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

During forced expiration, actively contracting muscles include the

  1. Diaphragm

  2. External intercostals

  3. Abdominal muscles

  4. Diaphragm and intestinal muscle
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The most important muscles of forced expiration are those of the abdominals. When these muscles contract, intra-abdominal pressure is raised, and the diaphragm is pushed upward. These muscles also contract forcefully during coughing, vomiting, and defecation. The internal intercostal muscles assist active expiration by pulling the ribs downward and inward thus decreasing the thoracic volume. 

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

The exchange of gases in the alveoli of the lungs takes place by

  1. Osmosis

  2. Simple diffusion

  3. Passive transport

  4. Active transport
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Passive or simple diffusion is the movement of solutes (gas or ions) from an area of high concentration to an area of low concentration. Gases diffuse across the systemic capillary membrane and the cell membranes of the target tissue. Carbon dioxide diffuses from systemic tissues to lungs, and oxygen diffuses from lungs to systemic tissues
So, the correct answer is 'Simple diffusion'
Multiple choice zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

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

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
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


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

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

  1. Exercise

  2. Sudden back injury

  3. Expiration

  4. Inspiration
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During inspiration, the contraction of the diaphragm and external intercostal muscles increases the thoracic cavity volume. This movement causes the rib cage and sternum to move upward and outward.

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

During inspiration.

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Inspiration is an active process involving the contraction of the diaphragm (moving downward) and the external intercostal muscles (lifting the ribs).

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

Which is correct?

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Option A correctly describes the active phase of breathing. The other options are incorrect: cyanosis is a bluish discoloration due to low oxygen, eupnoea is normal breathing, and coryza is typically caused by rhinoviruses.