CIRCULATION AND GAS EXCHANGE
A patient with a heart rate of 70 beats per minute and a stroke volume of 70 mL/beat will have a cardiac output of ________.
4,900 mL/minute
A person with a tidal volume of 450 mL (milliliters), a vital capacity of 4000 mL, and a residual volume of 1000 mL would have a potential total lung capacity of _____.
5000 mL
Atmospheric pressure at the summit of Mount Everest is about one third the pressure at sea level, which is 760 mm Hg. If oxygen makes up 21% of the atmosphere by volume, the partial pressure of oxygen (PO2) on Mount Everest is approximately ________.
53 mm Hg
What is the physiological cause of a heart attack?
A blood clot lodging in a blood vessel supplying the heart
Which of the following is an example of a portal vein?
A blood vessel carrying blood from the stomach to the liver
What happens when the CO2 level from cellular respiration increases in the blood?
A decrease in the pH of the cerebrospinal fluid triggers the brain's breathing control centers, which stimulate diaphragm and rib muscle contractions.
Which lung structure is a tiny sac that functions as an interface between air and blood?
Alveolus.
_____ in carbon dioxide in your red blood cells, which causes _____ in pH, causes your breathing to speed up.
An increase ... a drop
Which of the following best describes an artery?
Arteries carry blood away from the heart.
How is most carbon dioxide transported from tissues to the lungs?
As bicarbonate ions (HCO3−HCO3−).
Which of the following is the main factor that causes lymph to move through lymphatic vessels?
Contractions of body muscles near lymph vessels
Which of the following maximizes gas exchange in the gills of a bony fish?
Countercurrent exchange
Why do larger animals, such as a bullfrog, require a circulatory system, but animals such as a planarian do not?
Diffusion is inadequate to move gases through the body surface and into all parts of a larger animal body. However, diffusion alone is sufficient to move gases in and out of the thin body of a planarian.
Which of the following describes the path taken by oxygen-rich blood?
From the gills to the body tissues
Which statement regarding the mammalian heart is correct?
In the adult heart, blood in the right chambers of the heart cannot enter the left chambers without passing through the lungs.
How are gases transported in insect bodies?
In tracheal systems
Which of the following factors would increase the release of oxygen from hemoglobin?
Increased exercise and decreased blood pH
What is the function of a circulatory system?
It brings a transport liquid into close contact with all cells in the body.
What is unique about blood in pulmonary arteries compared with blood in other arteries?
It is loaded with carbon dioxide.
What is the function of the left ventricle?
It pumps oxygenated blood around the body via the systemic circulation.
Which of the following statements correctly describes one of the differences between open and closed circulatory systems?
Open circulatory systems are less costly than closed circulatory systems in terms of energy expenditure.
Which of the following events would you predict as carbon dioxide is released from your muscles into the surrounding capillary bed?
Oxygen delivery to muscle is increased when more carbon dioxide is produced by the muscle.
Which three statements are true of blood flowing through a capillary at the location marked by the green circle?
Oxygen diffuses from the water into the blood. The water surrounding the blood has a low concentration of oxygen. Dissolved oxygen in the blood is lowest at this point.
Which of the following pairs correctly matches the blood component with one of its functions?
Plasma proteins; osmotic balance
Patients with leukemia, a type of cancer that affects the blood, often exhibit suppressed immunity and problems with blood clotting. Based on these two symptoms, which components of the blood are affected by this type of cancer?
Platelets and leukocytes
In the adult heart, blood in the right chambers of the heart cannot enter the left chambers without passing through the lungs.
Pulmonary veins carry oxygen-rich blood to the heart.
All of the following statements are correct regarding respiratory surfaces except which one?
Respiratory surfaces must be dry.
Which chambers of the heart respectively receive and pump oxygen-poor blood?
Right atrium and right ventricle
Imagine that you are walking to class and a person on a bicycle comes very close to hitting you. Your heart begins to beat faster. Which of the following structures is responsible for this reaction?
The SA node
Which event occurs first during atrial and ventricular diastole?
The atria and ventricles are relaxed, and blood flows into the atria.
Which of the following statements about the oxygen-hemoglobin interaction is true?
The binding of one oxygen molecule to hemoglobin stimulates the binding of other oxygen molecules.
Why do the circulatory systems of land vertebrates have separate circuits to the lungs and 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.
Which of the following statements comparing respiration in fish and in mammals is correct?
The movement of the respiratory medium in mammals is bidirectional, but in fish it is unidirectional.
Blood is pumped at high pressures in arteries from the heart to ensure that all parts of the body receive adequate blood flow. Capillary beds, however, would hemorrhage under direct arterial pressures. How does the design of the circulatory network contribute to reducing blood pressure to avoid this scenario?
The total cross-sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary, leading to a reduced blood pressure.
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.
Which of the following statements correctly describes some of the differences between arteries and veins?
The walls of arteries are much thicker and stronger than the walls of veins.
Which of the following is a function of the circulatory system?
Transporting nutrients
Which of the following correctly lists the sequence of blood flow in mammals?
Venae cavae, right atrium, right ventricle, pulmonary arteries, lungs, pulmonary veins, left atrium, left ventricle, aorta
Which of the following statements about blood circulation in the body is true?
Which of the following statements about blood circulation in the body is true?
Organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have _____.
a closed circulatory system
All known birds and mammals have ________.
a double circulatory system and a four-chambered heart
By picking up hydrogen ions, hemoglobin prevents the blood from becoming too _____.
acidic
An open circulatory system __________.
allows interstitial fluid to mix freely with vascular fluid
Gas exchange in the lungs of mammals occurs in the __________.
alveoli
Double circulation circulatory systems are found in ________, and single circulation circulatory systems are found in ________.
amphibians; fish
Your blood pressure is 120/70. The "120" indicates __________, and the "70" indicates __________.
arterial pressure during heart contraction; arterial pressure during heart relaxation
Most carbon dioxide is carried from the body tissues to the lungs _____.
as bicarbonate ions (HCO3 -)
When you exhale, __________.
both the diaphragm and the rib muscles relax
The smallest airway through which inspired air passes before gas exchange occurs in the mammalian lungs is the _____.
bronchiole
Which barrier(s) must O2O2 and CO2CO2 cross to pass between air and blood inside lungs?
capillary wall epithelial cells extracellular fluid
In the blood most of the oxygen that will be used in cellular respiration is carried from the lungs to the body tissues _____.
combined with hemoglobin
Large proteins such as albumin remain in capillaries rather than diffusing out, resulting in the _____.
development of an osmotic pressure difference across capillary walls
Countercurrent exchange in the fish gill helps to maximize _____.
diffusion
Damage to the sinoatrial node in humans would ________.
disrupt the rate and timing of cardiac muscle contractions
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.
false
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.
false
True or false? The pressure inside the human chest cavity is always positive, so the lungs stay relatively inflated even upon exhalation.
false
The only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart are the _____.
fishes
To become bound to hemoglobin for transport in mammals, atmospheric molecules of oxygen must cross ________.
five membranesin and out of the cell lining the lung, in and out of the endothelial cell lining an alveolar capillary, and into the red blood cellto bind with hemoglobin
To adjust blood pressure independently in the capillaries of the gas-exchange surface and in the capillaries of the general body circulation, an organism would need a(n) _____.
four-chambered heart
In which of the following organisms does blood flow from the pulmocutaneous circulation to the heart before circulating through the rest of the body?
frogs
In which of the following animals are the blood and the interstitial fluid considered to be the same body fluid?
grasshoppers
Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a
higher P(O2)P(O2).
The amount of oxygen bound to hemoglobin _____.
increases in the presence of high concentrations of oxygen
From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.
inferior vena cava
Heart valves function to __________.
keep blood moving in the correct direction
Voice sounds are produced by the _____.
larynx
From the pulmonary veins, blood flows to the _____.
left atrium
The primary functions of the _____ are to warm, filter, and humidify air.
nasal cavity
In an open circulatory system, blood is _____.
not always confined to blood vessels and is under lower pressure than in closed circulatory systems
To control breathing, the medulla of the human brain monitors the ________ of the blood and then sends out signals so that appropriate physiological adjustments can be made.
pH
Blood returns to the heart via the _____.
pulmonary veins
What would be the consequence if we were to reverse the direction of water flow over the gills of a fish, moving water inward past the operculum, past the gills, then out the mouth? This reversal of water flow would ________.
reduce efficiency of gas exchange
From the superior vena cava, blood flows to the _____.
right atrium
If resistance increases in the capillary beds of the lung, which structure would be affected first?
right ventricle
Which of the following develops the greatest pressure on the blood in the mammalian aorta?
systole of the left ventricle
Carbon dioxide levels in the blood and cerebrospinal fluid affect pH. This enables the organism to sense a disturbance in gas levels as _____.
the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing
The circulatory systems of bony fishes, rays, and sharks are most similar to _____.
the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber
Circulatory systems compensate for _____.
the slow rate at which diffusion occurs over large distances
The velocity of blood flow is the lowest in capillaries because _____.
the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any other part of the circulatory system
Pressure is greatest in the ventricles when __________.
the ventricles contract
The volume of air inhaled and exhaled with each breath is called _______.
tidal volume
True or false? The lungs of humans form from the embryonic foregut.
true
How many chambers are typically found in the heart of organisms with single circulation circulatory systems?
two
A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. To travel from the artery to the thumb and then back to the left ventricle, this red blood cell must pass through _____.
two capillary beds
All of the following increase blood pressure except _______.
vasodilation
Which of the following is the correct sequence of blood flow in birds and mammals?
vena cava → right atrium → right ventricle → pulmonary artery
Countercurrent exchange is evident in the flow of _____.
water across the gills of a fish and the blood within those gills
