Biology Exam 3
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Why do animals need oxygen?
Uptakeof O2 from environment and disposal of CO2 to environment
All respiratory surfaces need to be...
- Large enough to meet the oxygen demands of the organism
What causes oxygen to decrease it?s availability
- Higher altitudes
- Increasing water temperatures
How does a gas always diffuse?
A gas will always diffuse from a region of higher partial pressure to a lower partial pressure
Label Bronchioles, Trachea,
What are the challenges of aquatic organisms with oxygen?
- water contains only 3-5% of the oxygen present in air
- more dense than air and thus takes more energy to move
- O2 diffuses rapidly in water vs. air
What are the challenges of terrestrial organisms with oxygen?
Must prevent dessication of respiratory surface
What are they types of respiratory surfaces?
Open and Closed Circulatory Systems
Circulatory system distributes O2 and CO2
What respiratory surface do these organisms use/have?
Marine Flatworm, Leeches, Sponges, and Some Amphibians
extensions of body surface; aquatic; external or internal
What respiratory surface uses Coelomic fluid, hemolymph or blood distributes O2 and CO2
What respiratory system do these organisms use/have?
Marine Worms, clams, crayfish, sea stars, fish
What respiratory surface has Featherlike extensions of body surface; designed to extract O2 from water?
What is found within gill filaments?
Dense Capillary Bed
How do gills operate?
The water is pulled in through the mouth and then pumped out over the gill filaments
Which of the following statements is not true?
A. Respiratory gases are exchanged only by diffusion
B. Oxygen has a lower rate of diffusion in water than in air
C. The oxygen content of water falls as the temperature of water rises
D. The amount of oxygen in teh atmosphere decreases with increasing altitude
E. Birds have evolved active transport mechanisms to augment their respiratory gas exchange
Which statement about the gas exchange system of birds is not true?
A. Respiratory gases are not exchanged in teh air sacs
B. A bird can achieve more complete exchange of oxygen from air to blood than humans can
C. Air passes through birds' lungs in only 1 direction
D. The gas exchange surfaces in bird lungs are the alveoli
E. A breath of air remains in the system for 2 breathing cycles
Which statement about gas exchange in fish is true?
A. Blood flows over the gas exchange surfaces in a direction opposite to the flow of water
B. Gases are exchanged across the gill arches
C. Ventilation of the gills is tidal in fast-swimming fishes
D. Less work is needed to ventilate gills in warm water than in cold water
E. The path length for diffusion or respiratory gases is determined by the length of the gill filaments
In the human gas exchange system,
A. the lungs and airways are completely collapsed after a forceful exhalation
B. the average Po2 concentration of air inside the lungs is always lower than that in the air outside the lungs
C. The Po2 of the blood leaving the lungs is greater than that of the exhaled air
D. The amount of air that is moved per breath during normal, at-rest breathing is termed the total lung capacity
E. O2 and CO2 are actively transported across the alveolar and capillary membranes
Which statement about the human gas exchange system is not true?
A. During inhalation, a negative pressure exists in the space between the lung and the thoracic wall
B. Smoking one cigarette can immobilize the cilia lining the airways for hours
C. The respiratory control center in the medulla responds more strongly to changes in arterial O2 concentration than to changes in arterial CO2 concentration
D. Without surfactant, the work of breathing is greatly increased
E. The diagpragm contracts during inhalation and relaxes during exhalation
The hemoglobin of a human fetus
A. is the same as that of an adult
B. has a higher affinity for O2 than adult hemoglobin has
C. has only 2 protein subunits instead of 4
D. is supplied by the mother's red blood cells
E. has a higher affinity for BPG than adult hemoglobin has
The amount of oxygen carried by hemoglobin depends on teh Po2 in teh blood. Hemoglobin in active muscles
A. becomes saturated with oxygen
B. takes up only a small amount of oxygen
C. readily unloads oxygen
D. tends to decrease the Po2 in teh muscle tissues
E. is denatured
Most Co2 in teh blood is carried
A. in the cytoplasm of red blood cells
B. as CO2 dissolved in the plasma
C. In teh plasma as bicarbonate ions
D. bound to plasma proteins
E. in red blood cells bound to hemoglobin
A. binds oxygen at Po2 values at which hemoglobin is releasing its bound oxygen
B. has a lower affinity for oxygen than hemoglobin does
C. consists of four polypeptide chains, just as hemoglobin does
D. provides an immediate source of O2 for muscle cells at the onset of activity
E. can bind 4 oxygen molecules at once
When the level of CO2 in the bloodstream increases,
A. the rate of respiration decreases
B. the pH of the blood rises
C. the respiratory centers become dormant
D. the rate of respiration increases
E. the blood becomes more alkaline
Structures in the respiratory system of birds that receive inhaled air; they keep fresh air flowing unidirectionally through the lungs, but are not themselves gas exchange surfaces
A small, baglike cavity, especially the blind sacs of the lung
The fact that low pH decreases the affinity of hemoglobin for oxygen
The smallest airways in a vertebrate lung, branching off the bronchi
The major airway(s) branching off the trachea into the vertebrate lung
A chemosensor in the carotid artery that senses a decrease in blood supply or a dramatic decrease in partial pressure of oxygen in the blood
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