by-product of hyperventilation is much lowered levels of CO₂ in the blood. Which of the following would you also expect to find?

Accepted Answer

The answer of During certain stressful moments, some individuals will...

Question 6

To aid inhalation, both the diaphragm and intercostal muscles are used. By expanding the thoracic cavity, the action of these muscles creates a space with _____ atmospheric pressure.

Accepted Answer

By expanding the thoracic cavity, the diaphragm and intercostal muscles increase its volume, which leads to a decrease in pressure within the cavity. This decrease in pressure creates a pressure gradient between the thoracic cavity and the outside atmospheric pressure resulting in air being drawn into the lungs. Therefore, the pressure inside the thoracic cavity is lower than the atmospheric pressure.

Question 7

Imagine that a young girl suffers a horseback-riding injury, and one of her ribs punctures her diaphragm. How will this injury affect the girl's breathing?

Accepted Answer

The diaphragm is a major muscle involved in breathing, contracting to increase the volume of the chest cavity and decrease the air pressure inside to allow inhalation. If it is punctured, it may not contract properly, making it more difficult to increase negative air pressure and inhale.

Question 8

If water passed over the gills of fish in the same direction as blood flows through the capillaries in lamellae, how would gas exchange be affected?

Accepted Answer

The answer of If water passed over the gills of...

Question 9

Birds are able to extract more oxygen than mammals from an equal volume of air. Which of the following statements reflects why birds are able to do so?

Accepted Answer

Birds have a unique respiratory system in which air flows in a unidirectional manner across the lung surface. This means that freshly inhaled air moves across the surface of the lung before it mixes with stale air, allowing for more efficient gas exchange and extraction of oxygen.

Question 10

The respiratory system of which of the following organisms relies on air sacs to move air through the lungs?

Accepted Answer

Birds have air sacs in addition to lungs which help move air through the respiratory system. This is an adaptation that allows them to have a more efficient respiratory system, which is necessary for their high metabolic demands during flight. Mammals, fish, amphibians, and reptiles do not have air sacs.

Question 11

Which of the following statements is TRUE regarding respiration in mammals?

Accepted Answer

- C) Gas exchange occurs in the alveoli, which are the tiny air sacs in the lungs where oxygen is exchanged for carbon dioxide in the blood.- D) Respiration involves changes in air pressure within the chest cavity, which help to draw air into the lungs during inhalation and push it out during exhalation.- E) The diaphragm plays a crucial role in respiration by contracting and relaxing to change the volume of the chest cavity, thereby facilitating breathing.

Question 12

Which of the following would NOT be considered a step in gas transport and/or gas exchange?

Accepted Answer

All the choices listed are steps involved in gas transport and/or gas exchange processes.

Question 13

Which of the following present challenges that make gas exchange more difficult for fish than for terrestrial animals?

Accepted Answer

Water is denser and more viscous than air, making it more difficult for fish to move it over their gills for gas exchange. Additionally, water contains much less oxygen than air per unit volume, so fish need to extract as much oxygen as possible from the water that passes over their gills. Finally, diffusion occurs more slowly in water than in air, further limiting the efficiency of gas exchange in fish. While gills do have less surface area than lungs, this alone does not make gas exchange more difficult for fish than for terrestrial animals. Unidirectional flow of water may be less efficient than tidal ventilation, but this does not factor into the basic challenge of gas exchange in water.

Question 14

At the doctor's office, you may have noticed that when you are asked to "breathe deeply," your chest rises and falls and expands more dramatically than when you are breathing normally. Why?

Accepted Answer

When you are asked to breathe deeply, your intercostal muscles are activated to expand your chest cavity. These muscles are located between the ribs and help to increase the space in the chest, allowing for more air to enter the lungs. This is why you may notice your chest rising and expanding more dramatically than when you are breathing normally. The other options mentioned, such as air sacs, spiracles, and bronchioles, are not directly involved in the expansion of the chest during deep breathing.

Question 15

Below is a diagram of O₂uptake at the fish gill. The values shown indicate percent fluid saturation of O₂. Which choice below identifies the fluid and the direction of flow CORRECTLY?

Accepted Answer

The answer of Below is a diagram of O₂uptake...

Question 16

A man has just learned that he has a blockage in one of his arteries. Which of the following statements is TRUE regarding this blockage?

Accepted Answer

A blockage in an artery increases the resistance to flow in the circulatory system, which in turn decreases the rate of blood flow.

Question 17

A researcher is culturing cells in an incubator where the gas levels are carefully regulated. If the researcher observes that the pO₂ in the incubator is 200 mmHg, what can the researcher deduce about the pO₂of her cells?

Accepted Answer

The pO₂ of the cells will be equal to or less than the pO₂ in the incubator, as the cells will consume oxygen during metabolism. Therefore, the pO₂ of the cells cannot be greater than 200 mmHg.

Question 18

Which of the following will NOT pass through the phospholipid bilayer of a membrane?

Accepted Answer

Sodium ions have a positive charge and are therefore unable to pass through the hydrophobic, nonpolar interior of the phospholipid bilayer. Small, nonpolar molecules (like carbon dioxide and molecular oxygen) are able to pass through the membrane via simple diffusion.

Question 19

A school-aged child is dissecting a grasshopper as part of her biology class. As she breaks the exoskeleton, the grasshopper's circulatory fluid leaks out. This fluid would be referred to as:

Accepted Answer

The fluid in a grasshopper's circulatory system is called hemolymph, which acts as both blood and lymph. It does not contain red blood cells like vertebrate blood and is not separated into cells and plasma like vertebrate blood. Hemolymph is a mixture of blood and interstitial fluid that is not contained within blood vessels but instead bathes the internal organs directly.

Question 20

In mammals, bulk flow only refers to the movement of oxygen (either into or out of the lungs and within the bloodstream). Bulk flow never refers to the movement of carbon dioxide.

Accepted Answer

Bulk flow in mammals refers to the movement of both oxygen and carbon dioxide, as well as other substances, in the bloodstream and across respiratory surfaces.

Quiz 39: Animal Cardiovascular and Respiratory Systems

Chemoreceptors in the circulatory system detect changes in circulating pCO2. If CO2 concentrations get too high, the rate of ventilation increases. Why does this make sense?