Breathing and respiration: mechanism, exchange and transport of gases, volumes, disorders
- Match List - I with List - II.List - I: A. Emphysema; B. Angina Pectoris; C. Glomerulonephritis; D. TetanyList - II: I. Rapid spasms in muscle due to low Ca++ in body fluid; II. Damaged alveolar walls and decreased respiratory surface; III. Acute che… Answer: 4. A-II, B-III, C-IV, D-I Emphysema: damaged alveolar walls, less respiratory surface (II) Angina pectoris: acute chest pain when th... 1
- Match List I with List II :List I:A. Expiratory capacityB. Functional residual capacityC. Vital capacityD. Inspiratory capacityList II:I. Expiratory reserve volume + Tidal volume + Inspiratory reserve volumeII. Tidal volume + Expiratory reserve volum… Answer: 2. A-II, B-IV, C-I, D-III Key idea: capacities are sums of volumes. Expiratory capacity = TV + ERV (A-II). Functional residual capac... 1
- Which of the following factors are favourable for the formation of oxyhaemoglobin in alveoli? Answer: 3. High pO₂ and Lesser H^+ concentration Key idea: oxygen binding is favoured in the alveoli. Alveoli have high pO₂, low pCO₂, lower... 1
- Vital capacity of lung is ________. Answer: 1. IRV + ERV + TV Key idea: Vital capacity is the maximum air that can be breathed out after a maximum inspiration. VC = ERV + TV +... 1
- Which of the following is not the function of conducting part of respiratory system ? Answer: 1. Provides surface for diffusion of O₂ and CO₂ Key idea: The conducting part (nose to terminal bronchioles) carries air, but gas ex... 1
- Under normal physiological conditions in human being every 100 ml of oxygenated blood can deliver ______ ml of O_2 to the tissues. Answer: 3. 5 ml Key idea: Oxygenated blood has about 20 ml O₂ per 100 ml and deoxygenated blood about 15 ml per 100 ml. Delivered to tissues... 1
- Assertion (A) :A person goes to high altitude and experiences ‘altitude sickness’ with symptoms like breathing difficulty and heart palpitations.Reason (R) :Due to low atmospheric pressure at high altitude, the body does not get sufficient oxygen.In… Answer: 1. Both (A) and (R) are true and (R) is the correct explanation of (A) Altitude sickness gives breathlessness and palpitations at hi... 1
- Select the favourable conditions required for the formation of oxyhaemoglobin at the alveoli. Answer: 1. High pO ₂ , low pCO ₂ , less H ^+ , lower temperature Oxygen binds haemoglobin best where pO ₂ is high and pCO ₂ is low. At the a... 1
- The partial pressures (in mm Hg) of oxygen (O_2) and carbon dioxide (CO_2) at alveoli (the site of diffusion) are : Answer: 1. pO ₂ = 104 and pCO ₂ = 40 Standard values in the alveoli are pO ₂ = 104 mm Hg and pCO ₂ = 40 mm Hg. pO ₂ 40 and pCO ₂ 45 are deox... 1
- Identify the correct statement with reference to human digestive system. Answer: 3. Ileum is a highly coiled part. The ileum is the long, highly coiled part of the small intestine. Option 1 is wrong: the ileum ope... 1
- The enzyme enterokinase helps in conversion of : Answer: 2. trypsinogen into trypsin Enterokinase, secreted by the intestinal mucosa, activates trypsinogen into trypsin. Trypsin then activa... 1
- Identify the wrong statement with reference to transport of oxygen. Answer: 3. Higher H^+ conc. in alveoli favours the formation of oxyhaemoglobin. Key idea: Oxygen binding to haemoglobin is favoured by high... 1
- Select the correct events that occur during inspiration.(a) Contraction of diaphragm(b) Contraction of external inter-costal muscles(c) Pulmonary volume decreases(d) Intra pulmonary pressure increases Answer: 1. (a) and (b) Key idea: Inspiration is an active process that increases thoracic volume. The diaphragm and external intercostal mus... 1
- Tidal Volume and Expiratory Reserve Volume of an athlete is 500 mL and 1000 mL respectively. What will be his Expiratory Capacity if the Residual Volume is 1200 mL ? Answer: 1. 1500 mL Key idea: Expiratory capacity (EC) = tidal volume + expiratory reserve volume. EC = TV + ERV = 500 + 1000 = 1500\ mL . Th... 1
- Due to increasing air-borne allergens and pollutants, many people in urban areas are suffering from respiratory disorder causing wheezing due to : Answer: 2. inflammation of bronchi and bronchioles. Wheezing is typical of asthma, which is inflammation of the bronchi and bronchioles caus... 1
- Which of the following options correctly represents the lung conditions in asthma and emphysema, respectively ? Answer: 1. Inflammation of bronchioles; Decreased respiratory surface Key idea: Asthma affects the airways. Emphysema damages the alveoli. A... 1
- Match the items given in Column I with those in Column II and select the correct option given below :Column I | Column IIa. Tidal volume | i. 2500 – 3000 mLb. Inspiratory Reserve volume | ii. 1100 – 1200 mLc. Expiratory Reserve volume | iii. 500 – 55… Answer: 3. a-iii b-i c-iv d-ii Key idea: Recall the normal lung volumes of an adult. Tidal volume: about 500 mL (iii). Inspiratory reserve v... 1
- Which of the following terms describe human dentition ? Answer: 3. Thecodont, Diphyodont, Heterodont Key idea: Human teeth are of three kinds of arrangement. Thecodont: teeth are set in sockets of... 1
- Which of the following is an occupational respiratory disorder ? Answer: 3. Silicosis Key idea: Occupational respiratory disorders come from dust at work. Silicosis is caused by silica dust in grinding and... 1
- Lungs are made up of air-filled sacs, the alveoli. They do not collapse even after forceful expiration, because of : Answer: 4. Residual Volume After a forceful expiration some air still stays in the lungs. This is the residual volume, about 1100 mL to 1200... 1
- A baby boy aged two years is admitted to play school and passes through a dental check - up. The dentist observed that the boy had twenty teeth. Which teeth were absent ? Answer: 2. Pre-molars Key idea: A two-year-old has milk (temporary) teeth only, with dental formula 2102/2102 . Per half-jaw: 2 incisors, 1... 1
- The partial pressure of oxygen in the alveoli of the lungs is Answer: 1. more than that in the blood Gases move from higher to lower partial pressure (pO₂). Alveolar pO₂ is about 104 mm Hg, while deoxyg... 1
- Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because Answer: 1. there is a negative intrapleural pressure pulling at the lung walls The pleural cavity around each lung has a pressure lower than... 1
- Reduction in pH of blood will : Answer: 3. decrease the affinity of hemoglobin with oxygen. A fall in blood pH (more H⁺, higher CO₂) shifts the oxygen dissociation curve to... 1