Which is not a reason gas exchange is efficient at the blood air barrier?
A) Partial pressure differences are substantial.
B) Distance is short.
C) Surface area is large.
D) Gap junctions facilitate fast movement.
E) Gases are lipid soluble.
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Question 2) The space between the cornea and the iris is the
A) anterior chamber.
B) posterior chamber.
C) scleral venous sinus.
D) aqueous humor.
E) pupil.
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Question 3) A SCUBA diver has been deep underwater and suddenly rises to the surface too fast. Why does the diver get decompression sickness?
A) Pressure decreases and carbon dioxide rushes into cells.
B) Pressure changes too fast and the carbon dioxide in the blood forms bubbles.
C) Pressure decreases too fast and nitrogen gas in the blood forms bubbles.
D) The gas in the SCUBA tank had too much pressure and rapid ascent forces too much air into the blood.
E) Pressure increases too fast and too much oxygen enters the blood and forms bubbles.
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Question 4) The vitreous body
A) fills the anterior chamber.
B) helps to stabilize the eye and holds the retina up against the eyewall.
C) is replaced at the rate of 20 percent per year until middle age.
D) circulates through the pupil.
E) holds the retina against the lens for proper refraction.
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Question 5) The partial pressure of carbon dioxide is greatest in
A) venous blood.
B) alveolar air.
C) expired air.
D) inspired air.
E) arterial blood.
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Question 6) Which of the following produces a lipid-rich secretion that prevents the upper and lower eyelids from sticking together at their edges?
A) palpebra
B) lacrimal caruncle
C) chalazion
D) tarsal gland
E) conjunctiva
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Question 7) The partial pressure of oxygen in atmospheric air at sea level is
A) greater than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest.
B) less than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest.
C) equal to the partial pressure of oxygen in atmospheric air at the top of Mt. Everest.
D) equal to the sum of partial pressures from carbon dioxide and nitrogen.
E) equal to the partial pressure of carbon dioxide in atmospheric air at the top of Mt. Everest.
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Question 8) A structure that is located at the medial angle and contains glands that contribute to a gritty deposit is the
A) palpebra.
B) lacrimal caruncle.
C) chalazion.
D) tarsal gland.
E) conjunctiva.
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Question 9) Each of the following factors affects the rate of external respiration except the
A) PO2 of the alveoli.
B) PCO2 of the blood.
C) thickness of the respiratory membrane.
D) PN2 of the alveoli.
E) solubility of oxygen in plasma.
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Question 10) The human lens focuses light on the photoreceptor cells by
A) moving up and down.
B) moving in and out.
C) changing shape.
D) opening and closing.
E) dilating and constricting.
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