Multiple Choice Quiz 1


1	Which one of the below is not a function of the respiratory system:
	A)	allows oxygen from the air to enter the blood and carbon dioxide to leave the blood and enter the air.
	B)	can alter the pH by changing oxygen levels.
	C)	provides protection against some microorganisms by preventing their entry into the body and by removing them from respiratory surfaces.
	D)	allows for speech and sound generation.



2	The vestibule just inside each naris is lined by ________________ epithelium.
	A)	stratified squamous
	B)	simple cuboidal
	C)	stratified cuboidal
	D)	pseudostratified columnar



3	The external nose is the visible structure that forms a prominent feature of the face. The largest part of the external nose is composed of:
	A)	nasal bones
	B)	elastic cartilage
	C)	fibrocartilage
	D)	hyaline cartilage



4	The partition dividing the nasal cavity into right and left parts is called the
	A)	hard palate
	B)	nasal septum
	C)	nasal conchae
	D)	vestibule



5	Air is filtered as it moves through narrow curved channels in the nasal cavity called _______________ and the debris is trapped and moved towards the pharynx by _______________ epithelium.
	A)	meati, pseudostratified ciliated columnar
	B)	conchae, pseudostratified ciliated columnar
	C)	meati, stratified squamous
	D)	conchiae stratified squamous



6	Which one of the cavities or ducts does not drain into or out of the nasal cavity?
	A)	vestibule
	B)	paranasal sinus
	C)	choanae
	D)	auditory tube



7	Which one of the functions is not of the nasal cavity?
	A)	filters the air
	B)	provides exchange site for O₂ and CO₂
	C)	humidifies the air
	D)	warms the air



8	Which one of the below is lined by a pseudostratified ciliated columnar epithelium?
	A)	vestibule
	B)	nasopharynx
	C)	oropharynx
	D)	laryngopharynx



9	The posterior surface of the nasopharynx contains the ___________ tonsils.
	A)	palatine
	B)	oral
	C)	lingual
	D)	pharyngeal



10	The soft palate including the uvula closes off the ______________ when swallowing.
	A)	oropharynx
	B)	nasopharynx
	C)	glottis
	D)	laryngopharynx



11	The role of the false vocal cords or vestibular folds in swallowing is to
	A)	prevent air from entering the lungs too quickly.
	B)	support the true vocal cords.
	C)	prevent food and liquids from entering the larynx.
	D)	vibrate when air is forced over them resulting in sound production.



12	Laryngitis is an infection or inflammation of the mucosal epithelium of the
	A)	true vocal cords.
	B)	false vocal cords.
	C)	laryngopharynx.
	D)	oropharynx.



13	In a normal conversation, Sally and Dawn who are of similar age, height and weight, speak at the same decibel level, but Sally's pitch is always higher than Dawn's. What might cause this difference?
	A)	Sally has longer true vocal cords than Dawn.
	B)	Sally forces more air over her true vocal cords than Dawn.
	C)	Sally is probably a smoker while Dawn is not.
	D)	Sally vibrates only the anterior parts of her true vocal cords while Dawn vibrates a greater length of her true vocal cords.



14	The largest laryngeal cartilage is the ___________ and the only elastic laryngeal cartilage is the _____________.
	A)	thyroid, cricoid
	B)	cricoid, epiglottis
	C)	thyroid, arytenoid
	D)	thyroid, epiglottis



15	Coughing will cause the trachealis muscle to
	A)	contract, which will narrow the diameter of the trachea.
	B)	relax, which will increase the diameter of the trachea.
	C)	contract, which will close the false vocal cords.
	D)	relax, which will open the false vocal cords.



16	The inferior larynx and trachea are lined by __________________ epithelium.
	A)	stratified squamous
	B)	simple squamous
	C)	simple cuboidal
	D)	pseudostratified columnar



17	The carina forms a ridge, which is a radiologic landmark and physiologic landmark. The carina is the
	A)	last cartilage of the larynx.
	B)	the last area of the respiratory tree that can initiate a coughing reflex.
	C)	first cartilage of the trachea.
	D)	area where the Heimlich maneuver should be applied.



18	In the respiratory tree, that area where the C-shaped cartilages are replaced with cartilage plates and smooth muscle, which forms a layer between the cartilage and the mucous membrane, is the
	A)	primary bronchi.
	B)	secondary bronchi.
	C)	terminal bronchioles.
	D)	carina.



19	In an asthma attack the _________________ muscle in the ______________ contract.
	A)	smooth, trachea
	B)	skeletal, bronchi
	C)	skeletal, terminal bronchioles
	D)	smooth, terminal bronchioles



20	Ninety percent of the epithelium of the alveoli is
	A)	simple squamous.
	B)	simple columnar.
	C)	pseudostratified columnar.
	D)	stratified squamous.



21	If the elastic fibers were removed from around the alveolar sacs, the lungs in normal breathing would lose most of their ability to
	A)	expand so inhalation would be impeded.
	B)	expand so exhalation would be impeded.
	C)	recoil so exhalation would be impeded.
	D)	recoil so inhalation would be impeded.



22	Surfactant is a mixture of lipoprotein molecules released by special cells in the alveoli called
	A)	macrophages.
	B)	Type I pneumocytes.
	C)	Type II pneumocytes.
	D)	red blood cells.



23	The pathway of oxygen from the alveoli across the respiratory membrane to the capillaries is
	A)	simple squamous → basement membrane of alveolus → interstitial space → basement membrane of capillary → simple squamous
	B)	simple cuboidal → basement membrane of alveolus → basement membrane of capillary → simple squamous
	C)	simple squamous → basement membrane of capillary → interstitial space → basement membrane of alveolus → simple squamous
	D)	simple squamous → basement membrane of alveoli → simple squamous



24	The left and right lungs in humans do not contain the same number of lobes. The right lung contains _________ lobes while the left lung contains ________ lobes because
	A)	2, 3; the heart takes up space on the right side.
	B)	2, 3; the trachea, blood vessels and esophagus travel on the right side.
	C)	3, 2; the heart takes up space on the left side.
	D)	3, 2; the trachea, blood vessels and esophagus travel on the left side.



25	Two-thirds of the increase in thoracic cavity volume during inspiration is caused by
	A)	contraction of the diaphragm.
	B)	contraction of the external intercostals.
	C)	relaxation of the pectoralis minor and scalenes.
	D)	release of surfactant.



26	The muscles that are most active in expiration are the
	A)	diaphragm
	B)	scalenes
	C)	external intercostals
	D)	internal intercostals



27	The lungs are found within two cavities called the
	A)	pleural and abdominal cavities.
	B)	pericardial and thoracic cavities.
	C)	pleural and thoracic cavities.
	D)	pleural and pericardial cavities.



28	The membrane that lines the inner thoracic cavity wall, the superior surface of the diaphragm, and the mediastinum is the
	A)	parietal pericardium.
	B)	parietal pleura.
	C)	visceral pericardium.
	D)	visceral pleura.



29	The space between the two lungs that houses the heart, trachea, esophagus and associated structures is called the
	A)	mediastinum
	B)	pleural cavity
	C)	thoracic cavity
	D)	parietal cavity



30	Your vestibular and vocal cords close tightly, your abdominal muscles contract, and the muscles of expiration contract forcefully. You have just experienced the preparation for a(n)
	A)	cough reflex.
	B)	sneeze reflex.
	C)	hiccup.
	D)	shouting reflex.



31	Using the following formula: Where: F = airflow P₁ = pressure in the alveoli P₂ = atmospheric pressure outside the body R = resistance to airflow If R is kept constant, what would allow for the greatest airflow (F)?
	A)	P₁ = P₂
	B)	P₁ > P₂
	C)	P₂ > P₁
	D)	The relationship between P₁ and P₂ does not matter to airflow.



32	Using the following formula: In an asthma attack, you would expect the airflow (F) to
	A)	increase
	B)	decrease
	C)	not change
	D)	stop



33	Using the following formula: Where: P = pressure in a container n = number of gram moles of gas R = gas constant T = absolute temperature V = volume If the volume of a container doubles, you would expect the pressure in the container to be
	A)	twice the original pressure.
	B)	four times the original pressure.
	C)	half the original pressure.
	D)	one-fourth the original pressure.



34	Assume that the atmospheric pressure outside the body is 760 mm Hg. Assuming you are neither inhaling nor exhaling, the percent of gases in your alveoli is as follows: N₂ = 74.9% O₂ = 13.6% CO₂ = 5.3% According to Dalton's Law, the partial pressure of oxygen in your alveoli is approximately
	A)	104 mm
	B)	136 mm
	C)	569 mm
	D)	760 mm



35	Carbon dioxide has a solubility coefficient 24 times higher than oxygen. This means that carbon dioxide
	A)	has a partial pressure that is 24 times higher than oxygen.
	B)	diffuses 24 times faster in air than oxygen.
	C)	is 24 times more soluble in water than oxygen.
	D)	diffuses across the respiratory membrane 24 times faster than oxygen.



36	Type II pneumocytes of the alveoli produce a mixture of lipoproteins called
	A)	surfactant.
	B)	mucus.
	C)	pleural fluid.
	D)	pericardial fluid.



37	In premature infants with respiratory distress syndrome or hyaline membrane disease, surfactant is not produced in adequate quantities and a respirator may be required. This is because surfactant
	A)	increases the compliance of the lungs.
	B)	decreases the surface tension of the fluid that lines the alveoli.
	C)	decreases the elasticity of the elastic fibers in the alveolar walls.
	D)	increases the ability of hemoglobin to bind to oxygen.



38	At the end of a normal respiration, the pleural pressure is negative 5 cm H₂O and the alveolar pressure is 0 cm H₂O. The lungs do not pull away from the pleural wall but create a suction effect. This suction effect ( - 5 cm H₂O) is caused by
	A)	contraction of the internal intercostals.
	B)	elastic recoil of the lungs and surface tension of the fluid lining the alveoli.
	C)	elastic recoil of the central tendon.
	D)	contraction of the diaphragm.



39	Pneumothorax is the introduction of air into the pleural cavity through an opening resulting from penetration trauma, such as that caused by a knife. As a result of air in the pleural cavity the lungs tend to
	A)	be less elastic and you cannot exhale.
	B)	collapse.
	C)	over inflate.
	D)	increase the surface tension in the fluid lining the alveoli.



40	During a normal inspiration, the pleural pressure decreases to about negative 8 cm H₂O and the alveolar pressure __________ to about __________ cm H₂O relative to atmospheric pressure.
	A)	decreases, 1
	B)	increases, 1
	C)	increases, negative 1
	D)	decreases, negative 1



41	Emphysema causes destruction of elastic lung tissue. As a result of emphysema, the elastic recoil of the lungs would ___________ and the compliance of the lungs would _____________.
	A)	decrease, decrease
	B)	decrease, increase
	C)	increase, decrease
	D)	increase, increase



42	The amount of air inspired or expired in a normal inhalation or exhalation is called __________ and has a volume of about ____________ mL.
	A)	tidal volume, 4600
	B)	vital capacity, 4600
	C)	residual volume, 1200
	D)	tidal volume, 500



43	The maximum amount of moveable air in the lungs is called ______________ and has a volume of about _____________mL.
	A)	vital capacity, 4600
	B)	total lung capacity, 5800
	C)	inspiratory reserve volume, 3000
	D)	inspiratory capacity, 3500



44	You are exercising doing aerobics or a stair climber at your fitness center. As you increase to a high intensity of exercise, you would expect the tidal volume to ______________ and the frequency of respiration to _____________.
	A)	decrease, increase
	B)	increase, increase
	C)	stay the same, increase
	D)	increase, decrease



45	In a normal inspiration, the amount of air that is actually available for exchange of oxygen and carbon dioxide is about ____________mL.
	A)	150
	B)	350
	C)	500
	D)	650



46	You went snorkeling for the first time and noticed that breathing through the tube was more labored than breathing without the tube. This labored breathing was caused by:
	A)	increase in residual volume.
	B)	decrease in vital capacity.
	C)	increase in expiratory reserve volume.
	D)	increase in dead air space.



47	The formula for alveolar ventilation is: V_A = f(V_T - V_D) Where: V_A = alveolar ventilation f = respiratory rate V_T = tidal volume V_D = dead air space A resting person has a respiratory rate of 12 breaths per minute. What is the person's alveolar ventilation?
	A)	500 mL/min
	B)	4200 mL/min
	C)	6000 mL/min
	D)	7800 mL/min



48	A resting individual has a respiratory rate of 12 breaths per minute. How much air is wasted (not involved in gas exchange) per minute?
	A)	500 mL/min
	B)	1800 mL/min
	C)	4200 mL/min
	D)	6000 mL/min



49	Consider the table below (Table 23.2) Why is the partial pressure of water (PH₂O) 47 mm Hg in both the alveolar air and expired air?
	A)	Water is neither added nor removed in the respiratory passages.
	B)	The air that is breathed in has a humidity of 100%.
	C)	The air in the respiratory tract is humidified to 100% saturation of water.
	D)	Carbon dioxide and oxygen are exchanged equally across the alveoli for water.



50	Consider the table below (Table 23.2). Nitrogen is not normally exchanged in the respiratory tract, yet the partial pressures of nitrogen varies in inhaled air, alveolar air and expired air. The differences can be explained because
	A)	of random diffusing of N₂ across the respiratory membranes.
	B)	nitrogen is the only gas not to obey Dalton's Law.
	C)	nitrogen is added to the alveoli but removed from other areas of the respiratory tract.
	D)	oxygen is removed and carbon dioxide is added to the alveoli and water is added all along the respiratory tract.



51	A SCUBA diver who suddenly ascends to the surface from a great depth can develop decompression sickness or the bends in which bubbles of nitrogen gas form blocking blood flow through small vessels. This can be explained because nitrogen has a
	A)	low solubility coefficient but will diffuse into alveolar capillaries under high pressure.
	B)	high solubility coefficient and a high partial pressure in the alveoli.
	C)	low solubility coefficient but a high partial pressure in the alveoli.
	D)	low solubility coefficient at normal atmospheric pressure but a high solubility coefficient at very high pressures.



52	Individuals with tuberculosis or pneumonia have difficulty breathing because
	A)	solubility coefficients for oxygen and carbon dioxide are increased and the surface area of the respiratory membrane is decreased.
	B)	the thickness of the respiratory membrane is increased while the surface area is decreased.
	C)	the thickness of the respiratory membrane is increased and the partial pressure difference across the respiratory membrane for oxygen and carbon dioxide is increased.
	D)	the partial pressure differences across the respiratory membrane for oxygen and carbon dioxide are increased while the surface area is decreased



53	Toxins that decrease the abundance of cilia in the respiratory tract tend to increase the
	A)	partial pressures of oxygen and carbon dioxide.
	B)	thickness of the respiratory membrane.
	C)	coughing reflex.
	D)	surface area of the respiratory membrane.



54	After vigorous exercise, you increase your rate and depth of breathing. This will cause the
	A)	surface area of the respiratory membrane to increase.
	B)	partial pressure differences for oxygen and carbon dioxide to increase across the respiratory membrane.
	C)	thickness of the respiratory membrane to decrease.
	D)	solubility coefficients of oxygen and carbon dioxide to increase.



55	Deoxygenated blood from the bronchi and bronchioles mix with oxygenated blood in the pulmonary veins. This is called the
	A)	physiologic shunt.
	B)	pulmonary artery.
	C)	pulmonary vein.
	D)	anatomical shunt.



56	The major factor, which normally affects regional blood flow in the lungs, is
	A)	gravity.
	B)	the anatomical shunt.
	C)	cardiac output.
	D)	ventilation rate.



57	Blood entering the lungs has a PO₂ of 40 mm Hg while blood immediately leaving the lung capillaries has a PO₂ of _______ mm Hg because it has reached equilibrium with the PO₂ in the ____________.
	A)	45, interstitial fluid
	B)	45, alveoli
	C)	104, interstitial fluid
	D)	104, alveoli



58	Arterial blood entering the tissues has a PO₂ = 95 mm Hg and a PCO₂= 40 mm Hg. Venous blood leaving the tissues has a PO₂ = _________ mm Hg and a PCO₂ = __________ mm Hg.
	A)	104, 40
	B)	95, 40
	C)	40, 45
	D)	20, 46



59	Approximately 98.5% of the oxygen transported in the blood is transported
	A)	attached to the heme in hemoglobin of red blood cells.
	B)	combined with H₂O to form bicarbonate in the plasma.
	C)	attached to the globin in hemoglobin of red blood cells.
	D)	dissolved in the plasma.



60	Approximately 70% of the carbon dioxide in the blood is transported
	A)	attached to the heme of hemoglobin in red blood cells.
	B)	combined with H₂O to form bicarbonate in the plasma.
	C)	attached to the globin in hemoglobin in red blood cells.
	D)	dissolved in the plasma.



61	This question refers to "(a)" in the figure below (Figure 23.19a). In the "Curve before shift", a drop from a PO₂ of 100 mm Hg to 80 mm Hg will cause a _____% drop in oxygen saturation of hemoglobin while a drop from a PO₂ of 40 mm Hg to 20 mm Hg will cause a _____% drop in oxygen saturation of hemoglobin.
	A)	20, 20
	B)	20, 40
	C)	3, 40
	D)	3, 20



62	If you start exercising, your body temperature will rise, your CO₂ production will increase, and your pH will decrease. You are utilizing oxygen which will drop the partial pressure to about 18 mm of Hg. How much more oxygen will hemoglobin drop to the tissues at a partial pressure of 18 mm Hg when you are exercising (red curve) compared to resting (black curve). Use the figure below to answer the question.
	A)	0%
	B)	5%
	C)	14%
	D)	23%



63	According to the Bohr effect, as the pH of the blood declines, the amount of oxygen bound to hemoglobin at any give PO₂ also declines. This results from an increased production of ______ resulting in an increased production of _________.
	A)	oxygen, lactic acid.
	B)	oxygen, carbonic acid.
	C)	carbon dioxide, carbonic acid.
	D)	carbon dioxide, lactic acid.



64	In the lungs, as a result of CO₂ diffusing into the alveoli, you would expect hemoglobin's ability to bind to oxygen to
	A)	be unstable
	B)	stay the same.
	C)	decrease.
	D)	increase.



65	In carbon monoxide (CO) poisoning, CO binds to the heme of hemoglobin much easier than oxygen. What effect will this have on the ability of the tissues to get oxygen?
	A)	More carbonic acid will be produced, and the hemoglobin will give up more oxygen to the tissue.
	B)	Hemoglobin will bind to less oxygen, and hemoglobin will not release as much oxygen to the tissue.
	C)	Carbon monoxide makes hemoglobin give up oxygen more readily in the tissues.
	D)	Carbon monoxide ties up hemoglobin's ability to bind to oxygen, but more hemoglobin will be produced so no decline in oxygen in the tissue will be noticed.



66	People living at high altitudes have increased levels of 2,3-bisphosphoglycerate (BPG) in their red blood cells. This high level of BPG will
	A)	increase the Bohr effect and make oxygen more available to the tissue.
	B)	bind to hemoglobin and reduce the amount of oxygen available to the tissue.
	C)	bind to hemoglobin and increase the amount of oxygen available to the tissue.
	D)	shift the oxygen-hemoglobin dissociation curve to the left and reduce the amount of oxygen available to the tissue.



67	People with anemias involving disorders of hemoglobin such as thalassemia and sickle cell anemia are not getting enough oxygen to tissues. They have chemoreceptors in the walls of the large arteries going to the head that monitor oxygen concentration in the blood. However, in spite of tissues getting inadequate oxygen, the chemoreceptors do not reflexly increase heart rate and blood pressure to provide more rapid movement of blood to the tissues. What might explain this apparent paradox; chemoreceptors monitor oxygen in the blood but apparently they do not respond in people who have thalassemia or sickle cell anemia to provide adequate oxygen to the tissues.
	A)	Chemoreceptors only monitor oxygen in arterial blood so what happens in the tissues has no effect.
	B)	Chemoreceptors only monitor dissolved oxygen in the blood and that remains unchanged in the anemias.
	C)	Chemoreceptors are made up of similar amino acids as hemoglobin and are also damaged in the anemias.
	D)	Chemoreceptors actually inhibit the heart rate and blood pressure when oxygen falls below a certain level in hemoglobin.



68	Refer to the figure. Notice that blood entering alveolar capillaries of the lungs have a PO₂ = 40 mm Hg and a PCO₂ = 45 mm Hg. The alveoli have a PO₂ = 104 mm Hg and a PCO₂ = 45 mm Hg. The blood leaving the alveolar capillaries have partial pressures the same as in the alveoli: PO₂ = 104 mm Hg and PCO₂ = 40 mm Hg. In the short period of time (less than one second) the blood spends in the alveolar capillaries both gases reach equilibrium values with the alveoli. However, oxygen has a diffusion gradient of 64 mm Hg (104 mm to 40 mm) while carbon dioxide only has a diffusion gradient of 5 mm Hg (45 mm to 40 mm). How can CO₂ reach equilibrium the same as O₂ when O₂ has a partial pressure gradient over 12 times higher than the partial pressure gradient for CO₂?
	A)	CO₂ has a 24 times higher solubility coefficient than O₂.
	B)	O₂ has a 24 times higher solubility coefficient than CO₂.
	C)	The partial pressure gradient plays a minor role in the movement of O₂ and CO₂ across membranes.
	D)	CO₂causes a drop in pH in the respiratory membrane, and this causes CO₂ to diffuse faster and O₂ slower.



69	Hemoglobin that has released its oxygen binds more readily to carbon dioxide than hemoglobin that is highly saturated with oxygen. This is called
	A)	the Bohr effect.
	B)	Dalton's Law
	C)	Boyle's Law
	D)	the Haldane effect.



70	Bicarbonate ions are produced in red blood cells and then diffuse across the membrane and travel in the blood dissolved in the plasma. Carrier molecules move bicarbonate ions across the red blood cell membrane in exchange for ______ ions.
	A)	sodium
	B)	potassium
	C)	hydrogen
	D)	chloride



71	Which one of the following does not apply to fetal hemoglobin?
	A)	The concentration of fetal hemoglobin is 50% greater than the concentration of maternal hemoglobin.
	B)	Fetal hemoglobin can hold more oxygen than maternal hemoglobin.
	C)	Fetal hemoglobin creates much more acid conditions in the fetal tissue than maternal hemoglobin; this is called the double Bohr effect.
	D)	BPG has little effect on fetal hemoglobin.



72	The dorsal and ventral respiratory groups make up the respiratory center and are located in the
	A)	pons.
	B)	medulla oblongata.
	C)	mesencephalon.
	D)	hypothalamus.



73	The group in the respiratory center that is most active during inspiration is the
	A)	dorsal group
	B)	ventral group
	C)	pontine respiratory group
	D)	pons



74	When stretch receptors are firing in the bronchi and bronchioles of the lungs, you would expect
	A)	stimulation of the dorsal respiratory group.
	B)	inhibition of the dorsal respiratory group and stimulation of the expiratory center of the ventral respiratory group.
	C)	inhibition of both the dorsal respiratory group and the entire ventral respiratory group.
	D)	stimulation of both the dorsal respiratory group and the entire ventral respiratory group.



75	Which of the following would be a collection of neurons in the pons, formerly called the pneumotaxic center, which switches between inspiration and expiration?
	A)	apneustic center
	B)	pontine respiratory group
	C)	dorsal respiratory group
	D)	ventral respiratory group



76	Which of the following muscles is stimulated by the dorsal respiratory group?
	A)	external intercostals
	B)	internal intercostals
	C)	diaphragm
	D)	rectus abdominus



77	Which of the following muscles is (are) stimulated by the ventral respiratory group?
	A)	diaphragm
	B)	external abdominal oblique
	C)	internal intercostals
	D)	Both B and C.



78	A Type I diabetic whose insulin levels drop too low will produce metabolic acids that will lower the pH of the blood. You would expect the diabetic to
	A)	have brief periods of apnea.
	B)	have no change in respiratory rate.
	C)	decrease the respiratory rate.
	D)	increase the respiratory rate.



79	A person holds his or her breath until he or she passes out. The person will resume breathing because a(n)
	A)	decrease in oxygen is detected by chemoreceptors in the carotid and aortic arteries, which inhibits the inspiratory neurons of the respiratory center.
	B)	increase in pH is detected by chemoreceptors in the carotid and aortic arteries, which stimulates the inspiratory neurons of the respiratory center.
	C)	increase in carbon dioxide and a decrease in pH are detected by chemoreceptors in the walls of carotid and aortic arteries as well as chemoreceptors that detect changes in the pH of cerebrospinal fluid. These chemoreceptors excite the inspiratory neurons of the respiratory center.
	D)	decrease in carbon dioxide and an increase in oxygen are detected by chemoreceptors that monitor the blood and cerebrospinal fluid. These chemoreceptors inhibit the inspiratory neurons of the respiratory center.



80	Chemoreceptors are located in the
	A)	walls of the carotid and aortic arteries and in the medulla oblongata.
	B)	walls of the carotid and aortic arteries only.
	C)	medulla oblongata and in the walls of the superior and inferior vena cavas.
	D)	walls of the carotid and aortic arteries and in the walls of the superior and inferior vena cavas.



81	Strong emotions can sometimes stimulate hyperventilation. The best treatment for hyperventilation is to
	A)	just let the person relax and normal breathing will resume.
	B)	give the person oxygen.
	C)	have the person increase his or her rate of breathing.
	D)	have the person breath into a bag.



82	A drop in PO₂ has little effect on the respiratory centers until the arterial PO₂ drops by about 40%. However, a 10% rise in arterial PCO₂will cause the respiratory rate to double. This can be explained because
	A)	hemoglobin carries great reserves of oxygen while PCO₂ changes also cause changes in pH.
	B)	oxygen is not as important to the cells as is carbon dioxide.
	C)	chemoreceptors are not sensitive to PO₂ but are sensitive to PCO₂ and pH.
	D)	oxygen cannot diffuse from the blood into the cerebrospinal fluid while carbon dioxide can, and the chemoreceptors in the medulla oblongata are much more important in regulating respiration.



83	A decrease in oxygen in the tissues below normal levels is called
	A)	apnea.
	B)	hypocapnia.
	C)	hypoxia
	D)	hypercapnia.



84	If exercise exceeds the anaerobic threshold, skeletal muscle will
	A)	relax because without oxygen no ATP can be generated.
	B)	switch to the use of fatty acids to generate ATP.
	C)	produce and release lactic acid into blood.
	D)	switch to creatine phosphate reserves to generate ATP.



85	When you are exercising, your rate of breathing increases because
	A)	the PO₂ levels in the blood drop.
	B)	the ATP and creatine phosphate reserves in the skeletal muscle are used up.
	C)	the PCO₂levels increase and pH levels in the blood and cerebrospinal fluid drop.
	D)	your body needs more oxygen to contract its skeletal muscles.



86	After athletic training over a long period of time, your resting minute ventilation is
	A)	greatly increased.
	B)	unchanged or slightly reduced.
	C)	greatly reduced.
	D)	independent of the level of training.



87	Which of the following is FALSE concerning respiration after fitness training?
	A)	Vital capacity increases slightly
	B)	Tidal volume at rest and during submaximal exercise does not change.
	C)	Tidal volume at maximal exercise does not change
	D)	Maximal exercise respiratory rate increases.



88	Which of the following changes can be seen in respiration after fitness training?
	A)	Minute volume is greatly increased at maximal exercise.
	B)	Gas exchange between the alveoli and the blood increases at maximal exercise.
	C)	Minute volume is essentially unchanged at rest.
	D)	All of the above.

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