Tag: respiratory system of human

Questions Related to respiratory system of human

Which of the following activity does not take place during pulmonary respiration?

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

  1. Movement of buccal cavity

  2. Contraction and relaxation of sternohyal and pterohyal muscles

  3. Successive opening and closing of mouth and external nostrils

  4. All of the above

  5. No activity takes place

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Correct Option: C
Explanation:
Successive opening and closing of mouth and external nostrils do not take place during pulmonary respiration.
The mechanism of pulmonary respiration: It includes breathing movement, exchange of gases, in lungs, transport of gases by blood and exchange of gases by tissue. 
The medulla oblongata (with the inspiratory centre and expiratory centre) and pons varolli (with pneumotoxic centre) are the breathing centre that regulates the breathing mechanism. Inspiratory centre stimulates inspiratory muscle (diaphragm) to control the rhythm of respiration. Expiratory centre remains inactive during normal breathing but it controls both expiration and inspiration during exercise. Pneumotoxic centre controls the switch off point of the breathing sending signal to inspiratory centre. The medulla’s control centre detects low pH of tissue fluid during formation of more carbonic acids, the centre increases the rate of breathing to eleiminate the excess CO2. The concentration of O2 has little effect on breathing centers. However, when O2 level is severely depressed, O2 sensors in the aorta and carotid arteries send signals to breathing control center to increase the breathing rate.
The main purpose of the respiratory system is to provide oxygen to the tissues and to remove carbon dioxide from them. This entire process is achieved through the following steps:
  • Breathing or pulmonary ventilation leading to exchange of oxygen and carbon dioxide between the atmospheric air and the lungs
  • Exchange of gases at the alveolar surface
  • Transport and exchange of gases in the tissues
  • Cellular respiration


The O$ _2$ in the exhaled air is

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

  1. About 8%

  2. About 10%

  3. About 15%

  4. About 20%

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Correct Option: C
Explanation:

In respiration, the human body exhales about 15% of the oxygen that is not utilized by the body. 

In human beings, rib case and sternum move upwardly and outwardly during.

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

  1. Exercise

  2. Sudden back injury

  3. Expiration

  4. Inspiration

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Correct Option: D

Muscles attached to diaphragm contract during inspiration to make it.

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

  1. Flat

  2. Dome-shaped

  3. Concave

  4. Rotate

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Correct Option: A

In expiration, diaphragm becomes.

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

  1. Flattened

  2. Relaxed

  3. Straightened

  4. Arched/Dome-shaped

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Correct Option: B

At the time of inspiration, the diaphragm.

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

  1. Expands

  2. Contracts

  3. Relaxes

  4. Does not undergo any change

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Correct Option: B

During inspiration.

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

  1. Diaphragm and external intercostal muscles relax

  2. Diaphragm and internal intercostal muscles relax

  3. Diaphragm and external intercostal muscles contract

  4. Diaphragm and internal intercostal muscles contract

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Correct Option: C

Which is correct?

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

  1. During inspiration, external intercostal muscles and diaphragm contract

  2. Cyanosis means collapse of alveoli

  3. Eupnoea is slow breathing

  4. Coryza is caused by human corona virus

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Correct Option: A

Read the following statements regarding mechanism of respiration and choose the correct option.
$1$. Inspiration occurs only when there is negative pressure in the lungs with respect to atmosphere
$2$. Expiration takes place only when intrapulmonary pressure is lower than atmospheric pressure
$3$. Pressure gradients are generated with the help of diaphragm and intercostal muscles
$4$. Inspiration is initiated by relaxation of diaphragm
$5$. Contraction of diaphragm reduces pulmonary volume and increases intrapulmonary pressure causing expiration.

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

  1. $1, 2$ and $5$ correct

  2. $2$ only correct

  3. $2, 5$ correct

  4. $1, 3$ correct

  5. $1, 4$ correct

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Correct Option: D

With conscious efforts one can.

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

  1. Breathe out air totally without oxygen

  2. Breathe in and out by moving diaphragm alone without moving ribs at all

  3. Breathe out air through eustachian tube by closing both nose and mouth

  4. Empty the lungs completely by breathing out all air out of them

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Correct Option: B