Respiratory System

After jogging, Maria notices that she breathes faster. What is the best explanation?

• The lungs expand due to muscle fatigue
  

• Her body needs more oxygen for energy production

• The diaphragm stops working during exercise

• Carbon dioxide levels in the blood decrease

Answer explanation

After jogging, Maria breathes faster because her body requires more oxygen to produce energy for her muscles. This increased demand for oxygen leads to faster breathing.

A boy accidentally inhales water while swimming. Which structure prevents water from entering the lungs under normal conditions?

• 
  Diaphragm

• Epiglottis

• Trachea

• Alveoli

Answer explanation

The trachea is the main airway that leads to the lungs. It is lined with cilia and mucus that help trap and expel foreign particles, including water, preventing them from entering the lungs under normal conditions.

During asthma attacks, airways become narrower. What immediate effect does this have on gas exchange?

• Increases oxygen absorption

• Decreases oxygen intake

• Removes more carbon dioxide

• Increases ATP production

Answer explanation

During asthma attacks, narrowed airways restrict airflow, leading to decreased oxygen intake. This makes it harder for the body to absorb the oxygen needed for respiration, confirming that option b is correct.

A climber at high altitude feels dizzy. What causes this condition?

• High carbon dioxide in the atmosphere

• Low oxygen levels in the air

• Slow heartbeat

• Overexpansion of the lungs

Answer explanation

At high altitudes, the air has lower oxygen levels, leading to reduced oxygen availability for the body. This can cause dizziness and other symptoms of altitude sickness, making option b) the correct answer.

When carbon monoxide is inhaled, it can be fatal. Why?

• It reduces the size of alveoli

• It produces too much oxygen in the lungs

• It increases blood pressure

• It binds with hemoglobin, preventing oxygen transport

Answer explanation

Carbon monoxide binds with hemoglobin in red blood cells more effectively than oxygen, preventing oxygen transport to tissues. This can lead to suffocation and is why inhaling carbon monoxide can be fatal.

Why do patients with COVID-19 often have low oxygen levels?

• Their alveoli are inflamed and filled with fluid

• Their diaphragm no longer contracts

• They lack sufficient hemoglobin

• They inhale less carbon dioxide

Answer explanation

Patients with COVID-19 often have low oxygen levels because their alveoli become inflamed and filled with fluid, impairing gas exchange. This leads to reduced oxygen absorption in the lungs, making option a) the correct choice.

What physiological change occurs in the body during high-intensity exercise that affects breathing rate?

• Increased lung capacity

• Decreased oxygen demand

• Increased carbon dioxide production

• Decreased heart rate

Answer explanation

During high-intensity exercise, the body produces more carbon dioxide due to increased metabolism. This rise in carbon dioxide levels stimulates the respiratory center, leading to an increased breathing rate to expel the excess CO2.

How does smoking affect the respiratory system over time?

• It reduces the risk of infections

• It strengthens the alveoli

• It increases mucus production

• It improves lung function

Answer explanation

Smoking increases mucus production in the respiratory system, leading to chronic cough and obstructed airflow. This is detrimental to lung health, unlike the incorrect options that suggest benefits.

What role does the epiglottis play during swallowing?

• It helps in the exchange of gases

• It aids in the production of sound

• It prevents food from entering the lungs

• It allows air to enter the trachea

Answer explanation

The epiglottis prevents food from entering the lungs by covering the trachea during swallowing, ensuring that food passes into the esophagus instead. This is crucial for protecting the airway and preventing choking.

Inhaling polluted air for years may lead to emphysema. Which of the following best describes its effect?

• More efficient oxygen transport

• Strengthened diaphragm movement

• Destruction of alveoli reducing gas exchange

• Increased lung elasticity

Answer explanation

Emphysema causes destruction of alveoli, which are crucial for gas exchange. This leads to reduced oxygen intake and impaired lung function, making option c) the best description of its effect.