CH 42
What is the theoretical cardiac output of a patient with a heart rate of 70 beats per minute and a stroke volume of 70 mL/beat?
4,900 mL/minute
What is the partial pressure of oxygen (PO2) when the air in a testing chamber is mixed so that its oxygen content is 10% and its overall air pressure is 400 mm Hg?
40 mm Hg
Atmospheric pressure at the summit of Mount Everest is about one third the pressure at sea level, which is 760 mm Hg. What is the partial pressure of oxygen (PO2) at the summit of Mount Everest if oxygen makes up 21% of the atmosphere by volume at both locations?
53 mm Hg
__________ in carbon dioxide in your tissues leads to __________ in pH of cerebrospinal fluid and blood, which ultimately causes your breathing to speed up.
An increase, a drop
Dentists sometimes give a patient antibiotics after a teeth-cleaning procedure, especially if the patient is older or has heart disease. What is the best explanation for this?
Antibiotics help kill the bacteria that move from the mouth to the bloodstream, and prevent the bacteria from contributing to atherosclerosis.
Which of the following statements best describes an artery?
Arteries carry blood away from the heart.
Why does the velocity of blood slow greatly as blood flows from arterioles into capillaries?
Because capillary beds have a total cross-sectional area much greater than the total cross-sectional area of the arterioles.
Select the correct statement about capillary beds.
Capillary beds are the site of nutrient and oxygen delivery to tissues.
Why does the post-Medieval skull in the video have such bad teeth?
Diets during this time period were high in sugar.
Review this diagram of a gill filament from the video. Which three statements are true of blood flowing through a capillary at the location marked by the green circle?
Dissolved oxygen in the blood is lowest at this point. Oxygen diffuses from the water into the blood. The water surrounding the blood has a low concentration of oxygen.
Inhalation and exhalation move air into and out of the lungs. What happens when you inhale and exhale? Drag the labels to the correct locations on the flowchart to identify the steps of inhalation and exhalation.
During inhalation, the diaphragm and rib muscles contract, increasing the volume of the lungs. Air enters the nose or mouth and flows down the trachea, bronchi, and bronchioles, and into the alveoli.During exhalation, the diaphragm and rib muscles relax, decreasing the volume of the lungs. Air leaves the alveoli and flows up the bronchioles, bronchi, and trachea, and exits through the nose or mouth.
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 (The pulmonary circulation is the lower-pressure circuit to the lung, whereas the systemic circulation is the higher-pressure circuit to the rest of the body.)
Compare the dissociation curves of the two hemoglobins in the graph. How does the dissociation curve for fetal hemoglobin compare to that for maternal hemoglobin?
Fetal hemoglobin has a higher affinity for oxygen than maternal hemoglobin at any partial pressure of oxygen.
Which hypothesis best explains this difference?
Fetal hemoglobin's higher affinity for oxygen helps promote the movement of oxygen from mother to fetus.
Consider this diagram of blood circulation in a fish. Which of the following describes the path taken by oxygen-rich blood?
From the gills to the body tissues
Gas exchange involves the transport of two respiratory gases, oxygen and carbon dioxide. Review how each gas is transported between the atmosphere and the cells of your body by completing this exercise. Drag each statement into the appropriate bin depending on whether it applies to oxygen only, carbon dioxide only, or both oxygen and carbon dioxide.
Gas exchange provides the body's cells with oxygen, which is needed for cellular respiration.Oxygen diffuses from the alveoli to capillaries in the lungs.Almost all the oxygen in the blood is bound to hemoglobin.Oxygen is carried all over the body and diffuses from blood to body tissues. Gas exchange also removes carbon dioxide, a waste product of cellular respiration, from the body.Carbon dioxide diffuses from body tissues to blood.Carbon dioxide is transported either in the plasma, bound to hemoglobin, or in the form of bicarbonate.In the lungs, carbon dioxide diffuses from the capillaries into the alveoli. When you exhale, carbon dioxide leaves the body.
Which statement about lipoproteins is correct?
High-density lipoproteins are cholesterol transporters in the blood.
Which of the following mechanisms are used to regulate blood pressure in the closed circulatory system of vertebrates? I)changing the strength of heart contraction II)constricting and relaxing smooth muscle in the walls of arterioles III)opening or closing precapillary sphincters
I, II, and III
Which of the following statements 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
What is the function of a circulatory system?
It brings a transport liquid into close contact with all cells in the body.
Which statement about the gas exchange system in fish is correct?
It enables oxygen to diffuse from the water into the blood over the entire length of the gill capillaries.
What is the function of the left ventricle?
It pumps oxygenated blood around the body via the systemic circulation.
What is the best explanation for the fact that the two histograms overlap as much as they do?
Many factors in addition to PCSK9 enzyme activity affect plasma LDL levels.
Based on these two histograms, what conclusion can you draw?
On average, individuals with an inactivating mutation in the PCSK9 gene have lower plasma LDL levels than wild-type individuals.
Which of the following statements about human blood vessels is correct?
Pulmonary veins carry oxygen-rich blood to the heart.
People who produce very little saliva often have more cavities. What is the best explanation for this?
Since saliva normally helps neutralize acid and replace minerals on teeth, a lack of saliva leads to more cavities.
Which event occurs first during atrial and ventricular diastole?
The atria and ventricles are relaxed, and blood flows into the atria.
The table below walks you through a comparison of cooperative binding and noncooperative binding. By completing the table, you will learn why cooperative binding is an important adaptation that makes gas exchange more efficient. Drag the labels to their appropriate locations on the table. Labels can be used more than once.
The cooperative binding of oxygen to hemoglobin is an important adaptation for gas exchange. Cooperativity allows hemoglobin to release much more oxygen to an animal's body tissues.Compare the numbers for cooperative binding (circled in red) to those for noncooperative binding (circled in gold).In a resting tissue, hemoglobin releases 50% of its oxygen. If there were no cooperativity, it would release only 30% of its oxygen.In an exercising tissue, hemoglobin releases 80% of its oxygen. If there were no cooperativity, it would release only 50% of its oxygen.
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 correctly compares respiration in fish and in mammals?
The movement of the respiratory medium in mammals is bidirectional, but in fish it is unidirectional.
Which statement about oxygen in fish gills is correct?
The partial pressure of oxygen in blood increases as it flows through gill capillaries.
A rabbit taken from a meadow near sea level and moved to a meadow high on a mountainside would have some trouble getting adequate oxygen delivery. Which statement best explains why this would occur?
The partial pressure of oxygen in the air at high elevations is lower than at sea level.
How would you predict the risk for cardiovascular disease to compare between the study group and the control group?
The study group has a lower risk than the control group.
Select the correct statement about the three-chambered hearts of amphibians and nonbird reptiles.
The three-chambered hearts of amphibians and nonbird reptiles are facultative, allowing variation in blood flow through the heart.
Which of the following features of the mammalian circulatory system helps to prevent damage to capillaries from high arterial blood pressure?
The total cross-sectional diameter of the blood vessels 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.
While jogging, a person has a stroke volume of 130 mL/beat and a heart rate of 120 beats per minute. Their resting stroke volume is 70 mL/beat and resting heart rate is 60 beats per minute. Which answer best describes the effect of jogging on the person's cardiac output?
Their cardiac output increased from 4,200 mL/minute to 15,600 mL/minute when jogging.
Comparing these two histograms allowed researchers to draw a conclusion regarding the effect of PCSK9 mutations on LDL cholesterol levels in blood. Now consider two individuals with a plasma LDL level of 160 mg/dL, one from the study group and one from the control group. What do you predict regarding their relative risk for cardiovascular disease?
Their risk is equal because their LDL levels are the same.
Which of the following is true?
There is a correlation between periodontal disease and heart disease.
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 greater than 100 mm Hg.
Which of the following statements about blood circulation in the body is true?
Valves prevent the backflow of blood into the atria and ventricles.
Although having evolved independently, the tracheal tubes of mammals and insects are both supported by rigid tissues. The trachea of a mammal are supported by cartilage, and the tracheae of an insect are supported by chitin. Which of the following is a selective pressure that most likely led to the convergent evolution of these respiratory structures?
When breathing air, there is a risk that trachea and tracheal tubes will collapse.
Which letter indicates systolic pressure? (question 4)
a
Stroke occurs when __________.
a blood clot enters the cerebral circulation, blocking an artery and causing the death of brain tissue
Which type of circulatory system is most likely present in organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells?
a closed circulatory system
What percentage of individuals in the control group had an LDL level below 100 mg/dL?
about 17%
The results are presented using a form of bar graph called a histogram. In a histogram, the variable on the x-axis is grouped into ranges. The height of each bar in this histogram represents the percentage of samples that fall into the range specified on the x-axis for that bar. For example, in the top histogram, about 4% of individuals studied had plasma LDL cholesterol levels in the 25-50 mg/dL (milligrams per deciliter) range. What percentage of individuals in the study group had an LDL level below 100 mg/dL? (Hint: Add the percentages for the relevant bars.)
about 58%
What is the direct cause of demineralization of the enamel on teeth?
acids produced by bacteria
Which of the following is a normal event in the process of blood clotting?
activation of prothrombin to thrombin
Which of the following can increase your risk of atherosclerosis?
avoiding exercise
Which letter indicates diastolic pressure?
b
Which of the following indicates a diagnosis of hypertension in adults?
blood pressure being greater than 140 mm Hg systolic and/or greater than 90 mm Hg diastolic
The smallest airway through which inspired air passes before gas exchange occurs in the mammalian lungs is the __________.
bronchiole
Which letter indicates the arteries?
d
Countercurrent exchange in the fish gill helps to maximize ________.
diffusion
Damage to the SA node in humans is most likely to result in a ________.
disruption on the rate and timing of cardiac muscle contractions
Which letter indicates the vessels in which blood velocity is decreasing the most due to an increase in the total combined cross-sectional area of those vessels?
e
Which of the following organisms has no specialized respiratory structures? See Concept 42.5 (Page)
earthworms
Which letter indicates the vessels in which blood travels the most slowly?
f
Which of the following are the only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart?
fishes
Which biological membranes must atmospheric molecules of oxygen cross to become bound to hemoglobin for transport in mammals?
five membranes (in and out of the cell lining the lung, in and out of the endothelial cell lining an alveolar capillary, and into the red blood cell)one membrane (the lining in the lungs)
Which of the following examples illustrates the process of countercurrent exchange?
flow of water across the gills of a fish and the blood within those gills
Which of the following would an organism need to adjust blood pressure independently in the blood vessels of the gas-exchange surface and in the blood vessels of the general body circulation?
four-chambered heart
In which of the following organisms does blood flow from the pulmocutaneous circuit to the heart before circulating through the rest of the body?
frogs
Which letter indicates the venules?
g
Which one of the following organisms likely has the highest systolic pressure in its aorta?
giraffe
In which of the following animals are the blood and the interstitial fluid considered to be the same body fluid?
grasshoppers
Which letter indicates the vessels in which blood velocity is increasing the most due to a decrease in the total combined cross-sectional area of those vessels?
h
Pulse is a direct measure of
heart rate.
Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arterioles has a
higher PO2
Which letter indicates the vessels in which blood pressure is the lowest?
i
From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.
inferior vena cava
Organisms belonging to a species with a high resting cardiac output are most likely to have which of the following characteristics?
large distance between its heart and its brain
Which of the following represents the correct flow of air into the lung of a mammal?
larnyx → trachea → bronchi → bronchioles → alveoli
Voice sounds are produced by the _____.
larynx
From the pulmonary veins, blood flows to the _____.
left atrium
Blood returning to the mammalian heart in a pulmonary vein drains first into the
left atrium.
Some human infants, especially those born prematurely, suffer serious respiratory failure because of ________.
lung collapse due to inadequate production of surfactant
The primary functions of the _____ are to warm, filter, and humidify air.
nasal cavity
Atrial systole ________.
occurs at the same time as ventricular diastole
What is the direct cause of gum disease?
plaque formed by bacteria
Blood returns to the heart via the _____.
pulmonary veins (carry oxygenated blood from lungs)
An advantage of gas exchange in water, compared with gas exchange in air, is that __________.
respiratory surfaces remain moist
From the superior vena cava, blood flows to the _____.
right atrium
When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?
rising CO2
Which of the following results in the greatest blood pressure in the mammalian aorta?
systole of the left ventricle
A paleontologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, was well-formed, and had four chambers, with no connection between the right and left sides. Which of the following conclusions is best supported by these observations?
the animal was endothermic and had a high metabolic rate
One feature that amphibians and humans have in common is
the number of circuits for circulation.
The sun shining on a tidal pool during a hot day heats the water, causing some water to evaporate. Which of the following is most likely to occur because the water has become warmer and saltier?
the oxygen content will decrease
Which of the following is most analogous in structure and function to the circulatory systems of bony fishes, rays, and sharks?
the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber
The greatest difference in the concentration of respiratory gases is found in which of the following pairs of mammalian blood vessels?
the pulmonary vein and the superior vena cava
A molecule of CO2 released into the blood in your left toe can be exhaled from your nose without passing through which of the following structures?
the pulmonary vein.
An electrocardiogram (ECG) provides information about ________.
the rhythm of heart contractions
Circulatory systems help to overcome which of the following physiological challenges?
the slow rate at which diffusion occurs over large distances
The velocity of blood flow lowest in capillaries because ________.
the total cross-sectional area is greater in the capillaries than in any other part of the circulatory system
Which of the following respiratory systems is independent from a fluid-based circulatory system?
the tracheal system of an insect
How many capillary beds must a red blood cell pass through to move from an artery in the left arm to the left ventricle of the heart?
two
Which of the following is the correct sequence of blood flow in birds and mammals?
vena cava → right atrium → right ventricle → pulmonary artery
Recall the diagram showing the flow pattern of water and blood across a lamella. Which diagram best represents the efficient extraction of oxygen from water by the mechanism of countercurrent exchange?
water flow showing % O2 (90 75 35 10) Blood flow in capillary, showing % O2 (80 60 25 5)
