Question

Cells lining the respiratory passages have numerous filamentous structures that sweep mucus and debris up and away from the lungs. These filamentous structures are: a. microtubules d. microfilaments b. flagella e. microvilli c. cilia

Short answer

c. cilia

Step-by-step solution

Identify function

The function described involves sweeping mucus and debris away from the lungs. This action requires coordinated movement of filamentous structures.

Review options

Consider each option: a. microtubules d. microfilaments b. flagella e. microvilli c. cilia

Analyze microtubules and microfilaments

Microtubules and microfilaments are structural components within the cell but do not perform sweeping actions themselves.

Analyze flagella and microvilli

Flagella are involved in cell movement (like sperm) and microvilli increase surface area for absorption; neither perform sweeping actions.

Determine correct option

Cilia are numerous, hair-like structures capable of coordinated sweeping motions on the respiratory passage cells.

Key concepts

Cilia Function

Cilia are tiny, hair-like structures found on the surface of cells lining the respiratory passages. Their main function is to sweep mucus and debris away from the lungs and toward the throat, where they can be swallowed or expelled.
This sweeping action is critical in keeping the respiratory system clean and free from harmful particles and pathogens.
Cilia move in a coordinated, wave-like manner, often compared to rowing oars, which ensures that the mucus and debris are efficiently transported out of the airways. This coordinated movement is powered by energy from ATP, the cell's energy currency.
Proper function of cilia is essential for respiratory health, and damage or dysfunction can lead to respiratory illnesses like chronic bronchitis and primary ciliary dyskinesia.

Cell Structure

Cells in the respiratory passages have a unique structure tailored to their function of keeping the airways free of contaminants. These cells are lined with cilia, but they also have other important components:

• Microtubules: These are part of the cell's internal skeleton and help maintain its shape, though they don't perform the sweeping action of cilia.
• Microfilaments: These thin, thread-like proteins contribute to the cell's mechanical strength and assist in different cellular movements.

The cells also have specialized organelles that support the function of cilia:

• Basal bodies: Anchor the cilia to the surface of the cell and organize their microtubules.
• Centrioles: Involved in cell division but are also thought to play a role in the formation and function of cilia.

Understanding the structure of these cells and the role each component plays can help you appreciate how effectively our bodies are designed to protect our respiratory system.

Respiratory Passages

The respiratory passages include the nose, throat (pharynx), windpipe (trachea), and the branching tubes of the lungs (bronchi and bronchioles). These passages are lined with a type of special tissue called mucous membrane, which produces mucus to trap dust, bacteria, and other particles.
Cilia line these mucous membranes and work together to move the mucus laden with trapped debris up towards the throat. This is part of what's called the 'mucociliary escalator,' a key defense mechanism in the respiratory system.

• In the Nose: Cilia filter out large particles and contaminants that enter with the air we breathe.
• In the Trachea and Bronchi: Cilia ensure a continuous flow of mucus, keeping the lower respiratory tract clean.
• In the Bronchioles: Although smaller, cilia continue their sweeping actions to prevent infections from reaching the delicate alveoli where gas exchange occurs.

Understanding the function and importance of cilia in these passages highlights why maintaining their health through good hygiene and avoiding smoking is crucial for long-term respiratory wellness.