Respiratory System MCQ Quiz in मल्याळम - Objective Question with Answer for Respiratory System - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is A decrease in intra-pulmonary pressure

Concept:

• Inspiration (inhalation) is the process by which air is drawn into the lungs. This process is crucial for gas exchange, which provides oxygen to the body and removes carbon dioxide.
• The diaphragm, a dome-shaped muscle located below the lungs, plays a key role in the process of inspiration.
• During inspiration, the diaphragm contracts and moves downward, increasing the volume of the thoracic cavity and reducing intra-pulmonary pressure, which allows air to flow into the lungs.

Explanation:

• Option 1: A decrease in intra-pulmonary pressure - This is the correct answer. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity. This increase in volume leads to a decrease in intra-pulmonary pressure (the pressure within the lungs). As a result, air flows from the higher pressure outside the body to the lower pressure inside the lungs, causing inspiration.

Fig: Mechanism of breathing showing inspiration

• Option 2: An increase in intra-pulmonary pressure - This is incorrect. An increase in intra-pulmonary pressure would actually cause air to flow out of the lungs, which occurs during expiration (exhalation), not inspiration.
• Option 3: The relaxation of the intercostal muscles: The intercostal muscles play a crucial role in the mechanics of breathing. There are two sets of intercostal muscles: the external intercostal muscles and the internal intercostal muscles. During normal, passive exhalation (expiration), relaxation of certain muscle groups occurs:
  • External Intercostal Muscles Relaxation: After inhalation, the external intercostal muscles relax, leading to a decrease in the expansion of the thoracic cavity. This relaxation helps to return the ribs to their original position, reducing the volume of the thoracic cavity.
  • Internal Intercostal Muscles: These muscles are usually not engaged during passive exhalation. They remain relaxed unless there is a need for forced exhalation (as in heavy breathing or vigorous activity).

• Option 4: A rise in blood pH - This is incorrect. While blood pH can influence respiratory rate and depth through chemoreceptor feedback mechanisms, it does not directly trigger the contraction of the diaphragm during the specific process of inspiration.

The correct answer is option 2.

Concept:

• Human beings have a significant ability to maintain and moderate the respiratory rhythm to suit the demands of the body tissues.
• This can be done via - the respiratory rhythm center, pneumotaxic center, and chemosensitive area.
•  A specialized center present in the medulla region of the brain called the respiratory rhythm center is responsible for respiratory regulation.
• The center present in the pons region of the brain is called pneumotaxic center. 

Explanation:

• Pons regulates the functions of the respiratory rhythm center by sending the neural signal to reduce the duration of inspiration and thereby altering the respiratory rate.
• The chemosensitive area situated adjacent to the rhythm center is highly sensitive to CO₂ and hydrogen ions.
• An increase in CO2 and hydrogen ions substances activates this center which signals the rhythm center to make necessary adjustments in the respiratory process to eliminate these substances.

Option 1-  Medullary inspiratory center

• It does not reduce inspiration.
• So, this option is wrong.

Option 2-  Pneumotaxic center

• It reduces inspiration to eliminate substances toxic to the body.
• So, this option is correct.

Option 3-  Apneustic center

• This option is wrong.

Option 4-  Chemosensitive center

• This area is sensitive to hydrogen ion concentration, etc.
• So, this option is wrong.

Hence the correct option is (option 2) Pneumotaxic center.

The correct answer is option 1.

Concept:

• Respiration in insects is independent of their coelomic fluid.
• Insects have a network of tracheal tubes to transport atmospheric air within the body.
• Insects respire through a tracheal system where the cells exchange O₂/CO₂ directly with the air in the tubes.

Explanation:

• Tracheal tubes form a complex network of gas-filled vessels that divide throughout the body segments, legs, and wings.

Option 1-  The cell exchanges O2/ CO2 directly with the air in the tubes 

• Since insects use the tracheal system to exchange air which is independent of coelomic fluid.
• So, this is the correct answer.

Option 2-  The tissues exchange O2/ CO2 directly with coelomic fluid

• Respiration in insects is independent of the coelomic fluid.
• So, this option is wrong.

Option 3 -  The tissues exchange O2/ CO2 directly with the air outside through the body's surface

• This kind of respiration is found in invertebrates like sponges, coelenterates, etc.
• So, this option is wrong.

Option 4 - Tracheal tubes exchange O2/ CO2 directly with the hemocoel which then exchanges with tissues 

• Insect respiration is independent of coelomic fluid or hemocoel.
• So, this option is wrong.

Hence, the correct answer is option 1.

The correct answer is Only 1 and 3

Concept:

• Carbon dioxide (CO₂) is a waste product of cellular respiration and needs to be transported from the tissues to the lungs for exhalation.
• CO₂ is transported in the blood through three main mechanisms: dissolved in plasma, as bicarbonate ions, and as carbaminohemoglobin.

• Nearly 20-25 per cent of CO₂ is transported by RBCs whereas 70 per cent of it is carried as bicarbonate. About 7 per cent of CO₂ is carried in a dissolved state through plasma.

Explanation:

• Statement 1: CO₂ is transported as carbaminohemoglobin in RBCs: This is correct. About 20-25% of CO₂ is transported bound to hemoglobin, forming carbaminohemoglobin. This binding occurs at the amino groups of the hemoglobin molecule.
• Statement 3: The conversion of CO₂ into bicarbonate ions occurs in RBCs: This is correct. Around 70% of CO₂ is converted into bicarbonate ions (HCO₃⁻) in red blood cells. The enzyme carbonic anhydrase catalyzes this reaction, and the bicarbonate ions are then transported in the plasma.

The correct answer is The thoracic cavity is anatomically an air tight chamber.

Explanation:

The thoracic cavity, also known as the chest cavity, is the chamber of the body of vertebrates that is protected by the thoracic wall (rib cage and associated skin, muscle, and fascia). It is located above the diaphragm and below the neck and is one of the body's two primary cavities.

1. The contraction of internal intercostal muscles lifts up the ribs: Incorrect. The contraction of the internal intercostal muscles actually pulls the ribs downward and inward, helping to decrease the volume of the thoracic cavity during forced exhalation.
2. The RBCs transport oxygen only: Incorrect. Red blood cells (RBCs) primarily transport oxygen, but they also play a crucial role in transporting carbon dioxide from tissues to the lungs.
3. The thoracic cavity is anatomically an air-tight chamber: Correct. The thoracic cavity is indeed an air-tight chamber, which is crucial for the mechanics of breathing. The airtight nature of the thoracic cavity allows for the pressure changes necessary for inhalation and exhalation.
4. Healthy man can inspire approximately 500 mL of air per minute: Incorrect. A healthy man can inspire approximately 500 mL of air per breath during normal, resting breathing (this is known as the tidal volume). However, the minute ventilation (the volume of air inspired per minute) for a healthy adult is typically much higher. For example, with a breathing rate of about 12 breaths per minute, the volume would be approximately 6000-8000 ml of air per minute.

Therefore, the correct statement is: The thoracic cavity is anatomically an air tight chamber.

The correct answer is CO2 and H+ ions

Explanation:

The chemosensitive area adjacent to the respiratory rhythm center is located in the medulla oblongata of the brainstem.

It plays a crucial role in the regulation of breathing by responding to changes in the chemical composition of the blood and cerebrospinal fluid.

This area is primarily sensitive to carbon dioxide (CO2) and hydrogen ions (H+), which are critical regulators of respiratory activity. The chemo-sensitive area works by:
Detection of CO2 and H+:

• The chemo-sensitive area in the medulla detects changes in the pH of the cerebrospinal fluid, which indirectly reflects the levels of CO2 in the blood.
• CO2 can cross the blood-brain barrier and, once inside the cerebrospinal fluid, it combines with water to form carbonic acid. This acid then dissociates into bicarbonate (HCO₃–) and hydrogen ions (H+).

Response to Increased CO2 and H+:

• An increase in CO2 levels in the blood leads to an increase in H+ concentration in the cerebrospinal fluid, causing a drop in pH (acidic environment).
• The chemo-sensitive area detects this drop in pH and stimulates the respiratory center to increase the rate and depth of breathing, which helps to expel more CO2 from the lungs and restore normal pH levels.

The correct answer is Both A and R are true, and R is the correct explanation of A

Concept:

• Inspiration (Inhalation): Inspiration is the process of taking air into the lungs. It involves an increase in the volume of the thoracic cavity, which creates a negative pressure relative to the atmosphere, allowing air to flow into the lungs.
• Diaphragm and Intercostal Muscles: The diaphragm is a dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The intercostal muscles are located between the ribs. Both play crucial roles in breathing.

Explanation:

• Assertion (A): Inspiration involves an increase in the volume of the thoracic cavity. This statement is true. During inspiration, the thoracic cavity's volume increases to allow air to enter the lungs.
• Reason (R): The diaphragm and intercostal muscles contract to enlarge the thoracic cavity. This statement is also true. When the diaphragm contracts, it flattens out and moves downward, while the external intercostal muscles lift the ribs upward and outward, expanding the thoracic cavity.
• Since both A and R are true and R explains why A is true, the correct answer is "Both A and R are true, and R is the correct explanation of A".

Fig: Mechanism of breathing showing Inspiration

The correct answer is High pO2 and Lesser H+ concentration

Explanation:

• A sigmoid curve is obtained when percentage saturation of haemoglobin with O₂ is plotted against the pO₂.This curve is called the Oxygen dissociation curve  and is highly useful in studying the effect of factors like pCO₂, H⁺ concentration, etc., on binding of O₂ with haemoglobin.
• In the alveoli, where there is high pO₂, low pCO₂, lesser H⁺ concentration and lower temperature, the factors are all favourable for the formation of oxyhaemoglobin.
• In the tissues, where low pO₂ , high pCO₂, high H⁺ concentration and higher temperature exist, the conditions are favourable for dissociation of oxygen from the oxyhaemoglobin.
• This clearly indicates that O₂ gets bound to haemoglobin in the lung surface and gets dissociated at the tissues.

The correct answer is A-II, B-IV, C-I, D-III

Concept:

• Inspiratory capacity (IC)  - Total volume of air a person can inspire after a normal expiration. This includes tidal volume and inspiratory reserve volume (TV+IRV).
• Expiratory Capacity (EC): Total volume of air a person can expire after a normal inspiration. This includes tidal volume and expiratory reserve volume (TV+ERV).
• Vital Capacity (VC) - The maximum volume of air a person can breathe in after a forced expiration. This includes ERV, TV and IRV
• Residual Volume (RV) - Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL.
• Functional Residual Capacity (FRC): Volume of air that will remain in the lungs after a normal expiration. This includes ERV+RV.
• Tidal Volume (TV) - Volume of air inspired or expired during normal respiration. It is approx. 500 mL., i.e., a healthy man can inspire or expire approximately 6000 to 8000 mL of air per minute.

Explanation:

• A. Expiratory capacity: II. Tidal volume + Expiratory reserve volume
• B. Functional residual capacity: IV. Expiratory reserve volume + Residual volume
• C. Vital Capacity: I. Expiratory reserve volume + Tidal volume + Inspiratory reserve volume
• D. Inspiratory capacity: III. Tidal volume + Inspiratory reserve volume

The correct answer is Functional Residual Capacity (FRC).

Explanation:

Functional Residual Capacity (FRC): The volume of air that remains in the lungs after a normal exhalation is called the Functional Residual Capacity (FRC). This includes ERV + RV.
Definition: FRC is the total amount of air remaining in the lungs after a normal tidal expiration (normal, relaxed exhalation).
Components:

• Expiratory Reserve Volume (ERV): The additional amount of air that can be forcefully exhaled after the end of a normal tidal exhalation.
• Residual Volume (RV): The amount of air that remains in the lungs after a forceful expiration and cannot be voluntarily exhaled.

Importance:

• Functional Residual Capacity (FRC) plays a vital role in maintaining consistent gas exchange in the lungs.
• It helps to ensure that the alveoli do not collapse after each breath and provides a buffer of air, limiting large fluctuations in alveolar oxygen and carbon dioxide levels.

Thus, the Volume of air that will remain in the lungs after a normal expiration is called Functional Residual Capacity (FRC).