Biology

Respiration and Gas Exchange

989 Questions

Access a targeted set of questions on respiration and gas exchange for competitive exams. Topics include lung volumes, the mechanism of breathing, and respiratory anatomy. Understanding these physiological processes is essential for scoring well.

Lung volumes and capacitiesBreathing mechanismsRespiratory anatomyGas exchange processes

Respiration and Gas Exchange Questions

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

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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'.

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

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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
Multiple choice zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

Inspiration occurs when

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

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

The width of the chest during inspiration :

  1. Decreases

  2. Does not change

  3. Increases

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • When you breathe in, or inhale, your diaphragm contract and move downward. This increases the space in the chest cavity into which lungs expand.
  • The intercostal muscles between ribs also help enlarge the chest cavity.
So, the correct option is 'Does not change'.

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

Which respiratory associated muscles would be contracted if you blow up a balloon?

  1. Diaphragm contracts and internal intercostal muscles would relax

  2. External intercostal muscle contract and phrenic muscles would contract

  3. Internal intercostal and abdominal muscle would contract

  4. Internal intercostal muscles are external intercostal muscles would contract
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Intercostal and abdominal muscle would contract if we blow up a balloon. When this occurs, you are interrupting the natural rhythm of breathing. The inhalation process is blowing up a balloon. As you this movement is facilitated by the contraction of the external intercostal muscles.

So the correct answer is' Internal intercostal and abdominal muscle would contract'.

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

Volume of thoracic chamber increases in the anteroposterior and dorsoventral axis in the human by?

  1. Contraction of diaphragm and external intercostal muscles

  2. Relaxation of diaphragm and external intercostal muscles

  3. Relaxation of diaphragm and abdominal muscles

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Volume of thoracic chamber increases in anteroposterior and dorso-ventral axis in human by contraction of diaphragm and external intercostal muscles.

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

Conditioning of inspiratory air in mammals occurs in 

  1. Trachea

  2. Larynx

  3. Bronchioles

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

Nasal cavity opens to outside through external nares or nostrils. Nasal cavity occurs between palate and cranium. Nasal cavity is divisible into two nasal chambers by a nasal septum. Each nasal chamber has three parts - (a) Vestibule- It has hairs to filter out the dust particles, (b) Conditioner - respiratory region. It has bony projections and sinuses. It is abundant in blood capillaries, (c) Olfactory region- perceives sense of smell. The two nasal cavities condition the air to be received by the other areas of the respiratory tract.

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

Expiratory muscles contract at the time of

  1. Deep inspiration

  2. Normal inspiration and expiration

  3. Forceful expiration

  4. Normal expiration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During quiet breathing, there is little or no muscle contraction/relaxation involved in expiration. This process is simply driven by the elastic recoil of the lungs in healthy individuals. In certain conditions the elasticity of the lung can be lost, such as in emphysema. Forced or active expiration occurs in such individuals as well as occurring during exercise. The abdominal muscles and the internal and innermost intercostal muscles help expel air.

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

Any material entering the trachea causes

  1. Vomiting

  2. Coughing

  3. Sneezing

  4. Regurgitation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Coughing is an airway reflex mediated by airway receptors, that react to either pressure or chemical stimuli. The function of coughing is to assist the removal of material from the airways. This material may have been inhaled or produced in the airways. Coughing also prevents additional inhalation of material, or movement of inhaled material into the peripheral airways. Once material comes in contact with ciliated epithelium, it is transported by ciliary beating towards the trachea, where there is the highest density of cough receptors. Coughing then propels the material into the oropharynx, where it is swallowed. Coughing is an extremely important protective mechanism for the respiratory system.

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

The tissue respiration refers to

  1. Inspiration

  2. External respiration

  3. Internal respiration

  4. Expiration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Respiration is the process by which oxygen and carbon dioxide diffuse in and out of the blood. Respiration is also referred to as gas exchange, and it occurs in two areas of the body. External respiration refers to gas exchange across the respiratory membrane in the lungs. Internal respiration refers to gas exchange across the respiratory membrane in the metabolizing tissues, like your skeletal muscles. Expiration and inspiration are not the related terms of respiration. Thus, option C is correct.

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

Which is correct?

  1. Respiratory centres are not affected by $CO _2$.

  2. In humans vital capacity is just double the expiratory volume.
  3. A human lung has $10^3$ alveoli.

  4. During inspiration the lungs act as suction pump.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Inhalation involves a contraction of the muscles, an increase in the size or volume of thoracic cavity, an expansion of the lungs with a drop of pressure inside them and entrance of atmospheric air into lungs through the air passages. Thus during inspiration the lungs act as suction pump. Inhalation is followed by exhalation, which is effected by the contraction of the lungs.

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

Tissue respiration is a type of

  1. External respiration

  2. Internal respiration

  3. Encretion

  4. Expiration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

External respiration occurs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses into the alveolar air. Internal respiration occurs in the metabolizing tissues, where oxygen diffuses out of the blood and carbon dioxide diffuses out of the cells. Inspiration and expirations are breath in and breath out processes. 

Therefore, the correct answer is option B.