Selina Class 9 Biology Respiratory System Solutions Quiz

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Questions and Answers

What is the function of ciliated epithelium in the respiratory passage?

It helps in motion, driving any fluid that is on them (correct)
It provides structural support to the respiratory passage
It secretes mucus to trap foreign particles
It absorbs oxygen from the air

Where does the breakdown of pyruvic acid occur in the presence of oxygen?

Endoplasmic reticulum
Mitochondria (correct)
Nucleus
Golgi apparatus

What is the main contribution of diaphragm to the respiratory process?

Contraction of alveoli for gas exchange
Enlargement of the chest cavity lengthwise (correct)
Regulation of air pressure in the lungs
Production of mucus for lubrication

What is the primary function of intercostal muscles during respiration?

<p>Helping the inward and outward movement of ribs, enlarging the chest cavity all around (C)</p> Signup and view all the answers

What is the purpose of pleural fluid in the respiratory system?

<p>It provides lubrication for free movement of the expanding and contracting lungs (B)</p> Signup and view all the answers

Flashcards

What is the function of ciliated epithelium in the respiratory passage?

Ciliated epithelium in the respiratory passages has hair-like structures called cilia. These cilia beat rhythmically, propelling mucus and trapped debris upwards, preventing them from entering the lungs. This is called the "ciliary escalator."

Where does the breakdown of pyruvic acid occur in the presence of oxygen?

In the presence of oxygen, the breakdown of pyruvic acid occurs within the mitochondria. This is the process of cellular respiration, where energy is released from glucose.

What is the main contribution of diaphragm to the respiratory process?

The diaphragm is a dome-shaped muscle that separates the chest cavity from the abdomen. During inhalation, it contracts and flattens, increasing the vertical space in the chest cavity, which helps pull air into the lungs.

What is the primary function of intercostal muscles during respiration?

Intercostal muscles lie between the ribs. During inhalation, the external intercostal muscles contract, pulling the ribs upwards and outwards, enlarging the chest cavity. During exhalation, the internal intercostal muscles contract, pulling the ribs downwards and inwards, reducing the chest cavity.

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What is the purpose of pleural fluid in the respiratory system?

Pleural fluid is a thin layer of fluid that surrounds the lungs and lines the chest cavity. It acts as a lubricant, reducing friction between the lungs and chest wall as the lungs expand and contract during breathing.

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