Tag: breathing and exchange of gas

Questions Related to breathing and exchange of gas

According to Boyle's law, the product of:.pressure and volume is a constant. Hence,

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. if volume of lungs is increased, then pressure decreases proportionately

  2. if volume of lungs is increased, then pressure also increases proportionately

  3. if volume of lungs is increased, then pressure decreases disproportionately

  4. if volume of lungs is increased, then pressure remains the same.

Show answer
Correct Option: A
Explanation:
According to Boyle's law, the product of pressure and volume is a constant. Hence, if the volume of the lungs is increased, then pressure decreases proportionately.
So, the correct answer is 'if volume of lungs is increased, then pressure decreases proportionately'.

Which of the following is true regarding expiration?

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Exhaled air contains more moisture

  2. Lungs are not completely emptied even after forciful exhalation

  3. Exchange of gases takes place during expiration

  4. All of the above

Show answer
Correct Option: D
Explanation:

  • Expiration is a mechanism in which air which contains carbon dioxide release out from the lungs of the body.
  • This air is dry and contains more moisture from the lungs.
  • Lungs can never be empty even after force full expiration some amount of air remains in it known as residual volume.
  • The exchange of gases occurs only at cellular and alveolar site, not in expiration.
So the correct option is 'Both A and B'.

During inspiration, the diaphragm 

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Expands

  2. Shows no change

  3. Contracts and flattens

  4. Relaxed to become dome shaped

Show answer
Correct Option: C
Explanation:

During inspiration, the diaphragm contracts and flattens to increase the volume of the the thoracic cavity. This increase in volume leads to a decrease in intra-alveolar pressure, which is a pressure lower than atmospheric pressure and creates the pressure gradient. Due to the gradient the air is from the atmosphere is forced inside the lungs through nasal cavity.

So, the correct answer is 'Contracts and flattens'.

Which of the following does not happen during exhalation?

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. The space in chest cavity decreases

  2. Diaphragm goes up

  3. Air is released

  4. Ribs are pushed upward and outward

Show answer
Correct Option: D
Explanation:
  • During exhalation diaphragm relaxes. 
  • The intercoastal muscles also relax.
  • This makes ribs to move down and in.
  • It reduces the volume of the chest cavity and the air is pushed out
So, the correct option is 'Ribs are pushed upward and outward'.

In males, ______ play a role in the movement of respiratory system.

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Vertebrae

  2. Sternum

  3. Diaphragm

  4. Liver

Show answer
Correct Option: C
Explanation:

The diaphragm is the muscular organ situated between the thoracic cavity and the abdominal cavity. It contracts and moves downwards due to which the volume in the lungs increases and the air is inhaled. When it relaxes, the volume of the lungs decreases and the air is expelled out.

A. The vertebra is the short bone that makes up the vertebral column.
B. The sternum is the breastbone to which the ribs are attached.
C. The diaphragm is the muscular organ that plays role in the movement of the respiratory system.
D. The liver is the largest gland responsible for various metabolic activities.
Hence, the correct answer is 'Diaphragm'.

The exchange of gases between which of the following is called external respiration?

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Lung alveoli and blood capillaries

  2. Lung alveoli and bronchi

  3. The buccal cavity and the external atmosphere

  4. Lung alveoli and pulmonary artery

Show answer
Correct Option: A
Explanation:

When the gaseous exchange occurs due to a difference in the partial pressure of gases between alveoli of lungs and capillaries it is termed as an external exchange as it involves air that ix either inhaled or exhaled from the environment outside the body while when the exchange occurs between capillaries and tissue it is known as the internal exchange.

So the correct option is 'Lung alveoli and blood capillaries'.

Which of the following is the correct path of oxygen in humans during inhalation?

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Nostrils $\rightarrow$ Nasal Cavity $\rightarrow$ Pharynx $\rightarrow$ Trachea $\rightarrow$ Bronchi $\rightarrow$ Bronchiole $\rightarrow$ Alveoli

  2. Nostrils $\rightarrow$ Nasal Cavity $\rightarrow$ Trachea $\rightarrow$ Pharynx $\rightarrow$ Bronchi $\rightarrow$ Bronchiole $\rightarrow$ Alveoli

  3. Nostrils $\rightarrow$ Nasal Cavity $\rightarrow$ Pharynx $\rightarrow$ Trachea $\rightarrow$ Alveoli $\rightarrow$ Bronchi $\rightarrow$ Bronchiole

  4. Nostrils $\rightarrow$ Nasal Cavity $\rightarrow$ Pharynx $\rightarrow$ Bronchi $\rightarrow$ Trachea $\rightarrow$ Bronchioles $\rightarrow$ Alveoli

Show answer
Correct Option: A
Explanation:
The correct path of oxygen transfer is nostrils - external structures, nasal passage or the nasal cavity then into the pharynx followed by trachea and bronchii to smaller branches called the bronchioles and lastly the alveoli from where it is exchanged into the blood stream with the help of capillaries surrounding the alveoli.
So, the correct answer is Nostrils →→ Nasal Cavity →→ Pharynx →→ Trachea →→ Bronchi →→ Bronchiole →→ Alveoli

Which of the following is true for $CO _2$ concentration?

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. More in alveolar air than in expired

  2. More in expired air than in alveolar air

  3. More in inspired air than in alveolar air

  4. More in inspired air than in expired air

Show answer
Correct Option: A
Explanation:

In the alveoli, the oxygen is continuously absorbed by the blood and CO$ _{2}$ is continuously added by the blood. So, the alveolar air has more CO$ _{2}$ concentration than the expired air.

Hence, the correct answer is 'More in alveolar air than in expired air'

The gas which we breath out precipitates ______ into milky white.

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Sodium Chloride solution

  2. Calcium Carbonate solution

  3. Potassium Permanganate solution

  4. Potassium Bicarbonate solution

Show answer
Correct Option: B
Explanation:

The gas which we exhale or breath out is carbon-dioxide. 

When this gas passes through calcium carbonate solution there occurs precipitation reaction between the solution, as a result, the color of the solution turns to milky white.
When CO$ _2$ is passed through lime water which is a diluted solution of Ca(OH)_2, it turns milky due to the formation of calcium carbonate $CaCO _3$.

So the option B is correct.

Inspiration occurs when

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Pressure inside lungs is lower than atmospheric pressure

  2. Pressure inside lungs is higher than atmospheric pressure

  3. Pressure inside lungs is same as atmospheric pressure

  4. Pressure has no effect

Show answer
Correct Option: A
Explanation:

Air can be forced to move from one place to another by creating a pressure gradient. In the human body, the contraction of the diaphragm allows it to move down to abdomen cavity slightly. This increases the area in the thoracic cavity and the lungs expand. The intercostal muscles between the ribs also contract and allow the rib bones o come upwards and outward. Due to this, volume in the lungs increases and the pressure decreases. The pressure in the lungs is less than that of atmospheric pressure, so the air is drawn in and inspiration occurs.

Hence, the correct answer is 'Pressure inside lungs is lower than atmospheric pressure'