17

Q1. Name the muscles which increase the volume of the thoracic chamber.  

Solution

External intercostal muscles  

Q2. Represent diagrammatically the exchange of gases at the alveolar level and the tissue level.  

Solution

   

Q3. Describe the process of expiration.

Solution

When the diaphragm and intercostal muscles are relaxed, the thoracic chamber comes to its normal volume. This reduces the pulmonary volume. This results in an increase in the intra-pulmonary pressure in the lungs than the atmospheric pressure causing the expulsion of air from the lungs.

Q4. Name the following:

Volume of air which remains in the lungs after normal expiration

Total volume of air a person can inspire after normal expiration

Solution

Volume of air which remains in the lungs after normal expiration - Inspiratory capacity (IC)

Total volume of air a person can inspire after normal expiration - Functional residual capacity (FRC)

Q5. What does RV stand for? What is the average RV for a healthy person?

Solution

Residual volume. The average RV for a healthy person is 1100 to 1200 ml.

Q6. With respect to the partial pressures of oxygen and carbon dioxide, when are more molecules of carbaminohaemoglobin formed?

Solution

When the partial pressure CO₂ (pCO₂) is high and the partial pressure of O₂ (pO₂) is low, more carbaminohaemoglobin molecules are formed.

Q7. Name the structure which divides into the right and left bronchiole.

Solution

Trachea

Q8. Mention the two factors which can affect the rate of diffusion of oxygen and carbon dioxide during respiration.  

Solution

The two factors which can affect the rate of diffusion of oxygen and carbon dioxide during respiration are as follows:    

Solubility of gases  

Thickness of the membranes involved in diffusion

Q9. Where is the pneumotaxic region located in the brain?

Solution

Pons

Q10. Name the substance formed after the combination of oxygen and haemoglobin.

Solution

Oxyhaemoglobin

Q11. What is the average breathing rate in a healthy human?

Solution

The average breathing rate in a healthy human is 12-16 times per minute.

Q12. Where is carbonic anhydrase found? Write the reaction it catalyses.  

Solution

Carbonic anhydrase is found in RBCs. It catalyses the following reaction:    

Q13. Define rhythmicity centres.

Solution

Basic rhythm of respiration is regulated by three respiratory centres located in the floor of medulla oblongata and pons Varolli. These centres are together called rhythmicity centres.

Q14. Name the region present in the central nervous system which regulates respiration.

Solution

Respiratory rhythm centre

Q15. Name the two blood vessels which recognise the changes in H⁺ ions and CO₂.

Solution

Aortic arch and carotid artery

Q16. State the significance of the larynx.

Solution

The larynx is responsible for sound production.

Q17. What is fibrosis and how is it caused?  

Solution

Fibrosis is the uncontrolled proliferation of fibrous tissue which causes serious lung damage. Long exposure to dust particles weakens the defence mechanism of the body causing fibrosis.  

Q18. What is total lung capacity?

Solution

Total lung capacity is the total volume of air accommodated in lungs at the end of forced inspiration.

Q19. State the primary site of exchange of gases in lungs.

Solution

Alveoli

Q20. Name the process by which oxygen is taken in and carbon dioxide is released into the atmosphere.

Solution

Pulmonary ventilation (breathing)

Q21. In the kidneys, a blood vessel has pCO₂ = 45 mm Hg, which is lower than the kidney tissues. What will be the direction of the diffusion of blood?

Solution

The direction of diffusion of blood will be from the kidney tissue to the blood vessel.

Q22. How does the diaphragm help in inspiration?  

Solution

When the intra-pulmonary pressure, i.e. the pressure within the lungs, is lesser than the atmospheric pressure, the diaphragm contracts.     The contraction of the diaphragm increases the volume of the thoracic chamber, thus increasing space for more air which is withdrawn during inspiration.     Hence, the person is able to inspire.  

Q23. In which parts of the central nervous system is the respiratory rhythm centre located?

Solution

Medulla oblongata

Q24. Explain the mechanism of carbon monoxide poisoning in asphyxia

Solution

Carbon monoxide poisoning occurs because haemoglobin has more affinity with CO and unites with carbon monoxide instead of oxygen. The absence of sufficient amount of oxygen causes incomplete combustion of oxygen and CO is produced.

Q25. Name the cartilages that support the larynx.

Solution

Paired arytenoids and cartilages of Santorini and unpaired thyroid and cricoid cartilages support the larynx.

Q26. State the functions of the following:

Conducting part

Exchange part

Solution

Conducting part - The conducting part transports atmospheric air to the alveoli.

It humidifies and brings air to body temperature. It clears the air from foreign particles.

Exchange part - It allows the diffusion of oxygen and carbon dioxide between blood and atmospheric air.

Q27. Write the effects of the following disorders on the human body:    

Asthma  

Emphysema

Solution

Asthma - Difficulty in breathing, inflammation of bronchi and bronchioles  

Emphysema - Alveolar walls get damaged reducing the respiratory surface

Q28. Write the term for the additional volume of air which a person can forcibly inspire?

Solution

Inspiratory reserve volume (IRV)

Q29. Name the stage of breathing which occurs when the intra-pulmonary pressure is lesser than the atmospheric pressure.

Solution

Inspiration

Q30. How do the epiglottis and uvula differ in their role?

Solution

Epiglottis closes the glottis and the uvula covers the internal nares during swallowing so that food enters the oesophagus only.

Q31. State the steps involved in respiration.

Solution

Steps involved in respiration:

Atmospheric air is drawn in to obtain oxygen, and carbon dioxide-rich air is released out. This process is called breathing or pulmonary ventilation.

Diffusion of oxygen and carbon dioxide occurs at the alveolar membrane.

Gases are transported by the blood at the tissue level.

Diffusion of oxygen and carbon dioxide is at the tissue level.

Use of oxygen by the cells during the catabolic process results in the release of carbon dioxide.

Q32. Name the kind of volume the following components constitute:

TV + IRV

RV + ERV + TV + IRV

TV + ERV

ERV + RV

Solution

TV + IRV - Inspiratory capacity (IC)

RV + ERV + TV + IRV - Total lung capacity

TV + ERV - Expiratory capacity

ERV + RV - Functional residual capacity

Q33. Name the three layers which constitute the diffusion membrane.

Solution

The three layers of the diffusion membrane are

Thin squamous epithelium of alveoli

Endothelium of alveolar capillaries

Basement membrane or substance present between the squamous epithelium of alveoli and the endothelium of alveolar capillaries

Q34. State the two stages involved in breathing. Name the components which help in adjusting the volume of the thoracic chamber.

Solution

Two stages involved in breathing are 

Inspiration: Atmospheric air is drawn inside the body.

Expiration: Alveolar air is released out of the body.

The diaphragm and internal and external intercostal muscles help in adjusting the volume of the thoracic chamber.

Q35. Represent the human respiratory system diagrammatically.

Solution

Human respiratory system:  

Q36. Name one disorder caused by cigarette smoking.

Solution

Emphysema

Q37. How is the rate of breathing controlled by chemical control?

Solution

Rate of breathing is controlled by CO₂ level of the arterial blood and cerebrospinal fluid.

Q38. State the name of the form in which CO₂ is transported by blood.

Solution

Carbaminohaemoglobin

Q39. Name the structures which constitute the thoracic chamber. What is the significance of the closed thoracic chamber?  

Solution

Structures which constitute the thoracic chamber:    

Vertebral column on the dorsal side  

Sternum on the ventral side  

Ribs laterally  

Diaphragm on the lower side  

The change in the volume of the thoracic chamber helps to know the change in the volume of lungs.  

Q40. What is residual volume? What is its significance?

Solution

Residual volume is the volume of air remaining in the lungs even after forcible expiration. By adding a few respiratory volumes, pulmonary capacities can be derived which help in clinical diagnosis.

Take Another Test