Lecture 8: Respiration II Flashcards
What are the 3 different types of unidirectional flow?
a) crosscurrent, concurrent, countercurrent
b) Tidal gas exchange, concurrent, crosscurrent
c) active ventilation, passive ventilation cross ventilation
d) all of the above
a)
Which of the following is a characteristic of concurrent gas exchange?
A) Blood and medium flow in opposite directions.
B) Blood and medium flow in the same direction.
C) Blood is divided into multiple streams.
D) It is the most efficient form of gas exchange.
b)
In which type of gas exchange do blood and medium flow in opposite directions to maximize oxygen uptake?
A) Concurrent
B) Countercurrent
C) Cross-current
D) Bidirectional
b) counter current
Which form of gas exchange is most efficient in extracting oxygen from water?
A) Cross-current gas exchange in birds
B) Concurrent gas exchange in fish
C) Countercurrent gas exchange in fish
D) Tidal gas exchange in humans
c)
Cross-current gas exchange is found in which group of animals?
A) Fish
B) Birds
C) Mammals
D) Amphibians
B) birds
According to Fick’s law of diffusion, what effect does reducing the thickness of the membrane have on diffusion (gas exchange) ?
A) It decreases the diffusion rate.
B) It increases the diffusion rate.
C) It has no effect on the diffusion rate.
D) It reverses the direction of gas diffusion.
b) increases diffusion rate
Which of the following correctly describes the role of blood in cross-current gas exchange?
A) Blood flows in a single stream and encounters oxygen-poor air throughout.
B) Blood splits into multiple streams, each exposed to different oxygen levels in the medium.
C) Blood flows counter to the direction of the medium to maximize oxygen uptake.
D) Blood stagnates in the system, causing oxygen diffusion to be slower.
b)
How does the thickness of the gas exchange surface relate to efficiency in concurrent, countercurrent, and cross-current exchange systems?
short answer
According to Fick’s law of diffusion, the thickness (L) of the diffusion barrier plays a crucial role in determining how fast gases like oxygen can diffuse. In all three systems—concurrent, countercurrent, and cross-current—animals maximize efficiency by having thin exchange surfaces (e.g., alveoli in mammals, gills in fish).
While the method of gas flow (direction) affects the efficiency of oxygen transfer, minimizing the thickness of membranes in each system increases the rate of diffusion, ensuring that oxygen can pass through quickly and effectively into the blood.
Compare the efficiency of oxygen extraction between concurrent and countercurrent gas exchange. Why is countercurrent more effective?
short answer
In concurrent gas exchange, both the blood and the medium (e.g., water or air) flow in the same direction, and as they continue to flow, the partial pressure of oxygen in the blood begins to approach that of the medium. This reduces the oxygen gradient over time, limiting the total oxygen that can be extracted.
In contrast, in countercurrent gas exchange, blood and medium flow in opposite directions. This maintains a high oxygen gradient along the entire length of the exchange surface, allowing for a greater total transfer of oxygen from the medium to the blood. As a result, countercurrent systems are much more efficient.
What is the function of tracheoles in the insect respiratory system?
A) To transport blood through the body.
B) To deliver air directly to cells for gas exchange.
C) To pump air into the hemolymph.
D) To absorb oxygen from the air and circulate it through the body.
b)
What feature of the book lung maximizes the efficiency of gas exchange in spiders?
A) The lamellae, which increase surface area for diffusion.
B) The tracheoles, which bring oxygen directly to the cells.
C) The presence of hemoglobin in the hemolymph.
D) The open circulatory system which allows free diffusion of gases.
a)
Which blood vessel brings deoxygenated blood to the gill filaments?
A) Afferent vessel
B) Efferent vessel
C) Arteries
D) Veins
a)
How do tuna avoid damaging their gills while swimming at high speeds?
A) They slow down periodically to reduce water pressure.
B) They have a specialized buccal-opercular pump that reduces water pressure.
C) They have reinforced secondary lamellae with specialized tissue that stabilizes them.
D) They close their operculum tightly to protect their gills from water pressure
c)
Why do most fish, unlike tuna, rely on the buccal-opercular pump for breathing?
A) They swim too slowly to use ram ventilation effectively.
B) They have stronger operculum muscles than tuna.
C) Their gills are less reinforced and need a controlled water flow.
D) They can survive without constant water flow over their gills
c)
How do salamanders in the larval stage primarily obtain oxygen?
A) Through their unicameral lungs.
B) Through their skin.
C) By using external gills.
D) By absorbing air through their mouth.
c)
