Breathing and Exchange of Gases

NEET Biology · 40 questions · Page 2 of 4 · Click an option or "Show Solution" to reveal answer

Q11

A large proportion of oxygen is left unused in the human blood even after its uptake by the body tissues. This O2

A acts as a reserve during muscular exercise

B raise the pCO2 of blood to 75 mm of Hg.

C is enough to keep oxyhaemoglobin saturation at 96%

D helps in releasing more O2 to the epithelial tissues.

Correct Answer

Option A

Solution

(a) The unused oxygen acts as a reserve during muscular exercise.

Q12

In a figure of human lung showing exchange of gases, identify A as alveolar cavity.

A C : arterial capillary - passes oxygen to tissues

B A : alveolar cavity main site of exchange of respiratory gases

C D : capillary wall exchange of O2 and CO2 takes place here.

D B : red blood cell - transport of CO2 mainly

Correct Answer

Option B

Solution

(b) Alveolar cavity is the main site of exchange of respiratory gases.

Q13

Figure shows schematic plan of blood circulation. Identify C - Vena Cava.

A B-Pulmonary artery-transports blood from heart to lungs, PO2=90 mm Hg

B C-Vena Cava - takes blood from body parts to right atrium, PCO2=45 mm Hg

C D - Dorsal aorta - takes blood from Heart to body PO2=95 mm Hg

D A-Pulmonary vein - takes pure blood from lungs, PO2=100 mm Hg

Correct Answer

Option B

Solution

(b) Vena cava takes impure blood from various body parts to right auricle of the heart.

Q14

Approximately seventy percent of carbondioxide absorbed by the blood will be transported to the lungs:

A as bicarbonate ions

B in the form of dissolved gas molecules

C by binding to R.B.C.

D as carbamino-haemoglobin

Correct Answer

Option A

Solution

(a) 70% of CO2 is transported in the form of bicarbonate ions.

Q15

When you hold your breath, which gas change would first lead to the urge to breathe?

A rising CO2 concentration

B falling CO2 concentration

C rising CO2 and falling O2 concentration

D falling O2 concentration

Correct Answer

Option A

Solution

(a) Chemoreceptors in the medulla get stimulated by increase in CO2 concentration.

Q16

Identify the wrong statement with reference to transport of oxygen.

A Partial pressure of CO2 can interfere with O2 binding with haemoglobin

B Higher H+ conc. in alveoli favours the formation of oxyhaemoglobin

C Low pCO2 in alveoli favours the formation of oxyhaemoglobin

D Binding of oxygen with haemoglobin is mainly related to partial pressure of O2

Correct Answer

Option B

Solution

(b) Higher H+ concentration favours the dissociation of oxygen from oxyhaemoglobin in tissues, not formation.

Q17

Blood analysis reveals high carboxyhaemoglobin content. The patient has been inhaling high content of

A carbon disulphide

B chloroform

C carbon dioxide

D carbon monoxide

Correct Answer

Option D

Solution

(d) Carboxyhaemoglobin is the stable product formed by the association of CO and Hb in the blood.

Q18

Which of the following are the correct statements for respiration in human?

A Cigarette smoking may lead to inflammation of bronchi

B Neural signals from pneumotaxic centre in pons region can decrease the duration of inspiration

C Workers in grinding and stone-breaking industries may suffer from lung fibrosis

D About 70% of CO2 is carried by haemoglobin as carbamino haemoglobin.

Correct Answer

Option C

Solution

Pneumotaxic center limits (not decreases) inspiration duration.

About 25% CO2 is carried as carbaminohaemoglobin.

Q19

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

A Emphysema

B Pneumonia

C Asthma

D Pleurisy

Correct Answer

Option A

Solution

(a) In emphysema, alveolar surface area is reduced due to destruction of alveolar walls.

Q20

Name the chronic respiratory disorder caused mainly by cigarette smoking

A emphysema

B asthma

C respiratory acidosis

D respiratory alkalosis

Correct Answer

Option A

Solution

(a) Emphysema results when the air sacs in the lungs become damaged beyond repair, commonly from cigarette smoking.

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