Title Ex- 3 Breathng and Exchange of Gases (Solution file).docx.pdf ✅

108 BREATHING AND EXCHANGE OF GASES EXERCISE – 3: Achiever’s Section Breathing and respiration 1. Read the given statements characterizing certain types of animals. Select the option which correctly exemplifies each of these types. (i) Animal having external gills (ii) Animal having internal gills (iii) Animal showing tracheal respiration (iv) Animal revealing buccopharyngeal respiration (i) (ii) (iii) (iv) (a) Prawn Pheretima Unio Fish (b) Necturus Unio Prawn Frog (c) Pila Pheretima Unio Toad (d) Necturus Pila Millipede Toad Ans. (d) Sol. Necturus is a lizard-like amphibian having external gills to respire. In Pila, respiration occurs through internal gills or lungs. Millipedes are Arthropods having trachea and spiracles. Buccopharyngeal respiration occurs through linings of the mouth and can be observed in frogs and toads. Hence, option (d) suits the best. 2. Match Column-I with Column-II and select the correct option from the codes given below. Column-I (Animals) Column-II (Respiratory structures) A. Pigeon (i) Books gills B. Scorpion (ii) Pharyngeal wall C. Planaria (iii) Lungs D. Earthworm (iv) Gills E. Spiders (v) Book lungs F. King crab (vi) Body surface G. Prawn (vii) Skin H. Labeo (a) A-(iii), B-(v), C-(vi), D-(vii), E-(v), F-(i), G-(iv), H-(iv) (b) A-(v), B-(ii), C-(vi), D-(vii), E-(vi), F-(iv), G-(i), H-(iii) (c) A-(vi), B-(iv), C-(vii), D-(v), E-(i), F-(ii), G-(iii), H-(vii) (d) A-(i), B-(v), C-(vii), D-(iii), E-(vii), F-(ii), G-(iv), H-(vi) Ans. (a) Sol. Pigeons have lungs as a respiratory organ. Their lungs are highly vascularized with air sacs in them. Arachnids including spiders and scorpions respire through book lungs. Planaria (flatworms) have very thin bodies, therefore, gases can diffuse easily and they can respire through the entire body surface. Earthworms have moist cuticles (skin) to carry gaseous exchange even in the soil. King crab (Crustacean) has book gills as they live in water. Prawns and Labeo (a fish) respire through gills. 3. Match Column-I with Column-II and select the correct option from the codes given below. Column-I Column-II A. Yeast (i) Inspiration B. Diaphragm (ii) Hamburger’s phenomenon C. Insects (iii) Diffusion of Cl - ions into R.B.Cs D. Pons varoli (iv) Fermentation E. Chloride shift (v) Trachea (vi) Pneumotaxic centre (vii) Expiration (a) A-(iv); B-(i), (vii); C-(v); D-(vi); E-(ii), (iii) (b) A-(v); B-(i); C-(iv), (vii); D-(vi); E-(ii), (iii) (c) A-(ii), (vi); B-(i); C-(iii); D-(v), (vii); E-(iv) (d) A-(iii); B-(i); C-(ii), (v); D-(vi), (vii); E-(iv) Ans. (a) Sol. Fermentation is the process by which glucose is converted to alcohol. This is undertaken by yeast. The diaphragm is the dome-shaped muscle at the base of the thorax which helps in inspiration and expiration. Insects have trachea as a breathing organ. Pons Varolii is the exact site of the pneumotaxic centre in the brain. Hamburger's phenomenon also known as
109 BREATHING AND EXCHANGE OF GASES Chloride shift is the diffusion of Cl- ions into the RBCs. Human Respiratory System 4. Study the given figure of respiratory passage carefully and identify the parts labelled as A, B, C, D and E. A B C D E (a) Alveolar sac Secondary bronchus Alveoli Bronchioles Trachea (b) Alveoli Secondary bronchus Alveolar sac Trachea Bronchioles (c) Alveolar sac Tertiary bronchus Alveoli Trachea Bronchioles (d) Alveoli Tertiary bronchus Alveolar sac Bronchioles Trachea Ans. (a) Sol. The figure shows the conducting part and alveoli of a lung. Label A shows small round structures which are alveolar sacs attached to fine tubes called bronchioles (Label D). Label E marks the trachea which is dividing into secondary bronchus (Label B). Label C shows alveoli in alveolar sacs which are attached with alveolar ducts. 5. C-shaped cartilaginous rings supporting the trachea, are made of: (a) elastic cartilage (b) fibrous cartilage (c) hyaline cartilage (d) calcified cartilage Ans. (c) Sol. The trachea has a number of cartilaginous rings made of hyaline cartilage. It is transparent cartilage which supports the trachea and prevents its collapse during the exchange of gases. 6. The given figures are of human larynx, front view (i) and vertical section (ii). Identify the labelled parts A to D. A B C D (a) Glottis Larynx Vocal cord Cartilagino us rings of trachea (b) Epiglottis Cartilaginous rings of trachea Trachea Thyroid cartilage
110 BREATHING AND EXCHANGE OF GASES (c) Glottis Cartilaginous rings of trachea Thyroid cartilage Trachea (d) Epiglottis Bony rings of trachea Thyroid cartilage Trachea Ans. (b) Sol. Label A shows the covering of larynx which is the epiglottis. B depicts a number of cartilaginous rings present around the trachea to support the structure and prevent it from collapsing. Label C represents trachea or the windpipe through which the air passes to the lungs. D represents the thyroid cartilage. 7. Adam’s apple represents: (a) cricoid cartilage (b) thyroid cartilage (c) both of these (d) none of these Ans. (b) Sol. During puberty, the thyroid cartilage of the larynx grows and becomes visible through the skin in males and is called Adam’s apple. The thyroid cartilage is present ventrally in the neck region. 8. Voice in mammal is produced: (a) by syrinx (b) by bronchus (c) during inhalation (d) during exhalation Ans. (d) Sol. Larynx performs the function of sound production in mammals and hence is also called a voice box. When the air passes out through the larynx, vibrations are produced in the vocal cords resulting in voice production. 9. Which one is incorrect (a) Pleura is a double covering of the kidney. (b) Scurvy is due to vitamin C deficiency. (c) Pancreas is both exocrine and endocrine gland. (d) Blood from right side of heart is carried to lungs by pulmonary artery. Ans. (a) Sol. Pleura is a double-layered covering of lungs which is filled with a fluid in between. Hence, the statement (a) is incorrect. Scurvy is a deficiency disease and occurs due to the deficiency of vitamin C. Pancreas is a heterocrine gland having both exocrine (production of enzymes for digestion) and endocrine functions (production of hormones). Deoxygenated blood is carried to the lungs by pulmonary artery from the right ventricle of the heart. So, the other three statements are correct. 10. In human beings, oblique fissures are found in: (a) right lung (b) left lung (c) both lungs (d) none of these Ans. (c) Sol. Fissures are double-membrane structures which divide the lungs into lobes. There are two fissures, horizontal and oblique fissures which divide the right lung into three parts whereas, in left lung, only one fissure (oblique) is present. So, both the lungs have fissures in them. Mechanism of Breathing 11. Consider the following statements each with two blanks. (i) Diaphragm contracts to help in (1) while the contraction of abdominal muscles helps in (2). (ii)Vital capacity of trained athletes is (3) than that of non-athletes while the vital capacity of non-smokers is (4) than that of smokers. (iii) Alveolar pO2 is (5) then the venous Po2 while arterial pO2 is (6) than the alveolar pO2 . Which of the following options gives the correct fill-ups for the respective blanks numbers from (1) to (6) in the above statements? (a) (1)-expiration, (2)-inspiration, (5)-higher, (6)-lower (b) (3)-higher, (4)-lower, (5)-lower, (6)-higher (c) (1)-inspiration, (2)-forced expiration, (3)-higher, (4)-higher (d) (1)-expiration, (2)-forced expiration, (5)-higher, (6)-lower Ans. (c) Sol. The complete statements should be - Diaphragm contracts to help in inspiration while contraction of abdominal muscle helps in forced expiration. Vital capacity
111 BREATHING AND EXCHANGE OF GASES of trained athletes is higher than the non-athletes while the vital capacity of non-smokers is higher than smokers. Alveolar pO2 is higher than venous pO2 , arterial pO2 is equal to the alveolar pO2 . 12. In lungs, the air is separated from the venous blood through (a) transitional epithelium + tunica externa of blood vessel (b) squamous epithelium + endothelium of blood vessel (c) squamous epithelium + tunic media of blood vessel (d) none of these. Ans. (b) Sol. The separation of venous blood from the air in the lungs is done through alveoli present in the lungs. Alveoli are small sacs of a thin layer of squamous epithelial tissue which diffuses air to the endothelium of alveolar-capillary. 13. A child was born alive but was killed by a man. He told the mother later it was a still born. The mother doubted his statement and case was reported to police. Post mortem report confirmed that it was a murder. The test performed by the medical expert was taking a piece of lung and putting in water where it (a) kept floating (b) settled at the bottom (c) showed blood clots (d) none of these. Ans. (a) Sol. The lungs are the organs that are capable to float on water. The lung float test is done by the medical examiners during autopsies to determine if a baby was stillborn (died in the womb) or not. If the lungs did float, the baby was born alive then the lungs had undergone respiration after birth and if the lungs don’t float, the baby was stillborn. 14. Presence of large number of alveoli around alveolar ducts opening into bronchioles in mammalian lungs is: (a) an efficient system of ventilation with no residual air. (b) an efficient system of ventilation with little residual air. (c) inefficient system of ventilation with little of residual air. (d) inefficient system of ventilation with high percentage of residual air Ans. (b) Sol. The alveoli work as an efficient system of ventilation with little residual gas, these are sites of gas exchange in the lungs and are present at the end of bronchioles. Alveoli have a large surface area with an elastic thin membrane having a dense capillary network that allows gases to dissolve and diffuse in the blood. A small amount of gas present in the alveoli prevents it from collapsing. 15. Specialty common in the alveoli of lungs and villi of intestine in mammals is that both: (a) have ciliated epithelium. (b) provide a large surface area. (c) are suited for diffusion of gases. (d) have rich supply of blood vessels and lymph ducts. Ans. (b) Sol. Alveoli are present in the lungs and are a site for gaseous exchange. They have a very dense capillary network and also have a very large surface area which allows gases to diffuse easily. Villi of the intestine are the finger-like projections that are present in large amounts whose large surface area makes it easier for the uptake of nutrients from the food and makes it better for digestion and absorption. 16. Fill in the blanks : a. Breathing involves two stages: ...1... during which atmospheric air is drawn in and ...2... by which alveolar air is released out. b. The movement of air into and out of the lungs is carried out by ...3... gradient between the lungs and the atmosphere. c. Inspiration can occur if the pressure within lungs is ...4... than the atmosphere pressure i.e., there is a ...5... pressure in the lungs with respect to atmospheric pressure. d. Expiration takes place when the intra-pulmonary pressure is ...6... than atmospheric pressure. (a) 1-expiration, 2-inspiration, 3-concentration, 4-lower, 5-positive, 6-higher (b) 1-inspiration, 2-expiration, 3-pressure, 4-higher, 5-positive, 6-lower