Topic Resources To support the absorption of oxygen and release of carbon dioxide, about 5 to 8 liters (about 1.3 to 2.1 gallons) of air per minute are brought in and out of the lungs, and about three tenths of a liter (about three tenths of a quart) of oxygen is transferred from the alveoli to the blood each minute, even when
the person is at rest. At the same time, a similar volume of carbon dioxide moves from the blood to the alveoli and is exhaled. During exercise, it is possible to breathe in and out more than 100 liters (about 26 gallons) of air per minute and extract 3 liters (a little less than 1 gallon) of oxygen from this air per minute. The rate at which oxygen is used by the body is one measure of the rate of energy expended by the body. Breathing in and out is accomplished by
respiratory muscles
Control of Breathing Breathing is usually automatic, controlled subconsciously by the respiratory center at the base of the brain. Breathing continues during sleep and usually even when a person is unconscious.... read more .
The function of the respiratory system is to move two gases: oxygen and carbon dioxide. Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.Gas
Exchange Between Alveolar Spaces and Capillaries
Three processes are essential for the transfer of oxygen from the outside air to the blood flowing through the lungs: ventilation, diffusion, and perfusion.
Ventilation is the process by which air moves in and out of the lungs.
Diffusion is the spontaneous movement of gases, without the use of any energy or effort by the body, between the alveoli and the capillaries in the lungs.
Perfusion is the process by which the cardiovascular system pumps blood throughout the lungs.
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Solution
The correct option is C
(ii) and (iv)
The correct option is (C) (ii) and (iv).
The explanation of the correct options:
- The exchange of gases happens in the millions of alveoli in the lungs and the capillaries.
- The oxygen inhaled moves from the alveoli to the blood in the capillaries.
- The carbon dioxide from the blood moves in the capillaries to the air in the alveoli.
- Alveoli are the tiny,balloon-like air sacs that increases the surface area for the exchange of gases.
The explanation of the incorrect options :
Option A:
- During inhalation, the ribs move outward and upward.
- When we inhale, the contraction ofthe diaphragm occurs, moves downward, and increases the space in the chest cavity, and the lungs expand.
Option B:
- Hemoglobin has a higher affinity for smaller molecules.
- Hemoglobin has less affinity for CO2 than oxygen because carbon dioxide is a larger molecule than oxygen.
Final Answer: The true statements about respiration are that the gaseous exchange takes place in the alveoli and the alveoli increase surface area for the exchange of gases.
1. In which part of the respiratory system, gaseous exchange takes place?
(a) Alveoli
(b) Pharynx
(c) Larynx
(d) Trachea
Sol. (a) Alveoli.
2. ___________ is located between two pleural sacs and is the central compartment of the thoracic cavity?
(a) Hilum
(b) Pleura
(c) Mediastinum
(d) Thoracic cage
Sol. (c) Mediastinum.
3. Which of the following statements is true about involuntary breathing?
(a) It is controlled by the bronchioles
(b) It is controlled by the pulmonary arterioles
(c) It is controlled by the alveolar-capillary network
(d) It is controlled by the neurons, located in the medulla and pons
Sol. (d) It is controlled by the neurons, located in the medulla and pons.
4. Which of the following are parts of the human respiratory system?
(a) Trachea
(b) Diaphragm
(c) The lungs
(d) All of the above
Sol. (d) All of the above.
5. Which of the following gas is released out during the process of respiration?
(a) Oxygen
(b) Hydrogen
(c) Carbon dioxide
(d) None of the above
Sol. (c) Carbon dioxide.
6. The tiny air sacs present in human lungs is called_______.
(a) Alveoli
(b) Bronchus
(c) Bronchioles
(d) All of the above
Sol. (a) Alveoli.
7. Which of the following functions by filtering and keeping the mucus and dirt away from our lungs?
(a) Cilia
(b) Bronchioles
(c) Hairs in the lungs
(d) All of the above
Sol. (a) Cilia.
8. The total number of alveoli present in the human lungs is estimated to be around ______.
(a) 1 billion
(b) 800 million
(c) 500 million
(d) 1500 million
Sol: (c) 500 million.
9. The exchange of gases between the external environment and the lungs______.
(a) Respiration
(b) External respiration
(c) Cellular respiration
(d) None of the above
Sol: (b) External respiration
10. Which one of the following statements is false about the trachea?
(a) Has C-shaped rings
(b) It is covered by epiglottis
(c) It splits into the right and left lungs
(d) None of the above
Sol: (b) It is covered by epiglottis
11. The maximum volume of air contained in the lung by a full forced inhalation is called _________.
(a) Tidal volume
(b) Vital capacity
(c) Ventilation rate
(d) Total lung capacity
Sol: (d) Total lung capacity.
12. Which one of the following is correct regarding larynx?
(a) It houses the vocal cords
(b) It prevents the invading pathogens into the trachea
(c) It is an organ made of cartilage and connects the pharynx to the trachea
(d) All of the above.
Sol: (d) All of the above.
13. Which of the following is the function of the trachea?
(a) Gaseous Exchange
(b) Filters the air we breathe
(c) Exhales the air from the body
(d) All of the above
Sol: (b) Filters the air we breathe.
14. Which of these statements is true about internal respiration?
(a) Production of ATP
(b) Exchange of gases between the bloodstream and tissue cells
(c) Exchange of gases between alveoli and the bloodstream
(d) Breathing between the atmosphere and the alveoli
Sol: (b) Exchange of gases between the bloodstream and tissue cells.
15. Which of the following organs functions as an air conditioner?
(a) Larynx
(b) Pharynx
(c) Nasal chambers
(d) All of the above
Sol: (c) Nasal chambers.
16. The normal breathing process is controlled by ____________.
(a) Lungs
(b) Ventral respiratory group
(c) Dorsal respiratory group
(d) Both (b) and (c)
Sol: (d) Both (b) and (c).
17. In Aves, the exchange of gases occurs within the __________.
(a) Lungs
(b) Air sacs
(c) Air sacs and Lungs
(d) None of the above
Sol: (a) Lungs.
18. Which of the following statements is true about the entry of air into the lungs?
(a) Air enters the body and travels to the lungs through the mouth and the nose
(b) Air enters the body and travels to the lungs through the oesophagus and gullet
(c) Air enters the body and travels to the lungs through the windpipe and the pores
(d) Air enters the body and travels to the lungs through the nose and the nervous system.
Sol: (a) Air enters the body and travels to the lungs through the mouth and the nose.
19. The windpipe is also called the ________.
(a) Larynx
(b) Lungs
(c) Trachea
(d) Oesophagus
Sol: (c) Trachea.
20. In Earthworms, the process of respiration is through ________.
(a) Skin
(b) Head
(c) Lungs
(d) Pores on its anterior end
Sol: (a) Skin.
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