1. Skin is an accessory organ of respiration in
(a) humans
(b) frog
(c) rabbit
(d) lizard
2. The alveolar epithelium in the lungs is
(a) nonciliated columnar
(b) nonciliated squamous
(c) ciliated columnar
(d) ciliated squamous
3. Carbon dioxide is transported from tissues to respiratory surface by only
(a) plasma and erythrocytes
(b) plasma
(c) erythrocytes
(d) erythrocytes and leucocytes
4. Oxygen dissociation curve of haemoglobin is
(a) Sigmoid
(b) Hyperbolic
(c) Linear
(d) Hypobolic
5. Air is breathed through
(a) Trachea — lungs — larynx — pharynx — alveoli
(b) Nose — larynx — pharynx — bronchus — alveoli — bronchioles
(c) Nostrils — pharynx — larynx — trachea — bronchi — bronchioles — alveoli
(d) Nose — mouth — lungs
6. Although much CO2 is carried in blood, yet blood does not become acidic, because
(a) it is absorbed by the leucocytes
(b) blood buffers play an important role in CO2 transport.
(c) it combines with water to form which is neutralized by NaCO3
(d) It is continuously diffused through tissues and is not allowed to accumulate
7. The carbon dioxide is transported via blood to lungs as
(a) dissolved in blood plasma
(b) in the form of carbonic acid only
(c) in combination with haemoglobin only
(d) carbaminohaemoglobin and as carbonic acid
8. People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at an altitude of 5400 metres have around 8
million. This is because at high altitude (a) atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O2 to survive
(b) there is more UV radiation which enhances RBC production (c) people eat more nutritive food, therefore more RBCs are formed (d) people get pollution – free air to breathe and more oxygen is available.
9. The quantity 1500 ml in the respiratory volumes of a normal human adult refers to
(a) maximum air that can be breathed in and breathed out
(b) residual volume
(c) expiratory reserve volume
(d) total lung capacity
10. In alveoli of the lungs, the air at the site of gas exchange, is separated from the blood by
(a) alveolar epithelium only
(b) alveolar epithelium and capillary endothelium
(c) alveolar epithelium, capillary endothelium and tunica adventitia
(d) alveolar epithelium, capillary endothelium, a thin layer of tunica media and tunica adventitia
11. The exchange of gases in the alveoli of the lungs takes place by
(a) simple diffusion
(b) osmosis
(c) active transport
(d) passive transport
12. The process of migration of chloride ions from plasma to RBC and of carbonate ions from RBC to plasma is
(a) chloride shift
(b) ionic shift
(c) atomic shift
(d) Na+ pump
13. Which one of the following organs in the human body is most affected due to shortage of oxygen?
(a) intestine
(b) skin
(c) kidney
(d) brain
14. When CO2 concentration in blood increases, breathing becomes
(a) shallower and slow
(b) there is no effect on breathing
(c) slow and deep
(d) faster and deeper
15. Blood analysis of a patient reveals an unusually high quantity of carboxyhaemoglobin content. Which of the following conclusions is most likely
to be correct? The patient has been inhaling polluted air containing unusually high content of
(a) carbon disulphide
(b) chloroform
(c) carbon dioxide
(d) carbon monoxide
16. Which one of the following mammalian cells is not capable of metabolising glucose to carbon-dioxide aerobically?
(a) unstraited muscle cells
(b) liver cells
(c) red blood cells
(d) white blood
17. Intercostal muscles occur in
(a) abdomen
(b) thigh
(c) ribs
(d) diaphragm
18. What is vital capacity of our lungs?
(a) Inspiratory reserve volume plus tidal volume
(b) Total lung capacity minus expiratory reserve volume
(c) Inspiratory reserve volume plus expiratory reserve volume
(d) Total lung capacity minus residual volume.
19. Listed below are four respiratory capacities (i–iv) and four jumbled respiratory volumes of a normal human adult: Respiratory Respiratory capacities volumes (i) Residual volume 2500mL (ii) Vital capacity 3500mL (iii) Inspiratory reserve 1200mL volume (iv) Inspiratory capacity 4500mL Which one of the
following is the correct matching of two capacities and volumes? (a) (ii) 2500mL, (iii) 4500mL (b) (iii) 1200mL, (iv) 2500mL (c) (iv) 3500 mL, (i) 1200mL (d) (i) 4500 mL, (ii) 3500mL
20. Which two of the following changes (a–d) usually tend to occur in the plain dwellers when they move to high altitudes (3,500 m or more)? (i) Increase
in red blood cell size (ii) Increase in red blood cell production (iii) Increased breathing rate (iv) Increase in thrombocyte count Changes occurring are:
(a) (ii) and (iii) (b) (iii) and (iv) (c) (i) and (iv) (d) (i) and (ii)
21. Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort? (a) One can breathe out air totally without
oxygen. (b) One can breathe out air through eustachian tubes by closing both the nose and the mouth. (c) One can consiously breathe in and
breathe out by moving the diaphragm alone, without moving the ribs at all. (d) The lungs can be made fully empty by forcefully breathing out all air from them
22. Which of the following are the incorrect statement for respiration in human ?
(a) Cigarette smoking way lead of inflammation of bronchi
(b) Neural signals from pneumotaxic centre in pons region of brain can increase the duration of inspiration
(c) Workers in grinding and stone – breaking industries may suffer from lung fibrosis
(d) About 90% of carbon dioxide (CO2) is carried by haemoglobin as carbamino haemoglobin.
23. Breakdown product of haemoglobin is
(a) Bilirubin
(b) Iron
(c) Biliverdin
(d) Calcium
24. Child death may occur in the marriage between
(a) Rh+ man and Rh+ woman
(b) Rh+ man and Rh– woman
(c) Rh– man and Rh– woman
(d) Rh– man and Rh+ woman
25. Which one of the following is one of the paths followed by air/O2 during respiration in an adult male Periplaneta americana as it enters the animal body?
(a) Hypopharynx, mouth, pharynx, trachea, tissues (b) Spiracle in metathorax, trachea, tracheoles, oxygen diffuses into cells (c) Mouth, bronchial tube, trachea, oxygen
enters cells (d) Spiracles in prothorax, tracheoles, trachea, oxygen diffuses into cells
26.The muscles take part in rapid breathing
(a) Muscles of rib cage
(b) Muscles of neck region and abdominal region
(c) Thoracic and abdominal muscles
(d) Muscles of neck region and thoracic region
27.Oxyhaemoglobin can transport
(a) 8 ml of CO2/100 ml blood
(b) 5 ml of CO2/100 ml blood
(c) 3 ml of CO2/100 ml blood
(d) 2 ml of CO2/100 ml blood
28.Lungs are made up of airfilled sacs, the alveoli. They do not collapse even after forceful expiration, because of
(a) inspiratory reserve volume
(b) expiratory reserve volume
(c) tidal volume
(d) residual volume
29.Reduction in pH of blood will
(a) release bicarbonate ions by the liver
(b) decrease the affinity of haemoglobin with oxygen
(c) reduce the rate of heart beat
(d) reduce the blood supply to the brain
30.Skin is an accessory organ of respiration in
(a) humans
(b) frog
(c) rabbit
(d) lizard.
31.Approximately seventy percent of carbondioxide absorbed by the blood will be transported to the lungs
(a) in the form of dissolved gas molecules
(b) as bicarbonate ions
(c) as carbamino hemoglobin
(d) by binding to R.B.C
32.Presence of large number of alveoli around alveolar ducts opening into bronchioles in mammalian lungs is
(a) Inefficient system of ventilation with little of residual air
(b) Inefficient system of ventilation with high percentage of residual air
(c) An efficient system of ventilation with no residual air
(d) An efficient system of ventilation with little residual air.
33.At high altitude, the RBCs in the human blood will
(a) increase in number
(b) decrease in number
(c) increase in size
(d) decrease in size.
34.People who have migrated from the planes to an area adjoining Rohtang Pass about six months back
(a) have more RBCs and their hemoglobin has a lower binding affinity to O2
(b) are not physically fit to play games likefootball
(c) suffer from altitude sickness with symptoms like nausea, fatigue, etc.
(d) have the usual RBC count but their hemoglobin has very high binding affinity to O2.
35.Bulk of carbon dioxide (CO2) released from body tissues into the blood is present as
(a) free CO2 in blood plasma
(b) bicarbonate in blood plasma and RBCs
(c) 70% carbamino hemoglobin and 30% as bicarbonate
(d) carbamino hemoglobin in RBCs.
36.Severe Acute Respiratory Syndrome (SARS)
(a) is caused by a variant of Pneumococcus pneumoniae.
(b) is caused by a variant of the common cold virus (corona virus).
(c) is an acute form of asthma.
(d) affects non-vegetarians much faster than the vegetarians.
37.The exchange of gases in the alveoli of the lungs takes place by
(a) passive transport
(b) active transport
(c) osmosis
(d) simple diffusion
38.In lungs, the air is separated from the venous blood through
(a) squamous epithelium + endothelium of blood vessel
(b) squamous epithelium + tunica media of blood vessel
(c) transitional epithelium + tunica external of blood vessel
(d) none of the above
39.How the transport of O2 and CO2 by blood happens?
(a) With the help of WBCs and blood serum
(b) With the help of platelets and corpuscles
(c) With the help of RBCs and blood plasma
(d) With the help of RBCs and WBCs
40.Gases diffuse over the respiratory surface because of
(a) O2 is more in alveoli than in blood
(b) O2 is more in blood than in tissues
(c) CO2 is more in alveoli than in blood
(d) PCO2 is more in blood than in tissues
41.The ventilation movements of the lungs in mammals are governed by
(a) diaphragm
(b) muscular walls of lung
(c) costal muscles
(d) both (b) and (c).
42.The haemoglobin of a human foetus
(a) has only 2 protein subunits instead of 4
(b) has a higher affinity for oxygen that that of an adult
(c) has a lower affinity for oxygen than that of the adult
(d) its affinity for oxygen is the same as that of an adult.
43.The respiratory centre which regulates
respiration is located in
(a) cerebellum
(b) medulla oblongata
(c) cerebral peduncle
(d) the vagus nerve.
44.Although much CO2 is carried in blood, yet blood does not become acidic, because
(a) CO2 is continuously diffused through the tissues and is not allowed to accumulate
(b) in CO2 transport, blood buffers play an important role
(c) CO2 is absorbed by the leucocytes
(d) CO2 combines with water to form H2 CO3 which is neutralized by NaCO3 .
45.Blood analysis of a patient reveals an unusually high quantity of carboxyhaemoglobin content. The patient has been inhaling polluted air containing unusually high content of
(a) carbon disulphide
(b) chloroform
(c) carbon dioxide
(d) carbon monoxide
46. Lungs are made up of air-filled sacs, the alveoli. They do not collapse even after forceful expiration, because of:
(a) Inspiratory Reserve Volume
(b) Tidal Volume
(c) Expiratory Reserve Volume
(d) Residual Volume
47. Which of the following options correctly represents the lung conditions in asthma and emphysema, respectively?
(a) Inflammation of bronchioles; Decreased respiratory surface
(b) Increased number of bronchioles; Increased respiratory surface
(c) Decreased respiratory surface; Inflammation of bronchioles
(d) Increased respiratory surface; Inflammation of bronchioles
48. Match the items given in Column I with those in Column II and select the correct option given below: Column I Column II a. Tidal olume
i. 2500 – 3000 mLb. Inspiratory Reserve volume ii. 1100 – 1200 mLc. Expiratory Reserve volume iii.500 – 550 mL
d. Residual volume iv. 1000 – 1100 mL a b c d
(1) iii ii i iv (2) iii i iv ii (3) iv iii ii i (4) i iv ii iii
49. Which of the following is an occupational respiratory disorder?
(a) Anthracis
(b) Silicosis
(c) Emphysema
(d) Botulism
50. Due to increasing air-borne allergens and pollutants, many people in urban areas are suffering from respiratory disorder causing wheezing due to
(a) benign growth on mucous lining of nasal cavity
(b) inflammation of bronchi and bronchioles
(c) proliferation of fibrous tissues and damage of the alveolar walls
(d) reduction in the secretion of surfactants by pneumocytes.
51. 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?
(a) 1500 mL
(b) 1700 mL
(c) 2200 mL
(d) 2700 mL
52. Identify the wrong statement with reference to transport of oxygen
(a) Higher H+ conc. in alveoli favours the formation of oxyhaemoglobin
(b) Low pCO2 in alveoli favours the formation of oxyhaemoglobin
(c) Binding of oxygen with haemoglobin is mainly related to partial pressure of O2
(d) Partial pressure of CO2 can interfere with O2 binding with haemoglobin
53. 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
(1) (a), (b) and (d)
(2) only (d)
(3) (a) and (b)
(4) (c) and (d)
54. The partial pressures (in mm Hg) of oxygen (O2 ) and carbon dioxide (CO2) at alveoli (the site of diffusion) are:
(a) pO2 = 159 and pCO2 = 0.3
(b) pO2 = 104 and pCO2 = 40
(c) pO2 = 40 and pCO2 = 45
(d) pO2 = 95 and pCO2 = 40
Solutions :
1.Solution: (b)Frog has lungs as its main respiratory organs but during hibernation & aestivation and during its habitat in water it respires through skin.
2.Solution: (b)The very thin alveolar wall (about 0.0001 mm) is composed of moist, nonciliated,squamous epithelial cells.
3.Solution: (a)CO2 from the respiratory tissues to the lungs is transported by the blood in 3 ways: (i) In dissolved state or as a physical solution: Very small amount physically dissolved in plasma (7% i.e. 0.3 ml of CO2 by each 100 ml of blood) (ii) Bicarbonate ions: 70% (i.e. 2.5 ml per 100 ml of blood) CO2 diffuses in plasma & then into RBCs where it (in the presence of carbonic anhydrase) combines with H2O to form carbonic acid which is almost spontaneously dissociated into hydrogen
ion & bicarbonate ions. (iii) Carbaminohaemoglobin: 23% (i.e. 1 ml of CO2 per 100 ml of blood) combines with haemoglobin forming an unstable compound.
4.Solution: (a)It is the relationship between the percentage saturation of haemoglobin (by volume) in the blood and the oxygen tension (in partial tension) PO2 of the blood. It is usually a sigmoid plot. Haemoglobin molecules can bind up to four oxygen molecules in a reversible way. The shape of the curve results from the interaction of bound oxygen molecules with incoming molecules. The binding of the first molecule is difficult. However, this facilitates the binding of the second and third molecules,and it is only when the fourth molecule is to be bound that the difficulty increases, partly as a result of crowding of the haemoglobin molecule, partly as a natural tendency of oxygen to dissociate. (Bohr effect: CO p H, temp.) ↑ 2 ↓ ↑ pH DPG ↑ Temp ↓ ↑ pH DPG ↑ Temp (Haldane effect: O displaces CO for Hb) 2 2 The O2-Hb dissociation curve is a sigmoidal curve that represents the relationship between O2 concentration and the percentage saturation of Hb. As the concentration
increases from about 90% there is a significant plateau in the curve, which has several important biological repercussions.
5.Solution: (c)The pathway of inhaled air is – Nostrils -pharynx (common passage for food & air) -larynx (voice box) – trachea (the wind pipe) -bronchi (2 for each side lungs) -bronchioles (give arise to alveolar ducts) -alveoli (the exchange site for gases in theform of small sacs or pouches).
6.Solution : (b)CO2 enters RBC and reacts with water to form carbonic acid. Carbonic acid dissociates to form bicarbonate and hydrogen ions. Some bicarbonate ions are transported in erythrocytes while some diffuse into the blood plasma. Exit of bicarbonate ions change the ionic balance between the plasma and erythrocytes. To restore this balance chloride ions diffuse from plasma into erythrocytes. Due to this the pH of blood is maintained.
7.Solution: (d)Carbon dioxide is transported via blood to lungs mostly as carbaminohaemoglobin and carbonic acid. It is released in lungs in exchange with oxygen.
8.Solution: (a)At the altitude of 5400 meters the low atmospheric pressure of O2 will be too low so the solubility of oxygen in the blood will be very less hence the oxygen carried by each RBC will be too less. But to fulfill the oxygen requirement of the body blood has to carry more oxygen to the body tissue and this is done by the increased no. of RBCs.
9.Solution: (b)The total volume of air that can be expelled from the lungs after maximum inspiration and then expiring to the maximum is
known as the vital capacity. The volume of air that remains inside lungs at the end of maximum forceful expiration is the residual volume. Expiratory reserve volume is the maximum extra volume of air that can be expired by forceful expiration after a normal tidal expiration. Total lung capacity is the maximum volume of air that can be contained in the lungs after maximum inspirati on.
10.Solution: (b)Alveoli are the site of the respiratory exchange of gases. Oxygen from the alveolar air diffuses through the alveolar epithelium and the capillary ndothelium into the capillary blood and carbon dioxide diffuses in the opposite direction.
11.Solution: (a) Gaseous exchange between blood (dissolved phase) and alveolar air (gaseous phase) across respiratory membrane occurs by simple diffusion. Obviously, it depends upon the concentration gradient (=partial pressure) of the concerned gases in blood and alveolar air.
12.Solution: (a)During the transport of CO2 through the blood, bicarbonate ions diffuse out of RBCs while chloride ions from plasma enter the RBCs to maintain ionic equilibrium. This is called chloride shift.
13.Solution: (d)Brain is the most vital organ. It stops functioning in the absence of O2.
14.Solution: (d)The breathing becomes faster and deeper in order to oxygenate the blood at a fast rate. Shallow and slow breathing occurs during rest.
15.Solution: (d)arboxyhaemoglobin is the stable product formed by the association of CO and Hb in the blood. The association of carbon dioxide and haemoglobin forms carbamino haemoglobin.
16.Solution: (c)Since RBCS do not have mitochondria so they can respire only anaerobically.
17.Solution: (c)Intercostal muscles (External intercostal & Internal intercostal) are attached with the ribs which help in the movement of rib cage during breathing.
18.Solution: (d)Vital capacity of lungs is largest possible expiration after largest possible inspiration that is greatest. Volume of air can be exchanged in single respiration or amount of air breath in and out with greatest possible efforts. VC = TRV +TV + ERV = 3000 + 500 + 1100 = 4600 ml.
19.Solution: (c)
20.Solution: (a)At high altitude, the body undergoes numerous changes in order to increase oxygen delivery to cells and improve the efficiency of oxygen usage. The early changes include increased breathing rate and increased red blood cell production.
21.Solution: (b)Eustachian tube connect the middle ear cavity (Tympanic cavity) with nasopharynx, approximately it is 35 mm long in adults,which helps in breathing out by closing both the nose and mouth.
22.Solution: (c)(a) and (c) . Neural signals from pneumotaxiccenter in pons region of brain can limit the duration of inspiration. About 25% of carbodioxide (CO2) is carried by haemoglobin as carboxyhaemglobin.
23.Solution: (b) In this type of question one must answer reasonably as the breakdown products of haemoglobin are haem i.e. Iron & Globin protein which is then converted into yellowish substance bilirubin which is extracted by the liver cells from the blood & stored in the form of bile in gall bladder. The more appropriate answer is Iron as we have to mark only one option. If one had liberty to mark both the options then he/she would have marked both bilirubin and Iron.
24.Solution: (b)Rh factor was discovered by Karl Landsteiner. A child of Rh+ man will be Rh+ whether the mother is Rh+ or Rh–. If the mother is Rh+ then there will be no problem but if mother is Rh– so when the blood of Rh+ child (in womb) mixes with the blood of Rh– mother then some antibodies in mother‘s blood are formed against Rh+ factor which coagulate the womb blood causing death. If birth takes place then there is a possibility of child death in early years. This in known as erythroblastosis foetalis. In most cases the Ist pregnancy may succeed but after that it fails.
25.Solution: (b) The number of spiracles in cockroach is 10-pairs (2-pairs in thoracic and 8-pairs in abdominal region). The thoracic pairs of spiracles are present on pleuron between prothorax – mesothorax and metathorax. Each spiracle opens into a chamber called atrium. After atrium the tracheal tube ramifies into fine branches of tracheae, and then tracheole
26.(b) Muscles of neck region and abdominal region
27.(c) 3 ml of CO2/100 ml blood
28.(d) Residual volume (RV) is the volume of air remaining in the lungs after maximum forceful expiration. Due to this, lungs do not collapse even after the most forceful explanation, RV is about 1100 mL -1200 mL.
29.(b) Reduction in pH of blood will decrease the affinity of haemoglobin with oxygen.
30.(b) In addition to lungs, skin is also an organ of respiration in frog. It is practically the only mode of respiration when the frog is under water or hibernating. Skin is richly supplied with blood and is permeable to gases. That is why frogs always stay near water to keep their skin moist. It is further kept moist by secretion of mucus from its glands, and does not become dry out of water.
31.The largest fraction of carbon dioxide i.e., about 70% is converted to bicarbonates and transported in the plasma. About 70% of CO., (about 2.5ml per 100 ml. of blood), received by blood from the tissues, enters the RBCs where it reacts with water to form carbonic acid (H2C03). Carbonic anhydrase, exclusively found in RBCs, speeds up the formation of HC03 and rapidly converts it back to carbon dioxide and water when blood reaches the lungs. Almost as rapidly as formed, all carbonic acid of RBCs dissociates into hydrogen (IT) and bicarbonate ions (HCO3).
32.(d) The presence of large number of alveoli around alveolar ducts opening into bronchioles in mammalian lungs is An efficient system of ventilation with little residual air.
33.(a) At high altitudes, arterial pO2 decreases as density of air decreases. Number of RBCs per unit volume of blood is likely to be higher in a person living at high altitudes. More number of RBCs are needed to trap O2 from air having less O2.
34.(a) People who have migrated from the planes to an area adjoining Rohtang Pass about six months back have more RBCs and their hemoglobin has a lower binding affinity to O2.
35. (b) At the tissue site where partial pressure of CO2, is high due to catabolism, CO2, diffuses into blood (RBCs and plasma) and forms HCO2 and IT. At the alveolar site where pCO2, is low, the reaction proceeds in the opposite direction leading to the formation of CO2, and CO2. Thus, CO2, trapped as bicarbonate at the tissue level and transported to the alveoli is released out as CO2
36.(b) Severe acute respiratory syndrome (SARS) is caused by mutant form of Influenza/ common cold virus (Corona virus). SARS is caused by a variant of the common cold virus (corona virus).
37.(d) The exchange of gases in the alveoli of the lungs takes place by simple diffusion. The exchange of gases between the alveoli and blood in the lung is the result of difference in partial pressure of respiratory gases.
38.(a) In lungs, the air is separated from the venous blood through squamous epithelium + endothelium of blood vessel
39.(c) The transport of O2 and CO2 occurs with the help of RBCs and blood plasma. 97% of O2 is transported by R4BCs and 3% of O2 is carried by plasma. About 7% of CO2 is transported in plasma and rest by RBCs (23%) by binding with Hb and 70% reacts with water to form carbonic acid in RBCs.
40.(a) Gases diffuse over the respiratory surface because of O2 is more in alveoli than in blood
41.(d) Ventilation is the movement of air through the conducting passages between the atmosphere and the lungs. The air moves through the passage because of pressure gradients that are produced by contraction and relaxation of diaphragm and intercostal muscles during inspiration and expiration.
42.(b) The haemoglobin of a human foetus has a higher affinity for oxygen that that of an adult
43.(b) medulla oblongata
44.(b) Buffer of the blood is sodium bicarbonate which play an important role in CO2 transport. During CO2 transportation, carbonic acid dissociates into H+ and HCO3- (bicarbonate ions). This bicarbonate combines with sodium forming sodium bicarbonate. Thus, concentration of carbonic acid does not increase in blood due to the presence of sodium and thus blood does not become acidic. About 70% of CO2 released during cellular respiration is transported by blood in the form of sodium bicarbonate in plasma.
45.(d) carbon monoxide
46. (d)Residual volume is the amount of air that remains in a person’s lungs after fully exhaling. Doctors use tests to measure a person’s residual air volume to help check how well the lungs are functioning. It is normal to have some air remain after exhaling to keep the lungs from collapsing.
47 (a)Asthma is a condition in which your airways narrow and swell and may produce extra mucus. This can make breathing difficult and trigger coughing, a whistling sound (wheezing) when you breathe out and shortness of breath.Emphysema is a lung condition that causes shortness of breath. In people with emphysema, the air sacs in the lungs (alveoli) are damaged. Over time, the inner walls of the air sacs weaken and rupture — creating larger air spaces instead of many small ones.
48 (2)Tidal volume (symbol VT or TV) is the lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. In a healthy, young human adult, tidal volume is approximately 500 ml per inspiration or 7 ml/kg of body mass.The average inspiratory reserve volume is about 3000 mL in males and 2100 mL in females. Vital capacity. The total usable volume of the lungs that you can control. This is not the entire lung volume as it is impossible to voluntarily breathe all of the air out of your lungsYour expiratory reserve volume is the amount of extra air — above anormal breath — exhaled during a forceful breath out. The average ERV volume is about 1000-1100 mL in males and 800 mL in females.Residual volume is the amount of air that remains in a person’s lungs after fully exhaling. Doctors use tests to measure a person’s residual air volume to help check how well the lungs are functioning. It is normal to have some air remain after exhaling to keep the lungs from collapsing. Volume is about 1100 – 1200 mL
49 (b)Occupational respiratory disease is any lung condition you get at work. It occurs because of repeated exposure to certain toxins. You can even get a disease long after being exposed to those toxins. Certain workplaces lend themselves to disease.Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust. It is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis
50 (b)Asthma is a difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles. Respiratory disorders, or lung diseases, are disorders such as asthma, cystic fibrosis, emphysema, lung cancer, mesothelioma, pulmonary hypertension, and tuberculosis.
51 (a)Tidal Volume =500ml Expiratory Reserve Volume =1000mlExpiratory Capacity =TV+ERV =500+1000 =1500ml.
52 (a) The transport of oxygen is fundamental to aerobic respiration.Higher H+ conc. in alveoli favours the formation of oxyhaemoglobin Oxygen transport within the human body occurs through both convection and diffusion. Within the pulmonary capillaries, one haemoglobin molecule binds up to four oxygen molecules in a cooperative manner.Global oxygen delivery, or oxygen dispatch, describes the total amount of oxygen delivered to the tissues each minute, and is a product of the cardiac output and arterial oxygen content. Oxygen diffuses from both the alveoli into the pulmonary capillaries and the systemic capillaries into the tissues, according to Fick’s laws of diffusion and the random walk of the diffusing particles
53(c)Events that occur during inspiration are
(a) Contraction of diaphragm
(b) Contraction of external intercostal muscles
(c) Pulmonary volume increases
(d) Intra pulmonary pressure decreases
54(b) pO2 in alveoli is 104 mm Hg and pCO2 in alveoli is 40 mmHg. In atmosphere, pO2 is 159 mm Hg and pCO2 is 0.3 mm Hg. In deoxygenated blood, pO2 is 40 mmHg and pCO2 is 45 mmHg.In oxygenated blood, pO2 is 95 mmHg and pCO2 is 40 mmHg.
