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All living entities exhibit breathing, a fundamental characteristic. The human cells need to be continuously administered with oxygen to carry out their functionality. And in return the cells release carbon dioxide. Hence this exchange of oxygen and carbon dioxide by the cells is called breathing. This is also known as respiration. Respiration consists of two main processes namely, inspiration and expiration that are carried out by creating pressure gradients between the alveoli and atmosphere through specialized muscles. Here we will answer important questions about the respiratory organs and its different mechanisms that we go through in order to breathe.
Read More: Breathing and Exchange of Gases MCQ
Very Short Answer Question [1 Mark Questions]
Ques. List some of the respiratory organs present in humans.
Ans. Some of the human respiratory system consists of nasal cavity, nasopharynx, larynx, trachea, bronchi, bronchi and lungs.
Ques. Explain what is the partial pressure of a gas.
Ans. Partial pressure of a gas is the pressure exerted in a mixture of gasses and is equal to the total pressure of the mixture of gasses divided by the percentage of that gas in a mixture. We know that the atmospheric air pressure at sea level is 760mm of Hg and oxygen forms 35% of the air. Therefore, the partial pressure of oxygen is 760 × 35 / 100 = 266 mmHg.
Ques. Give 2 differences between tidal volume and residual volume.
Ans. As we know, Tidal volume is the amount of air inhaled or exhaled in one complete breathing. It is about 500 ml. However, Residual volume is the volume of air that remains in the lungs after the maximum effort of exhalation. This is about 1500ml.
Ques. State the need for a circulatory system in a bigger animal.
Ans. The deeper cells cannot obtain oxygen in larger animals directly from the atmosphere simply through the process of diffusion or eliminate CO2. In a situation like this, the respiratory system transports the respiratory gasses from the respiratory surface to the deep-lying tissues.
Ques. Do we experience difficulty at a high altitude?
Ans.Yes, at high altitude, the pressure of air falls and the person cannot get enough oxygen in the lungs for diffusion in the blood. Because of insufficient O2, the person has difficulty breathing at high altitude. And hence the person feels difficulty such as breathlessness, headache, dizziness, irritability, nausea, vomiting, mental fatigue etc.
Ques. In simple terms explain what a specialized respiratory surface is and state its advantages?
Ans. In simple terms, a specialized respiratory surface is thin, moist and highly vascular. And this respiratory surface remains in contact with the environment outside the body and tissues inside the body. Gasses diffuse from the respiratory surface between the body and outside the environment. Carbon dioxide is released by the epidermal capillaries and take up oxygen dissolved in the film of surface moisture.
Ques. Explain the process of respiration.
Ans. Respiration is a process of physiochemical change by which environmental oxygen is taken in to oxidize the stored food to release carbon dioxide, water and energy. The released energy is used for doing various life activities whereas carbon dioxide being foul gas is thrown out from the body. Following are the main sources of energy: carbohydrates, lipids and proteins.
Read more: Difference Between Pharynx and Larynx
Short Answer Questions [2 Marks Questions]
Ques. State the preventive measure of the disease Bronchitis.
Ans. This can be caused by cigarette smoking and exposure to air pollutants like carbon monoxide. Bronchitis can be prevented and cured by avoiding exposure to the cause i.e., smoke, chemicals and pollutants. For Bronchitis, the underlying infection of the disease is treated with suitable antibiotics Bronchodilator drugs (for widening the constriction of bronchial passage by relaxing the smooth muscles) provide symptomatic relief.
Ques. Why does smoking cigarettes cause emphysema?
Ans. Smoking causes Emphysema, a chronic disease of the respiratory system where inflation of the alveolar occurs. And after a period of time, cigarette smoking or even inhalation of smoke causes the damage of septa between the alveoli and of its elastic tissue is substituted by the connective tissue in the lungs. Due to smoking, the respiratory surface decreases which causes emphysema.
Ques. Hemoglobin helps in the transport of oxygen from the lung to tissues. Explain.
Ans. Previously we have read that blood is the medium for the transport of oxygen from the respiratory organ to the different tissues and carbon dioxide from tissues to the respiratory organs and 97% of the oxygen is transported from the lungs to the tissues in combination with hemoglobin (Hb + O2 — HbO2), oxyhaemoglobin and 3% is transported in dissolved condition by the plasma.
Ques. Explain how the skin of the earthworm helps in respiration.
Ans. O2 and CO2 are exchanged between the looped epidermal blood capillaries of earthworms and their body surface has a moist film. And carbon dioxide is released by the epidermal capillaries, then they take up the oxygen dissolved in the film of surface moisture.
Ques. Briefly explain breathing disorders.
Ans.
- Asthma. It is caused by an allergic reaction. It causes difficulty in breathing.
- Pneumonia. It is caused by a bacterial infection. It causes fever, pain and severe cough.
- Tuberculosis. It is an infectious bacterial disease of the lungs and in serious cases, blood may come out while coughing.
Long Answer Question [3 Marks Questions]
Ques. Explain how respiration fulfills the energy requirement of an organism?
Ans. As we have studied earlier, respiration is a catabolic process and a catabolic biochemical process of exchange of gasses by which atmospheric oxygen is taken in to oxidize the stored food to liberate energy, carbon dioxide and water. Energy set free is used for doing life activities. Generally, for oxidation, oxygen is used. Energy releases in steps from the continuous breakdown of foodstuffs and is stored in the high energy bonds of ATP molecules. And hence this energy obtained from ATP molecules is termed biologically useful energy as it allows the working of all life processes.
Ques. Explain the concept of partial pressure. State how it helps in gaseous exchange during respiration.
Ans. When we are performing inspiration and expiration, gasses move freely by the process of diffusion. And the diffusion of any molecule takes place from high to low concentration. There is a direct relation between the process of diffusion and the pressure caused by the gas alone. Thus, the pressure exerted by an individual gas is called partial pressure and is represented as PO2, PCO2, and PN2, for oxygen, carbon dioxide and nitrogen respectively.
After this, the inspired air ultimately reaches the alveoli of the lung, which in turn receives the blood supply of the pulmonary circulation. Finally, the oxygen of the inspired air is taken in by the blood and carbon dioxide is released into the alveoli for expiration.
Ques. Give few conditions essential for effective respiration.
Ans. Some of the conditions essential for effective respiration:
- Surface of respiration should be thin and permeable to O2 and CO2
- There must be a rich supply of blood to the respiratory surface.
- There should be a passage for bringing oxygen to the respiratory surface and removing CO2 through the same passage.
- Moisture should be there on the respiratory surface.
- There should be a presence of a circulatory system.
- There should be presence of a respiratory pigment to carry out the respiratory gasses (CO2 and O2)
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Very Long Answer Questions [5 Marks Questions]
Ques. Briefly explain the respiratory organs of the following.
(i) Insect
Ans. The skin covering of insects is thick and highly impermeable to minimize the loss of water through the environment. Thus the exchange of gasses cannot take place through the skin covering of these insects. Due to this, these insects have a highly developed complex system called the tracheal and the mode of respiration is called tracheal respiration.
(ii) Neries
Ans. The respiratory oxygen in neries is Parapodia. Respiration occurs through the skin covering the parapodia (Locomotory organs) in this organism, which is again very thin, moist, permeable and highly vascular.
(iii) Prawn
Ans. Gills, in the animals like prawns, certain molluscs, fishes, tadpoles, the process of gaseous exchange occur by special respiratory organs called gills. The gills are richly supplied with blood and readily absorb oxygen found dissolved in water and release CO2 back into the water.
(iv) Birds
Ans. The skin is impermeable in birds and mammals. Birds have a high metabolic rate and their oxygen requirement is very high. They have spongy lungs to have a more extensive respiratory surface. The bird lungs always remain in the body to keep the respiratory surface moist, which is necessary for the exchange of respiratory gasses.
Ques. Describe the function of the diaphragm and its Costals muscles in the breathing process.
Ans. In the process of breathing, when the lungs contract their volumes decrease resulting in the increase of air pressure in the lungs. Therefore, the air is exhaled from the lungs. The two breathing processes are called inspiration and expiration. When we breathe normally, the downward and upward movement of the diaphragm takes place. During the time when the diaphragm contracts, the lower surface of the lung is pulled downward consequently the volume of the lungs increases. And this process causes the inhalation of air or inspiration. At the time when the diaphragm relaxes, lungs are compressed and air exhaled, expiration takes place. This causes the demand for extra oxygen and it is fulfilled by the expansion of the rib cage, during exercise when the rate of breathing increases.
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