Breathing and Exchange of Gases

In humans, respiration occurs in the following steps. Arrange these steps in the correct order. Choose the correct answer from the options given below :

1. A, B, C, D, E
2. C, A, B, E, D
3. C, B, E, A, D
4. E, A, C, D, B

Sponges exchange O2 with CO2 by .

1. gills
2. simple diffusion over their entire body surfaces
3. moist cuticle
4. tracheal tubes

Which of the following factors are favourable for the formation of oxyhaemoglobin in alveoli?

1. High pO2 and High pCO2
2. High pO2 and Lesser H+ concentration
3. Low pCO2 and High H+ concentration
4. Low pCO2 and High temperature

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R. In the light of the above statements, choose the correct answer from the options given below.

1. A is true but R is false.
2. A is false but R is true.
3. Both A and R are true and R is the correct explanation of A.
4. Both A and R are true but R is NOT the correct explanation of A

Vital capacity of lung is .

1. IRV + ERV + TV + RV
2. IRV + ERV + TV − RV
3. IRV + ERV + TV
4. IRV + ERV

Under normal physiological conditions in human beings every 100 ml of oxygenated blood can deliver ml of O2 to the tissues.

1. 2 ml
2. 5 ml
3. 4 ml
4. 10 ml

Which of the following is not the function of conducting part of respiratory system?

1. It clears inhaled air from foreign particles
2. Inhaled air is humidified
3. Temperature of inhaled air is brought to body temperature
4. Provides surface for diffusion of O2 and CO2

Identify the region of human brain which has pneumotaxic centre that alters respiratory rate by reducing the duration of inspiration.

1. Cerebrum
2. Medulla
3. Pons
4. Thalamus

Which of the following statements are correct with respect to vital capacity? Choose the most appropriate answer from the options given below :

1. A and E only
2. B, D and E only
3. A, C and D only
4. A, C and E only

Select the favourable conditions required for the formation of oxyhaemoglobin at the alveoli.

1. Low pO2, low pCO2, more H+, higher temperature
2. High pO2, low pCO2, less H+, lower temperature
3. Low pO2, high pCO2, more H+, higher temperature
4. High pO2, high pCO2, less H+, higher temperature.

The partial pressures (in mm Hg) of oxygen (O2) and carbon dioxide (CO2) at alveoli (the site of diffusion) are :

1. pO2 = 159 and pCO2 = 0.3
2. pO2 = 104 and pCO2 = 40
3. pO2 = 40 and pCO2 = 45
4. pO2 = 95 and pCO2 = 40

Select the correct events that occur during inspiration.

1. Only (iv)
2. (iii) and (iv)
3. (i), (ii) and (iv)
4. (i) and (ii)

Identify the wrong statement with reference to transport of oxygen.

1. Binding of oxygen with haemoglobin is mainly related to partial pressure of O2
2. Partial pressure of CO2 can interfere with O2 binding with haemoglobin
3. Higher H+ conc. in alveoli favours the formation of oxyhaemoglobin
4. Low pCO2 in alveoli favours the formation of oxyhaemoglobin

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?

1. 2200 mL
2. 2700 mL
3. 1500 mL
4. 1700 mL

Due to increasing air-borne allergens and pollutants, many people in urban areas are suffering from respiratory disorder causing wheezing due to :

1. Proliferation of fibrous tissues and damage of the alveolar walls
2. Reduction in the secretion of surfactants by pneumocytes
3. Benign growth on mucous lining of nasal cavity
4. Inflammation of bronchi and bronchioles

Which of the following options correctly represents the lung conditions in asthma and emphysema, respectively?

1. Decreased respiratory surface; Inflammation of bronchioles
2. Inflammation of bronchioles; Decreased respiratory surface
3. Increased number of bronchioles; Increased respiratory surface
4. Increased respiratory surface; Inflammation of bronchioles

Which of the following is an occupational respiratory disorder?

1. Botulism
2. Anthracis
3. Silicosis
4. Emphysema

Lungs are made up of air-filled sacs, the alveoli. They do not collapse even after forceful expiration, because of

1. inspiratory reserve volume
2. tidal volume
3. expiratory reserve volume
4. residual volume.

Reduction in pH of blood will

1. decrease the affinity of haemoglobin with oxygen
2. release bicarbonate ions by the liver
3. reduce the rate of heart beat
4. reduce the blood supply to the brain.

Name the chronic respiratory disorder caused mainly by cigarette smoking.

1. Respiratory acidosis
2. Respiratory alkalosis
3. Emphysema
4. Asthma

Asthma may be attributed to

1. inflammation of the trachea
2. accumulation of fluid in the lungs
3. bacterial infection of the lungs
4. allergic reaction of the mast cells in the lungs.

The partial pressure of oxygen in the alveoli of the lungs is

1. equal to that in the blood
2. more than that in the blood
3. less than that in the blood
4. less than that of carbon dioxide.

Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because

1. there is a negative pressure in the lungs
2. there is a negative intrapleural pressure pulling at the lung walls
3. there is a positive intrapleural pressure
4. pressure in the lungs is higher than the atmospheric pressure.

Name the pulmonary disease in which alveolar surface area involved in gas exchange is drastically reduced due to damage in the alveolar walls.

1. Pneumonia
2. Asthma
3. Pleurisy
4. Emphysema

When you hold your breath, which of the following gas changes in blood would first lead to the urge to breathe?

1. Falling CO2 concentration
2. Rising CO2 and falling O2 concentration
3. Falling O2 concentration
4. Rising CO2 concentration

Approximately seventy percent of carbon dioxide absorbed by the blood will be transported to the lungs

1. as bicarbonate ions
2. in the form of dissolved gas molecules
3. by binding to R.B.C.
4. as carbamino-haemoglobin.

The figure shows a diagrammatic view of human respiratory system with labels A, B, C and D. Select the option which gives correct identification and main function and / or characteristic. [Figure]

1. A - Trachea - Long tube supported by complete cartilaginous rings for conducting inspired air.
2. C - Alveoli - Thin walled vascular bag like structures for exchange of gases.
3. B - Pleural membrane - Surround ribs on both sides to provide cushion against rubbing.
4. D - Lower end of lungs - Diaphragm pulls it down during inspiration.

Which one of the following is the correct statement for respiration in humans?

1. Cigarette smoking may lead to inflammation of bronchi.
2. Neural signals from pneumotaxic centre in pons region of brain can increase the duration of inspiration.
3. Workers in grinding and stone-breaking industries may suffer from lung fibrosis.
4. About 90% of carbon dioxide (CO2) is carried by haemoglobin as carbamino-haemoglobin.

Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort?

1. One can breathe out air totally without oxygen.
2. One can breathe out air through Eustachian tube by closing both nose and mouth.
3. One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.
4. The lungs can be made fully empty by forcefully breathing out all air from them.

Bulk of carbon dioxide (CO2) released from body tissues into the blood is present as

1. bicarbonate in blood plasma and RBCs
2. free CO2 in blood plasma
3. 70% carbamino-haemoglobin and 30% as bicarbonate
4. carbamino-haemoglobin in RBCs.