Question 1

The liquid portion of human blood cannot absorb enough oxygen to meet the body's demands. However, ________ in our red blood cells greatly increase(s) the oxygen-carrying capacity of human blood.

Accepted Answer

Hemoglobin is a protein found in red blood cells that can bind to oxygen molecules. This greatly increases the oxygen-carrying capacity of the blood. Carbon dioxide, ions, and water are also present in blood, but they do not play a significant role in increasing oxygen-carrying capacity.

Question 2

For a human to inhale, the rib muscles and the diaphragm must

Accepted Answer

When the rib muscles and diaphragm contract, the volume of the thoracic cavity increases, resulting in a decrease in pressure inside the lungs. This decrease in pressure allows air to flow into the lungs during inhalation.

Question 3

Why do humans rely on a circulatory system to distribute oxygen?

Accepted Answer

Diffusion is slow over long distances, so a circulatory system is needed to quickly deliver oxygen to cells. This is especially important for larger organisms like humans, who have a greater distance between their respiratory surfaces and their cells.

Question 4

Which of the following statements about hemoglobin is true?

Accepted Answer

Hemoglobin binds to oxygen in the lungs and releases it near cells that are performing cellular respiration in various tissues throughout the body. Hemoglobin is not an enzyme involved in cellular respiration, nor does it transport oxygen from cells undergoing cellular respiration. Hemoglobin does not affect the acidity of blood.

Question 5

The blood vessels that allow diffusion between blood and nearby body cells are

Accepted Answer

Capillaries are the smallest blood vessels in the body and their thin walls allow for diffusion of gases, nutrients, and wastes between the blood and nearby body cells. Veins and arteries are larger blood vessels that transport blood to and from the capillaries.

Question 6

Blood flows rapidly within the arterial system but slows dramatically as it enters the capillaries. What is the benefit of having blood move slowly through the capillaries?

Accepted Answer

The slow movement of blood through capillaries allows enough time for the exchange of materials with surrounding cells. Capillaries are the site of nutrient and gas exchange between the blood and body tissues. The slow flow rate allows sufficient time for oxygen and nutrients to diffuse from the blood into the surrounding tissues, while waste products (such as carbon dioxide) diffuse from the tissues into the blood. This process is facilitated by the thin walls of the capillaries and the slow movement of blood through them.

Question 7

Large blood vessels that return deoxygenated blood from the legs to the heart are

Accepted Answer

Veins are the blood vessels responsible for carrying deoxygenated blood back to the heart from various parts of the body, including the legs.

Question 8

Which of the following features could be found in a vein, but NOT in an artery?

Accepted Answer

One-way valves are found in veins to prevent blood from flowing backwards, but are not present in arteries. Arteries have thicker walls with muscle and are under higher pressure to help pump oxygen-rich blood throughout the body.

Question 9

People with sickle-cell disease have deformed hemoglobin molecules and often suffer muscle pains, even at low levels of exertion. These symptoms might occur because the deformed hemoglobin

Accepted Answer

Sickle-cell disease causes deformed hemoglobin molecules that are unable to carry the amount of oxygen required for normal muscle activities. This results in muscle pain, even at low levels of exertion, because the muscles are not receiving enough oxygen to function properly.

Question 10

A newborn is diagnosed shortly after birth with a rare heart defect that prevented the valve between the left atrium and the left ventricle from fully forming. Which of the following would be an expected outcome of this defect?

Accepted Answer

The valve between the left atrium and left ventricle is responsible for preventing the backflow of oxygen-poor blood into the left atrium. In the absence of a fully formed valve, oxygen-poor blood will mix with oxygen-rich blood in the left atrium and then be pumped to the body. Therefore, body cells would receive less oxygen-rich blood and hence less oxygen.

Question 11

Which of the following sequences correctly describes the journey of a molecule of oxygen from the pharynx to an alveolus?

Accepted Answer

The correct sequence is pharynx to trachea to bronchus to bronchiole to alveolus, which follows the path air takes through the respiratory system.

Question 12

At high altitudes, gases are less concentrated. You might gasp for air, because

Accepted Answer

At high altitudes, the atmospheric pressure is lower, which means there is less oxygen available in the air. This results in a decreased amount of oxygen that can diffuse into the blood, leading to difficulty in breathing or gasping for air.

Question 13

Which of the following does NOT facilitate exchange of materials by diffusion?

Accepted Answer

The extracellular matrix within connective tissue does not directly facilitate the exchange of materials by diffusion. Rather, it provides structural support and organization for the cells within the tissue. The other choices, cells lying within 0.03 millimeters of blood vessels, a large surface area within alveoli, and thin, porous walls in capillaries, all facilitate the exchange of materials by diffusion.

Question 14

The structure that is highlighted in this figure is the

Accepted Answer

The structure highlighted in the figure is a tube-like structure that is branching out into smaller tubes, resembling the structure of a trachea. The trachea is the windpipe that connects the larynx to the bronchi, and it is responsible for carrying air to and from the lungs. Therefore, the best choice is D, trachea.

Question 15

Shortages of iron in our diet can cause iron deficiency anemia, a condition that reduces the amount of hemoglobin in red blood cells. Iron deficiency anemia is a potentially serious condition that is characterized primarily by

Accepted Answer

Iron deficiency leads to a reduction in hemoglobin, which impairs the ability of blood to carry oxygen to body tissues. This can result in symptoms such as fatigue, dizziness, shortness of breath, and weakness.

Question 16

One side of the heart pumps blood into the pulmonary circuit, and the other side of the heart pumps blood to the systemic circuit. How do these different functions affect the structure of the heart?

Accepted Answer

The left side of the heart pumps blood to the systemic circuit, which includes the entire body. Therefore, it needs more pressure to pump the blood effectively, and hence, the muscular wall of the left ventricle is thicker than the right ventricle.

Question 17

The pulmonary ________ carries ________ blood from the heart to the lungs.

Accepted Answer

The pulmonary artery carries oxygen-poor blood from the right ventricle of the heart to the lungs for oxygenation.

Question 18

Blood leaving the right ventricle of the heart travels next to the

Accepted Answer

After leaving the right ventricle, blood travels to the lungs through the pulmonary artery to get oxygenated.

Question 19

Which component of whole blood would an investigator examine to determine the concentration of dissolved carbon dioxide or hormones, such as testosterone?

Accepted Answer

The concentration of dissolved carbon dioxide and hormones is measured in the plasma, which is the liquid component of the whole blood. Red blood cells transport oxygen and carbon dioxide while platelets and white blood cells have different functions in the blood.

Question 20

Another name for the "pacemaker" of the heart is the

Accepted Answer

The sinoatrial (SA) node is often referred to as the "pacemaker" of the heart as it initiates the electrical impulses that regulate heartbeats. The atrioventricular (AV) node is responsible for delaying and transmitting the impulses from the SA node to the ventricles. The atrium and ventricle are chambers of the heart.

Quiz 21: Circulatory, Respiratory, Urinary, and Nervous Systems