Tag: human respiratory system

Questions Related to human respiratory system

During heavy exercise, the breathing rate can increase upto ........... per minute.

  1. 35 times

  2. 40 times

  3. 20 times

  4. 25 times


Correct Option: D
Explanation:

During exercise, your lungs and respiratory system must provide more oxygen to the blood.  You will breathe harder and faster because: Respiratory muscles are stimulated by sympathetic nerves in order to increase the rate of breathing. If the exercise is intense, breathing rates may increase from a typical resting rate of 15 breaths per minute up to 40 – 50 breaths per minute. Hence, during heavy exercise, the breathing rate can increase up to 25 times.

So, the correct option is '25 times'. 

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

  1. One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.

  2. The lungs can be made fully empty by forcefully breathing out all air from them.

  3. One can breathe out air totally without oxygen.

  4. One can breathe out air through eustachian tubes by closing both the nose and the mouth.


Correct Option: A
Explanation:
  • Normally the inspired air constitutes about 20.84% of oxygen whereas the expired air constitutes about 15.7% of oxygen. And even if one holds his or her breath, it is not possible to breathe out air totally without oxygen.
  • The eustachian tube is a canal that connects the middle ear to the nasopharynx. It controls the pressure within the middle ear, making it equal to the air pressure outside the body. No one can breathe out air through eustachian tubes by closing both the nose and the mouth.
  • Yes, one can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.
  • The lungs cannot be made fully empty by forcefully breathing out all air from them. Residual volume is always present in the lungs, even after the maximum forceful expiration effort. It is about 1500 ml of the air.

Pick the correct statement.

  1. The contraction of internal intercostal muscles lifts up the ribs and sternum.

  2. The thoracic cavity is anatomically an air tight chamber.

  3. Healthy man can inspire approximately $500$ ml of air per minute.

  4. During expiration, the intrapulmonary pressure is slightly below the surrounding atmospheric pressure.


Correct Option: B
Explanation:

The thoracic chamber is formed dorsally by the vertebral column, ventrally by the sternum, laterally by ribs and lower side by the dome-shaped diaphragm, it is an air-tight chamber.

So, the correct option is 'The thoracic cavity is anatomically an airtight chamber.'

Which one of the following statements is incorrect?

  1. The principle of countercurrent flow facilitates efficient respiration m gilis of fishes.

  2. The residual air in lungs slightly decreases the efficiency of respiration in mammals.

  3. The presence of non-respiratory air sacs, increases the efficiency of respiration in birds.

  4. In insects, circulating body fluids serve to distribute oxygen to tissues.


Correct Option: D
Explanation:

In insects, blood (haemolymph) does not contain an oxygen-carrying pigment. Hence it does not help in respiration. Instead, insects have spiracles and tracheae that carry $O _{2}$ to different tissues.

The relationship between pressure and volume was first noted by ............. while ............. confirmed their discovery and ............ published the result.

  1. Richard Towneley and Henry Power, Robert Boyle

  2. Richard Towneley and Henry Power, Robert Hooke

  3. Robert Boyle and Robert Hooke, Robert Boyle

  4. None of these


Correct Option: A
Explanation:
  • Boyle's law (sometimes referred to as the Boyle–Mariotte law or Mariotte's law is an experimental gas law that describes how the pressure of a gas tends to increase as the volume of the container decreases. A modern statement of Boyle's law is - The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system.
  • This relationship between pressure and volume was first noted by Richard Towneley and Henry Power in the seventeenth century. Robert Boyle confirmed their discovery through experiments and published the results. So, the correct answer is A.

In man expired air contains oxygen about

  1. 4%

  2. 10%

  3. 16%

  4. 20%


Correct Option: C
Explanation:

A man exhaled the air almost equivalent to the mixture of the atmosphere which contains 78% nitrogen, 16% oxygen, 0.09% argon and 4% carbon dioxide.

So the correct option is '16%'.

Much developed larynx of human male is called as

  1. Aristole's lanttern

  2. Syrinx

  3. Adam's apple

  4. Muller's organ


Correct Option: C
Explanation:

The laryngeal prominence (commonly referred to as Adam's apple), a feature of the human neck, is the lump or protrusion that is formed by the angle of the thyroid cartilage surrounding the larynx. The structure of the laryngeal prominence forms a bump under the skin. It is larger in adult men, in whom it is usually clearly visible and palpable. In women, the bump is much less visible and is hardly perceived on the upper edge of the thyroid cartilage. The laryngeal prominence is related to the deepening of the voice.

Name the respiratory organ which is known as voice box. 

  1. Pharynx

  2. Vocal cords

  3. Trachea

  4. Larynx


Correct Option: D
Explanation:

The larynx is known as voice box or sound producing organ. A pair of membranous folds called vocal cords, stretch across the laryngeal cavity. In normal condition, the vocal cords lie apart so that the glottis remains widely open to allow free passage of respiratory air. For sound production, vocal cords come close together, they vibrate when air rushes out through glottis and produce voice.