Respiration-3 - NEET MCQ

Lining of Trachea and Bronchi
The lining of the trachea and bronchi consists of pseudostratified columnar ciliated epithelium. This type of epithelium is specialized for its protective and functional properties within the respiratory system.
Characteristics of Pseudostratified Columnar Ciliated Epithelium
- The epithelium appears stratified due to the presence of different types of cells, but all cells are in contact with the basement membrane.
- The cells are columnar in shape, meaning they are taller than they are wide.
- The cells have cilia on their apical surface, which are hair-like projections that move in coordinated waves.
- The presence of cilia helps in the movement of mucus and trapped particles out of the respiratory tract.
- Goblet cells, which secrete mucus, are also present in this epithelium.
- The mucus produced by goblet cells helps to trap particles and microbes, preventing them from entering the lungs.
Function of Pseudostratified Columnar Ciliated Epithelium
- Protection: The epithelium acts as a barrier, protecting the underlying tissues from mechanical damage and potential infections.
- Filtration: The cilia and mucus work together to filter and remove foreign particles, such as dust, pollen, and pathogens, from the respiratory tract.
- Moistening: The mucus secreted by goblet cells keeps the respiratory tract moist, preventing dehydration and facilitating the movement of cilia.
- Clearance: The coordinated movement of cilia helps in the clearance of mucus and trapped particles, allowing for effective respiratory function.
In conclusion, the lining of the trachea and bronchi consists of pseudostratified columnar ciliated epithelium, which plays a vital role in protecting and maintaining the health of the respiratory system.

Cyanosis is a condition characterized by a bluish discoloration of the skin, mucous membranes, and nail beds. It occurs when there is a decrease in the amount of oxygen in the blood or when there is a buildup of deoxygenated blood.
Causes of Cyanosis:
Cyanosis is related to the accumulation of CO2 in the blood. It can be caused by various factors, including:
1. Hypoxemia: This is a condition characterized by low levels of oxygen in the blood. It can be caused by respiratory disorders such as pneumonia, asthma, or chronic obstructive pulmonary disease (COPD).
2. Heart conditions: Certain heart defects or diseases can lead to cyanosis. These include congenital heart defects, heart failure, or pulmonary embolism.
3. Circulatory problems: Cyanosis can also occur when there is a problem with blood circulation. This can be due to vasoconstriction, blood vessel blockage, or peripheral vascular diseases.
4. Exposure to cold temperatures: Cold temperatures can cause peripheral vasoconstriction, reducing blood flow to the extremities and leading to cyanosis.
5. Carbon monoxide poisoning: Carbon monoxide (CO) is a toxic gas that can bind to hemoglobin in the blood, preventing the normal transport of oxygen. This can result in cyanosis.
6. Drug overdose: Certain medications or drugs can interfere with oxygen uptake or circulation, leading to cyanosis.
Summary:
Cyanosis is related to the accumulation of CO2 in the blood. It can occur due to various factors, including hypoxemia, heart conditions, circulatory problems, exposure to cold temperatures, carbon monoxide poisoning, or drug overdose.

Gills of mollusk are called Ctenidia.
Explanation:
The gills of mollusks are specialized structures involved in respiration. These gills are known as ctenidia. Here is a detailed explanation of this answer:
- Mollusks: Mollusks are a diverse group of invertebrate animals that include snails, clams, squids, and octopuses.
- Respiration: Mollusks respire through their gills, which are responsible for extracting oxygen from the water.
- Ctenidia: The gills of mollusks are called ctenidia. These are comb-like structures that are located in the mantle cavity of the mollusk.
- Function: Ctenidia are responsible for both respiration and filter-feeding in mollusks. They have numerous filaments that increase the surface area for gas exchange and capturing food particles.
- Variations: The structure and organization of ctenidia can vary among different mollusk species. For example, bivalve mollusks such as clams have gills that are specialized for filter-feeding, while gastropods like snails have gills that are mainly involved in respiration.
- Adaptations: Some mollusks, such as freshwater mussels, have evolved modified ctenidia called marsupial gills. These gills allow the female mussel to carry and protect the developing larvae.
- Importance: Ctenidia play a crucial role in the survival and ecological niche of mollusks. They enable these animals to extract oxygen from their aquatic environment and obtain nutrients through filter-feeding.
Therefore, the correct answer is C: Ctenidia, which refers to the gills of mollusks.

Answer:
To find out where Pinnaglobin is found, we need to analyze the given options and provide a detailed solution.
Options:
A: Crustaceans
B: Man
C: Molluscs
D: None

To determine the presence of Pinnaglobin, we need to analyze each option one by one.
A: Crustaceans
- Crustaceans include animals like crabs, lobsters, and shrimp.
- There is no specific information available regarding the presence of Pinnaglobin in crustaceans.
B: Man
- Pinnaglobin is not commonly found in humans or referred to in scientific literature.
- There is no evidence suggesting the presence of Pinnaglobin in humans.
C: Molluscs
- Molluscs are a diverse group of animals that include snails, clams, octopuses, and squids.
- Pinnaglobin is commonly found in the blood of molluscs, particularly in certain species of squids and octopuses.
- It serves various functions, including oxygen transport and immunity.
D: None
- This option implies the absence of Pinnaglobin in any of the mentioned categories.
Conclusion:
Based on the given options, the correct answer is C: Molluscs. Pinnaglobin is found in the blood of certain species of molluscs, particularly squids and octopuses.

Explanation:
The correct answer is option C: Straightening of diaphragm contraction of external inter-costal muscles. Here's a detailed explanation:
1. Straightening of diaphragm: The diaphragm is a dome-shaped muscle located at the base of the lungs. When we inhale, the diaphragm contracts and moves downward, straightening out.
2. Contraction of external inter-costal muscles: The external inter-costal muscles are located between the ribs. When we inhale, these muscles contract, pulling the ribs upward and outward. This action expands the chest cavity.
3. Inspiration: Inspiration refers to the process of inhaling or taking in air into the lungs. It is an active process that requires the contraction of various respiratory muscles.
4. Result of straightening of diaphragm and contraction of external inter-costal muscles: When the diaphragm contracts and the external inter-costal muscles contract, the chest cavity expands, creating a negative pressure inside the lungs. This negative pressure allows air to rush into the lungs, resulting in inspiration.
5. Relaxation of inter-costal muscles: Option B states that inspiration results from the straightening of the diaphragm and relaxation of inter-costal muscles. However, the relaxation of inter-costal muscles would not contribute to the expansion of the chest cavity and the inhalation of air. It is the contraction of the external inter-costal muscles that is responsible for expanding the chest cavity during inspiration.
Therefore, the correct answer is option C: Straightening of diaphragm contraction of external inter-costal muscles.

Condition: Swollen pleural membranes in pleural cavities
A: Emphysema
- Emphysema is a condition characterized by the destruction of the alveoli in the lungs, not the swelling of pleural membranes.
- It is caused by long-term exposure to irritants, such as cigarette smoke.
- Emphysema leads to difficulty in exhaling and shortness of breath.
B: Anoxia
- Anoxia refers to a lack of oxygen supply to the tissues and organs.
- It is not directly related to the swelling of pleural membranes.
C: Pleurisy
- Pleurisy is the inflammation of the pleural membranes, which are the thin tissues that line the lungs and chest cavity.
- It can cause swelling and irritation of the pleural membranes.
- Pleurisy commonly occurs due to viral or bacterial infections, pneumonia, or autoimmune diseases.
- Symptoms of pleurisy include sharp chest pain, coughing, and difficulty breathing.
D: None
- This option is incorrect as there is a specific condition associated with swollen pleural membranes, which is pleurisy.
Therefore, the correct answer is C: Pleurisy.

Condition necessary for a respiratory surface to be functional:
There are several conditions necessary for a respiratory surface to be functional. These include:
1. Thin surface:
- A respiratory surface must be thin to allow for efficient gas exchange.
- Thinness reduces the diffusion distance, allowing for the quick exchange of gases between the respiratory surface and the surrounding environment.
- It also allows for a larger surface area for gas exchange.
2. Richly supplied with blood vessels:
- Blood vessels play a crucial role in the transport of oxygen and carbon dioxide to and from the respiratory surface.
- A rich blood supply ensures a constant delivery of oxygen to the surface and removal of carbon dioxide.
- It facilitates the exchange of gases between the respiratory surface and the bloodstream.
3. Presence of mucous:
- Mucus helps to moisten and protect the respiratory surface.
- It traps dust particles, pathogens, and other contaminants, preventing them from entering the respiratory system.
- Mucus also aids in the movement of cilia, which helps to clear the respiratory surface of trapped particles.
4. All of these:
- All of the above conditions are necessary for a respiratory surface to be functional.
- A thin surface, rich blood supply, and presence of mucous work together to ensure efficient gas exchange and protection of the respiratory system.
In conclusion, a respiratory surface must be thin, richly supplied with blood vessels, and have the presence of mucous to be functional. These conditions allow for efficient gas exchange and protection of the respiratory system.

The trachea is absent in the frog.
Explanation:
The trachea is a respiratory structure found in many animals, including humans and most mammals. It is responsible for carrying air to and from the lungs. However, in some animals, such as frogs, the trachea is absent or not well-developed. Here's why:
- Frogs have a different respiratory system: Frogs have a unique respiratory system that allows them to breathe both underwater and on land. They have a pair of lungs, but they also have other structures that aid in respiration, such as the skin and the mouth lining.
- No tracheal tubes: Unlike mammals and some other animals, frogs do not have tracheal tubes. Tracheal tubes are the main air passages that connect the respiratory system to the external environment. Instead, frogs rely on their skin and the lining of their mouths for gas exchange.
- Gas exchange through the skin: Frogs have thin, moist skin that allows them to absorb oxygen directly from the environment. They can also release carbon dioxide through their skin. This is especially important when they are underwater and cannot use their lungs for respiration.
- Mouth breathing: Frogs can also breathe through their mouths. They have a lining in their mouths called the buccal cavity that allows for gas exchange. This is especially important during periods of high activity or when they need to take in more oxygen.
In conclusion, the frog is the animal in the given options where the trachea is absent. Instead, frogs rely on their skin, lungs, and mouth lining for respiration.

The diaphragm muscle is of the skeletal or striated type and is the major muscle of ventilation. It is the main muscle of respiration.

Number of spiracles/stigmata in cockroach
- Cockroaches have small openings on the sides of their body called spiracles or stigmata.
- These spiracles/stigmata are used for respiration.
- The number of spiracles/stigmata in cockroaches is different for different species.
- In the case of the common cockroach (Periplaneta americana), the number of spiracles/stigmata is as follows:
- There are 10 pairs of spiracles/stigmata in the cockroach.
- Each segment of the cockroach's body, except for the first and last, has a pair of spiracles.
- The spiracles are located on the lateral side of the body and are protected by small plates called tergites.
- These spiracles/stigmata allow air to enter the cockroach's body and reach the network of tubes called tracheae, which carry oxygen to the cells.
- The spiracles can also be closed to prevent water loss and regulate gas exchange.
- It is important to note that the number of spiracles/stigmata may vary in different species of cockroaches.
- Therefore, the correct answer to the question "Number of spiracles/stigmata in cockroach" is 10 pairs (option B).