Respiration and the Respiratory Tract

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Questions and Answers

What is the primary function of mucus in the respiratory system?

To serve as a lubricant for the bronchi

To trap and disable inhaled particles and pathogens (correct)

To promote the growth of cilia

To facilitate gas exchange in the alveoli

What is the mucociliary escalator?

A process that moves mucus towards the pharynx (correct)

A mechanism for gas exchange in the alveoli

A method of absorbing nutrients in the bronchi

A technique for strengthening alveolar walls

Which of the following correctly describes the structure of alveoli?

Hollow tubes lined with ciliated epithelium

Large air sacs with thick muscular walls

Flattened spaces with no blood supply

Small air sacs covered with capillaries (correct)

What role do macrophages play in the alveoli?

They engulf and digest foreign particles Signup and view all the answers

The blood-gas barrier consists of which two systems?

Respiratory system and circulatory system Signup and view all the answers

What describes cellular respiration?

The intracellular reaction of oxygen and glucose Signup and view all the answers

Which process is NOT part of external respiration?

Cellular respiration Signup and view all the answers

What is the primary function of the nasal cavity?

Filter air from large particles Signup and view all the answers

Which component is NOT found in the upper respiratory tract?

Trachea Signup and view all the answers

What characterizes the conducting zone of the airways?

Leads inspired air to gas-exchanging regions Signup and view all the answers

What type of tissue structure supports the primary bronchi?

C-shaped cartilage rings Signup and view all the answers

Which of the following best describes the function of the larynx?

Contains vocal cords for sound production Signup and view all the answers

How do airways change as they get deeper into the lung?

Become narrower, shorter, and more numerous Signup and view all the answers

What is the primary role of the conducting airways?

Routes for air to flow to the alveoli Signup and view all the answers

Which of the following statements about the respiratory zone is correct?

Gas exchange occurs in this region. Signup and view all the answers

According to the Weibel model, how many airway divisions comprise the conducting zone?

16 divisions Signup and view all the answers

What happens to inhaled medium-sized dust particles in the terminal bronchioles?

They often settle out in the region. Signup and view all the answers

How is the temperature of the inhaled air modified by the conducting airways?

It is warmed to body temperature (37°C). Signup and view all the answers

What is the main mechanism of air flow in the respiratory zone?

Diffusion Signup and view all the answers

Which component is NOT involved in the air conditioning process within the conducting airways?

Increasing air pressure Signup and view all the answers

What is the typical volume of the conducting airways, which is considered the anatomic dead space?

150ml Signup and view all the answers

Study Notes

Respiration

Respiration can be divided into cellular and external respiration.
Cellular respiration is the intracellular reaction of oxygen and glucose producing CO2, water, and energy (ATP).
External respiration involves four processes: ventilation/breathing, gas exchange between lungs and blood, transport, and gas exchange between blood and cells.

The Respiratory Tract

Divided into upper and lower parts.
Upper respiratory tract includes the mouth, nasal cavity (air filtration), pharynx (passageway for food and air), and larynx (vocal cords).
Lower respiratory tract includes the trachea (C-shaped cartilage), primary bronchi (2), bronchial branching, and lungs.

The Airways

Airways narrow, shorten, and become more numerous as they go deeper into the lungs.
Divided into conducting and respiratory zones.
Conducting zone leads inspired air to gas-exchanging regions.
Conducting airways lack alveoli and do not participate in gas exchange, forming the anatomic dead space (approximately 150ml).
Respiratory zone is where gas exchange occurs.
Includes terminal bronchioles branching into respiratory bronchioles, which have occasional alveoli.
Respiratory bronchioles lead to alveolar ducts, completely lined with alveoli.

Function of Airways (Air Conditioning)

Passage for air to reach alveoli.
Air is warmed to 37°C (body temperature) to prevent alveolar damage and avoid core temperature changes.
Air is moistened to 100% humidity.
Air is filtered from foreign particles through cilia and mucus.

The Blood-Gas Barrier

Formed from alveoli and capillaries.
Respiratory system (alveoli) and circulatory system participate.
Alveoli are small air sacs covered with capillaries.
Lack cilia but contain macrophages to engulf particles.
300 million alveoli per lung, each about 1/3mm in diameter.
Each alveolus is made of type I alveolar cells (95% of surface area, very thin for gas diffusion) and type II alveolar cells (5%, secrete surfactant to reduce surface tension).

The Pulmonary Circulation

Pulmonary circulation starts from the pulmonary artery and ends in the pulmonary vein.
Low-oxygen blood travels from the right ventricle to the pulmonary arteries.
Blood passes through pulmonary capillaries and then back to the heart via the pulmonary veins.
Capillaries form a dense network in the lungs, allowing for efficient gas exchange (0.75 seconds in capillaries per blood cell).
Pulmonary blood pressure is low (around 15mmHg) due to low resistance in the pulmonary vessels.

Functions of the Respiratory System

Gas exchange (O2 and CO2).
Regulates pH.
Temperature regulation.
Protection from pathogens.
Filtration of blood (small thrombi).
Metabolism (e.g., of Angiotensin).
Blood reservoir.
Olfaction (smell).
Speech generation.

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Description

Explore the two main types of respiration: cellular and external. This quiz covers the structure and function of the respiratory tract, including the upper and lower respiratory systems, and the pathways of airflow. Test your knowledge on how air travels through the body and the processes involved in gas exchange.