CHAPTER 42 CIRCULATory system

Blood returns to the heart via the _____.

aorta

pulmonary arteries

pulmonary veins

aorta and pulmonary arteries

aorta and pulmonary veins

pulmonary veins

From the pulmonary veins, blood flows to the _____.

right atrium

left atrium

aorta

capillaries of the lungs

inferior vena cava

left atrium

From the superior vena cava, blood flows to the _____.

right atrium

left atrium

aorta

capillaries of the lungs

inferior vena cava

right atrium

From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.

right atrium

left atrium

aorta

capillaries of the lungs

inferior vena cava

inferior vena cava

What is the function of a circulatory system?

It exchanges oxygen and carbon dioxide with the outside air.

It acts as a reservoir for the storage of blood.

It is the site of blood cell production.

It brings a transport liquid into close contact with all cells in the body

It brings a transport liquid into close contact with all cells in the body

Why do the circulatory systems of land vertebrates have separate circuits to the lungs and to the rest of the body?

Land vertebrates are bigger and require more tubing to reach all areas of the body.

Blood is pumped to the lungs to be oxygenated before being pumped to the rest of the body.

The large decrease in blood pressure as blood moves through the lungs may prevent efficient circulation through the rest of the body.

The circuits increase the amount of surface area available for the diffusion of gases and nutrients in the body.

The large decrease in blood pressure as blood moves through the lungs may prevent efficient circulation through the rest of the body.

True or false? The circulatory systems of land-dwelling vertebrates are composed of two pumping circuits: the systemic circulation, which is a lower-pressure circuit to the lung, and the pulmonary circulation, which is a higher-pressure circuit to the rest of the body.

True

False

False

• Pulmonary circulation → goes to the lungs → LOW pressure

• Systemic circulation → goes to the rest of the body → HIGH pressure

What is the function of the left ventricle?

It pumps deoxygenated blood to the lungs via the pulmonary circulation.

It receives deoxygenated blood from the lungs.

It receives oxygenated blood from the lungs.

It pumps oxygenated blood around the body via the systemic circulation.

It pumps oxygenated blood around the body via the systemic circulation.

Which of the following statements about blood circulation in the body is true?

Deoxygenated blood flowing through the pulmonary veins is carried to the right atrium.

During one cardiac cycle, the two ventricles contract first, and then the two atria contract.

Valves prevent the backflow of blood into the atria and ventricles.

As the right ventricle contracts, it sends oxygenated blood through the aorta to all tissues of the body.

Valves prevent the backflow of blood into the atria and ventricles.

Which event occurs first during atrial and ventricular diastole?

The atria and ventricles are relaxed, and blood flows into the atria.

Blood flows into the relaxed atria while the ventricles contract.

The atria and ventricles contract simultaneously.

The atria contract while blood flows into the relaxed ventricles.

The atria and ventricles are relaxed, and blood flows into the atria.

Which event of the cardiac cycle occurs when systolic blood pressure is measured?

The ventricles contract, carrying blood into the aorta, and blood flows into the relaxed atria.

The atria and ventricles contract simultaneously.

The atria and ventricles are relaxed, and blood flows into the atria.

The atria contract while blood flows into the relaxed ventricles.

The ventricles contract, carrying blood into the aorta, and blood flows into the relaxed atria.

As shown in the diagram detailed in the video, which type of blood vessel has the greatest total cross-sectional area throughout the whole body?

veins

arterioles

aorta

capillaries

capillaries

As detailed in the video, what is the effect of total cross-sectional area on the velocity of blood flow?

Vessels with higher total cross-sectional area have higher blood velocity.

Cross-sectional area only affects blood velocity in the veins.

Cross-sectional area has no effect on blood velocity.

Vessels with higher total cross-sectional area have lower blood velocity.

Vessels with higher total cross-sectional area have lower blood velocity.

Rank the blood vessels from lowest blood pressure to highest blood pressure. veins, capillaries, aorta, venae carvae, arterioles

Venae cavae < veins < capillaries < arterioles < aorta

Blood flow velocity is inversely related to cross-sectional area.

Blood flowing from one aorta into billions of capillaries decreases the velocity and pressure of the blood flow.

The lowest velocity of blood flow occurs in the capillaries.

✅ True

As blood flows from the aorta through the other vessels, blood pressure increases.

Blood flows from an area of low pressure to an area of high pressure. ❌ False

Blood flow is at its highest velocity in the venae cavae. ❌ False

❌ False

The primary functions of the _____ are to warm, filter, and humidify air.

lungs

trachea

bronchus

nasal cavity

alveoli

nasal cavity

Voice sounds are produced by the _____.

trachea

diaphragm

bronchioles

larynx

lungs

larynx

Which statement about the gas exchange system in fish is correct?

It enables oxygen to move from where its partial pressure is lower to where its partial pressure is higher.

It relies on the parallel flow of blood and water in the gills.

It enables oxygen to diffuse from the water into the blood over the entire length of the gill capillaries.

It relies on a higher partial pressure of oxygen in water than in air.

It enables oxygen to diffuse from the water into the blood over the entire length of the gill capillaries.

Which statement about oxygen in fish gills is correct?

The partial pressure of oxygen is greater in the blood than in the adjacent water.

The partial pressure of oxygen in blood increases as it flows through gill capillaries.

Oxygen diffuses from the bloodstream into the water along the entire length of the capillaries.

The partial pressure of oxygen in the blood is lowest where the partial pressure of oxygen in the water is highest.

The partial pressure of oxygen in blood increases as it flows through gill capillaries.

The partial pressure of oxygen at a particular point in the bloodstream is 100 mm Hg. Under what circumstance will there be a net diffusion of oxygen from the water into the bloodstream at this location?

There will be a net diffusion of oxygen from the water into the bloodstream only if the partial pressure of oxygen in the water is less than 100 mm Hg.

There will be a net diffusion of oxygen from the water into the bloodstream regardless of the partial pressure of oxygen in the water.

There will be a net diffusion of oxygen from the water into the bloodstream only if the partial pressure of oxygen in the water is greater than 100 mm Hg.

There will be a net diffusion of oxygen from the water into the bloodstream only if the partial pressure of oxygen in the water is equal to 100 mm Hg.

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There will be a net diffusion of oxygen from the water into the bloodstream only if the partial pressure of oxygen in the water is greater than 100 mm Hg.

True or false? The lungs of humans form from the embryonic foregut.

True

False

True

True or false? The pressure inside the human chest cavity is always positive, so the lungs stay relatively inflated even upon exhalation.

True

False

False

Which barrier(s) must O2

and CO2

cross to pass between air and blood inside lungs?

Check all that apply.

diaphragm

epithelial cells

capillary wall

extracellular fluid

epithelial cells

capillary wall

extracellular fluid

True or false? The driving force for the unloading of oxygen from hemoglobin into tissues is the difference in PCO2 levels between the blood and body tissues.

View Available Hint(s)for Part E

True

False

False

How is most carbon dioxide transported from tissues to the lungs?

View Available Hint(s)for Part F

As protons ( H+).

As bicarbonate ions ( HCO3−).

As carbonic acid.

As carbon dioxide gas.

As bicarbonate ions ( HCO3−

Which of the following statements about the oxygen-hemoglobin interaction is true?

View Available Hint(s)for Part G

The binding of one oxygen molecule to hemoglobin stimulates the unloading of the oxygen molecules that are already bound.

Each hemoglobin molecule can bind one oxygen molecule.

The binding of one oxygen molecule to hemoglobin stimulates the binding of other oxygen molecules.

The oxygen–hemoglobin dissociation curve is exponential, which means that hemoglobin can respond quickly to small changes in oxygen demand.

The binding of one oxygen molecule to hemoglobin stimulates the binding of other oxygen molecules.

Most carbon dioxide is carried from the body tissues to the lungs _____.

as bicarbonate ions (HCO3 -)

combined with hemoglobin

by the trachea

as hydrogen ions (H+)

dissolved in blood plasma

as bicarbonate ions (HCO3 -)

By picking up hydrogen ions, hemoglobin prevents the blood from becoming too _____.

acidic

basic

thick

low in oxygen concentration

red

acidic

In the blood, most of the oxygen that will be used in cellular respiration is carried from the lungs to the body tissues _____.

as bicarbonate ions (HCO₃⁻)

combined with hemoglobin

by the trachea

water (H₂O)

dissolved in blood plasma

combined with hemoglobin